Ready to pull my hair out - smoking

[firecop]

Hello everyone! I have a problem with my Tahoe, it was losing power and would blow black smoke on occasion. I had only 5" of vacuum at the waste gate so I replaced both the vacuum pump and the solenoid. I know have 13-15 inches of vacuum. Took the truck for a ride and it ran fine until the trip home and once again I lost power and started blowing a ton of black smoke.:confused:

Any thoughts will be greatly appreciated.

Thanks

[rustyk]

Hello everyone! I have a problem with my Tahoe, it was losing power and would blow black smoke on occasion. I had only 5" of vacuum at the waste gate so I replaced both the vacuum pump and the solenoid. I know have 13-15 inches of vacuum. Took the truck for a ride and it ran fine until the trip home and once again I lost power and started blowing a ton of black smoke.:confused:

Any thoughts will be greatly appreciated.

Thanks

Changer yer air filter. I had similar problems twice on my motorhome, and only after the second incident was I able to figure out the problem: A restricted AF caused enough vacuum in the AF to turbo inlet boot to collapse.

[Mark Rinker]

Also - look for a mouse nest or other foreign material in the fenderwell area that could be restricting the intake.

I had an aftermarket cone style gauze filter that would collapse on itself, then spring back to normal shape when you were looking for the problem...:o

[firecop]

Thanks, I'll look for obstructions and change the air filter today. I just ordered a Wix and it will be here later in the day. Funny thing is, it runs great while cold, when it warms up this will happen.

[DennisG01]

How about the vac lines, themselves? Maybe there's a small crack somewhere.

[firecop]

I changed the air filter today, still smokes and loses power when warmed up. Spoke with a diesel tech today and said it could be the shut-down solenoid, or the PMD. I have 13-15 inches of vacuum at idle at the waste gate.

He said there is no real way to "test" the PMD, except eliminate any codes and by feeling how hot the PMD is. I do have an SES for low coolant temp due to the thermostats being stuck open but with 95 degree heat here I'm gonna have the codes pulled and check the coolant temp, If it's 180 I'm calling it good for the summer.

Thanks!

[Robyn]

PMD and the shut down will not cause this type of issue.

The wastegate solenoid (LH VC near the back) could be bad and not keeping vacuum to the wastegate actuator. ( these are prone to failure)

Check the fender well snorkel for a creature calling it home as Mark suggested.
I had a friend who bought a Tahoe that smoked horribly. I took a look at it and found a big RAT living in the air box along with its family.

Nasty and not happy about being evicted.
The sucker hissed at me so we stuffed the cat under the hood and let him handle the issue. :D

The original owner parked the truck in the barn when not used and the critter moved in and set up house keeping.

Robyn

[firecop]

PMD and the shut down will not cause this type of issue.

The wastegate solenoid (LH VC near the back) could be bad and not keeping vacuum to the wastegate actuator. ( these are prone to failure)

Check the fender well snorkel for a creature calling it home as Mark suggested.
I had a friend who bought a Tahoe that smoked horribly. I took a look at it and found a big RAT living in the air box along with its family.

Nasty and not happy about being evicted.
The sucker hissed at me so we stuffed the cat under the hood and let him handle the issue. :D

The original owner parked the truck in the barn when not used and the critter moved in and set up house keeping.

Robyn

I replaced the front solenoid (green dot) which I was told and I ordered as the waste gate solenoid. I checked the air box and fender, no critters.

Thanks

[firecop]

Will the lift pump cause this sort of problem? I don't think it has ever been replaced and I don't hear any noise when I turn the key on. Sorry, it's all new to me.

[JohnC]

Have you checked for codes? Black smoke and bad performance after warmup sounds a lot like a wastegate fault. Check to be sure the vacuum pump is connected to the port on the solenoid with the restrictor (forward one, if I recall correctly).

[firecop]

Maybe I'm getting somewhere! Pulled the codes today and got a P1409 EGR Vacuum System Leak. Could that have been related to the ad vacuum pump? Would that cause driveability issues?

Sorry for all the questions!

[Warren96]

Look for cracks in the vacume lines. They get stiff and brittle with age.

[firecop]

Air filter is new, vacuum pump is new, etc. I had a P1409 code and I reset that today. So far nor more smoke, etc. It does seem to stumble a bit down the road, somebody suggested a PMD but that is remote mounted with the FSD atm. Fingers crossed.

[firecop]

Thank you! To everyone, I replaced the vacuum pump, the WG solenoid, gave the wg actuator a shot of WD40, reset the ses twice, (second one showed no codes) checked for leaks. After a couple weeks and no codes, the Tahoe runs great! Thanks again! Are the ECM's that slow in a '98?