Funny Engine Noise

[DieselNubie]

I'm getting a funny noise from my 94 6.5L Chevy Crew Cab. It is coming from the passenger side. It sounds like a whirring with a click. I thought it might be the compressor but I don't think it is it. I'm not getting any turbo boost. I hope it's not the Turbo. Since the diesel engine is noisy to start with I'm not too sure. I've been putting some upgrades on the truck. I install a 3" Cat-Back Exhaust from stock. I've installed a BD power chip. It was working great until the other day. Now I have no boost and I have the whirring noise with the click. Any ideas would be great. :confused:

[gmctd]

Do a "search" (above, opposite the truck) for 'DTC-78', and 'wastegate' for the most info in the quickest time.

Symptoms sound like no vacuum to wastegate.

[patrick m.]

noise, and no boost, leads me to think you should check the vac pump.

[DieselNubie]

I did some checking last night with a vacuum gauge. It looks like I'm getting about 5 to 7 (LB??) of vacuum. I'm not sure if that is enough or not. I also bought a wastegate solineoid. That didn't help.

The sound sounds like a baseball card clipped to a bike (Remember when we were Kids). It goes up and down with the throttle.

I'm going to have to take it to the dealership in the next couple of days to have them fix the noise and boost problem. I'm going on a camping trip next week.

Thanks for the info.

[Tony J.]

WOW- my truck (first diesel, just got it a month ago) makes the same noise. My fuel economy hasn't been what I had hoped for, and the power hasn't been either. Are these also symptoms? I hear it mostly driving down the street in my neighborhood with my window(s) down- the noise seems to bounce off houses and I hear it very clearly...

[ 03-30-2004, 01:38 PM: Message edited by: Tony J. ]

[gmctd]

I keep forgetting my accessory layout isn't '95 original.

The vacuum pump is down low on that side, and an idler pulley assembly is in there somewhere.
You might check those out for 'bearing chatter' noises.

At idle, vacuum at the wastegate should be around 15" - at the pump should be 25".

Noise and low vacuum would most likely be the pump, as Patrick suggests.

Low vacuum results in low power symptoms.

[patrick m.]

DieselNubie, 5-7inches is not enough vac, you should get 20+- inches at idle, at the wastegate actuator.
keep checking, hook you guage directly to the vac pump, using none of the vac tubing from the truck. Those little plastic vac tubes like to crack, and sometimes, the cracks are difficult to see.
if you get good vac at the pump, carefully trace the tubes to locate cracks.

[gmctd]

Also, CLOSELY inspect both the harmonic balancer and the accessory drive pulley for deteriorated rubber - cracks, oozing, etc.

Can be very noisy, but will not effect vacuum - will, however, result in broken crankshaft.

Meaning - if either, or both, is deteriorated, replace immediately.

[DieselNubie]

Thanks for all the info. I took it to the dealership and got charged a arm, a leg and my first born but it is now fixed. :eek: It was the vacuum pump. Everything else looked okay. I need to learn to do more of the work on the truck. That would make it more bearable.

Now the truck has alot ore power since I'm getting boost again. I'm getting a Heath Turbo Master so I hope to see a little more power. I hope my BD power chip works well with the Turbo Master. smile.gif

Thank you for all your help!!!! smile.gif