Intermittent starting problems-2000 jimmy
biglilwhateva
08-15-2006, 09:57 AM
2000 Jimmy, 4x4, 4dr., 4.3 113k miles.
When I bought it the gas gauge didn’t work correctly and 4HI wouldn’t engage
I’ve owned it for nearly 2 years but never had any major problems, until now.
A month ago I drove about 17 miles, made a stop, shut it off then tried to restart and it wouldn’t. The engine was cranking over but didn’t seem to be getting fuel (couldn’t hear fuel pump turn on). I sprayed starting fluid into the intake and it would start but only run long enough to burn that up. After about 6 hours of jiggling wires and scratching my head I gave up and called a tow truck. The driver arrived, cranked it over and it started without touching a thing other than the key. Hoping it was a fluke thing I drove it for the next 3 weeks with no problems (turning it on/off about 5 times a day).
Finally, after the truck had been sitting for a good 2 hours I went to leave work but it wouldn’t start. Same deal. This time it wouldn’t start for the tow truck driver, so he took it to a dealership. Once I paid the bill for the tow my truck decided to start, frustrated, I drove it home. I can start it up right now if I wanted but I’m afraid it will leave me stranded again. If the fuel pump didn’t cost nearly $300 ($550 for a Delco) I would have already eliminated that possibility, but I’ve always been under the impression that when a fuel pump goes, it goes. Bad wiring? Sensor? Any insight would be greatly appreciated, thank you.
When I bought it the gas gauge didn’t work correctly and 4HI wouldn’t engage
I’ve owned it for nearly 2 years but never had any major problems, until now.
A month ago I drove about 17 miles, made a stop, shut it off then tried to restart and it wouldn’t. The engine was cranking over but didn’t seem to be getting fuel (couldn’t hear fuel pump turn on). I sprayed starting fluid into the intake and it would start but only run long enough to burn that up. After about 6 hours of jiggling wires and scratching my head I gave up and called a tow truck. The driver arrived, cranked it over and it started without touching a thing other than the key. Hoping it was a fluke thing I drove it for the next 3 weeks with no problems (turning it on/off about 5 times a day).
Finally, after the truck had been sitting for a good 2 hours I went to leave work but it wouldn’t start. Same deal. This time it wouldn’t start for the tow truck driver, so he took it to a dealership. Once I paid the bill for the tow my truck decided to start, frustrated, I drove it home. I can start it up right now if I wanted but I’m afraid it will leave me stranded again. If the fuel pump didn’t cost nearly $300 ($550 for a Delco) I would have already eliminated that possibility, but I’ve always been under the impression that when a fuel pump goes, it goes. Bad wiring? Sensor? Any insight would be greatly appreciated, thank you.
biglilwhateva
08-16-2006, 12:55 PM
Replace the Fuel Pump !!!! this is very common..I own a repair shop and have been mislead by this same issue. many times after a GM car has been towed it will start up, but only to show an issue later.
no need to test fuel pressure , just replace the pump and be done with it.
www.freeautomechanic.com (http://www.freeautomechanic.com)
Well, I found another older thread on here with someone that had the same exact problem...he replaced the fuel pump 3 times.
Threads-
No-Start Nightmare!
'95 Jimmy no start - follow up
I sent him a message and now I'm waiting for a reply to see if he resolved this issue. In the meantime, are you saying that when fuel pumps go bad they will randomly work again? Someone please explain. Also, what is the difference between the sending unit and fuel pump? Thanks.
no need to test fuel pressure , just replace the pump and be done with it.
www.freeautomechanic.com (http://www.freeautomechanic.com)
Well, I found another older thread on here with someone that had the same exact problem...he replaced the fuel pump 3 times.
Threads-
No-Start Nightmare!
'95 Jimmy no start - follow up
I sent him a message and now I'm waiting for a reply to see if he resolved this issue. In the meantime, are you saying that when fuel pumps go bad they will randomly work again? Someone please explain. Also, what is the difference between the sending unit and fuel pump? Thanks.
biglilwhateva
08-16-2006, 01:30 PM
the sending unit is mounted on the side of the fuel pump located inside the fuel tank. the pump is a small electric pressure pump like you would see in a bird bath ... just pushes fuel , has brushes on the motor just like a starter motor and can in fact work intermitantly.. ( poor contact )
the sending unit is a small reastat type switch kinda like the volume control knob on an old radio... it sends a low voltage signal from 0 to 3.5 volts to the gauge on the dash and the contact points where easy ..
