Stalling Problem

[RumbleB]

Hi Guys,

I have a Mk II roadster with a 5.0 EFI motor and MSD ignition. I've owned the car just over a year, and have driven it over 5K glorious miles with no problems. The car has 35k miles on it, so it is definately a driver! In the past few months it has developed a very random stalling problem. It definately seems to be electrical as it is immediate. It usually occurs during deceleration, or sometimes when at idle. It starts right back up if at idle, and re-fires within a second or so when driving. Random means it may happen once or twice during a drive, or not at all for days.

I've played with wiring while at idle looking for a bad connection; checked ground wires; and recently replaced the coil and coil wire just to try something!

While it hasn't left me stranded, it is very unnerving anyway!

Any suggestions on what else to check?

Thanks!

Ralph.

[buildit]

Have no idea if this helps, but I had something similar and went thru the recommended "Idle Setting Procedure"......took care of my problem.

http://www.moddedmustangs.com/forums/5-0-mustangs/123164-mustang-idle-surge-base-idle-reset.html

http://www.ffcars.com/forums/17-factory-five-roadsters/9364-idle-screw-setting.html

Good luck!

[skullandbones]

Hi RumbleB,

You could be right but I wouldn't rule out anything. I have had two cars that had fuel pump issues and my son has had three instances where the electronic fuel pump caused a problem. Sometimes they die slowly causing strange symptoms and symptoms that change as they get worse. Just saying this is a common issue with EFI systems.

On the other hand, the links that "buildit" gave you are great. Do you have the "salt and pepper shaker" connections between the EFI harness and the body harness? If you do that could be a source of internmitant connections issues. One eye opening explanation for these issues is in the Ford Racing Performance Parts catalog (tech sections: 114-116 2007 ed) which says 3% of performance can be lost with poor grounds. So long story short: you could have a connection issue. The best way to trouble shoot is to multimeter each circuit to see if the optimal voltage is being transmitted to the PCM. Of course, if you service those other connections and the problem goes away, problem solved. I wish you luck. Troubleshooting wiring sucks! WEK.

[RumbleB]

Thanks for the suggestions!