1990 specific issues?

[FormulaReed]

Hello,

I’m looking at a 1990 zr1 this weekend and I was wondering if there are any specific issues that I should look for? I’ve done some searching here and so far it spends like the esm, tire pressure sensors, instrument cluster and secondary vacuum pump are only on the 1990 car. I also read that some oil burning when cold as well as cam chain noise are to be expected.

Are there any other things that I should look for? I’ve learned a ton from this message board so far, so thanks to all for sharing so much information.

Cheers,

Reed

[-=Jeff=-]

ESM?

- if you meant ECM, all are interchangeable 1990-1995 but you must use your PROM.

- Tire pressure sensors, mine are long gone, preference to me,

- Instrument cluster, 90-91 are interchangeable directly, later ones will work with some swapping of parts

Secondary pump, it is just the connector that is one year only..

Yes oil on cold is due to no exhaust valve seals.

Check the FX3 suspension, Shocks are not avail at the moment, but might be this year (So Bilstein says anyway)

Good luck on your search

[TX '90 ZR1]

Hello,

I’m looking at a 1990 zr1 this weekend and I was wondering if there are any specific issues that I should look for? I’ve done some searching here and so far it spends like the esm, tire pressure sensors, instrument cluster and secondary vacuum pump are only on the 1990 car. I also read that some oil burning when cold as well as cam chain noise are to be expected.

Are there any other things that I should look for? I’ve learned a ton from this message board so far, so thanks to all for sharing so much information.

Cheers,

Reed

Welcome Reed!
There is a pretty good pre-purchase checklist on the ZR1.net site. Check it out.
Also, I am attaching a checklist that Hans put together.
Get on here with any questions or concerns you have. There is a lot of knowledge on this site about the C4 ZR-1.
:cheers:
9009

[GOLDCYLON]

ESM?

- if you meant ECM, all are interchangeable 1990-1995 but you must use your PROM.

- Tire pressure sensors, mine are long gone, preference to me,

- Instrument cluster, 90-91 are interchangeable directly, later ones will work with some swapping of parts

Secondary pump, it is just the connector that is one year only..

Yes oil on cold is due to no exhaust valve seals.

Check the FX3 suspension, Shocks are not avail at the moment, but might be this year (So Bilstein says anyway)

Good luck on your search



What Jeff said... WURD !

[FormulaReed]

Thanks for the replays so far.

I was referring to the The ESC AKA called the electronic knock module. That's good to know that the ECM is interchangeable. Will full power mode work ok if the TPSM system is showing a fault?

I'm hoping that Bilstein does start making the FX3 shocks again, but I'm not going to hold my breath. I was planning on getting some blown ones to be rebuilt, just to have them.

[-=Jeff=-]

Ah ESC is available here:

https://www.ebay.com/itm/202578902658?ViewItem=&vxp=mtr&item=202578902658

[Ccmano]

All good stuff, the only thing we missed is the 90’ only chain rattle at start up, which does not harm anything, and the 90-92 fuel injectors (due to ethanol corrosion) which need replaced if they haven’t already been. There are many other things to look at but those are not unique to 90’s and included in my list that has already been referenced.
H
:cheers:

[FormulaReed]

Welcome Reed!
There is a pretty good pre-purchase checklist on the ZR1.net site. Check it out.
Also, I am attaching a checklist that Hans put together.
Get on here with any questions or concerns you have. There is a lot of knowledge on this site about the C4 ZR-1.
:cheers:
9009


I tried downloading that pdf, but I’m getting a permission denied error.

[TX '90 ZR1]

I tried downloading that pdf, but I’m getting a permission denied error.
Maybe this is OK to do. Don't know why the pdf showed locked. Pasting here.

Used ZR-1 Evaluation Checklist (via Hans Meyer)
Injectors
Vacuum leaks
Secondaries operable
Ingnition coils and wires replaced
Timing chain noise (normal to a small degree on 90's)
Starter
Oil leaks especially the pan and oil cooler lines
Fuel pumps
Is it throwing any engine, abs or body codes (multiple possibilities here)
Are any DIC lights on. (Multiple possibilities here as well)
Is the adjustable shocks system working
Windshield delamination
A/C functionality (compressor is unique to the Z, cooling capacity lower)
Power switch functionality and keys (are there 2)
Transmission syncro's, (first gear is always noisy) shifter alignment can mimick synco problems.
Clutch functionality (they all let in high, was it ever changed)
EGR system on later models
Engine mounts

C4 Issues
Head lights operable
Radiator blocked or simply clogged, electric fans operable
Wheel bearings
Suspension bushings
Condition of all door, top and hatch seals
Glass roof cracking
Instrument cluster functionality especially the tach (tends to read high with age) also note the lighting of the cluster.
DIC button functionality
Steering wheel excessive movement
Radio functionality (especially speaker amps) and antenna
Sport seat functionality (transmission, switches, pumps and bladders)
Door window switches
Door window lifter and internal rattles
Fuel tank bladder collapse (results in small capacity)
Differential noise (whine)

[FormulaReed]

Thanks for posting this.

The first zr1 I looked at failed a few of these. The clutch was the major one, on the car I drove it was really stiff and the engagement point was right on the floor. Could have been the master and/or slave cylinder. It had some other issues as well so I’ve decided to keep looking. I’m hoping to look at one this weekend, but the forecast is calling for a snow storm.

[Dynomite]

Nice List of things to check.
:thumbsup:

Just some Clarifications on severity of issues found on several ZR-1s......all fixes found in signature.

Do ask what Fluids have been used and Do Change ALL fluids on a ZR-1 when purchased...….see Post 3 - LT5/ZR-1 Fluids (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1580070550)

Do Run a Compression Check on ALL Cylinders once ZR-1 is received.



