Idle adjustment - Where on pump??

[tschwab]

Recently on a long trip down to CA and back, my truck began to sometimes not idle with the AC on while in gear. Sometimes it will even die when the AC is off. Current idle is around 700-750 with AC off and in drive, does this sound right?



Can anyone tell me where the idle adjusment is on a '98 12V pump and approximately how much to turn it to raise rpm's by 100 or so? Thanks.

 

[Cooker]

This topic has been discussed many times recently. Do a search over the last 30 days and you will get alot of threads.



700-750 seems a bit low w/ the AC off. That is about what you'd like w/ the AC on.



There also some info on Fritz's site that will help you figure out to adjust the idle.



-Ryan

 

[Evan A. Beck]

Terry,



I always set the idle to 900 on the 94-98 trucks. Really works well at that speed, especially on cold starts. Be sure to adjust the idle when the engine is warmed up.



https://www.turbodieselregister.com/forums/attachment.php?s=&postid=192867



See the locknut on the back of the pump? It's a 10mm... Loosen that, and screw the low idle screw up towards the top of the pump. You'll have to do all of this by braille, as it is really hard to see...



Haven't seen you around in a while Terry, good to have you back!

 

[danandamy]

I happened on this thread at just the right time. Thanks for the link Evan. My wife's truck needed the idle adjusted bad. My truck needed it too. Once I found the bolt it was easy (small hands) but I would have never found it without the picture.

 

[tschwab]

Thanks Evan,



You are definetly right, finding it by braile. I can get to the locknut on the bottom, but am having trouble getting to the top to adjust, any other tips or tricks to doing this?



Thanks again for the info.

 

[Turbo Thom]

TS:

Go in from the radiator side. Lay over on the radiator and snake the big right arm under to the nut. I don't seem to be able to get the box end to work but the open end of the wrench will break the nut. Take the left hand and gently push the linkage rearward to take the pressure off and with the right turn the idle screw up, toward the top just a little. Look at the RPM and repeat to get what you want. Snug back the 10 mm and you through.



Happy adjusting.



Preston

 

[tschwab]

Thanks to all for the directions and suggestions! So far, the adjustment is a success. The truck idles right under 900 rpm when warm in nuetral and no more dying when in gear with the AC on.

 

[Evan A. Beck]

Good to see you got it taken care of, Terry. If it starts doing it again, you probably have a fuel pressure problem of some sort.