Dyno Day results: "Your car has big problems"... HELP

OK, here's the deal on Pro-M mass air meters and a little history. There are 2 basic aspects to how the meter functions. One is by what means it samples the airflow and the other is how it sends the signal to the computer. The Univer has a far superior means of sampling the airflow as compared to the method used on the typical 75mm unit. The 77mm unit was a step in the right direction as far as sampling goes because the electronics element was buried inside the meter and was not effected by turbulant airflow. Problem was that the casting was very expensive and the large size made it only adaptable for draw through applications, which at the time was fine. ProChargers and the advent of more and more turbo kits started the trend toward blow through mass air meter configurations and Pro-M, actually late Bob Atwood, took up the challenge to make a meter that had an accurate way to sample airflow for blow through applications that was uneffected by how the pumbing was configured. They succeeded in that respect.

Now comes the problem area. How the signal gets processed and sent back to the computer. This has to do with modifying the meter electronics to trick the computer into thinking that the injectors are 19 pounders no matter what the actual injector flow rating was. Back when "big" injectors were 36 pounders, this was not much of a problem since the amount of "trickery" involved was fairly small. As injectors got bigger and bigger the margin for error in a given calibration got bigger and bigger as well. You can imagine how much tweeking is necessary in the electronics to make the computer unaware of the fact that you are running 72 lb injectors when the Ford program is saying 19's.

OK, so even with 42 lb injectors the calibration can be hit or miss and even more of a gamble as the injector size gets larger. When Bob was running the shop he was very willing to help out when the calibration was wrong/off and would recalibrate meters until they were "right". Unfortunately, or fortunately depending on how you look at it, Bob was a great people person and a true genius (he invented the aftermarket mass air meter) but he was not a very good business man due to his extreme willingness to help the customer at his own cost. Right or wrong, the current management seems more interested in making a buck (which is good business sense) then trying to handle some of the problems that go along with their products.

Anyway, to bring this long explaination to a close. Finding someone with a like calibration (as you have) and testing their meter out is probably the best way to solve a meter problem under the current circumstances.

John, you are right on. Thanks to Anthony (blownwindsor), I am luckily able to try a different meter out on my car. I met up with him yesterday and he let me borrow his 80mm C&L that is calibrated for #42 blow through. According to him, he said that the meter ran his car absolutely no different than his 3" Univer did, so we'll see how it works on my car. I ended up getting the meter a little later than expected yesterday, so I didn't have a chance to run it on the car. I will do so today and see what happens. So far, testing proves to show that it is my meter because with the meter un-plugged (my 3.5" Univer), after the car hunts for and finds it's idle, it runs and drives like a champ just as it should (going off of ONLY the O2 sensors in that scenario). Anyway, thank you for the informative post John, I will keep everyone updated and let you know what I found out after I run the car with this C&L tonight. Thank you again.

So if I understand it correctly, you could order a blow-through meter, calibrated to the injectors you are running, and there still stands a good chance that the calibration may be off?

And then, based upon Pro-M's latest business practices, it's very difficult (if not next to impossible) to get them to put it right?

If this is correct, then I am becoming discouraged, as I am (was?) planning on ordering a 4 inch blow-through calibrated to 83lb injectors.

Signed,

Nervous:(

Greg,

Wow, I didn't mean to discourage you with my post but there is a strong possibility that the calibration will be off, especially with 83# injectors. To be truthful, I don't know of anybody that is running that size injector with a mass air meter and Ford computer, even though it is working well for you. The fact that you have the ability to alter the injector pulse width with the PMS is a big plus and may help to get things sorted out. The problems I described are not exclusive to a meter that is set up for blow through, it can happen to any meter and size injector.

On one of my early setups with 36 lb injectors I had a 77mm Pro-M that had horrible cold start problems. It would buck like a carb motor that didn't have a choke until it warmed up, then it was fine. Turned out that the idle calibration was off and too lean, causing the bucking. I actually fixed that one myself by getting one of the Pro-M Calibrators. It is a device that allows you to adjust the idle voltage as well as the WOT voltage. This might be an option for you also if you want/need to fine tune the meter voltages.

