1995 GMC

[Coy Lancaster]

I have a 1995 GMC sierra that quit running and will not start back. I checked my flash codes and found three codes which are 28,32 and 54, all list the quad driver in the ECM. My question is how can I test the ECM and make sure it is at fault of if my problem is somewhere else?

 

[Jonas302]

Its not likely to be a ECM problem Keep it simple dont start by chasing codes Check fuel and spark No fuel? Make sure its getting power jump the fuel pump relay or apply power to the prime wire hanging nearby still no fuel whack the tank with a big rubber mallet while applying power see if the pump starts running
If no spark start looking at the module and coil

https://repairpal.com/gm-obd-i-code-chart

 

[Coy Lancaster]

I have no power on grn/wht wire that goes from ECM to fuel pump relay. All fries are good in cab and under hood.

 

[Old Doug]

Did you beat on the tank. 99.9% of the time its the pump. When the came out with in tank pumps i tested wires but its not always easy to do becaues you need some one to run the key. I am aginst replaseing parts before testing on every thing but a fuel pump. If i owned a pickup with a reguler bed i would cut a hole in the bed and build a bolt in cover.

 

[Coy Lancaster]

I have beat on the fuel tank but that didn't help. I am not getting voltage on my green/white wire for fuel pump relay that goes directly to ECM. I'm not getting any spark form my coil either.

 

[Old Doug]

If you dont have any spark it could be the pickup in the distributer.You didnt say what engine it has. The 454 are bad about distributers problems.I dont know if its the heat or what. I have been around alot of chevys and read every thing i could about testing things but i never had much luck i ended up replaceing parts. If you were closer i have alot of parts you could replace stuff until it started.Its about as cheap just to buy a complete distributer than one part for your old one then you know what you have.

 

[DMiller]

The older GMs had to see oil pressure prior to getting fuel pump Run, the bypass was during cranking and fed the pump on a short time relay if did not make oil pressure would NOT run.

 

[Coy Lancaster]

Thanks for feed back. Truck had good oil pressure when it died. Not getting voltage at terminal 85 for fuel pump relay though. Any ideas about that?

 

[DMiller]

There should be a three wire/two terminal oil pressure switch toward back upper block area, that should have one power in then the bypass when tap the starter and once oil is up a pair of flow thru hot to the fuel pump. Could be at the oil filter block boss, been a long time for me on these.

 

[Coy Lancaster]

Thank you everyone that gave me ideas to fix my problem. I found that the ignition control module was bad, replaced it and everything is good now.