I've posted here for help before but still haven't managed to solve the problem. I have a 1992 318 magnum out of a d150, it's been swapped into a 1956 dodge regent. It has an issue that when it gets warm, it starts to misfire, backfire, drops cylinders, and dies if I don't have my foot on the pedal. I have replaced every sensor on the engine, all of the ignition system, all of the fuel system, PCM, and recently the thermostat. I just ripped the front of the engine off today to check the timing chain, which was completely fine and aligned. It doesn't give any codes. I'm running out of things to check. Any ideas?

 

Does weather make any difference? Does it die faster if its warm out?

 

Weather does make a difference. I drove it today, and it started doing its thing after 10 kilometers. I drove it to Quebec from Nova Scotia during the winter, and it never acted up once.

 

So it is most certainly heat related then..... If you actually did indeed replace 'everything' trying to solve this, then you either got very bad luck with one of your components, or, the problem is the environment one of those components lives in... (under the hood......) I would suspect the PCM is simply getting too hot. Easy way to test that, is to mount it somewhere else, maybe where it can get some airflow.....

 

I already moved the PCM to under the dash because I saw how hot it was getting.

 

Interesting..... we are missing a trick here somewhere then..... When it dies, what's missing? Does the fuel pump prime when you cycle the key? Do you get spark?

 

It feels like it's running too rich when it happens. All you can smell is raw fuel, and it acts like a carburetor with the choke on. The pump still cycles, and there is still spark.

 

Running the OBDI PCM??? Do you have a scanner that can read live data? Would be interesting to see what the temp sensor is reporting, (there are two on that motor, one for the gauge, one for the PCM) and possibly O2 sensors as well....

 

I don't have a reader, but, my neighbor does. We scanned it as it was doing its thing a while ago and it read nothing abnormal.

 

Have you replaced any of the injectors?