DaBwyan61

Hello! New to this forum so I'll start here with an intro on me and my 94 z28. I hope I don't make a huge wall of text, but I'm exciting to share my car with others and learn/get advice on it. (Bear with me if I mess something up, I have a decent grasp on most things but I am by no means an expert)

To start things off, I'm an engineering student and while I've always been into cars, it wasn't until these past few years that I've started to get more serious about them and start to learn about them and how to work on them more. I've daily-ed an 2002 GS300, 2006 Civic Si, and a 2009 Accord (5-speed at least), so this is my first adventure into something with some decent torque and power. After a semester of an internship and little inheritance I decided to take the leap and explore my hobby more.

After some searching I thought I came across a deal that would be pretty hard to beat. I found a 1994 Z/28 6-speed with just under 90k miles and the guy just didn't have time to drive it anymore. $3200 later and I'm driving my new baby home. It's definitely not perfect, but it sure is a blast to drive.

This was back in May, so I'll put a quick summary of what the car has / problems & questions I'm still working on. I'll try and keep it as neat and organized as I can. I can also post other parts to their respective sections if need be, but I'll use this post as baseline as to where I'm currently at with the car.

Things the car came with:

6-speed Hurst Shifter
(Full?) Flowmaster exhaust (cat is gone and headers don't seem to look stock)
K&N Intake (not sure exactly which one)
BF Goodrich 245/50ZR16's all around on (stock?) chrome wheels. Seller also threw in 10-spoke wheels which I think are off a slightly newer 4th gen
3.42 rear end (GU6 code)
And that's about it. The rest of it is pretty barebones, including crank windows (which didn't bother me as I've heard the power windows can break easy)

Things we've done since getting the car:

New fuel filter
New spark plugs for cylinders 1-6, stopped there as the older plugs seemed to look fine and 7 & 8 are definitely not easy to get to (any advice/tricks on how to do 7 & 8 would be greatly appreciated)
New water pump
New optispark (Definitely helped me learn about the car and wrenching)

Things I have questions on / some ideas of:

1. ABS INOP / Low Trac lights
When you first start up the car and get moving the brakes feel a little funny and the low trac light will come on. It feels like it is coming from the front left brake. I did manage to pull the ABS codes from the inop light and they are and what the service manual says (with manual reference page #s):
28: Rear Excessive Wheel Speed Variation 5E1-66
32: LF Wheel Speed Snr Ckt Open or Short to G nd/Batt ( 1 fo 3) 5E1-70
33: RF Wheel Speed Snr Ckt Open or Short to Gnd/Batt (1 of 3) 5E1-72
16: ABS Enable Relay Coil Circuit Open 5E1-40
58: Left Front ABS Motor Circuit Shorted to Batt 5E1-116

I'll read more into the manual to see what each says, but if anyone knows anything about these any extra info would be appreciated. At first I thought it was just the front left ABS wheel speed sensor but having a second look at the codes I think it may be a little more than that.

2. Some stuttering while on throttle
Sometimes with some light throttle, or the car being in 6th, or if the engine is under a little bit more load (?) like going up a hill the car seems to stutter. I've heard some people suggest fuel filter (replaced already), and other say plugs/wires may be a possibility (could be, 7 & 8 plugs not changed yet and no wires have been changed). I also had the idea of a bad MAF sensor or a bad throttle cable, but I think those are less likely and I may not know enough about those yet to accurately guess.

3. Driveshaft shaking/vibrating
Easy to tell when in 6th on the highway, but once you start doing 70-ish+ it sometimes feels like the driveshaft or something will shake loose (to go along with the stutters). There's also quite a bit of vibration you can feel if you put your foot on the clutch pedal and push a little. The vibration I'm fairly certain is a U-Joint but I'm not sure about the shaking or if the shaking goes along with the stutters.

4. Rear end whine
Sound really comes out when you're in 5th & 6th. I don't think I should be too worried about this as I think it's the gears. Our trusted mechanic suggested trunnion gear (or maybe pinion?)

5. Strange idle behavior?
I'm not sure if this is a V8/LT1 thing but when idling the engine kind of has a wave-like behavior where the revs fluctuate 100-150rpm or so. Again, not sure if it is a real issue or not, just something I've noticed.

