My engine starts surging after idling for about 10 minutes, it doesn't do it all the time it just started doing this recently, it idles at 850rpm, and surges to 1100 or 1200 rpm does any one know what could be causing this problem? The engine was warm after driving 30 miles and i let it idle for about 10 min. and then it started to surge. Any suggestions?

 

No suggestions on the surging, but without a high idler or an exhaust brake, I would not idle that long.<br><br>The cooling system is almost too efficient, and after about 5 minutes, can &quot;overcool&quot; the engine and begin to cause problems...could be too low of a temperature to efficiently burn your fuel, and could cause cylinder washdown. I think it even speaks to this in the owners manual.

 

I replaced my lift pump after checking pressures on old one which were way below the board.......6psi at idle and 0 at wot.......got new cummins pump installed and check psi...was 16@idle and never fell below 12psi@wot. Also checked for error codes and came up with p1693..cleared out code and drove about a week rechecked for codes, no codes present truck runs great...thanks for all the info. It costed me about 180$ for pump and pigtail.

 

Farmerd. How did you clear the code? And how did you find the code? I am getting ready to install new lift pump on Wednesday.

 

Marky Mark. To answer your question about the code p1693. I used a Snap On OBDII scanner, to check for codes and i was able to clear it also with this scanner. This scanner won't let me in on the Cummins side, but i was able to plug right in under the dash to the OBDII connector. I have access to a laptop with Cummins software, which i plan to hook in and check things on the Cummins computer. I don't think that a 99 CTD will allow you to check for codes by cycling the ignition switch, I tried this several times and had no luck, some one from this site told me that you cycle the ignition and off 3 times and the error codes should appear on the speedometer. I had no luck with that all my speedometer would ever read is mileage. I hope I was able to help <br>if you have any more questions let me know i will try to help the best i know how.

 

Farmerd. Thanks for the info. I tried the cycling also without success.