I need help with a problem before I kill myself

[shikzachaser]

My 84 944 has developed a problem I cannot locate. After driving at highway speeds for about a half hour and I come to a stop the car will die and not idle. If I resume the highway speeds for another half hour or so it starts to cut out badly especially under load at lower RPMs. If I let it sit for an hour everything is fine except that the idle will surge from around 800-1200. After another half hour or so it again starts to cut out. It is intermittant in that it only happens maybe 20-30% of the time. The car has 75,000 miles on it and I have replaced most of the parts to include a new Lindsey fuel pressure regulator, injectors, fuel filter, etc. The only thing I have not replaced recently is the fuel pump. The car sat in our barn for 5 years before I started redoing it and I did replace the pump then. That was maybe 6 years ago. I am ordering a new high output pump as it will be required for the Supercharger that I will be doing over the Winter.




It had the problem prior to the MAF conversion. Any help or ideas will be greatly appreciated.

Steve

[scottcip1562]

Have you changed the DME relay? Mine stopped working and it was like the car would run out gas. I would get out open the hood, when I would close the hood, the shock would kick back in the releay.

[nynor]

relay or fuel pump is my bet. fuel pump is getting hot (which is why it works for a while) then starts to cut out and then gets worse.

[Razorback1980]

My bet is on the DME relay. Always good to carry an extra one in the glove box. The easy way to tell for sure though is since you have a fuel pressure gauge on the new regulator, when it is running poorly, check your fuel pressure. If it's low or jumping up and down, then you know what it is. If the pressure looks good, then let's look under the hood at night and see if there are any sparks jumping around.

[shikzachaser]

Relay has been changed. It turns out that the AFM boot was expanding?? when hot and causing a vacuum leak. I caught it while the idle was surging and was able to make the problem go away. (Thanks for the tip Eldorado). I orfdered a new one and also a new fuel pump and filter as I will need them for the SC kit anyway.

Thanks guys as all were good ideas.

Steve

[Ford-o-phobic]

You should move the air filter further away from the radiator. Trust me it will make a difference. When you do get the blower in where will you plumb it?

[shikzachaser]

A/C going away on a temporary basis. ATI procharge will sit there. Intercooler in the Fiberwerks nose along w/ the intake. I am going to plug the power steering and get my brother-in-law to machine brackets to move the A/C to the other side. I am just going to bite the bullet and buy the Speedforce kit, it's too expensive but Tim is working with me as I already have the same fuel regulator, rail, and MAF conversion they use. I will be adapting a later DME, 9PSI, 951 injectors, and hope for the best.

Steve