Again, didn't mean to make it a bad day for you but at least now you know there could be a problem with the calibration.

Hoping yours is one of the "good" ones.

John

Thanks for the heads up John.

With the PMS, fortunately I can lean or richen idle, so perhaps I can tune out any miscalibration. I guess I'll have to make it a point to buy the Meter on a credit card.

Talk to you later.....

Greg

Well, I spoke to the tech on the phone (not Jim) and he said to check the voltage between C&D on the meter and see what it reads at idle. He said that acceptable is between .6 and .9, optimal is .7-.8 volts. Mine is .200 - .260. Obviously that explains some of my issues, the callibration is whack for idle at least. As I drove the car, when it started to miss and buck and cut out, the MAF voltage *seemed* to be okay, it seemed linear with airflow, maybe way out of range for what it was doing, but it seemed to be registering as airflow increased, but as soon as my car does the stupid stuff, the A/F gauge immediately drops off of the lean end, FAST, like there is NO fuel at all. Interesting because walsh said it was going pig rich (8:1) at part throttle, but my O2's (granted they are bosh factory replacements, and the a/f gauge doesn't do anything but dance around) are reading that it is falling off of the lean end like you would not beleive. I don't know what to think. The meter feels like it may have a leak in it, somewhat of a noticible one, and that is definitely NO good... the welds on it are nasty and look burnt through in a couple of spots. I do know for a fact that the callibration is off... but unfortunately blownwindsor's C&L has a 4" inlet on it, so I can't hook it up... I spoke with him on the phone last night and I am going to stop by later today sometime and he is going to let me try the Pro-M out instead (THANK YOU VERY MUCH Anthony!). I guess it is just a giant guessing game till then. It is all pointing to the meter (I am almost 100%) because the voltage is way too low at idle, and if the meter is un-plugged, the car does none of this. It's just strange how when I was watching the meter's voltage when the car was freaking out how it looked like it was staying linear to airflow, but maybe the car is going into a different fuel table right then and the meter is sending it bad readings for it to know what is going on. Also if I put my foot into it a bit more (to kill the vacuum on the boost gauge), the car all of a sudden works fine and quits freaking out... who knows. I am going to check my TPS and throw that other meter on it to see what happens. I am so tired of this. Thanks for the help though guys, you are all a very big help. Too bad I am missing out on all of the usual car festivities in this season of BEAUTIFUL weather.

A bit more info on mass air meter voltage for you. If it is lean at idle it is most probably lean up top. Even though the voltage is moving in a linear fashion it is probably following a lean curve. This is why there are 2 potentiometers on the Pro-M Calibrator. Moving one voltage up or down, say the idle voltage, will move the whole curve, including WOT, in the same direction. So whenever a change is made to one Pot there needs to be adjustment made to the other. This is also why the mass air adjustment device from Interactive is not such a good tool, it only has the the idle voltage Pot.

With your idle voltage that low I have no doubt that your meter is the root cause of your problems. Did they send you the flow sheet with the meter like they are supposed to do? If so, what is the voltage value for FLO PT. 8 in the ACT VOLTS column?

http://wa2fast.corral.net/images/univer_flow_sheet.jpg
If that picture doesn't show up, then go to my site (http://wa2fast.corral.net) and go to the bottom of the Photo Page 3... it's there.

Funny story about my meter... originally I bought the meter SPECIFFICALY for an 87' Mustang GT with their Pro-M MAF conversion harness pigtail and an A9L computer. I watched the lady write my specifications down on the actual order form (again, I am local, I went right up to the Pro-M factory and ordered it... but of course Jim wasn't available then, so she had to take my order). 2 weeks or so later, they called and the meter was ready... I happily picked my bran new (EXPENSIVE) 3.5" Univer #42 Blow Through up from them... took it home, went to plug it in, realized that it had the EEC-V plug on it (rectangle, not oval like mine)... no problem, annoying, but people make mistakes. I went back up there DURRING BUSINESS HOURS and had to beat on the window practically right in someone’s face (on the other side of the window) as they pretended NOT to hear me because the door was locked as if they were closed. The guy (obviously an engineer) FINALY acknowledged my existence and met me at the door... I explained him the problem, he could BARELY speak English, but whatever, I wrote down EXACTLY (and even drew a picture of the two plug styles just to make sure they got it right) just to be sure what the deal was and stuck it in the meter and he took it back and told me that it should be done sometime in the next couple of days. The next day, I picked up the meter and the new flow sheet (pictured above, or on my site) which is different than the first one.

