sethreesh

Are there any concerns/precautions I should have prior to pulling the ECM plug? I will be testing that resistance once I get off of work today. I'm really hoping it's the wire and not the ECM.

Yes it's not reading any codes. I've hooked up both my cheap scan tool and a friend's snap on scan tool. Nothing whatsoever. You could see on the snap on it would flatline the ECT and then spike back of to NOT. I'm assuming I should find s165 and inspect it's physical integrity? The day the VP44 died it threw several codes. P118 being one of them. However when I installed the new equipment and cleared codes nothing came back. The surging and ECT gauge bouncing stayed. Here's videos:

I will go through and clean them all again. Can you give me a list of all of them? I want to make sure there's none that I'm missing.

Another symptom when I unplug the sensor it reads 293F. I'm assuming the ECM is intact and there's a short in the wires.

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.