Sorry for all the threads, I just don't know how to get any better advice, anyway if my wastegate isn't working properly would that make my turbo very loud when its spools, don't get me wrong I LOVE to hear it spool (or what I think is spool, loud turbo whistle) but I would much rather the truck perform like its supposed to than hear the turbo so basically what I need to know is if my wastegate isn't functioning properly would I get the loud turbo whistle?

 

When the truck is not running can you move the wastegate freely??and are you throwing any codes??

 

If the vac pump isnt working, assuming you still have one, you will get lots of black smoke. Gm8 turbo noise is not very loud or at least mine wasnt. The wastegate opening should kill the whistle as it is losing boost with it open. Not opening will give you some whistle and if it stays shut it should overboost and give you a code. This would be for a factory setup. GM8 turbo may not overboost as it is a poor flowing turbo.

 

Factory setup is near impossible to get whistle, what kind of intake do you have, if you still have the factory box and a plain paper filter, I'd guess that your boost sensor might be bad, and telling the computer your getting less boost than ya actually are, therefore the computer says make more boost. Usually over boosting is electrical like sensors, solenoids etc.

I think if ya got a bad boost sensor, it could throw those p0236 and p0238 codes you were talking about on the other thread.

 

I don't think my turbo is factory my turbo says Borg Warner (spelling?) On it and I'm not sure if that's factory or not, and my intake is just the factory intake, well its the factory intake box I haven't had it open to see the filter yet, but idk whether to buy a vacuum pump or boost sensor? Any help?

 

That sounds like the OEM turbo - they were made by Borg Warner. When the engine is running very carefully try to pull down on the rod that goes into the wastegate actuator. If it holds steady and you can not move it then you know you have vacum to the wastegate. If you can move it easily , while engine is at idle, then you may have a vacum problem.

~GOD BLESS~

john

 

Process of elimination. Probably start by seeing if ya got vacuum to the wastegate. If not then follow the lines to all the components and find where its losing the vacuum. But If you're getting good whistle from the turbo then your vac systems is getting vacuum to the wastegate. No vacuum = no boost = no whistle. Especially on the factory air box and paper element filter if you're getting a good amount of whistle then you're making more boost than factory settings. I think the whistle is caused by the volume of air that is moving through the turbo, that is why the "hot" air intakes will give you whistle, but not any power. With the hot air your pulling a greater volume of air, but of less quality. Anyhow, back on subject, The higher volume of air might be that you have a hole in the air filter, highly doubtful, but the more air in is more whistle. Or the boost sensor on the intake manifold is going bad, that should be the last thing on the elimination list.

Pulling down on the wastegate rod when engine is at idle is one way to check for vacuum, but I personally take the vac line off the wastegate because then you and use your finger to "plug" the wastegate and see if its sealed and by putting your finger on the end of the vac line you can feel the vacuum. But start with the easy stuff (vac system) and eliminate the suspects and keep moving along until you find the culprit. From there you'll know whether you need a to replace vac components or sensors/solenoid, over boosting is more likely sensors/solenoids, or maybe you're wastegate is stuck. Either way just eliminate the things you know aren't the problem and narrow down the problem to hopefully a single thing and go from there.

My personal guess is one of two things, the boost sensor is bad and reading low so you're making more boost, or the boost solenoid is stuck open so your getting 100% of the vacuum from the pump and the computer isn't controlling the amount of boost, boost sensor triggers the codes ya got and over boosting = excessive whistle.

Good Luck

 

Well I just checked the vacuum line going to the wastegate with the truck idling and its got vacuum and I also pulled down on the wastegate rod with the truck idling and couldn't move it so apparently I'm getting good vacuum? I'm guessing a sensor or something?

 

Yes, I would say boost sensor then. Its located on the intake manifold under the "turbo power" cover. Kinda guessed you were getting vacuum if your turbo was whistling. The only other thing I can think of is the boost solenoid is staying open and allowing all the vacuum to the wastegate.

I suppose that you're getting good vacuum, at idle it puts a good suck on the wastegate.

I'd say try boost sensor now and if the codes pop up again, boost solenoid would be the next best bet. I could only find the boost sensor at Autozone for 80 bucks, but thats in Butte, MT so maybe elsewhere will still have them.

Good Luck

 

On my 1994 the clamp for the down pipe came loose and I had screaming stock turbo crawl under the truck and grab ahold of the down pipe and see if it moves freely if so take the passenger side inner fender out and you can access it easily enough