Well, when I explained this to Walsh (what happened with the plug and the meter electronics change and everything) he got a smirk on his face and was like "how much do you want to bet that they just slapped on the electronics from a different one and gave you the flow sheet for that one and didn't actually flow/calibrate your meter with those electronics on it?" As soon as he started to say it, I was thinking the exact thing... why else would I get a call at 9am (very shortly after they open) saying that it's done when I KNOW they didn't touch it that night (soon before they closed).

Things that make you go Hmmmmm...

We'll see what Anthony's meter does. I KNOW that this one will fit my tubing :p

I'm starting to get a sense of humor with this whole situation... the Chevy people around me are lovin' the fact that my Ford isn't working, none the less that it's a Mustang (Chevy driver's most hated car).


I know that the callibration is completely out of whack, but would that explain why it freaks out at part throttle too?

Ahhh yes, the plot thickens! Sounds like Walsh (and you simultaneously) have hit on what is going on. That place has never been that quick in their entire history. As if someone worked overtime that night to do the recalibration on your meter? I seroiusly doubt that! Well, the flow voltage looks right but who knows what meter it is for.

All of this makes me feel real good about not having a mass air meter anymore. Maybe something to start to consider for yourself as well.

Anyway, good luck and keep us posted on the coming events.

John

Yea, but what do I do instead of my current setup? What options do I honestly have for my car other than the MAF system (that are not going to put my wallet in a world of hurt)?

I know in my case that hindsight was definitely 20/20 because when I added up all of the meters I have had and all of the transactions with shipping meters back for re-recalibration plus the cost of my old Crane Interceptor II and or custom chips and dyno time...whew, I could have purchased 2 FAST systems. No kidding! I partially paid for my FAST setup by selling the Interceptor and meters. I understand about the money part though but it might be something to think about.

Do they have a site or anything like that where I may be able to get some more information?

BTW, the meter makes my car run different, but not too much better. The voltage seems to be at least a little closer to the acceptable range, but the car still does strange things. It blows my mind that it does not do this without the meter and I am finding that no matter what meter I am running, it still does it. It is like the injectors just turn off. I know Walsh said that my car was going pig rich, but it totally feels like the factory rev limiter fuel cut off if you remember what that is like... it feels EXACTLY like that, and the A/F gauge immediately goes lean as hell and falls off of the scale. As soon as I take my foot off of the gas or whatever, it comes back to normal, doesn't stall or anything. Free-revving, it doesn't always do it, it is sometimes hard to get it to do it, but driving... forget it, just as soon as I get the clutch out all of the way to start moving, it literally falls on it's face and feels like it's pulling ALL fuel out for some reason. I don't get it. What the hell could be wrong with my car? The meter is DEFINITELY part of the problem, that is my lean idle and lean WOT without a doubt, but not my part throttle issues... is there a sensor or something that could be doing this?

I ran codes, came up with the usual emissions BS... thermactor air system 1 and 2 inoperative, egr vacuum control solenoid failure, charcoal canister purge valve failure (none of those things are on the car anymore), it said that it could not control the idle speed, egr flow was low, drivers side O2 indicated a lean condition (during the test, the a/f gauge went off of the scale lean the entire time... the gauge is hooked up to the drivers side O2) and I think that is it... I will see if I have the sheet of paper with me in a couple of minutes with the exact KOEO and KOER codes. Anyway, I checked the TPS voltage thinking that maybe it had a blip in it... nope, that's fine too.

