Need Help From The Pros Please

[tnance82]

Hey Guys,
New to the forum here. I have been pouring over all the info on here and haven't come across an answer for the issue I am having. Any input you guys have is greatly appreciated.

1998 Mustang Gt 4.6/ 5 Speed /120,000 miles
Pretty much stock, Headers, Xpipe, Flows, 4.10s

I inherited this car from my brother who past away last year. The car had sit for probably 5 years and just before he died he tried to get it running again. We threw some parts at it and never got it going. Now I have it in my shop and i have done everything I know to do and can't get it going either.

Problem I have is that the car can sit overnight and start right up for about 3 seconds then die. It sounds good when it starts but if you try to start it again it will just crank/cough like it out of time and and backfire once and a while. When it does start the throttle pedal doesn't respond so i cant try and keep it running. Car has no DTC's. So far I have replaced the fuel pump, fuel filter, injectors, crank sensor, cam sensor, plugs/wires and the IAC. Sent the computer to Garrett Tuning and had them delete the PATS so i don't think that's an issue. I have taken off all the grounds and cleaned/ polished them. I have fuel pressure, good spark and have injector pulse. Tested the TPS and is good. Tonight I checked the CCRM to the best of my ability. Have 12.5 volts on Pin 8,10, 11 with key off and 12.5 volts on pin 12 and 24 with key on. Any thoughts on where to go from here? I'm leaning to a PCM issue but that's why I'm here.

 

[lwarrior1016]

Why did the car get parked initially? Did any internal engine work get done?

 

[tnance82]

He thought it had a knock but when i heard it, it sounded like a header gasket leaking. Just a slight ticking. When it starts now i think it sounds good. No noticeable concerns although it only runs a few seconds.

 

[lwarrior1016]

So the engine ran when parked?

Do you have any way to scan live data? I’d like to know if the crank and cam sensors are reading.

Did you put a gauge on it to see what fuel pressure is? It’s possible that the injectors are stopped up also.

The coughing when cranking really makes me thing is a cam/crank sensor error.

 

[lwarrior1016]

That’s something check also, pull the crank sensor out, and put a screwdriver in the hole. Try to move the crank trigger wheel up and down. Those things break sometimes.

 

[tnance82]

Yes. It ran. It has a fuel pressure gauge on the rail it says 38-40 psi when the pump primes. Has new injectors. I have a friend who can read live data but when i had him over he thought it was the PATS. I have since learned that its not. I can have him back over and post what the cam and crank are doing. Ill try moving the tone ring tomorrow. I didn't think of that. Thanks

 

[96blak54]

Failed wiring harness some where or computer would be my guess. Assuming all parts are ford original type replacements and no piggy back electronics. Dood we feel your pain and we have all been down this road, so you definitely not alone and we are here to help. Just keep coming back with the good info of what you have performed and together we will figure this out

 

[tnance82]

Today i checked cont. between the crank sensor and PCM and the cam sensor and PCM. All was good and ground was good on the cam sensor. Pulled the crank sensor and checked the ring like you said with a screwdriver and didn't feel any play in it. Didn't fell broke to me. Is there a fairly reasonable scanner that i could look at the live data and get back to you guys with the results? I looked at a few of the Harbor Freight scanners but not real sure if that is worth the money or is there better ones out there. Thanks guys

 

[GTamas]

I am wondering what could make the difference in starting after sitting overnight and starting after the 3 seconds run?
3 secs are probably not enough for any electronics or connections to get warm.
Is there a way to reset the computer, by disconnecting the battery for a short time? If yes, then you could try to reset it after the "3 sec run" and see if it starts again for 3 secs, or just coughs. Maybe that could give a hint at a computer fault.

 

[tnance82]

I will try a couple cycles of trying to start it and disconnecting the battery for a while. Every time I go out to work on it I will try and start it and it will idle up to about 1500 RPM and sound good, then after it dies it wont start back up. Then the next day or next time i try it it does the same thing.

 

[badass98svt]

Is the theft light blinking abnormally?

 

[tnance82]

Yes it blinks rapidly. From what I read after a PATS delete it will still blink. I still have fuel pressure, injector pulse and spark after it dies.