Hey guys. New to the forum here. I have a 1998.5 Cummins that has been in my wife's family since day one. My wife grew up getting to drive the truck to high school when her Dad wasn't using it for work. He also used it to tow his mega truck "Crawldad II" to events in the southeast. Anyways he passed away 2 years ago and my wife wanted me to make the truck my daily driver a remembrance of her dad. When I got back from deployment this past spring we flew to TN and proceed to drive the truck from TN to WA with no issues. I only flushed/changed the fluids/filter and replaced the brakes. Outside of that the truck drove great. About a month the truck started surging at idle. When it surges the ECT will immediately drop to zero. First I replaced the ECT sensor and the issues continued. Then the VP-44 and lift pump decided to quit. I thought this may of been the problem. Replaced the VP-44 (from thoroughbred diesel) and installed a 165 FASS pump. When I did the pump I also did a timbo apps sensor. The surging problem continued. I thought it may of been due to old batteries. I replaced those. Still there. Replaced alternator as it had excessive AC noise before and after I did the ground mod. I have replaced the Tstat with a cummins Tstat and burped the system for about 30 minutes. The surging continues and the ECT drops with it or even fails to respond with a change in coolant temp. The tan and brown wire for the ECT sensor has 5v at it. The sensor itself shows a change in resistance for coolant temp (decreasing as the temp goes up) I found the vacuum line from the power steering pump to the manifold to be missing (this explains the blow by/not going into 4wd/only having defrost on the AC) replaced that line with a flexible rubber hose with clamps. Solved that problem but the surging continues. It happens in park and drive. I have videos of the surging if needed. I'm at loss. It's throwing no engine codes. The WTS light always comes on immediately. With a scanner it reads everything at the right value expect the ECT will flash from NOT to -40, or will stay at -40 for long periods of time. I am assuming the ECT is causing the surging due to the changes in fuel delivery and timing.

 

Any advice would be greatly appreciated. I am trying to get this fixed before I deploy again later this week.

 

There are no mods done to the truck besides a larger horn for the intake. It had a banks engine calibration module but nothing was plugged in and I don't know anything about it so I took it all out. 

I paid 1400. They gave me a military discount and a forum discount. They also did the PCM and ECM harness. The work they did was really good. Not one drop of oil or residue. Even smells clean. All the insulation and wrap is new and tight. I was hesitant at first but am very happy.

Thanks for the business Seth, we are confident that all your issues will be resolved.  We strongly suggest that your batteries are in top condition, and free of corrosion and super clean terminals. Low voltage is a killer on these trucks, you will have good flow now that your harness is in perfect condition.  Disconnect the batteries before installing the harness, make sure all grounds that will be plugged in are super clean, shiny metal. Make sure all sensor outlets are spotless, use some brake cleaner and a tiny brush to get into the plugs and blow out with air. On behalf of ACS, we sincerely THANK YOU for you service, we strongly support the men and women of our Military.   Best Regards, ACS

@IBMobileI got an email that you replied to my post, but I don't see it.  Is it between pages 3 & 4???  Or deleted, like an accidental post?

15 hours ago, LorenS said:

Critter Ridder applied every couple weeks didn't prevent another nest, but no more damage.

Critter Ritter won't keep them out but makes their "food" taste bad so they don't eat the hoses or wires.  I don't think Month balls work and you need a magnifying glass to find them.   

4 hours ago, IBMobile said:

Critter Ritter won't keep them out but makes their "food" taste bad so they don't eat the hoses or wires.  I don't think Month balls work and you need a magnifying glass to find them.   

do you put the moth balls in there as a warning to the other moths? 

1 hour ago, hdpwipmonkey said:

do you put the moth balls in there as a warning to the other moths? 

I think that's how it works when you put them with your clothing.

16 hours ago, IBMobile said:

I think that's how it works when you put them with your clothing.

don't forget the golf tees, when driving, to go with them.

The squirrels got me again! Maybe because of the mothballs only on one side, nest moved to PCM. I hadn't sprayed that with Critter Ridder in over a month I'd guess. 

Loren that’s wild. Sorry it keeps happening to you. 
 

On a good note the truck it up

and running no more surging!! Thanks for all the advice and patience with me as we figured it out. 
 

 

 

Now put some miles on it. Verify it doing good.