I remember after I swapped my motor mounts and headers at the end of last season, the car doing some weird things right afterwards... I also remember not liking how the intake looked like it was kind of pinning the harness in-between it and the firewall when the motor was lifted up to swap the headers and mounts. A short time afterwards the car started doing some strange things, but then I stored it for the winter. My problems were not like this though, so maybe that was a start or something? I just don't understand why when the meter isn't plugged in, it doesn't have the part throttle problem.

Any ideas before you guys hear an A-bomb go off in my garage? I am honestly at wits end with all of this, man am I ever running out of steam here.

I still have to deal with Pro-M any my meter issues, cause .2v is way out of range without a doubt, so the whole Pro-M thing doesn't change a bit... lean idle, lean WOT, but my part throttle issue is now a concern because it seems somewhat un-related. Oh yea, the welds on my Univer look like they went through hell and back compared to Anthony's... the guy who welded the sample tube on mine may have been drunk at the time. I'll see if I can take some pics of it today after I get home... it's rather scary to say the least.

Well, this is a longshot but how are the ground connections on the motor? You should have the orange wire from the harness going to the back of the drivers side head and also a braided ground wire that goes from the firewall to the same spot on the head as the orange wire. I'm pretty sure the orange wire is a computer ground. Any chance you have a short or bad connection in that harness somewhere? Dunno, just throwing out some ideas.

You are right. The orange wire goes to the back of the cyl. head on the drivers side along with the braided ground strap from the firewall right there. That is the HEGO ground (for some reason it's on the main harness and not the O2 harness), but that is a VERY crucial ground indeed... the block's factory 4awg ground cable goes to the frame up front instead of the battery (as it was from the factory) and that is the common ground point that I was talking about before that I have the main computer ground going to. That is where I ran the 8awg ground cable from the battery directly as well. So on that ground point, I have the 4awg block ground cable, the main computer ground (10awg wire that used to go directly to the battery), and the 8awg wire that is run directly from the battery... so I don't think that my grounding is an issue anymore honestly. Also my O2's seem to be running just great (first time in a long time)... gauge is reading (which means that the voltage is good), the computer is making the appropriate changes and everything. I don't know. I was thinking the same thing, but again when the car is on just the O2's it seems to run it's best.

I have the original harness that is on the car that has been converted to MAF spec via Pro-M's pinout directions along with their pigtail for the meter and the VSS line inserts and all of that. I also have a harness out of a 93'GT with injector harness and all. I am a bit afraid to install this though, as there are things on this harness that mine doesn't have. Naturally it is different, I realize that, so the airbag sensors don't scare me too much, it's the fuel pump relay mainly. Mine happens to be under my driver’s seat... the 93 harness has it on the harness! Will the car still work? I don't know, it's hard to tell... that's a TON of work to find out that it isn't going to work, but then again, look at what I am up against. I think my next step is going to be a compression test just for good measure, and then I'm going to yank the upper and pull that main harness out and inspect it wire for wire.

I unfortunately don't have a proper pinout for it, all I have to go off of is tmoss' diagram for the "88 to 91" harness... from what it looks like to me, it is identical to the 93' I have, and pinout wise it is the same as my converted 87', but the picture "roadmap" that I have as I call it... (a nice actual picture of the full harness with each plug labeled) looks different from my 87' which is what scares me.

Do you think some of these problems could possibly have anything to do with either the engine temp gauge or the air charge temp sensor? The computer didn't report any problems or codes for them, but then again, my car is one of the worlds great wonders right now too.

BTW, I found F.A.S.T.'s website... looks awesome, how much did you pay, and which kit did you get? I know that it is no answer to my problems right now, but definitely something to look into for a future project because you are totally right with the money spent in this crap.

Oh yeah, sorry I forgot to give you the FAST website. I paid $2200 for mine at the time but I believe I have seen them advertised for around $2000 now. I know that sounds like a lot at first but it is a very complete system and some of the cost could be offset by selling your MA and PMS. My system is the Bank to Bank with wide band O2 option. You would also need a laptop to do tuning and data logging.

