Purchased a '91 ZR-1 today. New member here.

[ColinOpseth]

I've been looking for low mileage C4 for a few weeks now. Saw a couple good examples and was very near to purchasing a 34k original mile 91. Then I saw this ad on Craigslist:

http://inlandempire.craigslist.org/cto/2885827873.html

Seems to be a decently solid car. Probably has shot 3rd gear synchros because it jumps out of gear anything over part throttle. Paint is about and 8.5/10. 65k miles.

Here's what I noticed:
- Leaking oil from the bottom of the engine somewhere. Bad enough the bottom of the ZF is oily and dripping on the exhaust.
- Pops out of gear anything over part throttle in 3rd (also doesn't seem to engage all the way when I shift into third...maybe a bent shift fork?)
- Headlight motors are perfect
- Cold AC
- Possibly runs a bit hot but I'm not sure how "hot" they run. It's in the top 1/3 of the temp gauge when it warms up.
- Has a pretty bad mid-RPM stumble that gets worse as it warms up. When it stumbles it'll flash the SES on the dash but it goes away as soon as I get through the stumble higher in the RPM.
- Doesn't seem to have a lot of power. When I use the valet key and turn it to the right there isn't an appreciable increase in power.
- Has both tops but the clip on that holds the removed top in place near the back of the hatch is broken. Also, both trim pieces on the left and right of the car where the top stores into are broken.
- Brakes are good, e-brake is good, doors close nice. Weatherstrip is good but dry rotted in a few minor places. New tires.
- Looks like there isn't any delamination of the glass. How would I know?
- Hood is cracked a bit right in the middle near the glass. About 1" in. Fatal for the hood? Underside looks good.

Anyone seen this car around? I bought it from an older gentleman in his 80s. He said his family had the car from 3,000 miles. Unsure about that. I'm taking a check down there tomorrow so it isn't too late to back out.

Got it for $12k. Decent deal?

Thanks,
Colin

[cvette98pacecar]

Originally Posted by ColinOpseth

I've been looking for low mileage C4 for a few weeks now. Saw a couple good examples and was very near to purchasing a 34k original mile 91. Then I saw this ad on Craigslist:

http://inlandempire.craigslist.org/cto/2885827873.html

Seems to be a decently solid car. Probably has shot 3rd gear synchros because it jumps out of gear anything over part throttle. Paint is about and 8.5/10. 65k miles.

Here's what I noticed:
- Leaking oil from the bottom of the engine somewhere. Bad enough the bottom of the ZF is oily and dripping on the exhaust.
- Pops out of gear anything over part throttle in 3rd (also doesn't seem to engage all the way when I shift into third...maybe a bent shift fork?)
- Headlight motors are perfect
- Cold AC
- Possibly runs a bit hot but I'm not sure how "hot" they run. It's in the top 1/3 of the temp gauge when it warms up.
- Has a pretty bad mid-RPM stumble that gets worse as it warms up. When it stumbles it'll flash the SES on the dash but it goes away as soon as I get through the stumble higher in the RPM.
- Doesn't seem to have a lot of power. When I use the valet key and turn it to the right there isn't an appreciable increase in power.
- Has both tops but the clip on that holds the removed top in place near the back of the hatch is broken. Also, both trim pieces on the left and right of the car where the top stores into are broken.
- Brakes are good, e-brake is good, doors close nice. Weatherstrip is good but dry rotted in a few minor places. New tires.
- Looks like there isn't any delamination of the glass. How would I know?
- Hood is cracked a bit right in the middle near the glass. About 1" in. Fatal for the hood? Underside looks good.

Anyone seen this car around? I bought it from an older gentleman in his 80s. He said his family had the car from 3,000 miles. Unsure about that. I'm taking a check down there tomorrow so it isn't too late to back out.

Got it for $12k. Decent deal?

Thanks,
Colin

12k is a good price gives you a couple grand to fix the things that need to be fixed. Trim pieces can come off of any C4, Weatherstripping will cost about 800.00 for GM parts, injectors will probably solve your stumble, plan on getting a trans from ZFDOC.

