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Rebuilding A 6.5 Diesel First Time Need Help

The switch on the cable wont matter, just those COM port settings mentioned.

Attached are some ground pics, I would focus on the one on the OBD1 connector and there are 3 at the rear of the engine. One on the back of it G106, and two on the top rear Passenger Side G109 and G108
 

Attachments

  • ALDL Instrument Panel Ground.jpg
    ALDL Instrument Panel Ground.jpg
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  • Engine Rear ground.jpg
    Engine Rear ground.jpg
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  • PS Rear Engine grounds.jpg
    PS Rear Engine grounds.jpg
    61.4 KB · Views: 12
  • Rear Lamp wiring.jpg
    Rear Lamp wiring.jpg
    50.3 KB · Views: 10
  • battery grounds.jpg
    battery grounds.jpg
    35.1 KB · Views: 9
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I seen your idle was at 1000rpm, did chris have the high idle mod done, or perhaps you didnt get the Coolant temp sensor plugged back in. The one on the thermostat crossover. It would make the PCM think the engine is at like -20 degrees so max advance and rpms.
 
I did not have the high idle mod installed on that truck....gotta check all that wiring....
 
Good point buddy, im going to look at that coolant temp senser. The truck is booked in for monday at the shop. I will post the result's on what they find wrong with it. when i was talking to him yesterday he said maybe i need the 97 module in the truck for the engine to work. What do you guys think?
 
The toggle on the scanner cord is supposed to be forward while plugged in. There is a little tit on the plate below the toggle, point it in that direction.
 
Why would you need the 97 module? I assume you mean the PCM. If it was wired for OBD1 you need a 94 or 95 PCM. Most shops are clueless about this truck, so dont take their word for anything. Its not just because their crooked either, just uninformed, and the service manual leads them to the wrong conclusion.
 
buddy said:
Why would you need the 97 module? I assume you mean the PCM. If it was wired for OBD1 you need a 94 or 95 PCM. Most shops are clueless about this truck, so dont take their word for anything. Its not just because their crooked either, just uninformed, and the service manual leads them to the wrong conclusion.
Click to expand...

x2
 
Maybe the shop says you need a 97 PCM because thats the first year they can actually scan for emissions. A lot of emissions laws only apply to OBD2 trucks, which is why I am glad to have the 94 OBD1.
 
Well i called today an aparently they got it fixed. Was a bad ground they said. I havent picked it up yet i will have it back tomarrow. Buddy, your camshaft was mailed to you today PM me.
 
Glad to hear that the hotrod is back up and running!

Keep that boost under 15 psi at WOT..
 
He diden't say whitch one just said a couple of them. I havent been able to work on it since it's been -20-30 here for the past week with over a foot of snow. And the starter is gone to im thinkin the dummys at that shop cooked it caues they said it had a rough time starting. Probley caues they dident plug it in or use the glow plugs and cranked the shit out of it. But i got thinkin about why it's idling so damn high is it possible that the coolant temp senser on that 1997 engine is different from the 1995?? like i said it worked great when the 97 harness was on there but is way different now that the stock one is back on. I wish i could post more on here but i have no internet at my new place yet waiting for telus to mail me my modem.
 
Try jumping the wiring harness for the coolant temp sensor and see if that allows the idle to drop...
 
If you hook up that GMTDScan you can see what the PCM thinks the coolant temp is. With the CTS unplugged it would be around 1000rpm, and PCM would show like -40F.

That could show you if the CTS is not functioning. Then if you jumper the CTS harness connector, like Chris suggested you should see the PCM thinking it is about 300F and idle around 656rpm.

If you do not get those reading changes, the harness might have an issue.
 
So i called a guy in reddeer who know's alot about the 6.5's and he said the 1997's have a higher out put injection pump then the 1995's and recommended putting the 1997 harness back on to bring down the idle. Im going to try juming it first to see is that fixes it. and im gonna try get that scantool to work also. will post result's in a couple days.
 
There is nothing different about the IPs. If it worked different before it may only have been because the one you have now is damaged in some way.

The fuel rate isnt much different, and its only a software thing easily updated in the OBD1 systems. The difference isnt anything to even comment on. In 94 they had a high output pump, but in no other year. Thats the only different IP.
 
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