Actually, this could be the answer to your problems right now if there is a glitch in your harness. The FAST system comes with a complete new harness and all sensors. Only drawback is that if you remove your factory harness completely, like I did, you will not have some of your factory gauges. Not a big loss in my mind since I have Autometer gauges to cover everything needed anyway and the factory stuff just isn't very accurate.

I'll tell you, I really love the FAST system and how easy it is to use as it turns out. The data logging function is incredible for tuning and trouble shooting problems. It has already shown me that early on I had a miss in my ignition system. Cured that problem with some new plug wires, cap & rotor and tightened the plug gap. This was some of the best 2 grand I have spent, that's for sure.

That wide band also saved my butt once when one of my pumps went out on me. The remaining single A1000 was struggling to keep up with flow demand so the computer kept raising the duty cycle on the injectors all the way up to 100% to maintain my set A/F ratio. Normally I'm at 82-85% duty cycle on the 83 pounders.

Listen to me....I'm sounding like a salesman for FAST.

Anyway, from your description of the problem it sounds more like a short or bad connection somewhere and not so much a bad sensor.

so how did the car ruu when you put the other meter on.

Hey Anthony... the meter made my car run different, but not too much better. I never tried to drive it because I could free-rev it and get the same problems. Your meter's voltage is a little bit better than mine (in the .350-.450 range at idle) but still not right... that would explain why your car won't idle without the chip... funny how mine won't either though! It took about a minute and a half before my car would idle by itself with your meter on it... that's funny because my meter is more out of whack at idle than yours and my car idles just fine with my meter in it. Whatever... anyway, thank you again very much, I will get that meter back to you later today.

I guess I just have a compilation of problems here... the meter is DEFINITELY not callibrated right (even though the flow sheet says so), and that explains idle A/F and WOT A/F, but the part throttle is something entirely different... but possibly somewhat related. I don't know, like I said above, next course of action is compression test for good measure, then the main harness is coming out and I'm going to disect it and test EVERY wire in it. Hopefully it's obvious as to what's goin on, but I am not counting on it.

maybe I could hoke my c/l and test it and see how it works voltage wise. because my car will run with no chip and the c/l but not the pro m

Well, I am going to finish compression testing later today, so far things look just fine, all within 5 or so of each other right around 150-155 which is what I expected anyway. Once I am done and assuming no low readings (otherwise I will be doing a hot compression test), I will be yanking out my wiring harness and either possibly looking for any problems / testing it and repairing it or just simply installing the 93' harness that I have and giving that one a shot. It can't be much else. This problem started last year after the header/motor mount change, and I am willing to bet that my wiring harness got damaged from how high the motor was jacked up and possibly smashed against the firewall... we'll see. The meter still needs to go back to Pro-M as the voltage is way out of range, but I am still in dispute with them about that one.

In case you guys are interested, I took a bunch of pictures of Anthony's 3" Univer vs. my 3.5" Univer. I will post a few on here just so you can see. Note that his welds are 10-fold better than mine (thanx Pro-M).

This first picture, you can see the sampling difference between the 3" and the 3.5" clearly... the 3" simply uses restriction for air to be forced through the passages because of the size reduction. The 3.5" does the same thing, but "cuts" the air to sample it too... the sample holes are between the outer lip and the inner lip on the inlet side... I believe this is to sort of force the air to be sampled at low volumes (idle).
http://wa2fast.corral.net/images/both_univers_1.jpg

Here are 3 pictures that show the size proportion differences along with the weld quality differences around the sampling tube apparatus :mad:
http://wa2fast.corral.net/images/both_univers_4.jpg
http://wa2fast.corral.net/images/both_univers_5.jpg
http://wa2fast.corral.net/images/both_univers_3.jpg

Here are a couple more of my meter up close to show welding.
http://wa2fast.corral.net/images/3.5in_univer_3.jpg
http://wa2fast.corral.net/images/3.5in_univer_7.jpg
http://wa2fast.corral.net/images/3.5in_univer_8.jpg


Anthony (blownwindsor), sorry for not talking to you before putting pic's of your meter up, let me know if you would like me to take them down.

no its cool, if I knew they were going to be on the spotlight I would of cleaned it up a little.

