E-350 PCM bad?
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Joined: Mar 2006
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E-350 PCM bad?
We've inherited a 1993 Grumman Stepvan with the E-350 chassis, 5.8L engine. It was running a year ago, but has been sitting and won't run now.
Two things we've noticed - no fuel, no spark. Engine does crank.
Fuel pump relay isn't being pulled in. Fuses ring out good as does wiring to PCM. Inertia switch rings good. Fuel pump is good. PCM relay is being pulled in when ignition in the run position. PCM has 12V at appropriate supply pins on connector (possible ground problem?). Pin and socket connections on the PCM connector appear to be OK, no corrosion or oxidation noted.
It seems that if the PCM was working, the fuel pump relay should be pulling in and in worst case, a fail-sale program should be in effect allowing some spark and injector control.
Any suggestions on further troubleshooting or shotgunning? We're dirt poor bee farmers, so we're trying to deal with this ourselves - we've got hive tools and smokers, but no code readers or test tools (other than a DVM).
Thanks in advance!
Two things we've noticed - no fuel, no spark. Engine does crank.
Fuel pump relay isn't being pulled in. Fuses ring out good as does wiring to PCM. Inertia switch rings good. Fuel pump is good. PCM relay is being pulled in when ignition in the run position. PCM has 12V at appropriate supply pins on connector (possible ground problem?). Pin and socket connections on the PCM connector appear to be OK, no corrosion or oxidation noted.
It seems that if the PCM was working, the fuel pump relay should be pulling in and in worst case, a fail-sale program should be in effect allowing some spark and injector control.
Any suggestions on further troubleshooting or shotgunning? We're dirt poor bee farmers, so we're trying to deal with this ourselves - we've got hive tools and smokers, but no code readers or test tools (other than a DVM).
Thanks in advance!
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
There is another relay in that box for the ECM. Make sure it's working too. It sounds more like a bad ground, or ignition module. If the computer doesn't sense the spark, then it won't pulse the injectors. The fuel pump also should not run all the time with the key in the on position. It should run only breifly (2 to 5 seconds) to build pressure, and then it should shut off. Check all your ground cables to and from the PCM.
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