1991 Zr1

[Les G.]

I am looking at an original owner ZR1 1991 today. Any tips or things that I should concentrate on.

[Tom H.]

Re: 1991 Zr1

Fuel system ( injectors, fuel pump ), CD player and stereo system. Look for deterioration of the windshield lamination. Electronic heater controls are often not working. Lumbar seat bladders often fail. ( Pretty easy fix ) Check to see if it was a 2 top car. Look for C2L code on the RPO sticker. Any service history you can find. Pretty good cars that don't give us a ton of problems. Engine is bullet proof. Go through the whole car and make sure every button works. Some of the little nick nak items on these cars are impossible or very expensive to replace. Look for any warning lights on the dash. Like INFL REST, or Service LTPWS etc. Let me know what you see or send me some photos. I'll be glad to pitch in my .02. I've sold a ton of 'em. If he has accumulated any spare parts, try to get them too. Plug wires, water pumps, starters, etc. If it has any mods, be sure to get stock parts back too. Many guys changed wheels, PROMS, air boxes, exhaust etc.

If he is the original owner, he should have the owners box and good documentation. Ask where it came from too. If it came from BUDS Chevrolet in St. Marys, I may still have the original invoice for it !! Never know.

How many miles are on the car ?

[Clem Z.]

Re: 1991 Zr1

Fuel system ( injectors, fuel pump ), CD player and stereo system. Any service history you can find. Pretty good cars that don't give us a ton of problems. Engine is bullet proof. Go through the whole car and make sure every button works. Some of the little nick nak items on these cars are impossible or very expensive to replace. Look for any warning lights on the dash. Like INFL REST, or Service LTPWS etc. Let me know what you see or send me some photos. I'll be glad to pitch in my .02. I've sold a ton of 'em.

If he is the original owner, he should have the owners box and good documentation. Ask where it came from too. If it came from BUDS Chevrolet in St. Marys, I may still have the original invoice for it !! Never know.

How many miles are on the car ?

would the VIN record be on the GM tech wedsite or is it too old ?

[Tom H.]

Re: 1991 Zr1

would the VIN record be on the GM tech wedsite or is it too old ?

Too old. Might possibly show any stray recalls, but I doubt it.

[Dick W.]

Re: 1991 Zr1

If the engine makes 2,000 miles they usually will run forever.

[Ed H.]

Re: 1991 Zr1

If you are going to drive it, and not participate in NCRS judging, all of the above advise is very good. I just finished helping a friend prep his 1,600 mile 1990 ZR-1 for NCRS judging. The main problem was the fuel system, as the car had not been started in over 18 years. He had to replace the fuel tank, flush the fuel lines, replace the filter and injectors. The Bose radio worked, but not the tape or CD player. We replaced the motor for the seat bladders as a unit. You can replace the small pump bladder which is a lot cheaper. After all of the repairs the car scored a Chapter 98.9 with later model tires (Goodyear) and replacement battery. Next we are going to remove the radio complete unit and have it repaired. You can buy replacements but the color of the inset on the radio buttons are grey not gold. As far as the windshield is concerned, all ZR-1's from 1990 to 1995 suffer from some form of delamination. Originality is better than condition, its a one or two point deduct. As far as the engine is concerned they are shotgun proof. Good luck. Oh by the way what is the mileage on the car.

[James W.]

Re: 1991 Zr1

If you are going to drive it, and not participate in NCRS judging, all of the above advise is very good. I just finished helping a friend prep his 1,600 mile 1990 ZR-1 for NCRS judging. The main problem was the fuel system, as the car had not been started in over 18 years. He had to replace the fuel tank, flush the fuel lines, replace the filter and injectors. The Bose radio worked, but not the tape or CD player. We replaced the motor for the seat bladders as a unit. You can replace the small pump bladder which is a lot cheaper. After all of the repairs the car scored a Chapter 98.9 with later model tires (Goodyear) and replacement battery. Next we are going to remove the radio complete unit and have it repaired. You can buy replacements but the color of the inset on the radio buttons are grey not gold. As far as the windshield is concerned, all ZR-1's from 1990 to 1995 suffer from some form of delamination. Originality is better than condition, its a one or two point deduct. As far as the engine is concerned they are shotgun proof. Good luck. Oh by the way what is the mileage on the car.