Compression testing came out fine. I have 150-160 across the board. Obviously that is not my problem... I didn't think so, but it is good piece of mind and I wouldn't feel "dumb" later down the road if I never did one, then finaly decided to do one and had half a blown motor ;) Anyway, I fired the car up yesterday when I was done compression testing and I kind of have a better idea as to what is happening... I just need to find out why now. I know that my a/f gauge is no true test to a/f ratio, but in this case, it is saying something, that is for sure. I have the gauge probed into the drivers side O2 wire. Once sensor warms up, the gauge starts dancing around and so on. If I hold the RPM's up around3-4k (which is VERY light throttle pressure), it will hold just fine, then about 4-5 seconds later, the a/f gauge drops off of the lean end FAST, and the rpms fall (obviously) and it will sit there caughing and sputtering till I take my foot off, then it immediately goes back to normal, a/f gauge starts dancing around again... it is a little sluggish and towards the lean end for a few seconds (almost like it is trying to catch back up) but then the car is fine. It never hunts for idle, it never stalls, nothing... it just INSTANTLY goes super lean, totaly like a fuel cut, and when I let off... it goes back to normal right away. This seems to be a load issue because at idle, I can rev it quite a bit before it does this, but when trying to actually drive the car, it falls on it's face right from a start bassicaly. Has anyone heard of this before? I checked the TPS voltage and it seems linear, no blips or anything. A few people are still pointing fingers at the meter, but why did my car do the same thing with Anthony's on it then? Any ideas? I feel like a dog chasing it's tail in circles.

I think its in your EEC, I had similar problems and they still existed even when I forked up the cash and bought a Univer. I ended up playing with the wideband in my car for a few days and used my eec tuner to cut off closed loop operation and the problem went away instantly! To this day my car will not run in CL with the blower. It doesn't run any worse in open loop and is actually easier to tune cause I'm not fighting the EEC trying to tune "around" me. It is so much easier to tune in open loop. I'm not sure who is tuning your car, but get them to lock it in OL and see what it does...

Well, my car was run in open loop with the N/A setup I had for years, but I don't know if that is the answer. In Open Loop, it still needs the MAF transfer function, and if that is out of whack (which mine is) then it's not going to be right. I think that my car is ready to hit the dyno again, so we'll see what Don Walsh says when I call him up. I feel half confident at least that I may get a working car back this time.

I'd almost bet that Don (or any good tuner) can get that problem fixed. So does Don tune in open loop or closed? what type of chip is he using? Autologic, Superchips? I am curious as to what the real tuners do with blown cars because in closed loop the EEC will constantly be trying to correct your Air/Fuel to a set value in the tables but in open loop you have full control over what tables and values it uses with no corrections and with a blower you naturally run much richer than what the factory intended.

He tunes most of the time in Open Loop as Closed Loop is very seldomly used to my understanding unless it is absolutely needed. He uses Autologic chips. As far as tuning a blown car in open loop, I was always under the impression that it was a very bad idea to do so because the ambient temps, air temps, and so on change so much. I could see a nice open loop tune that just dumps fuel, but that can hardly be efficient in making power considering the fact that you would have to compinsate for when the air was less dense and hotter so that in those conditions you don't blow the motor, but I could be wrong. When I originally spoke with him about my car, even though my car had been tuned in open loop with my N/A setup (I have never been happier with a tune... that was the best tune ever, being in OL definitly helped it too cause it was consistant), he wanted me to put in new O2's and make sure that they were working properly cause that is crutial. He made it sound like he would never tune a blown car in OL, but again, he never said that, just going off of how he acted when I asked about the O2's.

