Engine rpm's still surging up & down at idle, replaced vp again..help!!

[98whitelightnin]

Well, I was in a hurry and pullin the tubes as I got to the injector instead of pullin them and then the injectors and I gorgot one. It was a little tight but I wasnt thinking and popped it out, soon as I did it I knew I messed it up and sure enough the end was boogered up. I got a new one and it idles smooth as glass again.

[jlwelding]

Yes, reflashed old ecm there and new ecm, it was lined with sparkles of gold for 1400.00

[Mopar1973Man]

JL Welding... wild idea I came up with and as a matter of fact I found another person that has your problem too... But I started to think about it again and though about the shield that covers the signal leads into the VP44. The shield lead is ground at the ECM side but never completes the path to the VP44 end so there is technically no way to test this... But What if the shield is no longer doing its job of keeping AC noise out because its broke loose from the ground...

[balsip]

My experience with surging has been exhaust gas getting in the return line from a sticking open injector or sucking air on the supply line from the tank.The easy way to check is by putting a short section of clear PVC tubing in series where the supply to the VP44 has a short rubber hose to give flex when servicing. You need to watch carefully right from a cold start since the bubbles magnify by going via return line into the pickup chamber in the tank and come back worse in the supply side. A mechanical pump governor (the 89 to 93 Bosch VE44) will surge 650 to 1000 rpm while a a computer controlled governor like the VP44 may be worse. Remember those bubbles are compressed back to nil at 17,000psi and the pump sees a smaller fuel charge from the variable displacement injection pump. The governor sees the lower engine speed due to bubbles and tries to up the displacement and a surging cycle starts. Do not leave that PVC section in too long since it is not rated for diesel fuel.The reason I know the above is that two dealers, two VE44's on warranty, and 10 hours of Chrysler diagnostic authorization could not find my surging until I started talking to Cummins technical support directly myself. A dealer had gotten flakes of that brittle black Cummins paint into the injector lines when replacing my VE44 on safety campaign in 1996 causing exhaust gas to enter the return fuel line.

[rburks]

Yes, reflashed old ecm there and new ecm, it was lined with sparkles of gold for 1400.00

JL...Where did yo get Buy your ECM????.......................