What things to be aware of on a 1990

[Aurora40]

What things to be aware of on a 1990?

So one of the Corvettes I am considering buying is the 1990 ZR-1. I love the old body-style of it. I know there were some changes during the year, and just wanted to make sure I have my bases covered.

I will of course want to check it mechanically and such, but am wondering more about changes and such to the cars.

There were some with manual hvac, and some with iron driveshafts in 1990, correct? The hvac isn't a biggie, but I'd want the aluminum driveshafts (if for no other reason than how awesome a 3" shaft of aluminum looks).

Was 1990 the year they introduced that passive key fob? I thought it was the 1990 ZR-1, but could be mistaken. Was it standard or an option, or am I totally off?

1990 PCM's should have been replaced under warranty for basically all cars, correct?

Do the windshields all have delamination problems? Or are some great and others not? I'm fine with a non-original windshield, but I think another UV one would be nice (newer ones don't delaminate and you can't even see the film).

What kind of maintenance things are a must on the car regardless of mileage? Is the LT-5 sensitive to coolant maintenance? The all-aluminum Premium V8 (Northstar/Aurora) can literally endure or die due to cooling system maintenance. The aluminum engine means the coolant never gets dirty/rusty looking, so it may look clean and new but have all the protection additives depleted, thus leading to headgasket failures and other problems. True of the LT-5, or not so true?

Finally, curiosity: The oil filter upside down on top of the engine... Does oil chug out of that thing all over the place when you unscrew it??

Thanks for any info!

 

[B17Crew]

I know the answer to one of your questions!

Passive Keyless Entry (PKE) was introduced in 1993. It was standard and never an option.

B17Crew

 

[B17Crew]

Don’t know where you are located, but for comparison, this ZR-1 was listed at Bob McDormans Chevrolet. You have to select “Corvette” then scroll down. The cars are listed in chronological order. I have dealt with McDormans in the past. Bought a new ’93 there, their service department was honest as well, never tried to pull one over on me.

http://www.diamondlot.com/bobmcdormanchev/

B17Crew

 

[Jeffvette]

There were some with manual hvac, and some with iron driveshafts in 1990, correct? The hvac isn't a biggie, but I'd want the aluminum driveshafts (if for no other reason than how awesome a 3" shaft of aluminum looks).

The cutoff point has never been given a exact number. But it's around the 700 series. I have the steel halfshafts, and you never see them anyways.

Was 1990 the year they introduced that passive key fob? I thought it was the 1990 ZR-1, but could be mistaken. Was it standard or an option, or am I totally off?

Nope 93, even though several other GM cars had remote fobs prior.

1990 PCM's should have been replaced under warranty for basically all cars, correct?

PCM's? The proms should have been updated, unless you found one that has been in storage for a long time.

Do the windshields all have delamination problems? Or are some great and others not? I'm fine with a non-original windshield, but I think another UV one would be nice (newer ones don't delaminate and you can't even see the film).

Delam is a strange subject. It appears on cars that have been in storage. My car has none and it has 44,000 miles on the clock.

What kind of maintenance things are a must on the car regardless of mileage? Is the LT-5 sensitive to coolant maintenance? The all-aluminum Premium V8 (Northstar/Aurora) can literally endure or die due to cooling system maintenance. The aluminum engine means the coolant never gets dirty/rusty looking, so it may look clean and new but have all the protection additives depleted, thus leading to headgasket failures and other problems. True of the LT-5, or not so true?

Every car needs a routine flush. Never heard of those issues with the Northstar motor, not any with the LT5.

Finally, curiosity: The oil filter upside down on top of the engine... Does oil chug out of that thing all over the place when you unscrew it??

Depends on the filter you use, and how long you wait until you remove the filter.

 

[Aurora40]

Don’t know where you are located, but for comparison, this ZR-1 was listed at Bob McDormans Chevrolet. You have to select “Corvette” then scroll down. The cars are listed in chronological order. I have dealt with McDormans in the past. Bought a new ’93 there, their service department was honest as well, never tried to pull one over on me.

http://www.diamondlot.com/bobmcdormanchev/

B17Crew

The Old Dominion = Virginia.

I contacted the dealer about that car when it was posted here in the "for sale". They sent me a lot of picts, and I may drive up to Ohio to check it out. Glad to see they have some other picts up, the ones I got were not good lighting and the car was very washed out and orangish looking. Orange on orange isn't quite as appealing looking...

Hey Jeffvette, so some oil filters chug out and some do not? Is that due to some kind of valve thing or something that's absent on the cheapies? Also, the oil drains out of it? Does that mean it takes longer for oil to circulate on a cold start? Do they still make the "correct" black filters, or at least one with the same internals/features as the original black ACDelco ones?

Thanks for all the info, folks!

 

[Aurora40]

Hmm, another question. Does the engine controller limit the revs? I mean, does it have safeties in place (spark or fuel cutoff) to keep the engine from spinning past 7,200 rpm?

 

[8388]

I have no problems still getting the black factory filter. PF970c. Most of the oil will drain out after sitting for at least a day.

 

[8388]

Hmm, another question. Does the engine controller limit the revs? I mean, does it have safeties in place (spark or fuel cutoff) to keep the engine from spinning past 7,200 rpm?

Stock chip will shut off the fuel at just over 7000 rpms.

 

[B17Crew]

Hey, you should ask Rob to do a road trip with you to look at the car. From the pics he’s posted of his car, it’s pretty sweet. I think he’s from VA too.

Good luck with your search, it’s got to be a blast looking for a Z.

