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Discussion Starter #1
I have a question about setting the timing on my truck. I have a mechanical injection pump which I just installed and I lined up the timing marks. It seems to start and run good but smells kind of rich and the fuel gauge seems to be going down fast. Should I be advancing or retarding the timing? I've heard some people do it by ear, does anyone know how this works?

Thanks
 

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I will not say this is the right way to set the timing but years age I stopped in to see an Old Diesel type with a question on something other than timing. As he walked past the tail pipe on my truck he said you are running too rich. I asked why do you say that and he said I can smell it back it off 1/8 in against the mark. I did an to the best of my knowledge it is still there and running fine with 240,000 miles on it.


I admit there is a better way if you do not have a calibrated noise.
 

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Discussion Starter #3
by backing off do you mean retarding the timing, also is retarding turning it towards the passengers side (when facing from the front)?
 

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best power/lowest EGT/highest noise on mine comes when pump is advanced (never can remember which way that is...) until I get a rattle at idle-mild rattle. Be aware the more advanced the timing the quicker the glow plugs seem to die...
 

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Rotate toward drivers side to advance.
 

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I'm a long time VW diesel guy - new to GM diesels,





I ALWAYS set the VW diesel by ear. I've found that to be the most reliable way to get it right. On those engines to do it "right" you use a dial indicator on the high pressure piston of the pump. I've found that due to engine/pump wear that measurement frequently doesn't get the job done. In most cases,especially in a worn engine advancing the timing from spec is necessary.


Just some semi-useless (in this forum) info for thought.
 

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Discussion Starter #7
I tried retarding the timing and that made it impossible to start, it would just fire and then stop. So then I tried advancing it and it seems to run better and have more power. I think advancing it probably takes up some of the slack in the timing chain.
 

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Now that you got it running might want to go in search for somebody with a T2 or snap on scanner in your area to see where it is actually at too much advance, or too much chain slop can be a bad thing so Iv'e heard, I'm not up on mechanical IP so not sure it can be done that way but worth checking in to. Edited by: Turbine Doc
 

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Discussion Starter #9
Yeah, I think I will take it in to get the pros to do it, they told me its only about 60 bucks and I think its worth it to have it running just right. I took off the cover to look at the chain slop and it doesn't seem to bad for over 200k.
 

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JJW,


With that many miles do a good inspection on the crankshaft pulley if the rubber is starting to crack or swell from long term oil exposure you need to change it; if the rubber fails you can set yourself up for broken crankshaft I've read where change at 100K as a prevention measure is a good idea.
 

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TD,


I was looking at the harmonic behind the pulley( '94 k3500) and the erathane was swollen on it. I noticed the erathane ring was much smaller than on the pulley but same basic design (concentric circles with erathane sandwiched between). have you heard of this one failing too?


I have my IP as far as it will go ( advanced) on the stepper motor. It shows about 7-8 degs. actual timming (advance) on the scanner.


I don't think the '93 can display timing on the scanner. mine doesn't.Edited by: quantum mechanic
 
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