Tank_66

when I start up my 12 valve, it has a very low idle, but when it warms up the idle gradually increases, I've adjusted the idle, and it does the same thing if I have it set at 700rpm it will warm up and be around 800-900RPM. the lift pump is new, injection pump was rebuilt not long ago, and I've got 75hp ddp injectors.
an Ideas, or is this normal

joem

mine does that too, 400 rpm at cold start 600 warm. then back down to 400 if its over 110F I always figured it was the thick oil and less effecent of a cumbustion burn+ mechanical throttle without any electronic idle control

Tate

Back off the gov. springs a click, then readjust the idle.

gorms

Mine is the same way, regardless of "cold" starting temp, will be about 200 rpms less then warm engine idle. A few seconds with foot on the throttle gets it closer pretty quick.

Tmello401

same thing cold its about 400-500 and warm 600-750. Just is Cold, is normal ive come to realize.

jdwest

Seems most mechanically injected diesels do this...nature of the beast. No computer to compensate for a cold engine and cold start to advance more fuel.

eng208

My P pumped Cummins has always done this. Figure it is normal. I also have to apply a touch of throttle to get an immediate start, otherwise it turns over a couple of times like an older gas engine. The VE pumped Cummins had neither of these issues.

NE frmhnd

Or new gas engines or new diesels. I can't tell you how often I get in a p-pumped or gas truck and touch the starter and sit there with a dead engine.

Diesel Dave2

My truck does the same when cold...I thought that was normal...I have a manual high idle cable for warm up ...

Tate

Or adjust the governor springs and idle and it fires up immediately. Seems like a simple solution.

Tmello401

How and where did you get the cable/switch or if you made it how?

9812vram

X2

I've been down this road already, argued about it in another thread somewhere. Tate has the answer, and it is simple.

Chris W

Do you have a resource on how to do that?

texasprd

Tate hasn't been on since Dec 2014, according to his user info - and this thread died in 2012. Do you need a resource for adjusting the idle, or the governor springs? Do a google search for "p7100 pump adjust governor springs", or use the search facility on here to search this forum. This should come up in your search results...

Chris W

So I did search for it but everyone is either replacing them or bench adjusting it, I’m not finding anything of adjusting them on the truck. It does it anytime it gets below 65 or so, but if I plug it in it doesn’t have much of a problem until it gets to teens.