Hi,

I have a 94 SSEI. It'* making a horible metalic clunking noise, which goes away as the engine is rev'd up. I thought it was the Supercharger coupler, but after upgrading that, it is worse now than ever. I read a few posts and am guessing it might be the harmonic balancer. Does anyone have pics of a repair or of what the balancer looks like? Cost to replace?

Also, this is kind of a dumb one, while doing the SC job, i replaced the plugs and wires, I think I put one the wires on the wrong plugs, anyone have a diagram of the proper firing order?

Thanks for any help out there!

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I'd check the harmonic for sure. You should be able to see the wear/damage.

As you're facing the engine, cylinders 1, 3, and 5 are in the front, left to right.
2, 4, and 6 are in the rear, left to right.

Firing order (not that it matters) is 612345

The noise could be the balancer. This happened to me a couple of weeks ago. If you use a small mirror, you can look at the side of the balancer and see the cracks/gaps in the rubber. Mine separated where the rubber meets the inside edge of the pulley, and I could see almost completely through the rubber all the way around the perimeter.
Mine made a terrible rattling noise while starting and idling but little or noise otherwise; it didn't make a clunking noise though.

I got the balancer from the dealer because no local parts stores had it on the shelf and I wanted it replaced right away. Cost at the dealer was $155...the GM part was made in India! I had a local shop install it for $70 and it took them less than 1 hour.

To make sure it'* actually the balancer before you replace it, remove both belts and run the engine for just a few seconds. Make sure both belts are out of the way of the moving engine parts before you crank the engine though. It should only take a second or two to see whether or not the noise is present while the belts are off.

The 3 coils should have white numbers (cylinder) printed on top of them. As you face the front of the car and look under the hood, the front cylinders are (from left to right) #1 #3 #5 and the rear cylinders are #2 #4 #6. Just connect the wire from each coil # to the correct cylinder # on the engine.

Good luck.

Thanks for the tips!

Ok,

I'll be attempting this after work tonight. Ok so here is the plan.. I remove the belts, and listen for noise. If I don't hear noise, I can start to check belt related items ie: water pump, idlers... the Harmonic balancer... If I hear noise with belts off it may be engine related... Also to make sure, the harmonic balancer is driven off of the 2 belts? Also what tools are required to remove it? I'll go buy'em after work.

Any help with the diagnosis/removal/installation is very appreciated.

You got it backwards...the harmonic balancer is what drives the accessories and the supercharger.

When my balancer broke, I was able to see the broken rubber using a small mirror...and there were small chips of rubber under the car, on the driveway. I was also able to rotate the balancer pulley by hand (with both belts removed) but mine was still hard to move - you shouldn't be able to rotate it by hand at all.

To keep it simple, try to listen to each moving part with the engine running, then if necessary remove 1 belt and listen again to see if it'* something driven by that belt. If that'* not it, then replace that belt and remove the other and listen. If that'* not it, then remove both belts and listen - with both belts off, it'd have to be the balancer or something inside the engine (not good). Important: Only run the engine for a few seconds if 1 or both belts are removed.

To remove the balancer, you'll need a gear puller and some bolts. I don't know what size the bolts are because I chose not to replace mine myself. Search the other posts - other people have said what size bolts they used, but also note that some people had problems trying to remove their old one.
Normally I would have replaced it myself, but mine broke on a weekday and I needed to get the car back on the road asap.

Do not run for extended periods of time with the belt removed from the water pump. And start with a cold engine if possible.

With the engine off, see if you can move the belts and accessories back and forth at all. Is there any slack?