[Paul Workman]

Sounds like injectors need changing, and maybe O2 sensors too.

http://www.zr1.net/forum/showthread.php?t=17014

Oil leak could be pan gasket, the low oil pressure (dash idiot light) switch, the oil coolant line connections, oil filter housing gasket, oil temp, oil pressure guage sender, dipstick tube grommet, and on the 90s (91s too?) there is a bolt in the center of the exhaust manifolds that if it does not have sealant on it, it can leak. Then, the front and rear crank seals, and the breather gasket (very common) under the plenum (leaks and oil runs out of the drain tube that opens aft of the pan - about where you would expect to see oil from the rear main seal to be leaking, if it were the main seal.

Late for work... Mo later!

P.

[bdw18_123]

Welcome and congrats on the purchase! When you get your 'new' to you Z running properly, you will understand what "perma-grin" is!

The oil leak could from a number of places. Oil cooler lines at the front, right part of the engine are one of the common oil leak areas. The oil pan bolts also can get loose, you might try checking them for tightness. The rear main crankshaft seal could also be leaking. And a number of other areas too. It will be very hard to tell where the leak is coming from without cleaning up the existing oil mess though.

On the power key issue, more than likely your vacuum system has a major leak somewhere or the vacuum actuators or secondary solenoid (controls vacuum to the actuators) are bad, that is the most common source of issues. When you turn the key on, you should hear the vacuum pump run for a bit and then shut off (it's located underneath the right headlight). If it never stops running, you have a vacuum leak or it might not be running at all if it went bad. When the secondary system is working properly, you will definitely know when it activates!

Phrogs already mentioned fuel injectors on the other forum, if the injectors are original, then that is probably the cause of the misfiring. The original fuel injectors in the '90-'92 ZR-1's cannot handle the ethanol in today's fuels and it is a matter of when, not if they will fail.

You will want to get a factory service manual for sure. And if you can't do your own work on the car, repairs can get very expensive as there aren't many shops out there that know how to work on an LT5. Oh, and DON'T spray the engine off with a water hose or clean with any harsh chemicals! Cleaning has to be done by hand only.

There are several ZR-1 guys in Southern California, they would probably be more than willing to lend a hand in getting your Z sorted out.

[VetteMed]

windshield delamination is easy to spot. The stock windshield has a purple tint to it, when it delaminates at the edges it looks more bronze or gold.

[Blue Flame Restorations]

Congrats on yuor new "Z"

[mike100]

I think you can probably get the engine stuff ship-shape for around $1200 if you do your own work (not including the transmission work!). not sure about the leak- but the oil cooler lines usually make more of a mess on the pass side than on the oil pan/trans (usually).

vacuum leaks and injectors are par for the course- you can always do a compression check while you are looking at the plugs- these cars should read 200-210 on the gauge.

The transmission will be expensive- you will probably have to buy an entire gear cluster to get the synchro fixed for 3rd, plus the general rebuild cost. Getting another trans could be an option. I'd budget 3 grand on that.

[Bob Eyres]

Sounds like a solid Z for a good price. My 91's got the same mileage, and some of the same problems.

Got a NOS ZF6 in the original box if you need one, $2K. Sorry for the blatant promotion.

[A26B]

+1 on the oil pan as the oil leak culprit. Remove the K-members to get to the front bolts. No worries about the engine, it's supported above the k-members. Remove each bolt. clean the oil off & apply blue (242 or 243) Loctite.

I went through a lot of spray brake cleaner for the same mess you have. Buy one of those large metal drip trays at Autozone & be sure to wear some goggles while spraying. Burns like the dickens if it gets in your eyes.

Your engine coolant temp sounds high. Check the digital readout to see what the temps really are. It will display in degrees centigrade. There are lots of references to causes of high temps, but the most common is debris in the "stack" A/C condenser, oil cooler & radiator. It really requires removal of the radiator to do the job right.

Any time you get an SES light, the secondaries are disabled. Pull the codes and follow the flow charts in the service manual for troubleshooting. Always start with the lowest numerical DTC first. Then, clear the codes and see if any codes reset before going on to the higher DTC codes.

Given the model & age of the car, the most common issues will be oil leaks, injectors, vacuum leaks, coils, plug wires & plugs. I'm a sticker on replacing the fuel system o-ring seals with Viton. The original seals are now over 20 years old, hard & deformed from new, plus the vast majority of fuel now contains ethanol.

Please let me know if we can help you with any gaskets, seals or parts.

www.jerrysgaskets.com

Welcome to the forum. I highly recommend you consider joining the ZR-1 Net Registry (owner of the forum) if you haven't already.

[Corbusa]

Welcome to the family Nice car ..