lack of power..no boost

[mikey007]

Yesterday, i was driving my 1998 6.5 silverado. It would come and go most of the time, but it had hardly any power. you'd boot it to pass, just black smoke and i could hardly get it to 110km/h. Then it would be ok again. And then the last time i tried, i don't think i heard the turbo kick in. Any ideas?

Mike

[Robyn]

Check the vacuum at the waste gate pod on the turbo.
Should be 26" and steady at idle.

If the vacuum is low and steady check the vacuum at the pump if ok move on to the waste gate solenoid over on the drivers valve cover.
The plastic lines from the pump to the solenoid and then to the waste gate pod can go bad too.

When working properly you should have 26" of vacuum at the wastegate and the little arm on the turbo housing should be pulled shut.

If the vacuum reading is wobbling the pump is toast.

If the electric solenoid is bad it will usually toss a code.

If you find issues with the plastic lines you can patch it up with rubber vacuum hose to get it going until you get new lines.

The waste gate actuator can also lose its diaphram.

Generally its the pump, tubing/hoses or the solenoid.

let us know

Good luck

Robyn

[mikey007]

Ok, how do i check the vac or boost? Is there a way to see if anything trips a code? cause on my car...you turn the ignition 3 times on off..etc. can you do that on a chevy?

Mike

[Robyn]

Use a vacuum gauge on the system.
Get one at the local parts store.

The boost should take care of its self

[mikey007]

ok. Isn't the pump like a $2000 fix, if thats the case?

Mike

[MTTwister]

That's more like the Injection Pump. This is the vacuum pod lower down. Not sure of the price - but you might have one too many 0's on that number...

[Robyn]

Vacuum pump is down on lower pass side front and cost about $60 for a reman.

[mikey007]

woah, haha. sorry, i was thinking of the fuel pump i believe.

[rtphillips370]

I am having a similar problem that is intermittent. At high speed cruise the turbo will drop down to 0 PSI and I will not hear any whistle, then when I have slowed down and tried to accelerate the turbo does not come back up as it normally does. I have had on two random occasions, where i started from stop sign and the turbo never came up at all, just showed 0 PSI and the truck was lacking acceleration power. I get this with and without the TD-MAX Turbo Boost Controller installed. And regardless of what I set the controller screw at, there is very little if at all improvement turbo boost pressures.

Both occasions have occurred in warm (80+F) weather and after running 60+mph. I checked the vacuum at by disconnecting vacuum line from the waste gate actuator and at idle (started from cold) I showed a reading of 21-22inches of vacuum, with the needle bouncing wildly between 21 and 22.

This morning I drove it home from work in 65 deg F temp at the same speeds and never had the turbo drop. as described above.. Lastly, none of the idiot lights came on, so far as i know there are no codes.

Any ideas out there what I should look at to remedy the problem? Im unsure if I should look replace the solenoid or the vacuum pump, the vac lines appear to be in good condition...

[bbtlr3]

rtphillips,

Check the wastegate linkage with the engine off it should move smoothly with the only resistance coming from the vacuumm canister. You might have a wastegate that is sticking. I had it happen to me, similar results, intermitttent no boost condition. If it is just sticking and not completely worn out (mine was just sticking), then remove the turbo, or at least the exhaust side, and use some form of penetrating oil spraying where the wastegate shaft goes through the housing and work the linkage back and forth until you get full range of motion. You may have other issues as I don't know your vehicle, but this is how I was able to fix mine when a shop told my wife while I was away that the turbo was shot and needed to be replaced. It has worked fine ever since. Keep us posted on how it goes.

[rtphillips370]

Thanks, Ill look into that this weekend and let ya know...

[rtphillips370]

Update:

I did check the linkage / servo, no apparent hang ups. Since last post, the truck did throw a DTC of P0236, the turbo boost sensor, I replaced the sensor as well as the waste gate solenoid, and the vacuum lines from the pump, to solenoid, to waste gate. No more issues with the loss of the turbo, it runs without loss now.

I have since gone on a 600 mile road trip from Jackson MI to Mackinaw City, MI and back with the trailer and it pulled great however, I still have the issue with the TD-MAX Turbo Boost Controller, no matter where i have set the screw, there is no significant change in boost. There is a 2-3 pound loss of boost if i remove it. I have checked the gauges and tried a different set to make sure the gauges are not a fault, i have also checked the feed line to the gauge for damage and none were found.

On the trip, I would get 4-6 PSI boost while running 70-75MPH with the trailer and 2-4 PSI when running 60-65MPH. It did throw a code on the homeward bound leg for the P0236 when I hit a hill (IH-75 near Waters, MI) at the 75MPH and it bogged down a bit and down shifted.

I haven't had much luck with the TD-MAX Turbo Boost Controller i'm starting to wonder if the TD-MAX Turbo Boost Controller chip is bad and/or a bad vacuum pump as Robyn states it should have 26" steady vacuum and i'm getting a needle bouncing between 21"-22".

I look forward to some ideas if anyone has any...