6.9 cranking but no start

IDIBRONCO

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I've pulled out 4 of 8 and four of them so far are bad. I'm going to have to wait till tomorrow to get the next 4 out. That one plug spot filled up with water. So I had to blow it out and shoot some more wd-40 at it
Maybe my assumption that they were bad was right. At least it's starting to look that way. Just don't forget to put anti-seize on the threads before you put the new ones in.
 

Selahdoor

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I've pulled out 4 of 8 and four of them so far are bad. I'm going to have to wait till tomorrow to get the next 4 out. That one plug spot filled up with water. So I had to blow it out and shoot some more wd-40 at it

Maybe my assumption that they were bad was right. At least it's starting to look that way. Just don't forget to put anti-seize on the threads before you put the new ones in.
Agreed.

Also, I would suggest that once you have all of them out..... When you are about to put the new ones in... Turn the engine over with the starter a good bit. With no glow plugs in yet. Point is to make sure you get any water out of the cylinders before you put the new GPs in.
 

IDIBRONCO

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Toward the end of my visit, I came up with an overall theory to explain multiple issues here. I think that the controller stuck on (some time after the one new glow plug was installed) and burned out the glow plugs. It was disconnected and a manual control was installed with very poor wiring, but the glow plugs weren't changed out. I think that the truck was driven for a while like that. It would have taken more cranking on the starter to get it running like this which would have started to wear it out and cause it to turn the engine over slower. As all of this came together, the PO finally got tired of it getting harder to start or maybe it got cooler and wouldn't start as easily. Either way, I'm guessing that the PO couldn't get it to start and just gave up on it. The excuse that he gave to Derek was basically "I'm too old to try to figure it out". As we all know, that's a crock and a cop out. It's also used by people to cover up their bad choices that they used to try to rig a truck together to make it keep going.
If my theory comes out even half true, I'll be very happy since I was tired enough that I was maybe operating at 50% while I was there. Overall, other than some stupid, lazy things that were done by the PO, I think that this may be a pretty decent truck assuming that the engine is still good. The body is pretty straight with little damage.
 

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Okay so update, have installed eight new glow plugs. Had good well charged batteries and hit the glow plug switch everything looked good unfortunately no start. Put the pedal to the floor while attempting to start. Possible it's too cold currently 34°. It did seem like it wanted to turn over a couple times not entirely sure. Thinking I'll wait till it gets a little warmer shouldn't be too long
 

IDIBRONCO

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Did you make sure that the air was back out again? Have you tried the block heater trick?
 

dreed86

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Did you make sure that the air was back out again? Have you tried the block heater trick?

I have not tried the block heater truck yet. I was hoping that it would start with out that. Will attempt the block heater tomorrow morning and let it sit for a few hours while I am at work. also I did make sure the fuel is pumping. You can smell the fuel at the exhaust pipe
 

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Yeah, it would have been nice to get confirmation and do a cold start. But just try the block heater trick next time. It's important to help narrow down the problem.

Also, if you have a 12V test light, set it up to probe one of the glow plug connectors while the WTS light is on (so you can see the light from in the cab). That will verify that power is in fact getting to your glow plugs. These old wiring harnesses can develop gremlins as they age. And the 83-86 controller is simply a thermo-timer switch, so it's not smart enough to know if the glow plugs are connected or not.
 

dreed86

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Yeah, it would have been nice to get confirmation and do a cold start. But just try the block heater trick next time. It's important to help narrow down the problem.

Also, if you have a 12V test light, set it up to probe one of the glow plug connectors while the WTS light is on (so you can see the light from in the cab). That will verify that power is in fact getting to your glow plugs. These old wiring harnesses can develop gremlins as they age. And the 83-86 controller is simply a thermo-timer switch, so it's not smart enough to know if the glow plugs are connected or not.

Hey David, I have bypassed the gp controller and made it manual. I also rewired the harness

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IDIBRONCO

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Yeah, it would have been nice to get confirmation and do a cold start. But just try the block heater trick next time. It's important to help narrow down the problem.
This is true. At this point, we're just trying to get the engine to run. Then it's time for the smaller issues.
 

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Sorry, I forgot this truck already had a manual setup. Did you also check or bypass the connector near the passenger side valve cover?

If testing tools are unavailable, another simple trick is to pull one of the glow plugs and leave it connected to the harness. Then attach a temporary ground to the threads and turn on the power. If it glows after 7 seconds, you know the harness doesn't have excessive resistance.
 

hacked89

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You need to compression test this motor and post the numbers, also either video tape or note how many rotations it takes to reach the peak.

All the diagnostics were good but it was a red flag when it didn't start on ether. It should start at a whiff of it even below 30.

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IDIBRONCO

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It's also possible that the starter isn't spinning the engine fast enough to get it running even with ether. I've been saying to start with the least expensive things first. To me, this means trying new glow plugs and block heater before buying a compression tester or a starter. He does want to get a compression tester and test it out. If it doesn't try to start with the block heater plugged in, then it's time to move on to something else. Either an inexpensive starter or a compression tester would be a good next step. He has no idea of the condition of the engine and only the PO's word that it was running. I've been trying to help keep him from sinking a lot of money into this truck until he knows that it's going to be a good runner. At some point, he may have to decide whether to spend money on it or get rid of the whole truck.
 

hacked89

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@IDIBRONCO in theory yea I read all your diagnostics and saw you say it dragged a bit and spun faster cabled to your truck so it didn't sound thst slow.

My diesel compression tester was $29 and my new glow plugs were $94 (7.3).
I don't consider tools a money sink personally especially when they aren't vehicle specific.

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dreed86

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@IDIBRONCO in theory yea I read all your diagnostics and saw you say it dragged a bit and spun faster cabled to your truck so it didn't sound thst slow.

My diesel compression tester was $29 and my new glow plugs were $94 (7.3).
I don't consider tools a money sink personally especially when they aren't vehicle specific.

Sent from my SM-G955U using Tapatalk

I will try the block heater in tomorrow and go pick up a compression tester.
 
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