I just finished up a 4 day debacle of tracing and rewiring for my charging system. I was getting a code (I think 41) generation field trouble code. After replacing numerous parts, battery, alternator, wiring, battery terminals, clean up terminals... I was left with replacing the ECM.

When I replaced the ECM everything worked properly again. However, about 4 hrs. in to driving it, it would just stop running.... Sometimes it would go to full cut out. others, it seemed like it would give me symptoms of running out of gas.

Right before it started this I put 8 gals. of super unleaded in... as soon as this started happening, I went and put another 20 of regular grade gas in (fearing I may be too high on the octane level for an older vehicle.) but it made no difference.

It is completely intermittent.

Any help will be appreciated, do not be afraid to use tech. terms with me, I know my way around a vehicle pretty well.

 

It might help if you told us what vehicle we are talking about. (year, model, engine, tranny) Are you sure the numbers on the new computer were exactly the same as the old one?

 

LoL, that would help. Sorry I have a VW, and belong to a VW forum and my sig says it all.. obviously I am brand new around here.

1991 Dodge W150
5.2L 318hp
Automatic 4 Speed Transmission
Federally Regulated Emissions

ECM was matched up. Laid eyes on the "replaces" part number and it matched.

All day (24 hours after ECM replacement) it did not cut out once. Not even a sputter. I wiggled the entire wiring harness in the engine compartment. Followed a lot of wires around and wiggled all of them while the truck was running.

Could this be a fuel issue?

 

91 would be TBI. If you suspect a fuel problem look down in the throat of the throttle body to check the injector spray pattern. There should be a fine cone of atomized fuel that reaches the sides of the throttle body with no gaps or streams. Low ambient light and a flashlight helps to show off the fuel cones easier.

 

the only thing i can think of is maybe checking for power at all the fuses with the key in the run possition.