Hi everyone, I'm brand new to this board and just bought a cream puff 1988 GTA (Notchback) with 33,xxx documented original miles. The car looks, drives, and smells like new. I've been mainly a Corvette man for the past 10 years (I have 3), but this Pontiac came along and I had to have it. I love this car!!! I wanted one sooooo bad my senior year of HS (also 1988).

Compared to prices for Corvette cars, parts and accessories, third-gen stuff is cheap and plentiful. I look forward to a lot of projects for this car.

Anyway, the only issues it has are smoke on startup (common from what I hear) and this loud popping noise that sounds like it is coming from the passenger side rear suspension area. I mean it is REALLY loud, like someone hitting the bottom of the car with a hammer. I have checked the rear control arms/sway bar, trans mount, shocks (new), and other things looking for something that is broke or loose.....nothing.

It only makes the sound on uneven parking lot ramps or off camber turns, seems like only when the chassis is being twisted. Any ideas???? I would really appreciate any information.

thanx......

 

It's the sound of the car asking for subframe connectors.

 

Have you checked to see if the spare tire is mounted in the back properly? that's the area they put those things. Just my thought.

 

Try your ball joints first. They are probably shot. Then check and make sure the steering box is securly mounted to the frame and there are no cracks in the frame, lastley check the idler arm assembly and make sure everythign has new grease.

Good Luck

 

don't know if youd consider the sound of a wheel rubbing the quarter on a bump a poping noise, check for scores on the sidewall, and outer tread, if your running aftermarket tires or rims, they may be sticking out to far (like mine )

 

does it happen when u accelerate usually? i had the same problem turned out to be rear trans mount. Dont know if this helps!

 

I doubt it could be balljoints or steering box if the noise is from the back, but what about the driveshaft, is it hitting the exhaust pipe? I lost the right rear hanger on the exhaust, and the whole system slid towards the center of the car... one day, i step on the gas, BANG BANG BANG... I get home, and find out the rear u-joint was beating the crap out of the exhaust pipe. Oops.

Might also be something wrong with the passenger door, like a busted hinge pin, causing the door to jump or pop. The doors are integral to the "frame" of the car, and if the hinges are weak, you'll get funny noises. Do the doors close easily or do ya have to slam one?

I'd say try pushing the car back and forth "sideways"... know what I mean? Push your rear tire like you're trying to push it under the car. Get the whole rear of the car swaying side-to-side... see if the clunk comes back.

 

Hey TomP, I have to slam one of my doors real hard. I think the hinge is screwed up. Is this something I really need to fix?

 

If it happens when you get on the gas, or when the trans is shifting you have a broke rear trans mount, common on these cars, although not really for 33,ooo miles. My mount didn't go out until 130k. There is bushings in the lower control arms, could be poping but shouldn't be that loud. The arm that runs down the length of the drive shaft, may be lose that would make a loud pop. If it is happening like you said in turns it could be the posi messing up if so equiped. Its hard to say, get some one to sit in the pass or back seat, get on the gas, or do what you must to make it pop, while they have there hand on the floor hump just behind the console. This is where the trans tail will hit the floor pan if the mount is broken.

Is it the V6 car? I mean my car with the 305 now has 174,000 miles on the orginal engine and car (trans rebuilt) I don't have any smoke and my car uses hardly no oil, maybe a half qt between changes.

Also look at the pan hard bar, it could be lose/ or bent.

Could also be the sway bar, if you have one in the rear part of the ws6 package.

Could also have a bent flange at the rear wheel, and druing the suspension drop on the turns on a hill, the wobble in the wheel could be hitting the inner or outer wheel well.

But if I had to take a guess, I would say start at the trans mount.

 

Thanx for the info guys.... I will check the trans mount tomorrow.

As far as the oil burning on startup, there is a Pontiac TSB on the issue relating to faulty exhaust valve umbrella seals. Replace the seals and the smoke goes away. No big deal.....I ordered the following today:

TPIS Big Tubes and ported/matched plenum
Scoggins-Dickey Vortec/TPI base
52 mm Holley billet TB
GMPP Fast Burn Heads with LT-4 1.6 roller rockers
Jegster Subframe connectors (welded in)
Hooker shorty headers and 3-inch Y-Pipe (ceramic)
Dynomax 3-inch cat
3-inch Flowmaster cat-back (American Thunder)

I will use the stock short-block for now, but, as soon as the snow flies, a ZZ-4 is going in its place. I will bolt all of the above on next weekend. What is the opinion on comp ratio with the 62cc chambers of the Fast Burn heads???

Also, I am still undecided on a cam....any recommendations???

thanx,