Thats what I was always told, because even with the wide band and my tuner I cannot get consistent tunes with Closed loop, the EEC always ends up tuning out what changes I make with adaptive strategy. Once I figured out how to lock my EEC in OL my tuning got so easy, all I did was watch the wideband and set the fuel tables to where I wanted it. It stays dead on now and makes great power, with just a slight drop in MPG. Since my blower let go I have bypassed it and have been running the car N/A with the big injectors and the Univer and I actually have it running great in closed loop now, so I may just TRY closed loop when the blower goes back on but it probably wont work..

Hmm, I wonder why it makes a difference between having the blower hooked up or not... as far as drivability is concerned (out of boost), your car should run exactly the same with or without the blower. If it is running okay now without the blower attached, I have a feeling that you will be able to tune it in CL.

Well, not actually because when in boost I want the car really safe with a max of 12.0AFR and the factory has it a little leaner than I like especially with the Univer. It always seemed to buck at part throttle with the blower and in closed loop but that goes away as soon as I force open loop. I'm sure a GOOD tuner could probably fix that with the MAF curve but I haven't gotten that good yet...

Yea, I hear you.... well with my car, just for an update, I had O2 harness problems, big time. After fixing those problems, my a/f gauge finally reads really well and the car seems to be acting like a normal car (compensating using the O2's). Without the meter plugged in, the car runs just fine now, no problems what so ever (obviously not in boost). With the meter plugged in, the a/f gauge falls off of the lean end after about 3 seconds of part throttle and heavy vacuum (20-23), (especially under normal operating temp) and misses like crazy, in fact, it doesn't miss, it's like a flat out fuel cut basically... its almost like someone cut the bat cable till you let off of the gas, then it comes right back to life where it should be, never stalls afterwards. With the meter un-plugged, you can see it do the same exact thing on the gauge (go to the lean end quickly), but it doesn't fall off, and that's when it starts fluctuating to regulate it's a/f... so there are no problems. So what I get out of that, is that the meter is making the car run so damn lean, that when it goes to make that compensation, it goes too far because the meter is off... otherwise it wouldn't go that far lean (just like how it does it without the meter plugged in). Those things compiled with the fact that I have long tubes is just spelling out L.E.A.N. all over the place. Long tubes move the O2 sensor so far away from the combustion chamber, that the car has to run lean in order to heat it up to the correct range, hence it is getting a false reading... which is why any car with long tubes should be tuned no matter what. Anyway, the car seems to be running a ton better since I fixed my few harness problems, so we'll see what happens on the dyno once I can get a hold of Walsh.

Cool, sounds like your getting to the bottom of it finally. But as an FYI- When you run longtubes the 02's are kept cold and don't heat up as fast therfore the EEC ENRICHENS the fuel because it thinks the motor is colder than what it really is. At least that is what I have been told by some very reputable tuners. I am getting ready to go with 1 3/4" longtubes myself and cant wait to see what it does to my tune... back on with the wide band!

Nope, that's backwards... rich a/f results in cooler exhaust temps, lean conditions result in hotter exhaust temps. The thing is, is that the EEC thinks that it is doing the right thing, it's just that the O2's have been moved from their original place, so the heat range for them is going to be different... that's why anyone with longtubes should have their car tuned... they aren't going to get any of the added benefits of them if the computer is screwing up the a/f ratio.

Okay, so after a long and involved process of troubleshooting and fixing things, I have fixed wiring harnesses, I had my upper intake machined to get rid of the warps on the base plate so that it wouldn't leak anymore, I sent the meter back to Pro-M, they supposidly fixed it, re-adjusted my rocker arms, and here I am now with a car that still isn't working right.

I think I see now what is happening. I was monitoring the meter's voltage very closely yesterday after starting it up for the first time with EVERYTHING done (intake and all) and the voltage range was amazingly at .600-.700 at idle! That was a nice suprise... the car seemed to be running great, no problems at all. I noticed as time went on and the car started warming up, the meter's voltage started dropping lower and lower gradually. Finally by the the time I got to normal operating temp (180), the meter's voltage was right back down to .200-.300 where it was before... car was running terribly lean, eyes were burning and all.

