hard to start after 80 or 90 miles drive
#1
hard to start after 80 or 90 miles drive
Gmc 99, 6.5, with relocated PMD, after driving a good distance becomes hard to start. Once it does, drives back OK. What could it be? Changed PMD a few months back, as well as fuel filter, fuel pump injector(under drivers side) it's increasing hard to start. It cranks and cranks as if no fuel was flowing thru. It only does this after a long hot drive. Any suggestions? dont know of any codes. It has over 220k miles, sems if i shift from park to drive before turning the key on got it started once. Thanks
Last edited by littletex1; 06-07-2014 at 08:03 AM. Reason: spelling
#4
#5
IP is your injection pump, its not cheap or easy to change. As Mase said next time it does not start try pouring water on it to cool it down and see if it starts, also check to see if your lift pump in the frame rail is actually working, it works off of the oil pressure sensor and that circuit often fails which starves the IP for fuel and eventually makes it go bad.
#6
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IP is your injection pump, its not cheap or easy to change. As Mase said next time it does not start try pouring water on it to cool it down and see if it starts, also check to see if your lift pump in the frame rail is actually working, it works off of the oil pressure sensor and that circuit often fails which starves the IP for fuel and eventually makes it go bad.
The ECM controls LP operation at all times through the LP relay on 96+ trucks.
the only time the OPS should be noticed activating the LP is after engine shutdown while oil pressure bleeds off-the LP continues to run for a few seconds.
The advise is great as the LP should be operational and able to move a good volume and pressure of fuel though-if replacement of the LP is required AC Delco EP158
DELPHI Part # HFP905
#7
#8
hard to start.
What is LP ? What does it stand for?
On a 99 the OPS is only a back up power supply.
The ECM controls LP operation at all times through the LP relay on 96+ trucks.
the only time the OPS should be noticed activating the LP is after engine shutdown while oil pressure bleeds off-the LP continues to run for a few seconds.
The advise is great as the LP should be operational and able to move a good volume and pressure of fuel though-if replacement of the LP is required AC Delco EP158
DELPHI Part # HFP905
The ECM controls LP operation at all times through the LP relay on 96+ trucks.
the only time the OPS should be noticed activating the LP is after engine shutdown while oil pressure bleeds off-the LP continues to run for a few seconds.
The advise is great as the LP should be operational and able to move a good volume and pressure of fuel though-if replacement of the LP is required AC Delco EP158
DELPHI Part # HFP905
#9
LP is short for lift pump. It's the same thing as the electric fuel pump your talking about. To test it open the t - valve at the front of your engine or unscrew the plug at the top of the filter (with the engine running) You will get steady flow of fuel coming out if the LP is working properly.