B17Crew

 

[koolaid117]

Aurora40 -
You might want to send a PM to Jagsfan here at CAC. He is a salesman at Bob McDorman. I wish I had more knowledge of what to look for in a ZR-1 because McDorman's is only about 40 minutes from my house. Also, you might want to read The Heart of the Beast by Anthony Young. It's all about the development of the LT-5 engine. Its a great book. After reading it, I wouldn't hesitate to purchase a ZR-1.

Good luck in your search!

Jim

 

[tomtom72]

Chance to repay a kindness!

Hi Aurora40, I'm a new Z owner so take this with a dose of skepticism. I've been reading up on the cooling system at the ZR1net.Registry. There is good info there about the system that bears reading. The "common issues" & "maintenence" sections are worth reading if you are interested. A good deal of accuimulated info. It's worth a read if buying is in the cards for you. They also got a "for sale" section. Good luck with your search, Tom

 

[Aurora40]

Hey Tomtom, good suggestion on the "common issues" stuff there. I have been to that site a few times, but didn't think about that.

There are a lot of issues there, but of course any car has a lot of possible issues.

But one I am interested in more info about is the backfiring while starting one. If you let off the key before it's totally started, you can backfire the car and damage vacuum hoses, PCV valves, etc? Is that really true? The fact that a PCM would ever fire a plug on the intake stroke of a cylinder (unless the sensors were messed up or the crank and cams were wildly out of synch) is pretty astounding.

I often don't fire a car long enough to start because I am used to the Aurora. The Aurora fires the engine for you, so you only need flip the key to start for but an instant and let go, and the car will do the rest (or you can hold it in "start" forever, and never grind the starter).

 

[tomtom72]

Starting is a bit different...

Hi Aurora40, Yea that starting thing threw me the first time I read the owner's manual, and then I experienced it. It's different from my DD, a Tempo, cause it cranks for what seems like about 4 to 8 seconds before it fires. It's just something I've gotten used to now. The old school "just touch the key" thing to test your tune-up work don't seem to apply here. The owner's manual gives a fairly specific non-mechanic language explaination of why & what's going on. I'm not gonna try to tell you I understand it all, but I sat in my Z with the manual and read the "start you car" section as I was starting my car and it behaved just like the manual said it would. Sometimes it starts quicker than other times. It never seems to take longer than the 4 to 8 sec time span. Maybe that has something to do with where the engine stopped the last time it was shut off. I will tell you this I have yet to hear a back fire like some old clunker. I think I hear a muffled pop sometimes when it cranks closer to the 8 sec. mark, but you gotta listen for it cause it's not obvious. I know this isn't very scientific of an answer, but all I can say is sometimes it takes longer to start than my tempo. I notice it cause I'm from the old school. If you want I can hunt up the passage in the owner's manual & write it to ya? Tom

 

[Aurora40]

Hey Tom, you don't have to write up the whole thing. Thanks, though! But does it mention it can damage the engine if you don't start it up properly? If it just can be hard to start, that's no biggie. But if you can backfire through the intake by not cranking it long enough, that is a very odd thing, and a little troubling.

 

[tomtom72]

Hi Aurora40, The regular manual says 3 seconds & your corvette should fire. The ZR-1 manual says in cold weather it will crank longer than 3 seconds. The reason for the longer cranking, in any weather, is the way the ignition system works without a distributor. I was told about the backfire thing by reading up on the forums. The manuals do not say anything about that. If I should be worried about it I guess I'm in for trouble because I'm not worried. I wrote about hearing something if you listen closely, well I went to move it yesterday & it's been sitting a week in a cold garage & I must be hearing things. After it is warmed up it starts quick enough. It's only when stone cold does it crank longer. I guess I'm not using it enough. Anyway the orig. owner told me "crank it till it starts if it's stone cold". Usually it starts before 10 seconds stone cold. I'm not using a stop watch but you know you got a good idea how long is too long to crank a car? Anyway if ya got a hanker'in for one all I say is get ya one of these & it'll be a cure for the common car! Good luck in your search! Tom.

 

[ronbidwell]

check out zr1netregistry.com for a wealth of information on the ZR1.

 

[BLOWNZR1]

my 90 is soooooooooooo sweeeeet nuthin wrong wit it

now i gots the blower motor in the 90 is sweeeeeeeeet

 

[Jeffvette]

freaking troll

 

[RedRiderZR1]

Aurora40,
I have not heard of the backfiring causing any damage since I have been an owner. It is true that it can take awhile to start when cold. When warm it fires right over. When I start mine, I let the engine start then back off the ignition. I found out this problem just after I bought the car. Only has happened that one time now that I know the issue. Just in case though I keep 2 spare MAP hoses in the glove compartment just in case I screw up.

Enjoy your search.

Greg

 

[tomtom72]

more important than....

Hi Aurora40, I think this is more important than this backfire thing...Secondary Port Vacuum System. Why? The first time you have to go under there it can be a bit intimidating & certainly a PIA. Do the KOEO vacuum test on any Z you look at. See Rob's sticky in this section. If it flunks there are some expensive parts involved in getting the problem resolved. I just ordered the gaskets I think I need to do the job from White Racing & spent about $190.00 just on gaskets. Then there are the other parts under there that will eventually fail & that means go back in again or do it all at one time. The way I see it there is a better chance of SPV sys trouble than this backfire thing causing damage. JMHO from a non-mechanic's point of view! If you think about it the chances of vacuum diaphram failures are more likely than backfiring problems. I ordered a parts CD from KWR.com along with the gaskets because I want to know everything that is under the plenum before I start to repair the SPV sys. I will probably replace all of the system's parts as pre-emptive along with the bad part causing my vacuum leak. Then I will make as educated guess as I can as to what other parts under there are likely to fail in the near term and address those parts at the same time. Tom.