Cold start, sputters, then dies

larrym1961 · Feb 21, 2011

I am experiencing a cold start problem that started about 8 months ago. On a cold start, after sitting overnight. I can start the car and it will fire right up and then it will spit and sputter then die. then I restart and it will run just fine. Now the last few day, after a cold start it does this several times and then will run. After the initial warm up the motor starts just fine, no problems. It does not do this all the time, it seems like it goes in spurts. Any Ideas what could be causing this?

I also found that after I turn the car off I lose feul pressure too, I believe it should hold some pressure for a wile. I have a new BBK adjustable feul regulator and a Walbro 155 LPH feul pump. Also the feul pump and Ford Racing 24 LB injectors are 5 years old and have about 8000 miles on them). I do have a Walbro 190 LPH that I am replacing it with.

Could this be attributing to the funky cold start problem? It seems like it is allways something! But I've had this Mustang 23 years and it is far from stock, So I have to take the good with the bad.

Any Ideas on what my problem could be and how to fix it would be appreciated as allways

Kdubslugga · Feb 21, 2011

Of course its always something, its a Mustang. lol. The very first things Id do is, take the IAC off and clean the heck out of it, soak it in carb cleaner or brake cleaner or something get all that gunk outta there. Next remove the mass air sensor and clean the sensor carefully with carb cleaner and then blow it dry. Id also take an old tooth brush and carb cleaner and really clean the inside of the throttle body and then wiping it clean. This has fixed many idle problems in my past. Good thing about your problem is it is a very common one. Check out Jrichker's Idle Surge checklist. I'll try and find it for ya, if he doesnt post it up soon!

Kdubslugga · Feb 21, 2011

http://www.stangnet.com/mustang-forums/698148-help-me-create-surging-idle-checklist.html

larrym1961 · Feb 21, 2011

The IAC is a new Motorcraft, the throttle body is a new Edelbrock 70MM, and the Pro M 75MM bullet air meter just came back from Pro M for a re-cal for the injectors and conical filter attached to the meter. So all the parts listed are clean as a whistle.

So there has to be something else causing this problem. I just installed a new SCT custom tuned 4 bank eliminator Chip. although this problem existed before I put it in. But it would run after the 1st spitt and sputter and would run on the second start before the SCT chip.

HISSIN50 · Feb 21, 2011

Any codes?

It can be normal for FP to drop almost immediately with an aftermarket FPR. You have over 30 PSI before the car is cranked over for the first time? You could try priming it several times before ever trying to start it.

Kdubslugga · Feb 21, 2011

Trying starting it cold with the Mass Air meter unplugged, see if if dies then.

larrym1961 · Feb 22, 2011

I'll see what my feul pressure is at the first turn of the key, and I'll also try a cold start with the mass air meter unpluged to and see what that does.

I believe I read some where that some after market feul pressure regulators can cause a hard start?
I had a Kirban regulator on there before, and this start problem seemed to start after I switched to the BBK.

As for codes, the only code I get is 15, and that is with the chip. I get 11's without it.

stangman11 · Feb 22, 2011

I would have to agree I think it may be in issue with your FPR try to do some tweaking or if you still have your old one switch it back to see if that makes the concern any better.

jrichker · Feb 22, 2011

See the "Surging Idle Checklist for help with all your idle/stall problems.

The quick and easy way to dump the codes is in there too, and all you need to do it is a paper clip! The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes] for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

larrym1961 · Feb 23, 2011

HISSIN50 said:
Any codes?

It can be normal for FP to drop almost immediately with an aftermarket FPR. You have over 30 PSI before the car is cranked over for the first time? You could try priming it several times before ever trying to start it.

Mr. HISSIN50
I cycled the key 3 times this morning, the feul pump cycled all three times with the turn of the key but my feul pressure gauge shows 0 feul pressure. Once the car is running I have around 36 PSI @ idle, so what does that tell you?
I am suspecting my BBK feul pressure regulator may be a pile! Like I mentioned later I had a Kirban feul pressure regulator before, and this problem never arised untill I switched to the BBK.

HISSIN50 · Feb 23, 2011

I would jump the FP test connector on a cold motor and watch how long it takes to build pressure.

The other likely issue you could have is a bad check-valve in the tank. When the car is running it's not an issue, but during prime-outs, the primed fuel goes back into the tank as soon as the prime-out is over.

To do further testing, one needs fuel line crimping pliers.

larrym1961 · Feb 23, 2011

HISSIN50 said:
I would jump the FP test connector on a cold motor and watch how long it takes to build pressure.

The other likely issue you could have is a bad check-valve in the tank. When the car is running it's not an issue, but during prime-outs, the primed fuel goes back into the tank as soon as the prime-out is over.

To do further testing, one needs fuel line crimping pliers.

I have suspected that also, as the feul pressure drops immedietly after the motor is shut off. I need to drop the tank anyway as I am putting in a new sending unit and 190 LPH pump. Where is this check valve, is it the little rubber flapper type thing @ the end of the return line? I believe the last time I had the tank out that had a small tear in it, I am sure it has completly gone since then. I will replace it too when I do the others.

And thanks for the info!

HISSIN50 · Feb 24, 2011

If it's a check valve issue, it should resolve itself when you do the pump.

The valve keeps inlet fuel from traveling backwards.

larrym1961 · Mar 6, 2011

HISSIN50 said:
If it's a check valve issue, it should resolve itself when you do the pump.

The valve keeps inlet fuel from traveling backwards.

Well I finally got the old feul pump out today, and the check valve was torn in half! So there was no way for it to hold any pressure. But there is a new one in there now along with the Walbro 190 LPH Pump. And a new sending unit to boot.

91StangGT5.0 · Mar 8, 2011

My car has cold start issues too. ECT, ACT, TPS, and MAF replaced and brand new/cleaned. TB cleaned. TPS Voltage set....Could my issue be caused by something similar? I have a stock FPR though.

Cold start, sputters, then dies

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