Not going back to the dealer.
May 7th, 2009, 9:55 PM
#1
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Not going back to the dealer.
I dont expect anybody to fix over the internet for me, but I have a problem that I do not know how to diagnose and thats all I'm asking for help with, cause the current dealer in the area is not an option, ever again.
Truck: 2001 2500HD 8.1L, Auto 4WD.
Problem: Intermittent starting problem. Cranks good. Runs real good. Will not start on the first cold crank of the day or if the truck has sat for more than 15 mins. IF I turn key on, let pump pressurize, turn off and repeat that procedure 5 to 6 times, truck will fire without hesitation. NOW, when I first turn key on to pressurize fuel line, the pump has a higher pitch, as if there is no line pressure. The second time, the pitch is lower. The third time the pitch is even lower again. Now the pitch stays pretty much the same to the 6th cycling of the key till I fire the engine. The pump is not loud, sounds normal. The plugs are not fouled-engine is not flooding. This truck has left me sitting before, after very short stops like into a convenience store, stopping to refuel, you get the point. But it always restarts after sitting for about 4-5 mins.
Known things:
1)New dealer installed Crankshaft Position Sensor. (Thanks ShawnVW for the CORRECT diag.
)
2)New AC Delco battery. Currently cranks @ 920 CCA's
3)Alternator produces 110 amps @ 14.5V
4)Again, truck runs real good and hard, great power.
5)Age of fuel pump is unfortunately UNKNOWN
Questions:
How much pressure does it take to fire injector?
What's minimum current required to run fuel pump correctly?
What pulses injector?
What purpose does the crank sensor have/serve during cranking before initial ignition?
How do I:
-Test fuel pressure regulator correctly?
-Test fuel pump relay ? (if possible)
I dont have access to SnapOn scanner anymore and I need to diagnose/fix this myself due to local dealership's lack of diagnostic knowledge capacities. If someone has fixed this exact problem, great. But I will follow knowledgeable diagnostic procedures to the best of my abilities if someone knowledgeable would be kind enough to help. I put myself through school writing service under one of the best diagnostic tech's walking, and I understand it's a systematic process of elimination. But I'm not a tech, or even close to and do not have diag tools, but will purchase if needed. So any knowledgeable help or answer will be appreciated. Thanks again ShawnVW.
Truck: 2001 2500HD 8.1L, Auto 4WD.
Problem: Intermittent starting problem. Cranks good. Runs real good. Will not start on the first cold crank of the day or if the truck has sat for more than 15 mins. IF I turn key on, let pump pressurize, turn off and repeat that procedure 5 to 6 times, truck will fire without hesitation. NOW, when I first turn key on to pressurize fuel line, the pump has a higher pitch, as if there is no line pressure. The second time, the pitch is lower. The third time the pitch is even lower again. Now the pitch stays pretty much the same to the 6th cycling of the key till I fire the engine. The pump is not loud, sounds normal. The plugs are not fouled-engine is not flooding. This truck has left me sitting before, after very short stops like into a convenience store, stopping to refuel, you get the point. But it always restarts after sitting for about 4-5 mins.
Known things:
1)New dealer installed Crankshaft Position Sensor. (Thanks ShawnVW for the CORRECT diag.
)2)New AC Delco battery. Currently cranks @ 920 CCA's
3)Alternator produces 110 amps @ 14.5V
4)Again, truck runs real good and hard, great power.
5)Age of fuel pump is unfortunately UNKNOWN
Questions:
How much pressure does it take to fire injector?
What's minimum current required to run fuel pump correctly?
What pulses injector?
What purpose does the crank sensor have/serve during cranking before initial ignition?
How do I:
-Test fuel pressure regulator correctly?
-Test fuel pump relay ? (if possible)
I dont have access to SnapOn scanner anymore and I need to diagnose/fix this myself due to local dealership's lack of diagnostic knowledge capacities. If someone has fixed this exact problem, great. But I will follow knowledgeable diagnostic procedures to the best of my abilities if someone knowledgeable would be kind enough to help. I put myself through school writing service under one of the best diagnostic tech's walking, and I understand it's a systematic process of elimination. But I'm not a tech, or even close to and do not have diag tools, but will purchase if needed. So any knowledgeable help or answer will be appreciated. Thanks again ShawnVW.
Last edited by allbusinessbuggy; May 9th, 2009 at 9:15 AM.
May 7th, 2009, 10:06 PM
#3
Super Moderator
ROTM Coordinator
ROTM Coordinator
Sorry to hear about your bad experience.
To test the fuel pressure regulator on my truck the book says to install a valve on the return line from the regulator, turn the valve off and see if your problem gets better. This blocks the flow back to the tank from the regulator. Some people pinch the line with vise crimps or other tools, but in my opinion that can damage the fuel line. Do you have a Fuel pressure test guage? you dont want the fuel pressure to go over 70 or so PSI during this procedure since your regulator is basically bypassed.
Anyone please correct me if I am wrong about on anything in this procedure.
To test the fuel pressure regulator on my truck the book says to install a valve on the return line from the regulator, turn the valve off and see if your problem gets better. This blocks the flow back to the tank from the regulator. Some people pinch the line with vise crimps or other tools, but in my opinion that can damage the fuel line. Do you have a Fuel pressure test guage? you dont want the fuel pressure to go over 70 or so PSI during this procedure since your regulator is basically bypassed.
Anyone please correct me if I am wrong about on anything in this procedure.
Last edited by Mike Sigmond; May 8th, 2009 at 1:03 AM. Reason: spelling
May 7th, 2009, 10:14 PM
#4
Super Moderator
you are right for the fuel pressure regulator but i think the fuel pump has to be tested with a voltometer. you might also try fuel filter! have you changed it latlely?
May 7th, 2009, 10:17 PM
#5
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May 9th, 2009, 10:36 AM
#8
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I am trying to get a look at my pickup today, I've been working 12-14 hour days. Thanks for the input. Will be checking FPReg, & volt the pump. You're right I need a manual for this pickup, I was spoiled with Alldata (and a great diag. tech) for a long time. Get back to you soon.
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