lopey idle?

[bigrigr]

Hey guys, just got a question. My 2000 psd idles a bit rough, runs great, no noticeable problems other than it lopes at idle. Don't know if it could be a dirty injectior or what. Any ideas would be great. Ive got less than 500 miles on the filters and the sevice. Also, is there a way to calibrate the speedo for oversize tires? Heard sometime back there was a wire to ground behind the glovebox?

 

[JLDickmon]

does it do it mainly when cold?

does it improve with rise in engine temperature?

 

[aggitator]

My 99 does the same thing.It idles fine cold then when its warm it lopes like a gasser with a radical cam in it. Power seems fine,throttles up quick too,just lopes at idle.Would like to hear what others might think also.

 

[Zookie400]

i had an injector crap out twice, but it would still fire just weak. it would make it have terrible idle characteristics. swapped it out for a good one and it idles perfect. i found the dead one by unplugging each injector until i found one that didnt make a change in idle.

 

[JLDickmon]

i had an injector crap out twice, but it would still fire just weak. it would make it have terrible idle characteristics. swapped it out for a good one and it idles perfect. i found the dead one by unplugging each injector until i found one that didnt make a change in idle.

like you would on a gas motor..

 

[bigrigr]

Sounds like aggitator an I have the same thing goin on. temp doesnt matter. How hard are the injectors to do? what did you unplug, the electrical connector on the injector itself? Can you change out just one?

 

[Zookie400]

pop the valve covers off, throw some rags or kitty litter under the engine (just in case) and run it. unplug one injector at a time and listen. if the problem is a bad injector, when you unplug it you shouldn't notice any change in idle quality, or if its a weak injector it will barely change compared to the others.

 

[Crumm]

Also, is there a way to calibrate the speedo for oversize tires? Heard sometime back there was a wire to ground behind the glovebox?

The ground wire under the glovebox trick is for 94-97' trucks not for your 99'. Dealership can re-calibrate yours. You can also use a TruSpeed from SuperLift or a Hypertech Speedometer Calibrator Programmer(both are a little over $200).

 

[Hooper]

My 99 just started this rough idle thing when cold, but smooths out when it
warms up. If it's not an injector, what else should I look at?

 

[DaveBen]

The oil can do that. My 6.0 would lope when cold started, by California standards. I changed from 15W40 to 5W40 and it went away. The 5 part of the oil weight is only the cold start weight of the oil. The 40 portion is the operating weight of the oil and it is the same with 5W40 or 15W40.

Dave