I have a 99 24V cummins in my motorhome and had to change the tappet cover due to an oil leak. The injector pump was pulled to access the cover and now that everything is back together she doesn't want to start during the start cycle. We can spray some silcon spray in the intake and she'll start and run fine. Even after its warm the engine will only crank and not start. It's as if the fuel soleniod isn't opening for the start cycle but once the engine is hit with silicone it runs fine so the soleniod must be open. Is there something else that would prevent the engine from wanting to start during start process? Is the fuel solenoid in the injector pump on this model? We have an aftermarket engine diagnositic system and we're not receiving any codes.
Anyone know what pins to check for power or continity on the injector pump?
Any help would be greatly appreciated!
Clunk
05-21-2008, 07:52 AM
The fact it runs after you "prime" the motor indicates the injector pump is ok...right now. The injector pump requires fuel to be delivered to it under pressure...stock spec is 10psi.
Do you know the lift or delivery pump fuel pressure? It can be checked by removing the most foward pipe plug on the fuel filter top and screwing in a 0-15 psi pressure gauge...1/8" NPT I think.
Start the engine then check the pressure with the engine idling.
Halibutgrove
05-21-2008, 11:49 AM
Clunk thanks for the reply. We check the pickup pump and we have 10psi so we've ruled it out. The engine when primed runs smooth and revs up fine indicating the IP is working fine but as soon as you shut it off it won't start unless its prime. Even immediately following turning the key off.
BOS5a
05-21-2008, 04:33 PM
A fuel volume test is a more important than pressure. u need at least 40 oz in 30 sec, if u dont get that u need a new lift pump sum injection pumps are able to pull enuff fuel to stay running once they r started how does the truk run down the road after started? do do test put supply line into cup and the bump the key to crank just to hear starter engage and then pump will run 4 the 30 sec
Clunk
05-21-2008, 06:37 PM
I don't know how much applies to a motorhome application but cracked fuel lines between the lift pump and fuel tank are being reported on '98.5-'99 Dodge/Cummins.
Have you tried parking with the front of the motorhome higher or lower than the rear then trying a restart? This would indicate a loss of prime/airbound lift pump condition.
Is your supply pump mounted on the side of the engine?
Halibutgrove
05-21-2008, 07:35 PM
Yes it's mounted on the side of the engine. I'm not sure my buddy did a volume test or not or just checked the pressure. Will check the pump volume and let you know.
