More Newbie Questions...

[Racinfan83]

Now that I have driven this thing some more - and I feel like an idiot for posting this - there are some things that have me wondering and nervous.
I have driven MANY vehicles with manual transmissions - up to and including dump trucks and semis. So I think I have a fairly good idea how to drive one :confused:
This thing makes quite a bit of noise in first gear and reverse. Just sounds like gears - but I would think a car of this caliber wouldn't make gear noises? Is this normal?
Clutch engages rather harshly - in fact my wife commented that I didn't know how to drive it. I probably have a million miles in all different vehicles and construction equipment. I think I know how to drive. Is there a trick to smooth shifts with this thing?
Idles about 1400 and then will slowly drop down to about 800. Will almost die at normal idle when A/C clutch kicks in. Just had that serviced - so it isn't the A/C I don't think???
Car makes a rattling sound from underneath when I shut it off? Like a tinny plate kind of rattle?
Seems to have a minor oil leak somewhere on the passenger side of the engine - you can smell it when you are driving - but I can't see where it might be coming from? Ideas?

Just wanting to get an idea what is "normal" and what I need to look into further.... Thanks

[-=Jeff=-]

As for the Idle change..

in anther post you stated:
My A/C is also now converted to R134 and works great!

This is why the car almost dies with the AC on.. R134a runs a higher Head pressure then R12, which in turn loads the motor a bit more, when the AC is on will cause it to almost stall because the a/c idle adder (in the PROM) is set too low. The Factory cal changed in later years to accommodate this I believe but not in the 1990 Cal

Oil leak on Passenger side...

Depends.. it could be a sensor, oil cooler lines or a stud int he middle of the exhaust manifold causing the leak

the rattle could be the trans which is not uncommon.. do you know if the Dual Mass flywheel is still installed or is there a lighter single mass in its place

As far as shifting, I would look at the Clutch hydraulics sounds like they may need attention too

[QB93Z]

Sorry to hear that you are having drivabilty issues with your ZR-1.

Regarding the clutch, I think that the ZR-1 clutch is a little "grabbier" than some other cars and may take some getting used to. That said, the clutch should work smoothly and may need to be serviced on your car.

Regarding the transmission noise in first and reverse, I suggest checking the oil level in the transmission and probably replace the transmission oil soon if you do not know that it was done recently. Another source of gear noise can be one or more failed fuel injectors. If your 1990 ZR-1 still has the original injectors, I strongly recommend replacing them before you do any other drive train analysis.

Regarding the oil leak on the passenger side, it does happen on some cars. The oil may be seeping onto the exhaust manifold so you smell it but not see it on the garage floor. Two possible sources I have seen are a cam cover leak from the rear part of the cam cover to head seal or a leak from a bolt that secures the exhaust manifold to the head. The bolt (near the center of the manifold, under the manifold, is a stud that goes all the way to the oil gallery of the head.

Regarding the rattle on engne shut off, I would start by checking the exhaust manifold heat shields. There are about 6 of them and a loose bolt could cause the noise you describe. Get under the car and tap lightly with a rubber mallet or a plastic screwdrive handle and see if you can duplicate the noise.

I hope you will be coming to the ZR-1 Gathering at Bowling Green, KY in May. I will be glad to let you drive my ZR-1 so you compare your car to another example.

Good Luck.

Jim

[Scrrem]

Your noisy first and reverse gears are very common in the early ZF transmissions. They are referred to as "Black Tag" tramissions, do to the fact that they were manufactured in Germany and the tag on the transmission is black. The gears are cut in a way that makes them very noisy, my 90 was like that, very "Truck Like".

