Hot restart problem!

[mongol]

I put this here only because I had no problem until I installed the sn93. I don't have the fmu on it yet so I haven't had a chance to drive it yet. Just idle time.

It will start when its cold no problem.

When it is hot and I turn the igniton on it will turn over great, start up, rev up and then die.

To keep it running when hot I have to give it gas to keep it alive and slowly let out until it levels off other wise it will die.

I know its not the starter as it turns over very fast just won't hit.
When I do get it running I'm seeing 10-12 lbs vacuum.

Heres the situation. I had no problem last year with this issue. Its a donor 302 from a 89 mustang that has been parked over the winter. Like I said no issues when I parked it last year. I did however have to unhook the battery when I was removing the trans for a pilot bearing and throw out bearing.

This is whats different from last time I ran it.

I vented the drivers side valve cover. Removed the pcv and plugged the port on the intake. Since I don't have the fmu hooked up just yet I have done nothing but idle to burp cooling system. My first thought was that I had a problem with venting the valve cover or the pcv so I put it all back the way it came stock but still no fix.

Could this be an issue of the computer haveing to relearn everything thats in my signature line again. I'm searching as we you read this in the archives as I have been doing for awhile. Any help is very much appreciated. THanks Kris

[speedytang]

The Paxton when not in boost is not doing anything. You can even take the belt off and air will still past the unit and the car will run. The low vacuum is probably because your not getting a smooth idle. Have you played with the fuel pressure. Have you adjusted it to high causing a flood/rich condition or to low/lean condition. What size injectors? Stock/Aftermarket.
Do you have a leak at the Mass Air? Have you pulled a plug to see if it wet?

[mongol]

I don't have the fmu on it yet. That doesn't matter right. I haven't driven it just let it idle to get hot. Hope this is a simpler explanation...

When I start it cold it runs like a champ. Once hot it still runs great as long as I don't cut it off. But the moment that I cut it off it doesn't want to start back. It cranks over fast and starts, but it idles up and then back down and die's.

Here something weird!!!!! I was playing around with the vacuum lines to check for a leak. When i pulled the plug off of the port where pcv ran and start it, it starts up and run's. It doesn't die, it just surges. Of course this is a massive vacuum leak!!! But it starts and runs that way. When I put my finger over the hole where its suckin in air it die's instantly.

If it runs while having a massive vacuum leak that means it's starving for air right.

When I go to start it I can keep it running with the pedal by feathering it. After a while of that it will settle down and idle like a brand to car. Shut it off and try again and the same thing happens.

I have the stock fuel pressure regulator and haven't changed it in anyway. Here's everything on my car as of now.

Rebuilt 5.0, Paxton Supercharger, 5-6 PSI,Gt40 Heads, Trickflow Stage 1 Cam, Gt40 Tubular upper and lower,65mm TB,70mm MAF,24lb inj's,255lph pump,

[mongol]

Is 10-12 lbs vacuum low? I haven't pulled a plug yet. They are brand new autolite 103's

[mongol]

Also the plugs are not wet, but they are solid black which to me indicates a rich condition.

[speedytang]

You should be at 18+ lbs on vacuum.
Pull the plug off the ISC after it starts and see if it holds idle. If it does not adjust the idle screw to the correct rpm(800) then plug the ISC back on while it is running and see what happens.

[mongol]

Whats the ISC? Did you mean the IAC?

Could it have anything to do with going to colder plugs and not running hte car other than idling. Making them so black that is. I'm getting desprate. I'll go and try what you suggested now.

[mongol]

The car has been sitting for 45 minutes now and still won't start and run on its own. I was able to get it started after feathering the throttle. It was idling around 850 rpm's like normal. When i unplugged the IAC it die's instatly.

[speedytang]

Mustang it is the IAC. Sorry, I am also answering questions on the Talon web site and it is called ISC.

Adjust your idle with the IAC unplugged.
Next take the vacuum line off the Fuel Regulator and plug the line and see what happens.

[mongol]

I was able to get it started again. When I remove and plug the FPR hose nothing happens. I can't keep it running with the IAC unplugged. It smeels like it is running very rich and I don't think that it was a hot start issue anymore. I think maybe it is fowling out the plugs. I don't know though as I'm not a gas mechanic.

The plugs are fouling for sure.

[mongol]

Would it matter that my pro maf is only like 6-7 inchs away from the paxton head unit.

[mongol]

Should I install the old plugs back in the car. The one's before I went one step colder?

[speedytang]

You really don't need the colder plugs. Do you mean the rear of the meter has only a 6-7" of hose to the supercharger? Have you verified that the meter is working. When you get it running unplug the Pro-M and see what the car does. The MAS/MAP/O2 can cause any of your problems since they all three control your fuel.

[slownlow]

sounds like you are having same issues that I am having..

[mongol]

Yes the rear of the maf has 6-7 inchs between it and the supercharger.

Check this out. I take the belt off of the paxton supercharger and the car starts up and runs good, hot or cold every time!!!

I put the belt on the paxton and when I go to start it hot it rev's up and then down and die's.

Whatya think now.

The thing is this is a supercharger that was developed to work specificly on the 87-93 mustangs with no modification needed.

Higher octane fuel and a fmu is all it requires.
I don't have the fmu on it yet but I don't think that it will matter as I have just been idling and its not seeing any boost. Also I currently have 89 cotane fuel in the tank.