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Discussion Starter #1 (Edited)
My 95 6.5 is about to break me. I'm ready to give up and throw it in the trash heap! It's making a loud growl on start up for about 2 second then seems to run okay but the service light is on? Any clear reasons for this without the 6 years of diagnostics?

It's got a bulletproof pmd with the new wires and nothing else special done. Anyone with the same problem and what you did to correct it is appreciated. If I can't figure this out she's going to the junkyard! Sick and tired of the constant problems!
 

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My 95 6.5 is about to break me. I'm ready to give up and throw it in the trash heap! It's making a loud growl on start up for about 2 second then seems to run okay but the service light is on? Any clear reasons for this without the 6 years of diagnostics?

It's got a bulletproof pmd with the new wires and nothing else special done. Anyone with the same problem and what you did to correct it is appreciated. If I can't figure this out she's going to the junkyard! Sick and tired of the constant problems!
If the service light is on what is the code? ( This will give you a direction for diagnostics)
FYI.. There is no such thing as a bulletproof PMD. They are designed as a weak link when any fuel system issues arrise.
Posting a video of the noise will also help diagnostics
 

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How to check your trouble codes is in the FAQ sticky. Its simple and free. Listed under OBD1 Codes.
The growl ? Might help to know what part of the truck it is coming from. Could be anything from a starter hanging up to a Tiger in your tank.
 
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Discussion Starter #4
It's obviously coming from the engine and trouble codes are practically worthless on these things. But here a video of the start up. The file is too big for the servers so I'm adding a link to my you tube page is you want to see it.
 

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It sounds to me like you have no pre-start glow of any kind, can you verify that you have GP operation before starting?

Steve
 

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I agree with glenlloyd. A cold engine will clatter like that. Verify that your wait to start light appears on the dash for 5-10 seconds and then goes out.
Inspect your glow plug system.
If you have not replaced your glow plugs then do so. Make sure your glow plug wire harness and connectors are intact
 

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It's obviously coming from the engine and trouble codes are practically worthless on these things
Trouble codes are a valuable tool in diagnostics and are essential in correctly fixing your issues.
 

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Discussion Starter #8
Well, yes, the light is working properly for the glow plugs I'll check to see if they're actually getting current.
 
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Well, yes, the light is working properly for the glow plugs I'll check to see if they're actually getting current.
Test plug condition and that they're getting voltage, the fusible links might be bad.

I'm not real familiar with how the GP system on the 6.5 works or whether it knows if GP's have failed, but I do know from the old VW days (latter 80's) that the glow light would come on in the dash even if the plugs were dead in the water. It wasn't until the TDI cars that they actually had a ECU that knew if voltage draw wasn't correct.

Steve
 

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Discussion Starter #10
Thanks for the responses fellas.
I got these codes just now

17 - High Resolution Circuit Fault
DTC 18 - Pump Cam Reference Pulse Error
DTC 35 - Injection Pulse Width Error (Time Short)

Before I parked it last year I was driving around 50mph and there was a big bang. It shook the entire truck as if I hit a wall. Then it wouldn't run worth a crap. I changed out the pmd and it seemed to run better. It has done this start thing before but not all the time.

I'm not sure exactly what is going on with it but the truck itself is in great condition and I hate to dump it all because the motor is junk.
 

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Thanks for the responses fellas.
I got these codes just now

17 - High Resolution Circuit Fault
DTC 18 - Pump Cam Reference Pulse Error
DTC 35 - Injection Pulse Width Error (Time Short)

Before I parked it last year I was driving around 50mph and there was a big bang. It shook the entire truck as if I hit a wall. Then it wouldn't run worth a crap. I changed out the pmd and it seemed to run better. It has done this start thing before but not all the time.

I'm not sure exactly what is going on with it but the truck itself is in great condition and I hate to dump it all because the motor is junk.
The later 6.5 ecu checks all the time that the pulsed from the crank sensor match with the hi res and low res signals from the fuel pump. If they don't match, it gets all uppity and throws a tantrum and cuts out. Also it may not start at all.

Unplugging the optical sensor off the top of the injection pump should make the truck start without the confusion, but in "limp home" mode. A broken wire could have the same effect.

Before you throw the IP or optical sensor in the bin, check to see if the wiring between the ecu and the optical sensor is good, ditto for the ecu to crank sensor, and check the crank sensor too. These are all a lot cheaper than diving into your injection pump. My truck threw similar codes and I have found that there seems to be a wiring problem above the bellhousing, I haven't found yet whether it is a short or a break or interference, but moving those wires apart has made a huge improvement, but not solved the issue.
 

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The Crankshaft Position Sensor (CPS) may be the issue.
 
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Discussion Starter #13
The later 6.5 ecu checks all the time that the pulsed from the crank sensor match with the hi res and low res signals from the fuel pump. If they don't match, it gets all uppity and throws a tantrum and cuts out. Also it may not start at all.

Unplugging the optical sensor off the top of the injection pump should make the truck start without the confusion, but in "limp home" mode. A broken wire could have the same effect.

Before you throw the IP or optical sensor in the bin, check to see if the wiring between the ecu and the optical sensor is good, ditto for the ecu to crank sensor, and check the crank sensor too. These are all a lot cheaper than diving into your injection pump. My truck threw similar codes and I have found that there seems to be a wiring problem above the bellhousing, I haven't found yet whether it is a short or a break or interference, but moving those wires apart has made a huge improvement, but not solved the issue.
Thank you I'll check these things out, but I'm not sure where the crank sensor might be?
 

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Thank you I'll check these things out, but I'm not sure where the crank sensor might be?
follow the electrical connection down the driver side at the front of the motor. Facing front of motor it plugs in to roughly the 3 o clock position above crankshaft. It is held in by one bolt. If you are lucky it will come out in one piece. If yours snaps... do a lot of readup before you attack it as you do not want to have to bull the timing cover. Lots of methods to extract it before resorting to that.

Good luck.
 

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I had to butcher the CPS in mine, unboltt the P/S pump and set it aside.
Make sure you get an ACDelco CPS.
 
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