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raymire59
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Hi- Just made a deal on a 1990 TGP. Couple of issues, could be major. First, when shifting from park to reverse or reverse to drive, there is a noticeable "clunk". Already changed the dogbones(which were worn), but it didn't help. My guess is transmission. Also, the ABS light flashes while driving along with the "check gauges" light. The brakes seem to work pretty well, but I haven't driven it much. From what I understand, these can be very costly issues. Any comments-insight? Thanks

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Forgot to mention in first post, going by the boost gauge , it might read 2 or 3 lbs. when you first accelerate, but quickly drops to 0 and "flattens out". Checked inside turbo & it spins freely, maybe just a little play. New to turbo cars, what to check first? What are the best manuals for these cars? Thanks again

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Best manuals would be the factory service manuals:

 

eBay link

 

WAY more info, details and photos than any Chilton's or Haynes is going to give you. As for your issues...

 

1. I wouldn't jump to the transmission just yet. Check the engine and trans mounts first, and it wouldn't hurt to check the engine cradle bolts/bushings. The trans usually doesn't clunk when it's ready to go. It usually starts slipping, or does nothing at all.

 

2. Yes, the ABS/mastercylinder going out in any early ABS equipped car is very common, and yes, parts will be hard to find, and expensive. If the brakes are working OK right now, it may just be the accumulator making insufficient pressure for ABS purposes. Can you hear the pump motor come on (buzzing sound behind the dash)? If so, how often does it kick on, and how many seconds does it last each time?

 

3. The stock boost gauge in these cars (and most any GM) is worthless, and completely inaccurate. I'd get an actual gauge first, and see what reading that shows you before we know for sure that there's something wrong.

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all the stock boost gauges I have seen/ had all work great for some reason. I had an autometer boost gauge that sucked though. I can't say the same for most of the other functions on the cluster. every speedo, check gauges light and tach I have ever seen have functioned improperly. flashing abs light always goes away when I replace the accumulator.

 

if it hovers around 0 it might be the rubber fittings are cracked and leaking on the turbo vac lines. this is very common. or lines are hooked up wrong. pics would be good.

 

also many people go with a fresh vacuum harness upon purchasing a tgp just to rule out vacuum leaks. the dealership has these for 30-40 bucks.

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Chances are that that clunk is subframe bushings, get that checked soon or you may drop out the engine in the back like what happened to my old 91 Prix. It's not very pleasant, luckilly it happened when the light turned green and I went to go.

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Thanks for the responses guys. I'll check all the mounts & see whats going on there. I hope it's something simple like that, but the car has less than 70K & spent it's life in the south. I know when I replaced the dogbones, they seemed a bit sloppy.

 

As for the brakes, what is the best source for parts? If I needed an accumulator, what are my options? I have only driven about 80 highway miles after purchase & didn't notice any "buzzing" sounds. If anything, they seemed a tad "mushy", but stopping wasn't a problem.

 

With the boost issue, maybe I need to get an aftermarket gauge & compare readings. But I do know that when accelerating(65-80) it goes to about 3lbs, then quickly falls to zero. I've never driven one of these cars before for comparison, but it feels "mushy" when it falls back to zero. I also don't notice much of a "spooling" sound. If this is the way it performs in stock condition, it really isn't impressive at all. I understand they weren't "powerhouses" in stock form, but my 92 Z34(stock) would have no problem running away from it. Does this seem right? I'll get a manual & start checking vacuum lines.

 

One more thing. It needs an AC compressor. The best deal I've found so far on a GM unit is $300 from Rockauto. Has anyone had good luck with any of the "lesser" brands? As always, cost is a factor, but I want to make quality repairs as this is a low mileage car and still in nice original condition.

 

Thanks again.

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Hopefully you just need a accumulator. Way cheaper and easier to find then a new master cylinder will be. Heres a link to a thread about them:

http://www.w-body.com/forum/index.php?topic=77962.0

The master cylinder may need to be replaced at some point anyway if its original. They all end up going.

 

Your boost gauge is probably just bad. Mine almost always reads vacuum, but i have a Auto Meter one that works perfect.

 

Get a K&N filter on there that goes directly on the turbo, then you will hear it spool!

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-For the boost issue, check the air filter to make sure it isn't plugged. If the filter is fine, temporarily drive the car with the hose at the turbo inlet removed. The stock hose commonly collapses under boost and will choke down the engine. If the car boosts fine w/ the hose disconnected, you've found your issue. The majority of us run K&N filters directly on the turbo or various other intakes. The stock airbox doesn't flow very well...

 

As others said, check the lower mounts(trans, engine, and cradle). Chances are you'll find a bad mount...this could also be causing the hard downshift that the previous owner mentioned. :wink:

 

 

There's a vacuum line diagram located here by the way: http://www.tgpforums.com/index.php/topic,4463.0.html

 

Last but not least, I've had good luck with "factory air" compressors from the Advance Auto chains(others probably carry them too). I've installed a few of these in various cars and some are now 4-5 years old and still working great.

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Thanks again for all the responses. As far as motor mounts, what is considered "acceptable" as far as brand/cost? I have a friend at a GM parts dept & gives me his discount. They are still way more costly than the chain stores. Are any of the cheaper ones of good quality? I also came across a choice of hydraulic or solid. I would imagine the hydraulic would be the better choice far a DD. Autozone also listed the same part# for both sides-? Although cost is always a concern, this is a lower-mileage car that hasn't been tampered with. I want to do quality repairs with regards to cost.

 

As for the brakes, is there a specific way to check the accumulator? As previously mentioned, ABS flashes while driving, usually accompanied by CHECK GAUGES. While feeling a tad "mushy", they do stop without a problem. Someone mentioned listening for a sound as a clue. Just exactly what am I listening for and when?

 

With regards to manuals, someone kindly posted an Ebay link. While checking that out, I searched around & found service manuals, supplements & updates including different years (1989, 1990) for some. Do I need all of these, a combination of, or just one? One with a good section on troubleshooting would be VERY helpful.

 

About photos, I haven't taken any, but here's the link to the seller's photobucket pics. http://s298.photobucket.com/albums/mm256/redtj1997/For%20sale/

 

Once again, I do appreciate all the responses & info. I'm not familiar with these cars, but have a couple weeks off from work starting next week, and want to take care of all issues at one time. This week is dedicated to research & acquiring parts needed. Bob

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you can hear the pump running for a moment when you press on the brakes.

 

anti-lock will usually be flashing if the pump runs every or every other pedal press. it will still brake like normal.

 

If you got a brand new accumulator and have it bled properly, it should run every 3rd or 4th pedal press.

 

 

I like the hydraulic motor mounts. just remember that if you get oil on it it may get soft and blow out again within a year or so. when changing the oil filter, stuff some rags on the subframe to keep the oil from pooling up there by the engine mount.

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I remember that car being for sale. Didnt someone on here go look at it?

 

Turbo V-sick aka flybinite was thinking about buying it and went to check it out IIRC.

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