I have a Speed Density 350 Stealth Ram motor with alum. heads, various other aftermarket parts, and a custom chip. For some reason the car will no longer run. It will start, and seems to run fine, but will stall after about 20-30 seconds. If I try to start it again right after it stalled, it will not start. If I let it sit for about 10-15 min. after it stalled, then I will be able to start it again, but it will stall again after about 20-30 seconds. I tested the TPS and got normal voltage readings. There is no code thrown, so I'm thinking the ECM might be fried. I'm also thinking it could be the MAP sensor, b/c I know that it controls fuel delivery and timing. I checked all vacuum lines and grounds, and all seem fine. Also, right after the problem occurred, I replaced all igniton components. This includes: plugs, wires, cap, and rotor. The coil is only about a year and a half old. Same with the 6AL box. It back-fired out the exhaust, which made me think the it was crossfiring due to moisture under the cap. Like I said, all ignition components are new and the car still stalls. If anyone has any ideas please let me know. I need to get my car running ASAP.

 

Check all your electrical connections at the Distributor, Coil and Alternator. If it's all good, then pull the plug wires off one at a time and check for cracked spark plug insulators, a burnt wire, and make sure the cap has a tight seal. If you still haven't found a problem, then you need to start testing the various pieces of your ignition system to make sure nothing has gone weak on you.

 

The plugs, wires, cap, and rotor are all brand new. I changed them right after the problem started. I'm thinking it is a sensor or the ECU.

 

I'm not trying to be a jerk about it, but you really need to check those things again. Your plug wires could be new, but if a header burnt one of them you would have a problem similar to the one you have. If water soomehow got on the inside of your cap, you would have a problem. If the wires going to your pick up coil are rotted you could have a problem. The same holds true for the wires going to the Ignition Module. If your coil was weak before, but the ignition system components were worn out, your tune-up could have made this stand out a lot more. If the wire that allows you to bypass the Electronic Spark Timing is still disonnected you would have problems. If the connection to your E.C.M. is dirty, loose or corroded, the E.C.M. couldn't do its job and you would have a problem. Even if all these things are right, you also have to remember that the H.S.R. intake has created a lot of problems where the intake and cylinder heads match up, which could create a vacuum problem. Don't blame the E.C.M. until you have eliminated the other variables. If you do, then you might find out that spending 100 bucks doesn't fix your problem and you're right back at square one. Again, I'm not trying to be a jerk. I just want you to look at the big picture and why it's necessary, and worth it, to check out the various possible problems.

 

If after it starts and then dies, if you prime the fuel pump with your key does it start up again for that 20-30 seconds? It could be possible you're just running on the prime-shot, and after you start the car the fuel pump doesnt keep pushing.

 

Try starting it and letting it die. Than spray some carb cleaner into the intake and try starting it again. If it starts on the carb cleaner than dies, you have a fuel problem. If it has no effect look somewhere else. Try eliminating one thing at a time to find your problem.

 

After the car stalls and I try to start it again, I will prime the pump and it will not start. It will crank over and sputter alittle, but will not run. It will only start after I let it sit for 10-15 min. then the whole cycle starts over again.

 

I have a fuel pressure gauge mounted on the fuel rail so I can keep an eye on the fuel pressure. When the car is running it sticks at about 48psi. If it is a fuel problem it could only be the injectors or pump right?

 

doesnt sound like a fuel problem than.

 

Should test your pickup coil, and ignition module. Either can be notorious for giving some weird starting/running conditions.


I know that this pic is for a V6 distributor, but the same principles apply in the same areas. All you'll need is a voltometer.