Car backfires a lot after S-trim install...HELP ASAP!!!

[MEAT315]

Registered: Feb 2002
Location: Central Illinois
Posts: 123
Corral IM:
Car backfires a lot after S-trim install...HELP ASAP!!!
Well I have my car running now. It is a 95 Cobra, S-trim w/3.33 pulley right now. Base timing set @ 10, BTM @ 1.5, FP set at 40 psi w/no vac. I have a 190lph intank, t-rex, Pro-m 80mm S/C, AFM PP, 42lb injectors. I have a 255lph intank on the way to replace the 190lph. Car idled ruff. I found a vac leak on the TB gasket which I fixed. After that my car seemed to idle ruff again. The tube comming off of the oil fill tube was supposed to route into the inlet tube of the s-trim. The AFM PP does not have a inlet for it. It was being vented back into the atmosphere. I then tried to plug the tube to see if it mattered. After I plugged the hose my car idled better. When I take it out around the block my car wants to "pop" quite a bit. It is not quite what I would consider a "back fire". Nuthing like Uncle Buck's car...haha. But I am getting pretty pissed. I also am now leaking coolant from the lower intake. It's the inlet right above the water pump that goes to the radiator. Would a over filled radiator cause this? I never had any coolant leaks before the install. Any thoughts or advice would be greaty appreciated. Later, Josh.


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[Goliath 5.0]

Regarding the popping sound... did you install MAF Sensor in the correct position? Located on the sensor is some text that says "AirFlow ====>" did you place the sensor in the right direction?

[VibrantRed94GT]

Not sure if this relates to what u are talking about, but i am having similar problems with my 94 GT. Its an automatic, and if i leave it in drive and nail the gas, it will rev out to about 5400rpms or so, and go bang, really loud out the exhuast. When it backfires the motor falls on its face, then shifts and goes. Im not sure if i am hitting the rev limiter or not, but i am getting really close to it, concidering its at 5450RPMS... But if it is hitting the limter, that would cut back fuel. What i dont get is, backfires are cuased by a rich condition or the timing way off, right? So how does cutting back fuel from hitting the limter, cuase a backfire? someone explain to me what goes on when u hit the limter, and what exactaly happens.. I cant tell if i am hitting the limiter, or just maxing out my 19lb injectors, or pegging my pro-m75 bullet mass air meter. If it means anything, heres my set-up..
94 AODE GT convertible
Vortech S-trim (10lbs @5400rpms)
powerpipe, 7"/3.3" pulleys
FMS 65mm T/B
Pro-M75mm Bullet mass air
B&M shift kit
FMS 373 gears
BBK headers/ x pipe/ flows

[MEAT315]

Ya the Pro-m is set up right. I think I may have found the problem. After reading a post on Corral I think I may have two Vac lines mixed up. At least I hope that is what it is...

[ray95]

I know it's simple but just triple check you spark plug wires again. Make sure they are hooked up right. I can't remember which 2 got mixed up on a friends car that I found but the simptoms were the same.

[Trey]

You have the bypass ran back to the power pipe right? If its venting back into the atmosphere then your causing a rich condiction. The MAF is telling the computer X amount of air is going into the engine. When the air is not there cause of the venting its giving a rich condiction. I had this problem when I first installed my S-Trim.

Another thing you might want to check is the clocking of your MAF sensor. On mine (75mm ProM) when the black box is it the 12 oclock position it maxes out the MAF. But when I clocked it to the 3 oclock position it stoped.

Hope this helps. Let us know.

Trey

[whiner]

Myself and others has had the same problems try setting the spark gap to .35 or .37 and it should stop it did with mine and a few of my friends. I couldn't belive something so small could cause that backfiring.

[MEAT315]

I had the plugs gapped @ .35, it was a timming issue. I backed the timming off and it stopped. But now I have a blown head gasket...so I am starting over on the whole deal....

[interlord]

Originally posted by MEAT315
I had the plugs gapped @ .35, it was a timming issue. I backed the timming off and it stopped. But now I have a blown head gasket...so I am starting over on the whole deal....

A timing issue??? W/ 10 degrees base and 1.5 set on the BTM? What did you have to back the timing off to?

[MEAT315]

I know, I think my distrib was a tooth or two off. Its down to around 7...

[interlord]

Originally posted by MEAT315
I know, I think my distrib was a tooth or two off. Its down to around 7...

I don't believe that is actually possible. You would just have to turn the dist a little bit farther to get it in time. You are pulling the spout connector to set the timing? Correct?

[Sinful]

MEAT315

you still havin problems?

lets talk on yahoo
my id there is netslider6192002

[Redsnk95]

I think the blown headgasket came from not having a tune with the 42lbs injectors, since your not running an FMU. And I wouldn't plug that vent tube coming off the oil fill tube, that helps vent crank case pressure. I have a breather on the oil fill and on that vent tube, to help vent positive crank case pressure. The coolant leak sounds like you created some pressure. Hope you get it running soon. I'm fairly knowlegeable with the J4J1 EEC so maybe I can help when you get the car running.

Troy

[MEAT315]

Thanks guys. I have the passenger's side head off. I am having trouble getting to the driver's side head due to the power steering pump. I can't seem to get the pulley off to get to the last mount bolt. I have the pulley puller but can't seem to get the center bolt out of the pulley. Any suggests???

[5LVENOM]

I just use an open end wrench for that bolt, and pull the bracket off as I back out that bolt. BTW take the other two out first, and when reassembling, start that bolt first. Hope that helps.