Well, I finished up my 98 the other day. I did get the blocked EGR gaskets. The local shop carries them only. He takes the metal block out if you want the egr, only have to stock one set then. Other things I did was: new pmd, new ops, new lift pump, new intake gaskets (both upper and lower with the EGR opened), hot tanked the intakes to get good and clean, new fuel filter, and new air filter. The pump was stamped with 7/2001 under the serial number. It was not taged at all. I was hoping that my problem is in this somewhere's. Unfortunitly, I am still experiencing my light blue smoking problem at lower RPM. For those that have not saw my other posts, it is "missing" or "hooking" at lower RPM on light acceleration. I can accelerate harder and it will clear up, no smoke and no hooking. Going down the highway it runs good, maybe low on power. The turbo wg is working with about 21 in of vac. The pickup has 111,000 miles on it now. I have been thinking maybe the EGR is not closing at low RPM. It could be the IP? Any other ideas? I would also like to thank all the good input. Much better than GMDIESEL@ yahoo or what ever it was. Not wanting to start anything. That is something I like about this site, not many wars and lets keep it that way.

I was having some trouble figuring out my boost loss recently but when I had the head off and the vac pump I saw the big line off the pump had chaffed itself against a mounting blot.I replaced it and the boot on the actuator and it went from 21" vac to 25". 3.5 psi boost at 2000 rpm before to 5 psi at 2000 rpm now. For testing purposes I plumb the vac line directly from the pump to the turbo and exclude the solenoid, this doesn't set a code if you have a fooler on the MAP. Edited by: quantum mechanic

thats nice. I understood that 21 in of vac is about right. Is this light blue smoke turbo related? 21" was withen spec.?

You should have a metal shim under the egr or at least a screw in the vac line.


I'm not sure about the blue smoke, but I would look for a leak on the egr solenoid's vac lines and the rest. Especially between the egr and baro sensor on the fire wall.

Is an EGR problem similair to what I am experiencing. The metal shim?? Should I try to block off the erg? I have been thinking of the EGR sticking open, therefore running better at higher RPM. But the thing idles perfect. I'm at a lost on this thing.

If it's not a lack of boost I would check the compression.

The boost is working good as far as I can tell without a gauge. On cold morning, 25 F, it has been putting out a good stream of white smoke, but clears up to nothing once the plugs have done their cycling. Burn no oil at all, so I don't feel that compression is low. I would be seeing alot of blow by and oil consumption. I have been playing with the idea of a bad injector? I hate to have anyone work on the truck, but it might come to that soon.

If you have a EGR with a weak spring it can lift off it's seat especially when at higher boost, I did that to mine with positive result.