Newb needs help with idle on m35 a2!!!

[DDoyle]

Does the change in idle speed only when the air compressor cycles?

 

[WillWagner]

TacticalTruck is right, the compressor only takes around 3 HP to run in a loaded state and even if it had a failure in the compressor or locked up, the engine RPM wouldn't be effected very much, 100-200 rpm, maybe. I remember seeing a problem sort of like this once before. A C series had a low idle, no biggie, just turn it up, right? Did that, but when the compressor cycled, the RPM would fall off to around 450, and when it unloaded, RPM jumped to 1200 or so and would slowly come back to an unstable 750 or so. Did all the checks, low PSI fuel pressure, base pump timing, even pulled the nozzles and checked the pop off pressure. Pulled the pump, a Bosch P7100, sent it to the ADS shop. Ended up being really messed up from water intrusion.

 

[cranetruck]

Sort of like the IP governor nor governing.

 

[devilman96]

Speaking of fuel issues... Your filters good? Supply pump moving fuel ok? Does it do it when only cold?