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View Full Version : lots of new parts still not quite right, help



eembry
12-25-2006, 21:19
I have a "92 6.5 turbo have been having quite a bit of smoking and some rough running when first starting up cold. It was the consenses that I needed to change the injector pump as my engine has 128,000 miles on the original. I put a rebuilt pump on also changed the injectors, new gm injectors, new oil pressure switch,new glow plugs and glow plug controller. I am still having some smoke when I start cold. It is not as bad if I don't mash the accelerator down prior to starting. I don't understand what is going on with that as that is the way I thought you were suppose to do prior to cranking. I have checked and I have 12 volts to the solonid to advance the timing. I can unplug it and plug it back in and I can hear a click but it doesn't sound as much as a clunk as I remembered the old one doing. I can start it without setting the accelerator then hit the accelerator and there is no change in the timing.I know it is suppose to advance but for whatever reason I don't think it is. Is there an easy check to tell if it is working or do I need to look for something else? I think if I can get to the bottom of this problem I will have my problems solved. The truck runs better that it ever has other than the smoke when I first start it cold. By the way the smoke is not white smoke feel sure it's fuel because the truck doesn't use oil. Thanks in advance for any help. Eddie

Robyn
12-25-2006, 22:59
HI

There are two main wire leads going to the IP.
One turns the fuel solenoid on and off and the other is the CCA
Cold Case advance.
Check when the engine is cold and see if both these lines have 12V
If the one going to the CCA is dead the engine will not get advance for a cold start and will run crappy.
If no 12V at the advance check the coolant temp sensor on the water crossover.

This truck has a very simple ECM that runs the cold advance, fast idle,
EGR (if equiped)
and the tranny (4L80 if equiped)

Check the wires to see if you have 12V first and then the sensor.

With the CCA working you should get a nice clean start.
How about Glow plugs???

Is there a buttload of slop in the timing chain???
A sloppy timing chain will really hurt cold starts as well as power

OH BTW
The cold advance does not make any noise, what you are most likely hearing is fuel shut off solenoid.

The fast idle pod should have 12V also during warmup.

Let us know

Robyn

eembry
12-26-2006, 19:38
Thanks Robyn been busy so it will probaly bee the weekend before I get a chance to check any further. Doesn't seem to be a lot of slop in the timing chain. Did advance it a little when the new pump was installed, helped on the start up smoke. Another problem I forgot to ask about is the trannyfeeling as if the converter is locking and unlocking when going down the road. You can put your foot on the brake and get the same results as that the truck is doing on its own. I have replaced the brake switch didn't quit. Took it to a transmission shop a couple of times they replaced a valve they said was causing some kind of code. Helped for a while then started again. Really no rhyme or reason as to when it is going to do it but it is always after it warms up good. Any ideas surely I'm not the only one that has had this problem?
Thanks again, Eddie

bcbigfoot
12-28-2006, 14:09
A possible cause of the trans lockup going on and off is a bad temp sensor in the trans. wiring harness that is located in the pan. My 93 had this problem last summer, it would throw a low trans temps code (can't remember the number) I replaced the internal wiring harness to the new updated version because you can't buy just the .20$ sensor.

moondoggie
12-28-2006, 15:56
Good Day!

"new glow plugs" What brand/model? AC-60G's will probably never burn out and/or swell, but don't heat as good as the otherwise much inferior 9G's & 11G's. If you have 60G's or Kennedy's glow plugs, it might do to search for circuits that have been described in topics over the years for adding glow time. This characteristic is definitely worth living with - you don't want to have to deal with trying to extract a blown and swelled 9G or 11G, assuming you could even locate a source.

"It is not as bad if I don't mash the accelerator down prior to starting. I don't understand what is going on with that as that is the way I thought you were suppose to do prior to cranking." It's not prior to, but during cranking. Anything you do to the footfeed prior to cranking has no effect whatsoever - there's no choke to set, eh? ;) The idea of pushing down the footfeed during cranking is to squirt more fuel during cranking.

"I can start it without setting the accelerator then hit the accelerator and there is no change in the timing." Yup - no effect (see above).

If your 93 is like my daughter's 89 & my 82, there are two things that change on the IP when the coolant temp is low: 1) the idle speed is increased by a solenoid clearly visible on the linkage, & 2) the internal IP pressure is changed (increased?), which has the effect of advancing the injection timing. 1) If yours is built like this, then the throttle linkage ought to be pretty easy to figure out, but of course this would have limited effect on cold-start smoke. 2) Seems to me that while the engine's idling, a guy oughta be able to disconnect the cold advance wire & hear a difference in how the engine idles - maybe rattle a little more? Hopefully an expert will chime in on this possibility.

Keep us posted.

Blessings!

More Power
12-28-2006, 16:48
Another problem I forgot to ask about is the trannyfeeling as if the converter is locking and unlocking when going down the road.

Since you replaced the injection pump, the Throttle Position Switch (TPS) may be out of adjustment. You should be able to find numerous forum topics here using the search function that explain how to correctly set it using a multi-meter. :)

Jim