PDA

View Full Version : testing pcm



canada cold
03-01-2004, 14:31
Does anyone know how to test a PCM or anywhere to get one tested. I am still having long starts and I have changed almost everything possible cleaned all connectors, replaced glow plugs, lift pump, fuel filter and almost everything else. I beleive that the computer is not allowing fuel to the injector pump causing long starts.

Barry Nave
03-01-2004, 16:05
Can I say this again, Replace the crank pick up.
They go weak, yet still work but not true.
I have not heard any one talk about this with the trouble of all thr code's
The ECM will not see the pick up as a cause of codes, yet it will through other codes that will lead us to think some thing else is at fualt.
If I am the frist to have this,
(think not)then give this a try.
PCM can go bad though unlikey.
It will see that something is not right, though it can and will lead us to think it is something else.
This is my thinking, for dealing with the Elct. on the DS4,
( now 6yers) we have over looked one part, the pick up.
? does this pick up get dirt,oil,water,Etc. and work at times and other times not.
My hard starting was as other, when warm it run fine.
How does this pick up work?
All I know once I changed this all the trouble codes went away.

[ 03-01-2004, 03:22 PM: Message edited by: Bnave95 ]

tom.mcinerney
03-01-2004, 18:05
C-Cold--Another possibility. Someone here updated the liftpump wiring on his rig so that it would start pumping as soon as the glowplugs activated. They noted much improved initial starting. On old FIPumps sometimes the shaft seal bleeds a bit of air, takes a few cranks to get right. G Luck.

canada cold
03-02-2004, 18:52
Where is the pickup on the crank located as I will try and check this to see if this could be the problem and hope it is as it very frustrating. The lift pump is new and it is the old style which is located on the block not electric.

BUZZ
03-03-2004, 14:17
The crank pick up is pocated on the drivers side front right beside the harmonic balancer. Single bolt holds it in place. It has 3 wires coming out and the follow the fuel drain hose up to the IP.
I have not replaced to see if my long retarded start goes away but I will.
Thanks Jim!
Buzz

BUZZ
03-03-2004, 14:20
Canada cold, what year truck do you have?

canada cold
03-03-2004, 18:26
I have a 94 Chev G20 van with approximently 225,000 km on it or about 150,000 miles.