I just married into a '95 Bonne, and my wife, as a single gal, couldn't keep up with it like she should have in times past so I'm trying to get caught up on a few things.
Just finished putting a new harmonic balancer on, which the forum was very heplful for because for some reason, even though it'* a '95, it took what napa calls a '94 balancer? part no. 600-5322. with the '95 balancer-napa part no. 600-5277 on, it ran rough, missed, no power. The mechanic who put it on wanted to do a bunch of electrical stuff after that, but I recognized the symptoms from a HB post I read where the guy had the wrong part. So I switched off the part for he '94 balancer and sure enough she'* not missing and she'* got power.
But now there is a steady shake at idle. It'* pretty pronounced. It'* not missing, but almost like something is out of balance. I don't think it was doing this before. Is it possible the balancer is not "balanced"? Like defective? Or should I be looking for something else. The "check engine" light has been coming occasionally, so I need to get the codes on that, but was wondering if the balancer needs to be tuned at all. There was a extra part in the box with it, like a little piece of metal. It didn't look broken off, but now I'm wondering if that was some sort of weight to tune the balancer like you would a wheel out of balance. Any thoughts?

You've got a SC motor...

The 94 balancer isn't the right one IIRC. I'm off to find the post.

The shake is most likely the wrong balancer. Here'* the thread. My suggestion is to check the Dorman part number and GMPartsdirect.com. Cross reference those two back to the correct part. Then go from there to the Napa part number.

Something is really messed up with the part numbers for the balancers around these years.

http://www.bonnevilleclub.com/forum/...monic&start=20

Yeah, I know it technically is the wrong part by the book, here'* the deal. The right part according to the alldata is 88960265, which napa has as the '94 part 600-5322. But when you search GM for the right balancer for a '95 Bonne, it comes up as 88960264 which napa as the '95 part 600-5277. I called the dealer and they said the balancer napa has listed as a '94 would fit a '92-95 "H-body GM car". So who knows who to believe. The point is we put the '95 part on and it ran HORRIBLE - missing on two cylinders, no power, horrible smelling exhaust. I don't care what the numbers say, it sure seems that was the WRONG part. So we put the other balancer on, which napa has as the '94, but alldata says is right for the '95 and it was like a different car- running smooth, not missing, full power. But now there is this shutter. I'm not sure if it'* related to the balancer at all, but if it'* possible for the balancer to be tuned or "balanced" before you put it on, then maybe, because I didn't do that, I just took it out of the box and put it on. So my question really is do you ever have to balance a balancer?

Hold on a second..Alldata isn't GM.

I have a theory misinformation was released at some point and everyone seems to have it, except GM.

I can't check GMpartsdirect.com from here. Mmmm WillWren changed his 95... let me see if I can find that post...he usually puts the part numbers in there.

It is very confusing, I tried to do my homework as much as possible but, everbodies info is conflicting. All I know is, the "94 part runs DRAMATICALLY better that the '95 part. The dealer said the OEM part number 88960265 was listed as running on a 92-95, that'* the one I have on there now.

Ok...a quick search on Dorman and Hollander shows

Dorman # 594-122
hollander exchange#'* 309-510/309-517

I had found the Dorman number to be 100% correct... we need to get these confirmed and interchanged with the GM numbers.

Pete'* car ran good...but with that same shake you are explaining when we had the wrong balancer.

OK, I plugged the dorman # into napa and it came back 6005277, which is the "95 balancer which is the first one we put on when it ran horrible. So I know what your saying but the '94 part runs so much better how could the '95 be the right one?
You guys are great by the way! I appreciate the feedback.

Hang in..I'll get out of here sooner or later and get to GMPD.

I should expound all details here too, so you know exactly what I've done. After the mechanic put the new "95 balancer on, the clatter of the bad balancer was gone of course, but it was missing on the 3 and 6 cylinders. He changed the coil pack for those two, but that didn't help. So he said I needed a new ignition control module...makes sense. So we had a couple modules laying around, and we swapped out two different ignition control modules with no effect, so it wasn't that. So I put in all new plugs and wires, it needed that done anyway, and still running bad. So then we began to suspect we put in the wrong balancer, and so I decided to swap that out for the one napa has as the '94 after some research suggested that that one might work, and there was a huge improvement, the car was virtually as good as new with the exception of that shake.
Another thing is the car was manufactured in June of '94. Is that an early date for that model year and could that effect which part it takes?