The failure is in the manufactures design(GM uses cheap parts from the factory)
Ok, I think I understand, but when it comes to getting the parts do the sending unit and fuel pump come together? Also is there anything else I should replace while I have the tank dropped? My fuel gauge doesn't work but doesn't that also connect to the top of the sending unit? Also I take it that buying the cheaper non-dealer part may be better, especially considering the delco only provides a 1 yr warranty anyways (and twice the cost). I intend on doin this myself so please feel free to throw any other pointers at me. Thank you much for your time and knowledge
the sending unit is a small reastat type switch kinda like the volume control knob on an old radio... it sends a low voltage signal from 0 to 3.5 volts to the gauge on the dash and the contact points where easy ..
The failure is in the manufactures design(GM uses cheap parts from the factory)
Ok, I think I understand, but when it comes to getting the parts do the sending unit and fuel pump come together? Also is there anything else I should replace while I have the tank dropped? My fuel gauge doesn't work but doesn't that also connect to the top of the sending unit? Also I take it that buying the cheaper non-dealer part may be better, especially considering the delco only provides a 1 yr warranty anyways (and twice the cost). I intend on doin this myself so please feel free to throw any other pointers at me. Thank you much for your time and knowledge
MT-2500
08-16-2006, 02:42 PM
2000 Jimmy, 4x4, 4dr., 4.3 113k miles.
When I bought it the gas gauge didn’t work correctly and 4HI wouldn’t engage
I’ve owned it for nearly 2 years but never had any major problems, until now.
A month ago I drove about 17 miles, made a stop, shut it off then tried to restart and it wouldn’t. The engine was cranking over but didn’t seem to be getting fuel (couldn’t hear fuel pump turn on). I sprayed starting fluid into the intake and it would start but only run long enough to burn that up. After about 6 hours of jiggling wires and scratching my head I gave up and called a tow truck. The driver arrived, cranked it over and it started without touching a thing other than the key. Hoping it was a fluke thing I drove it for the next 3 weeks with no problems (turning it on/off about 5 times a day).
Finally, after the truck had been sitting for a good 2 hours I went to leave work but it wouldn’t start. Same deal. This time it wouldn’t start for the tow truck driver, so he took it to a dealership. Once I paid the bill for the tow my truck decided to start, frustrated, I drove it home. I can start it up right now if I wanted but I’m afraid it will leave me stranded again. If the fuel pump didn’t cost nearly $300 ($550 for a Delco) I would have already eliminated that possibility, but I’ve always been under the impression that when a fuel pump goes, it goes. Bad wiring? Sensor? Any insight would be greatly appreciated, thank you.
Proper testing would be in order.
First check for lose of spark or fuel when no start.
May be fuel pump and may not be.
But if it is go the good AC delco. Check around they can be found for around 300 more or less.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
When I bought it the gas gauge didn’t work correctly and 4HI wouldn’t engage
I’ve owned it for nearly 2 years but never had any major problems, until now.
A month ago I drove about 17 miles, made a stop, shut it off then tried to restart and it wouldn’t. The engine was cranking over but didn’t seem to be getting fuel (couldn’t hear fuel pump turn on). I sprayed starting fluid into the intake and it would start but only run long enough to burn that up. After about 6 hours of jiggling wires and scratching my head I gave up and called a tow truck. The driver arrived, cranked it over and it started without touching a thing other than the key. Hoping it was a fluke thing I drove it for the next 3 weeks with no problems (turning it on/off about 5 times a day).
Finally, after the truck had been sitting for a good 2 hours I went to leave work but it wouldn’t start. Same deal. This time it wouldn’t start for the tow truck driver, so he took it to a dealership. Once I paid the bill for the tow my truck decided to start, frustrated, I drove it home. I can start it up right now if I wanted but I’m afraid it will leave me stranded again. If the fuel pump didn’t cost nearly $300 ($550 for a Delco) I would have already eliminated that possibility, but I’ve always been under the impression that when a fuel pump goes, it goes. Bad wiring? Sensor? Any insight would be greatly appreciated, thank you.
Proper testing would be in order.
First check for lose of spark or fuel when no start.
May be fuel pump and may not be.
But if it is go the good AC delco. Check around they can be found for around 300 more or less.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
biglilwhateva
08-18-2006, 08:58 AM
Proper testing would be in order.
First check for lose of spark or fuel when no start.
May be fuel pump and may not be.
But if it is go the good AC delco. Check around they can be found for around 300 more or less.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
The problem is the fuel pump won't engage (intermittently) when the key is turned on. But after no specific change it will engage and it runs normal, no stalling or sputtering and definitely no drops of fuel. My buick century had a loss of fuel pressure caused by the fuel pump, it would start but wouldn't accept any fuel when pushing the pedal, new pump fixed that. Unfortunately I don't have the tool to test fuel pressure but I'm working to get the money for the overly priced fuel pump that may or may not solve my problem. Thank you for all your help.
