Engine/Transmission (1998.5 - 2002) 2001 cummins bad surge !!!!

[drandle]

Hey guys,



I have 2001 dodge cummins that i am having issues with. Its a 2001 Dodge Cummins 3500 with the 5 speed manual transmission. It has a really bad surge/buck @ approx 2000 rpms. When it acts up you can push the go pedal to the floor and makes no difference just keeps surging. RPMS will gradually increase but still with vehicle bucking away. Had no fuel pressure to IP so replaced lift pump with a ddrp fass system. Also replaced VP 44 IP. Still no change in the way it runs. Also no DTCs. So i replaced the apps sensor with a new one. Still no change. Scan vehicle and no dtcs present. Was wondering if anybody out there has run into this problem?



TIA



randle

 

[JFought]

change the fuel filter(s)?

 

[drandle]

sorry forgot to metion that i did change the fuel filter when i changed the IP.

 

[drandle]

When iam driving and it starts to surge LP pressure holds steady @ 10psi.

 

[JLandry]

Randle,



Several questions...



Have you replaced either the MAP (Manifold Absolute Pressure) or camshaft position sensors?



Did this condition come on suddenly or gradually and did the start coincide with any other maintenance or upgrades?



Are you running any sort of add-on performance computer or an ECM program?



Best regards,



John L.

 

[drandle]

Hey John,



No i haven't replaced the CMP sensor or MAP sensor. Wouldnt i have a dtc for these sensors? Or can they cause problems without throwing a DTC. The problem happpenend one evening driving home from the city. It would act up around 2000 rpm. But if you hard accelerate through all gears it doesn't seem to act up. It wasn't after i changed a part or did any work on my truck. Just have the cold air intake 4 modifications.

 

[JLandry]

Randle,

Those sensors can go bad with or without TDC's. Since you've already replaced the usual culprits, it sure can't hurt to swap out the CMP and MAP sensors also. Worst case there's nothing wrong with them and you'll have the old ones as spares.

Does it do this with the coolant both cold and warm?

John L.

 

[drandle]

John,



Okay. Thanks for you're help. i ll look into replacing those sensors and let you guys know how i make out. Yeah it doesn't matter what the temp. is. It acts up cold or hot but hopefully this will fix it.



thanks.

 

[drandle]

Hey guys,



So on my truck i replaced the ECM with a known good one that a buddy had in his garage. So i install the ecm and the truck runs great, no problems, no running issues. So i plug my original ecm back in and the truck also runs with no issues. I have been driving it for a day now with no issues. With me disturbing the wiring harness could there be a bad wire (circuit), loose pin at the ECM connector??? I looked everything over fairly good. Nothing looked rubbed through or loose. Any ideas whats going on here. Sure is a weird one!!!!!!

 

[JLandry]

Sounds like it could have been a slightly oxidized connection on one of the ECM pins. Remember we're dealing with very low voltages for the control circuits.



Hopefully this ends your problems, but if it comes back, try disconnecting the 50 pin connector again, spray it with aerosol electric contact cleaner, then after thoroughly dry, spray with aerosol silicone lubricant and then reconnect.



Good luck,



John L.

 

[drandle]

Yeah john hopefully everything will be fine. Thanks for you re help. Have my fingers crossed that everything works out!!