Obviously the meter is the problem, but the question is WHAT is making it go out of range? What exactly is making it lose it's refrence? The ONLY thing I can think of is heat. The only thing that changes on that car as it warms up is the fact that it is warming up. It seems like this meter is GREATLY affected by heat. I took the meter off of the car for about 5 minutes to let it cool off, plugged it back in and the voltage was right around .400-.500 for a short while before it dropped again.

My question is this. I am pretty sure about this, but the meter's voltage is NOT adjusted by any other sensor on the car right? What I mean is that the coolant temp sensor doesn't affect the voltage that the computer sees from the meter right? I am 99% sure that all of the sensors talk to the computer individually and the computer makes it's decision based on that, the voltages from sensor to sensor have nothing to do with eachother.

Any input? I am running out of time fast here. My patients are gone too... so any help is greatly appreciated. Thanx guys.

There is nothing else that affects MAF voltage. It sounds to me like the board in the Meter is getting hot and when transistors and resistors get hot, their resistance values change which would cause your varying voltage. Is there anyway you can cover the MAF with something to sheild it from heat? maybe header wrap or and aluminum shroud of soem type.... if that doesn't do it then I'd demand Pro M to replace your meter.

Pro-M's outstanding customer service provails as they NEVER called me back yesterday and I now have to wait for them to answer the phones so that I can try again today. Does anyone have any suggestions or ideas as to why my meter is reading different once the car is running?

Okay, so I finaly got ahold of Pro-M and the guy that I talked to bassicaly said "well if the meter is running fine when the car is cold then there is nothing wrong with it. If you try un-plugging the O2's see if that cures it. Short of that I can't help you unless you bring the car in. I will have Jim call you back." Unless there is another sensor on my car that directly affects the voltage being sent from the meter to the computer, it IS the meter or design of the meter that is bad since it doesn't work right once the car starts warming up. I told him the O2's have nothing to do with it because it's the meter's voltage that is going down when the car is running not the O2's.

What do I do!!!??? I am so tired of this! I can't stand it anymore!

Snake, I totaly agree... what you said is EXACTLY what I am thinking... there is nothing else in my mind that would do this. The only problem I have with this, is that the meter isn't getting ANY hotter than anything else in that car under that hood! If it was too hot to the touch or something like that, then fine, that's my problem, but come on! Pro-M is so rediculous to deal with, I know that it's going to be another fight once Jim calls me back, so I don't even want to deal with them anymore. I SO wish there was someone in this area with a Bullet #42 that I could hook up, you have no idea. I am just beside myself because this is the ONLY thing holing me back! My car hasn't worked ALL year because of the hoops they have made me jump through. I am SO tired of this.

At this point I would just buy a new meter. If the car runs fine after that then you should make Jim reimburse you for the meter that is faulty. It does sound like the electronics is screwed up on the current meter so I think the odds are pretty good that the $250 investment in a new meter will pay off. Biggest question is whether Jim will own up to his responsibility and refund your money on the first meter.

I hope Pro M is easier to deal with than ATI.... I got the run around from those guys so much it ain't funny. They did end up cutting me a deal on my seals though...

Anyway back to your post, I would definitley try and find another meter to borrow before you dump the cash on another one, cause odds are Pro M won't refund you for yours. I have a perfect 42# Univer that I'd let you borrow but its the only one I have and my car is my daily driver at the moment... wish I could help you out man. Maybe give Dan a call, and see if he could spare his for a few days....

The sad thing, is that if the meter was sitting in a cool place that doesn't have a lot of ambient temp change like an engine compartment (the fender) which is where most meters are located anyway, it wouldn't be an issue. If we heated the meter up and then tuned the meter accordingly, it would probibly be fine. I think I am just going to go and buy another meter that Walsh says will work well with my setup and just call it a day. It's just frusterating that all of this has led to this conclusion. I guess my car is more solid than it has ever been and I have worked out a lot lf little quirks that needed to be dealt with anyway, just too bad that all of this had to happen like this. I will keep you guys posted.

Good luck Don, It seems like blown mustangs are a very complicated thing sometimes! I know mine has had me ready to sell it about once a month, but when it does run right, I love it!