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DTC 29 & 36

Big T

Big T

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While moving the '95 I saw the SES light come on briefly. Previous to this I saw some white smoke at start-up. Had my son check it (I'm on the road) with the GMTDScan and he got the following codes from memory:

29 - glow plug relay fault

36 - injection pulse width error


The SES light has not returned. What are these codes conveying?
 
it means that the problem was there long enough that the computer could no longer ignore it. Needs work.

Check the grounds, battery connections and the contacts at the glow plug relay - esp. the big ring power terminals for corrosion and arcing. Disassemble the connections to check them...
 
I've done the battery post mod and that was within the last 2 months. Other than the ground I removed from the driver's side while doing the cooling mods, I've never touched the gounds on the passenger rear side. They're pretty caked in grease back there. I have no idea where the glow plug relay is located. Could any of this be the result of the fact that both the injectors and the glows are original?
 
No. Your 'primitive' computer doesn't care if all the glows are burned out. It has no way to monitor the plug condition like the new diesels do. Miles don't affect glow plugs like injectors. However it is best to do both at the same time.

Pic of glow plug controller here:

http://www.thetruckstop.us/forum/showthread.php?t=9494

Use a pressure washer to clean the gunk off the pass head ground then disassemble it and clean it. Computers go nuts when the grounds are bad. Things also quit working.

Also you may try removing 'bypassing' the optical filter harness for code 36. These fail with age.
 
Glow plug controller checked out fine. Need to clean the gunk off the passenger side rear grounds. Have already done the battery post mod. It definitely needs new injectors. Trying to decide whether to rebuild one of the two sets I got with the '99 or to buy those reported Bosch new for $35 from Clearwater?
 
Update: Son drove the truck up to Big Bear with no problems from Thursday through Saturday. Then on the way home the SES light popped on several times. He said that he had the cruise control set at 60 mph and 2000 and the engine suddenly lost rpm all the way down to 600 rpm, but it did not stall. Plugged in the GMTDScan and same codes: 29 & 36. I'll have him clean up the rear passenger ground area. Then it's looking like we'll dig in and do injectors, glows, feed the beast and replace that optical filter harness.
 
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