Engine/Transmission (1998.5 - 2002) Need Direction for Surging...

[kdw75]

Well, I have been putting up with the surging that started a few weeks ago but it is really getting old and Cummins is my last resort since they are 60 miles away and I don't have the cash to spend with them right now. I am having random surging and the sound like the engine timing changes breifly. The dealer is stumped and so far I have replaced the MAP sensor, Crank Sensor, Cam Sensor, cleaned the IAT sensor and replaced the ECM. What else can I test at home or do to try and diagnose what is wrong. With my Powermax hooked up it is very easy to watch the fuel surge since it has the little green fuel light on it. You can see it get real bright when it surges then go back to normal. This surging happens though even without the box on the truck. I am at wit's end and about broke after the dealer saying my ECM was bad so I need to try and do everything I can to figure it out. I also had reman VP44 put on by the dealer about 9 months ago.



Thanks for any help,

Keith



'98. 5 RAM 2500 QC, DDIII, PMax 2

 

[BillGotthelf]

The only thing left that might cause what you are describing would be a problem with the ECM. Pull the plug on the ECM and check for corrosion on the pins especially the grounding pins and ground connections. If the ECM looses the ground (part or all) the voltage signal to the injector pump changes (higher) for a short period causing surging.

 

[kdw75]

Ok, I will give that a shot. When you say the grounds, where do you mean? Are you referring to another ground other than the plug pins? When the dealer replaced the ECM they had the plug off there. This all started when they replaced my Crank sensor since the Tach stopped working so I am thinking they must have messed with something that is causing this. So again where do I find the grounds to check?



Thanks,

Keith

 

[BillGotthelf]

If you pull the plug, I seem to remember, looking at the firewall from the front the bottom right side pin is a ground-mine had a little green corrosion on it. Also there is a ground wire attached to the screw that holds the pin mount to the firewall. Anything else you need a repair manual to see the functions of the pins.

 

[kdw75]

Ok, thanks. I will give that a try and see what it looks like.

 

[BillGotthelf]

Be sure you look at the pins with a magnifying glass. The corrosion is hard to see with just your eyes (at least mine).

 

[LoneRam]

I've had a surge. Mine was here and there. It eventually led to a stalling condition. The culplrit ended up to be a cut wire to the lift pump. The engine would starve for fuel. I guess you could check this with a fuel pressure gauge.

 

[kdw75]

Yeah, I am going to check the pressure too. I have my life pump mounted closer to the tank though and I can hear it running all the time.



You said the ground was on the plug near the firewall. Are you talking about the PCM? The ECM is on the engine.



Keith

 

[WestTN]

surging...

You might want to check the APPS (Accelerator Pedal Position Sensor). They can cause surging if dirty. I'm not sure your service tech is up to date on the diesel. They have a crank sensor OR a cam sensor, depending on year, but not both.

 

[BillGotthelf]

Check both PCM and ECM plugs and grounds.

 

[RobertMiller2]

What you have explained happened exactly to me. If I were you I would take care of the problem right away. My lift pump was going bad. I put up with the surging for quite sometime and it led to the engine stalling and me having to pump the fuel pedal just to get the damn thing running. If my truck were idling it would surge and the lights would dim. The problem at the time wouldn't be that bad if I were driving down the freeway, but it would still be noticable. I would definalty take into consideration that it is your lift pump.

 

[kdw75]

Well, I don't think the surging is caused by the lift pump. I put the gauge on it and at idle it is 12 psi. Driving it is 8 and under hard acceleration it is about 3 psi. That is using the test port closest to the front of the truck. The other test port is to the drivers side and to the rear slightly. I also unplugged the main pump plug and the ECM plug and both had copius amounts of grease and looked good. The PCM plugs though didn't seem to have any grease and were somewhat dusty.



Keith

 

[kdw75]

top

 

[dezeldog]

RE: Surging

Perfect timeing on this as I to am going through the same thing. Truck will start and run very ruff with no tach if I don't keep the rpm's up it will stall. By keeping the R's up ie 1000 it will run and then all of a sudden the tach will work and all appears normal. WUWT-----TIA



Jim

 

[JTBMC]

Do you need to disconect the batteries before unpluging the plugs from the ECM & PCM to clean & check for corrorision

TJ