New Z34 Owner and have some questions

[5spdz34]

 Great site you guys have, I'm glad I found it! I just bought myself a '93 Z34 pretty cheap for my everyday driver to let my Monte's rest while I'm in college and while finishing out my senior year in high school. What closed the deal was that it's a 5-speed. I heard not many of these were made. It's in really good shape but the motor is falling flat on it's face while driving. More on this later.

First off, I do all my own car work and a lot of my neighbor's car work as well. I have worked at a GM dealership for almost 2 years now. I'll be 18 on November 19th. I learn a lot at work but all the mechanics hate the 3.4 DOHC so I can't really get any info from them, so I'm turning here.

I'll tackle anything dealing with a car so I'm all ears, or eyes really... I have been doing a lot of reading on these websites all over the place and have learned a lot from them already. The tranny is great and the motor seems very sound. The previous owner seems like he didn't give this car the attention it needed. I will be replacing the timing belt soon just because there’s no record of it being done. I got very little info about maintenance from the previous owner.

After getting it home, I started to check out what needs to be done. It had a really bad idle problem and I learned on these sites that usually a good intake clean will do the trick. Well it did and idles, for the most part, really good now. I can start it up now and it won’t try to find a good

idle for a minute or so, it goes straight to idle (about 600-800 rpm). While the engine is idling, I hear some tapping noise on the upper end. It only makes this sound every once in awhile. An oil change is on the first top 3 things to do before moving any further. I’ll be replacing the timing belt

hopefully this weekend. What else should I replace while I’m in there? Next weekend, the tranny guy at work is going to help me replace the throwout bearing, you can barely start to hear it. While I’m that far, I’ll go ahead and resurface the flywheel and replace the clutch.

Okay, the only thing I am stumped about (so far), is the idling problem. I replaced the air filter when I cleaned the throttle body. When I am just idling it and rev it a little, it does great. When I’m going down the road, it seems like no matter what gear I’m in, as soon as I pass about 1500-2000 rpm, the engine revs up to 4500 rpm and just stays there. I release the clutch at something like 35 in 3rd gear and the rpm drop but I can feel the car pulling and speed increasing. I depress the clutch and it revs back up to 4500 rpm again. It’s not until I am slowing down in a gear other than 1st and almost stalling it when it goes to normal “idle†again. Nothing is blocking the throttle cable or throttle body. Also, while doing the “high revâ€Â, giving it some gas just makes things worse. It starts bogging, stuttering, etc.. Any suggestions?

One last thing, the owner recently replaced the master cylinder, the front rotors, and pads and it’s still taking 3 miles for the thing to stop. He had the receipts and all this done less than 3 months ago (over $600 worth of stuff, more than what I paid for the car!). I know the ABS was

horrible on these cars but what do I do? BTW, the ABS light is on. Sorry for such the long post but I figured the first post better be worth it... and I have a lot of questions. My ‘86 Monte tags expire at the end of this month so the car must be ready to go soon. I want to start driving it daily and make sure everything is good before my Monte goes in storage just in case of something else going wrong. Again, sorry for the long post and thanks to anyone in advance. - Stephen

[Hippie]

I just bought a Monte Z34 that's making LOTS of "ticking" noises from the top end. From past experiences with other OHC motors I wouldn't drive it again until you get the timing belts done.

[Redfox340]

Welcome aboard. Oh geeze... we got ourselves some issues on your DOHC.

Does the tick grow louder at higher RPM's? If not, it's most likely your fuel injectors dying from age.

As for the RPM's not being able to go over 4500+, I would serious check the Secondary Timing Belt of yours.

I had the same thing happen when mine shredded on my old Cutlass DOHC.

As for it dying on the idle let-down, that could be related to a faulty or clogged EGR.

Are you getting a Service Engine Light (SES)?

If so, ground the system for Trouble Codes:

* W-Body Performance - Computer Dignostics (OBDI)

* W-Body.com - ECM Codes / Reading & Testing

Best of luck, let us know on your progress!

 

- Erik

[5spdz34]

Thanks for all the help so far. I'm getting the feeling that most of my problems are going to be with the belt so I might as well do that next, ASAP. WHAT SHOULD I REPLACE WHILE I'M CHANGING THE TIMING BELT? I'll probably be doing this Sunday. I have to work all day Saturday and the football game is tonight... I was planning on driving it to the game tonight but I probably just need to hold off until I can get the idle problem fixed.

 

I forget about how the tick was but I'm pretty sure it was just at idle (definately not over 1000 rpm). I'll check tomorrow and I will be sure to post it.

 

About the "high rev" problem. It's not that it WON'T go over 4500 rpm, it's that it stays at 4500 rpm when I'm not even pushing on the gas pedal. It does it all by itself. As soon as I give it some gas to take off and I get going, once it passes 2000 rpm, it revs up by itself, with my foot OFF the pedal, all the way to 4500 rpm. When I'm in a lower gear at higher speeds, when the RPM is naturally high, is when it starts to cough when I try to get on it. The whole motor seems to be dying when there's any load but will stay revved at 4500 rpm no matter what, assuming the clutch pedal is down. And yes, I am getting the SES light but it goes on and off while idle and most of the time stays on while driving.

 

I was thinking about the brake problem during 2nd period today and I realized that there could possibly be just air in the lines. When the previous owner had the master cylinder replaced along with the rotors and pads, I believe that the shop didn't do a good job of bleeding the brakes properly. Anything special I need to know about bleeding the Lumina brakes? Would it be like any other brake bleed? Reason I'm asking is because I've heard bad things about the ABS on these cars.

 

Alright, that should be good for now. Thank you again for the help so far.

I'll keep you all posted.

[Redfox340]

Thanks for all the help so far. I'm getting the feeling that most of my problems are going to be with the belt so I might as well do that next, ASAP. WHAT SHOULD I REPLACE WHILE I'M CHANGING THE TIMING BELT?

 

With the Timing Belt, replace the acuator and both of the plastic pulleys.

That'll insure that your new belt won't self-destruct (shreding) after installation.

Also, since you'll need to pull the intake manifolds, DO NOT re-use gaskets; snag new ones.

Check the Oil Pump o-ring to see if that's in need of attention while the intake is removed.

Clean everything, watch you parts label items if necessary.

 

I'm willing to be your high RPM problem is a leaking intake manifold gasket.

Common W-Body problem on the DOHC... best of luck

Any trouble codes by chance?

 

- Erik

[Baddflash]

As you said that the previous owner didn't take care of the car try replacing the fuel filter, it may be adding to your problems. Also your TPS my be causing the over-reving problem. I don't know much about the 3.4 but maybe that'll help.

[89oldscutlass]

On alot of the Abs brakes ive worked on the light comes on when the brake pads are gone in the front or rear. Try bleeding the brakes first like you were planning to do and then if that doesnt work check to see what type of shape the pads are in on the front and back. If he didnt keep the maintenance up on the car he more then likely put cheap brake pads on.

When I by a car I first change the oil, replace the plugs and wires and put new brakes on them. New brake pads might fix your abs problem if not you might have a sensor bad on one of the wheels.

[Jeorge]

for the reving check the Vacume on the Pass side of the intake there is a Black plastic piece attached to the intake and if that has a crack it will Rev to stay Running....