The later ZF's starting in 93 (may have the year wrong) are called "Blue Tags" and are US built and are much quieter due to the fact that ZF changed they way the gears were cut. I changed my to a blue tag last year, and it's much quieter.
Rich

[Racinfan83]

Thanks guys that helps! I know I have some kind of vacuum leak under the Plenum somewhere, as the pump runs on and off when u turn the key on. I ran it back to the Plenum, so its under there somewhere. Gotta get some $ together before I can think about changing or having the injectors changed out. As to the flywheel - I don't know if its been changed - but I really doubt it from what I can tell. Seems like a totally original car. Dealer checked the trans oil when I had it here the other day and it was good. A/C compressor was nearly killing the car before it got changed to R134. Only difference is that it actually blows cold air now...lol. posted this from my phone so if there are errors that's why...

[Schrade]

As for the Idle change..

in anther post you stated:


This is why the car almost dies with the AC on.. R134a runs a higher Head pressure then R12, which in turn loads the motor a bit more, when the AC is on will cause it to almost stall because the a/c idle adder (in the PROM) is set too low. The Factory cal changed in later years to accommodate this I believe but not in the 1990 Cal

Oil leak on Passenger side...

Depends.. it could be a sensor, oil cooler lines or a stud int he middle of the exhaust manifold causing the leak

the rattle could be the trans which is not uncommon.. do you know if the Dual Mass flywheel is still installed or is there a lighter single mass in its place

As far as shifting, I would look at the Clutch hydraulics sounds like they may need attention too

Yup. One of the few things I know about this car.

Dual mass F/W does NOT like low RPMs. It causes wear (and subsequent breakage) of the load springs in this unit.

[scottfab]

Thanks guys that helps! I know I have some kind of vacuum leak under the Plenum somewhere, as the pump runs on and off when u turn the key on. I ran it back to the Plenum, so its under there somewhere. Gotta get some $ together before I can think about changing or having the injectors changed out. As to the flywheel - I don't know if its been changed - but I really doubt it from what I can tell. Seems like a totally original car. Dealer checked the trans oil when I had it here the other day and it was good. A/C compressor was nearly killing the car before it got changed to R134. Only difference is that it actually blows cold air now...lol. posted this from my phone so if there are errors that's why...

Another source of noise for the ZF6 is the type of oil used. The GM part numbered oil (not available anymore ) or Havoline 10W30 or the Castrol 10w60 are quiet. The Amsoil is a bit noisier. Who knows what's in there. As for the pump running and the vacuum leak you should measure the time interval that it pumps. I recommend any thing <10 seconds be looked into eventually but if it's as low as 3sec then should be looked into fairly soon as that can effect "full power".
I converted to R134 and notice the "almost stall" with the stock chip in. With my DRM chip I don't.

Congrats on the car. Take your time learning it and fixing what you can when you can. The RIDE is worth it all. Cheaper that going to Disneyland every year and twice the fun.

The solutions for the oil leak already given are sufficient.
I'd say the noise on shut off is probably the timing chains and is normal.
You mentioned some shifting issues. I'll offer up one more that you may not have noticed yet. Aggressive shifting works as expected 1-4 but 5 and 6 not because of the ratio. When you go from 4 to 5 the rpm needs to come down a bit before the shift else you get lots of noise out of the dual mass flywheel. This takes some getting use to.

Probably the most urgent thing to look into right away is the hydraulics for the clutch. If you're low on fluid then the shift quality is crap. The reservoir is right under the brake vacuum assist on the firewall on the drives side.

[USAFPILOT]

black tag can handle more power right?

[efnfast]

If I remember, the black tag had a bearing or bearings rated at higher load. Don't know if it was over kill or not, but I'm happy to have a tougher geat box.

[GOLDCYLON]

Black tags were built and rebuilt by ZF. Blue tags were the replacement offerings offered by GM also rebuilt by GM by my understanding. Who really knows if the internals are different however the blue tag warranty transmissions did not hold up like the black tag units. Hence the greater desire for the black tagged units. My experience with these transmissions is the stock units are noisy, growl whine and complain. At least they did on my father stock zf6 unit. I was amazed how different it sounded from my ZFDOC unit. Apples to oranges in difference.