Used ZR-1 Evaluation Checklist (via Hans Meyer)
Injectors Have they been replaced
Vacuum leaks There will be minor vacuum leaks which do not effect performance unless you replace the vacuum lines and connectors ($100 Ebay)
Secondaries operable Can be viewed by grounding Hot wire (pin C17) on ECM
Ingnition coils and wires replaced A Note of reference if the engine stumbles
Timing chain noise (normal to a small degree on 90's) Only before full oil pressure within 10 seconds
Starter Most often the Starter Solenoid Points need reconditioning
Oil leaks especially the pan and oil cooler lines Check the Oil Pressure Regulating Valve Cover Plate
Fuel pumps Keep in mind Jim's Fuel Pump Switching connector
Is it throwing any engine, abs or body codes (multiple possibilities here) Mostly INFL REST which is easy fix
Are any DIC lights on. (Multiple possibilities here as well)
Is the adjustable shocks system working Replaced shocks on two Zs
Windshield delamination I had Safelite replace a 1990 windshield which I furnished with new gaskets
A/C functionality (compressor is unique to the Z, cooling capacity lower) Replaced Dryer, Fittings and added R12 on one ZR-1, R134 on 95'
Power switch functionality and keys (are there 2) Power switch fix (disassemble and bend points into position)
Transmission syncro's, (first gear is always noisy) shifter alignment can mimick synco problems. Had one Trans Rebuilt by ZFdoc
Clutch functionality (they all let in high, was it ever changed) Have replaced clutch plates and use Needle Pilot Bushings
EGR system on later models
Engine mounts No Fixes on 5 Zs

C4 Issues
Head lights operable Simple fix changing tip up Gears
Radiator blocked or simply clogged, electric fans operable Usually leaves and sometimes oil contamination from Oil Cooler Leaks but that is rare (install debris screen)
Wheel bearings Replaced Rear Wheel Bearings (good at 90K miles) and drive shaft/half shaft U-Joints on high mileage 95'
Suspension bushings No Fixes on 5 Zs
Condition of all door, top and hatch seals Window frame seals sometimes ragged
Glass roof cracking No Fixes on 5 Zs
Instrument cluster functionality especially the tach (tends to read high with age) also note the lighting of the cluster No Fixes on 5 Zs
DIC button functionality No Fixes on 5 Zs
Steering wheel excessive movement No Fixes on 5 Zs
Radio functionality (especially speaker amps) and antenna Usually CD may not function send to Doc Dons (Amps inexpensive Nissan Max 975s or 075s)
Sport seat functionality (transmission, switches, pumps and bladders)
Door window switches No Fixes on 5 Zs
Door window lifter and internal rattles No Fixes on 5 Zs
Fuel tank bladder collapse (results in small capacity) No Fixes on 5 Zs
Differential noise (whine) No Fixes on 5 Zs

Additionally...…..
1. Have replaced tires, Coils, Plug Wires, Plug on some Zs and have Replaced ALL Vacuum lines and Connectors on ALL Zs ($100 Ebay).
2. Have upgraded Air Intake, Brake Rotors and Brake Calipers, Headers and Exhaust, Injectors on some Zs.
3. Have Added Oil Catch Cans on some Zs, Modified Fuel Pressure Regulators on ALL Zs.
4. Have done a Top End Restoration on ALL Zs including Starter, Valley Drain, including New Thermostats and New Aluminum Radiators on ALL Zs.
5. Have Eliminated Secondary System on one Z.
6. Have installed MarcH Chips on all Zs.

[FormulaReed]

Good to know. It sounds like the these are pretty good cars, it’s funny to check a car forum and not have it all doom and gloom. All of my cars get driven regularly, so it’s good to here these are not a mess.

I was really hoping to look at one this weekend, but we got some snow and here in Seattle, snow just shuts down the city.

I’m glad that I passed on the first one that I looked at. I don’t think it was a total mess, but it was more of a project than I was looking for. The clutch needed work, bad tires, weather stripping was all bad and the full power key light would not light up. It ran good and drove well, but when I gave it some gas it threw a check engine light at me. It also had no records and had been passed around a few dealers here in town.

I’m hoping to find a decent driver grade car that’s been taken care of. I’m willing to take on some projects, but I’d rather get one that’s not a total mystery.

[jss06c6]

Recommend you look at the 1990 that Lloyd Meeks has for sale on this forum. It's already well sorted out. Buy and drive..

Sent from my XT1585 using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[FormulaReed]

I saw that one. Looks like a super nice car. I’m trying to find one a bit more local first. If that fails, I will probably be going for a road trip.

[lfalzarano]

You’ll have to wait until the snow melts in Seattle!


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[FormulaReed]

Yeah. I’m not stoked about this snow.

I’ve been trying to get a corvette for like 6 years. Every time, something has gotten in the way.... my wife said that at least this time, it’s not her fault. I’m not complaining too much, it’s not like I’ve had to drive a Prius, but it’s been one thing after another.

[lfalzarano]

I once had to drive a Chevette 3-speed to work, while my 1968 427 Vette convertible sat in the garage. I miss that 427! When it was 20+ years old I sold it for $13.5K, which was 3X+ its price when new. Sold it so the kids wouldn’t kill themselves on a joyride while we were out! [emoji22]


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[jss06c6]

I once had to drive a Chevette 3-speed to work, while my 1968 427 Vette convertible sat in the garage. I miss that 427! When it was 20+ years old I sold it for $13.5K, which was 3X+ its price when new. Sold it so the kids wouldn’t kill themselves on a joyride while we were out! [emoji22]


Sent from my iPhone using ZR-1 Net Registry (http://r.tapatalk.com/byo?rid=90383)Now that's hurts!!

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