When I bought my 13,000 mile 1990 (now 15,000) I had looked at a 1990 in Houston, TX that had 8,900 miles. It's a very involved story, but the Cliff Notes are that the left headlight didn't work (probably bearings), the horn didn't work, the seat inflators did not work, the SIRS light was on, it had a vacuum leak in the engine, the weatherstripping was shot and the CD player did not work. The paint and interior looked like new. The C4 has a lot of electrical switches and contacts and if the car is not stored in a good environment, there can be a lot of electrical gremlins. Look it over very carefully and be educated on the car. Visit ZR1netregistry and they have a (free) page you can access that has known common issues and their fixes. Most of them are fairly simple to correct. I replaced the injectors in my 90 without too much fanfare.

Good luck - you're going to love driving it

Jim

[Joe R.]

Re: 1991 Zr1

The 91 ZR-1's are great Corvettes. I wish I had my 91 back again! Do yourself a favor and put in 4.09 rear gears. What an improvement in performance and still great gas mileage with the 6 speed. They were originally scheduled for lower gears than the 3.45's but the feds had other ideas.

As mentioned above, just don't let them sit as the fuel system will bite you in the rear. The pumps and sending unit in the tank lists for over one thousand.

Purchase the book "The Heart of The Beast" and enjoy one of the best publications ever written on the development of the ZR-1.

Enjoy your new ride if you decide to purchase.

JR

[Robert S.]

Re: 1991 Zr1

A common C4 problem is that the clutch slave cylinder will leak. So check the fluid level in the resevior. When I bought my 94 with 10k miles, all I did was put in some fresh plugs and repaced the slave cylinder. Just to add to previous comments, the ZR-1 is a great driving car.

[John H.]

Re: 1991 Zr1

Ed,

Just wanted to check in with you and say thanks for looking at 1990 ZR1. I am having fun with it and put about 700 miles on so far. Couple of things you mentioned before when we talked. Fixing the seat bladders??? Can you elaborate on the surgical glove repair? Also Third brake light (hi mount) is inop. Bulbs all looked good so I guess I am going to have to find where it connects and hit it with some contact cleaner.

[Ed H.]

Re: 1991 Zr1

John,
remove the small air pump from under the seats. Remove the four (4) small screws and you will see a very thin rubber bladder.
Next, see if a friend in the medical field can give you the latest latex glove. Cut two small square patches the size of the air pump
bladder or the pump itself. Set the patch over the pump where the offending bladder sat. Use an ice pick to make four holes where
it fits over the pump bladder space. Do not use any glue as it my flake off and jam up the pump. Insert the four small screws, and
you will have a working pump.

[Mark H.]

Re: 1991 Zr1

Interesting thread. Thanks for the info. I'm looking at a '90 ZR1 that's got a little over 30k miles on it. It's just that it's been my experience that there are two kinds of cars. Those that have broken down and those that are going to break down. I have this image of going down to my local Chevy dealers parts department and asking for a part for my 1990 ZR1 and either being greeted with a blank stare or some "expert" telling me that there's no such thing as a 1990 ZR1 that they didn't start making them until around 2007.

[John H.]

Re: 1991 Zr1

Thanks Ed. I'll get to work on it this weekend and let you know.

John,
remove the small air pump from under the seats. Remove the four (4) small screws and you will see a very thin rubber bladder.
Next, see if a friend in the medical field can give you the latest latex glove. Cut two small square patches the size of the air pump
bladder or the pump itself. Set the patch over the pump where the offending bladder sat. Use an ice pick to make four holes where
it fits over the pump bladder space. Do not use any glue as it my flake off and jam up the pump. Insert the four small screws, and
you will have a working pump.

[John H.]

Re: 1991 Zr1

Mark,

I've been able to find a handful of little items I was looking for pretty easily. I do have a good friend who works the parts counter at a Chevy dealership and he is willing to search around and use the parts locator system though. I was lucky enough to have Ed Hoffman check the car for me prior to purchase and felt I was getting a solid car. Having an NCRS member who knew about the ZR1 gave me a lot of comfort with the purchase.

[Paul M.]

Re: 1991 Zr1

I have a set of seat bladders if you want them