First check for lose of spark or fuel when no start.
May be fuel pump and may not be.
But if it is go the good AC delco. Check around they can be found for around 300 more or less.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
The problem is the fuel pump won't engage (intermittently) when the key is turned on. But after no specific change it will engage and it runs normal, no stalling or sputtering and definitely no drops of fuel. My buick century had a loss of fuel pressure caused by the fuel pump, it would start but wouldn't accept any fuel when pushing the pedal, new pump fixed that. Unfortunately I don't have the tool to test fuel pressure but I'm working to get the money for the overly priced fuel pump that may or may not solve my problem. Thank you for all your help.
MT-2500
08-18-2006, 10:38 AM
The problem is the fuel pump won't engage (intermittently) when the key is turned on. But after no specific change it will engage and it runs normal, no stalling or sputtering and definitely no drops of fuel. My buick century had a loss of fuel pressure caused by the fuel pump, it would start but wouldn't accept any fuel when pushing the pedal, new pump fixed that. Unfortunately I don't have the tool to test fuel pressure but I'm working to get the money for the overly priced fuel pump that may or may not solve my problem. Thank you for all your help.
Proper testing would be in order.
May or not be a bad fuel pump.
MT
Proper testing would be in order.
May or not be a bad fuel pump.
MT
rlith
08-19-2006, 08:33 AM
Have you tested fuel pressure? Have you metered power to the fuel pump?
Also note that one of the biggest problems with no start or intermittent start issues with our trucks is the ignition module. (This module also can cause all sorts of other issues)
Personally I would start with the fuel pressure. Attach pressure gauge to the shrader valve. Turn the ignition to the run position without starting it. Look at the guage, what's the pressure? Should be 56-60 PSI. Now turn off the ignition, how long till the pressure drops? It should hold 10-15 minutes without dropping any significant amount.
If it doesn't drop more than likely your fuel pressure regulator is good and so is the fuel pump.
If it does, turn the ignition to the run position, find the rubber portion of the fuel line (not the return line) and clamp it. Does the pressure drop now when you turn the iginition off? If it does, it's your pressure regulator, if it doesn't then it's at the very least the check valve in the fuel tank. This is not that big of a deal as it will just take an extra crank or two to build pressure.
If your pressure does not reach 56-60 in the first place, you can use the above method to determine if it's the regulator or the pump
If after that everything is on track, then I would replace the ignition module.
I would also do a full tune up.
Also note that one of the biggest problems with no start or intermittent start issues with our trucks is the ignition module. (This module also can cause all sorts of other issues)
Personally I would start with the fuel pressure. Attach pressure gauge to the shrader valve. Turn the ignition to the run position without starting it. Look at the guage, what's the pressure? Should be 56-60 PSI. Now turn off the ignition, how long till the pressure drops? It should hold 10-15 minutes without dropping any significant amount.
If it doesn't drop more than likely your fuel pressure regulator is good and so is the fuel pump.
If it does, turn the ignition to the run position, find the rubber portion of the fuel line (not the return line) and clamp it. Does the pressure drop now when you turn the iginition off? If it does, it's your pressure regulator, if it doesn't then it's at the very least the check valve in the fuel tank. This is not that big of a deal as it will just take an extra crank or two to build pressure.
If your pressure does not reach 56-60 in the first place, you can use the above method to determine if it's the regulator or the pump
If after that everything is on track, then I would replace the ignition module.
I would also do a full tune up.
biglilwhateva
12-07-2006, 11:53 AM
I replaced the fuel pump and all is well so far with that problem so I'm hoping that fixed it. Fuel gauge is also working now. I think it's been about 4 months and roughly 5000 miles. My transmission went this morning 115k miles...ridiculous. I have 1st & 3rd gear only and waitin for the estimate. Thanx 4 all your help.
MT-2500
12-07-2006, 01:01 PM
I replaced the fuel pump and all is well so far with that problem so I'm hoping that fixed it. Fuel gauge is also working now. I think it's been about 4 months and roughly 5000 miles. My transmission went this morning 115k miles...ridiculous. I have 1st & 3rd gear only and waitin for the estimate. Thanx 4 all your help.
Thanks for posting back the fix and how it went on starting.
On the transmission check out the GM dealer rebuilt transmissios.
Not cheap but they are good.
3 year 50K parts and labor warranty at any GM dealer.
Mt
Thanks for posting back the fix and how it went on starting.
On the transmission check out the GM dealer rebuilt transmissios.
Not cheap but they are good.
3 year 50K parts and labor warranty at any GM dealer.
Mt
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