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lafrance
08-11-2003, 20:19
I have a 4mth old ds4 in my 94 blazer which I believe is defective.The truck is hard to start hot or cold. Glow plugs, Cylinder balance, Batteries all check out well.The truck has always started great until my dealer did the last pump change.I am getting also a very loud injection rattle both hot and cold start intermittently immediately after starting.It depends how long I wait between start attempts.
There are no codes filters and fuel pressure are bang on.I have substituted the pmd with a known good unit. No difference.I just also installed a gear drive from DAS. Truck runs great once its running. Lots of power but a little bit of a lumpy idle.Block has no cracks as I also did my pan gasket and front seal.I believe the pump is bad as indicated by the rattle and the fact that it always started well even when the last pump generated a code 35. HELP! Dealer will not do anything else unless a code is generated.
whatnot
08-11-2003, 21:19
Are you sure the timing is set correct? What is the TDC offset set at?
charliepeterson
08-11-2003, 21:45
The Diesel rattle you describe can be air in the fuel system. The longer between starts the longer the system can get air bound. It sounds like you're covering all the right bases with the tests and recent work done.
You could have a bad Injector leaking back to tank. When these Injection Pumps fail they will give a trouble code.
Try loosening the fuel cap after a ride to break any vacuum in the system then wait to see if it starts a little better.
You don't say how many miles on the current Injectors. After 70,000 they don't owe you anything.


Good Luck
lafrance
08-11-2003, 23:02
Hi,
Offset is at -1.7 degrees and the injectors have 70,000 km on them.The fact that this starting problem never ocurred until the pump change i.e. first start after I picked it up was a significant problem, leads me to believe that something is wrong with the pump.I will check for air and continue.

Thanks
lafrance
08-16-2003, 14:16
UPdate on ds4,
Pump is now causing extremely rattely starts but is intermittent. When it starts without the rattle it starts great. There was no air in the system. I have been told by an informed source that Stanadyne has had a run of pumps that have exhibited this symptom out of the box.Will be returning to a different dealer for further diagnosis. The service advisor almost fell off of his stool when he looked up the pump replacement history on this vehicle.
lafrance
08-20-2003, 23:28
G.M has authorised injection pump replacement.7 pumps in 9 yrs.