6. Bad start up every once in a while
Every once in a while the engine doesn't seem to want to start and will stall, and then if you try again it doesn't really want to turn over. After removing the key, waiting a few seconds, and trying to start it again it usually works. Not sure if it's a sign of a future problem or what, maybe related to the plug wires again.

Those are basically the main issues I'm working on right now. There are smaller issues such as the speedo being off by around 5-7mph (not a huge deal, but it makes me wonder since the tire size on the sticker on the door says 235, not the 245's that are on it now) and the gas gauge also being off (also not a huge issue, car regularly averages 18mpg and can easily calculate how much has been used in 15.5 gallon tank). Once those are sorted out I'd love to change a few things around on the car. I'll add them here and would love any suggestions and advice.

Possible Future Mods:

LT1 LE2 (still slightly confused on what it all consists of, any simple explanation and some advice for supporting mods would be greatly appreciated) LT1 LE2 «
3.73 rear end (always see this recommended, not sure where to find it to buy)
Subframe Connectors https://www.summitracing.com/parts/upi-2002-b/overview/
LT4 Hot cam https://www.summitracing.com/parts/nal-12480002 (if not LE2)
Different exhaust (I've heard flowmasters are not very good for actual flow/breathing, would love any suggestions)
Larger rear wheels maybe (fairly certain that would mean I would have to move up to at least 17's in the rear)

And that's pretty much it for now. I'll try to make update posts on things I fix for future reference or if anyone else has a similar issue

Injuneer

Welcome to CamaroZ28.com ! ! !

Always good to se another LT1 owner on the site.... about the only enthusiasts left here. Also good to see another (future) engineer on the site. I'm a licensed professional engineer (mechanical).

I would suggest that you take everything from "Things I have questions on / some ideas of:" to the bottom, and copy and paste it into a new post on the "LT1 Based Engine Tech" forum. Best place to focus tech help. Leave this post on "New Member Intro", but delete the part you copied and pasted. That way we'll have the tech discussions in the tech forums, and won't have duplicate responses in this forum.

Or if you want, I can copy this post to a new thread on "LT1 Based Engine Tech" for you, and delete the ”new to forum" section.

In any case, great questions, very clearly stated. Good way to start off.

PS:

https://www.camaroz28.com/forums/lt1...nature-879835/

DaBwyan61

Thank you for the welcome! Just added the signature and I'll take your advice on posting to the tech forum.

And I guess my engineering classes / co-ops have shown since I try to keep things clear and organized. Makes life a lot easier.

Injuneer

You have obviously learned one of the most important lessons.

DaBwyan61

I've picked up quite a bit from my program so far whether it be classes, co-op, or an unrelated note of car shows. Topics ranging from organization to simplification. I deal with a lot of records and other book-keeping related stuff at my co-op. Boeing's manuals are nicely organized and usually fairly easy to find stuff. Then you get to some smaller aircraft operators and their records are all over the place and a nightmare to deal with.

On the car show side there was just a show in Norwood commemorating the 30th anniversary of that factory getting shut down. Now that I understand cars/engines a little better I was blown away at how simple some engine bays seemed to be to work on. Everything is just right there in front of you and I almost shed a tear at how easy the distributor was to get to after spending many weekends figuring out the optispark replacement... Now I understand why my dad did all kinds of engine work/building with his cars in high school, everything was simpler back then.

Z28500

I get to hard to reach plugs from the fender well with the tires off on my '79 and since I have Dart Iron Eagle with long tube headers I use a specially ground down offset box end 5/8 wrench , ground to fit in the recess and I slide under the car to get to number 6. I can't even use a socket- that 5/8 wrench used to have a 11/16 on the other end, but it is gone now that I made a specialty tool out of it. Basically ground down the entire boxed end circle until it fit in the very deep spark plug recess yet still gripped the plug.I kept the handle about 5 inches long. Spark plugs don't need to have more than 20 lbs torque anyway, lube the boot put it on, you are done.

6 is the worst one, However, even though plugs are hard to get to doesn't mean "leave them"
that 4th gen is way under the firewall because of the windshield Plugs are just something you have to deal with
7 & 8, probably under the car and learn to be a contortionist
Maybe even drop the driveshaft and the cross member so the back of the engine goes down far enough to get from under the car.
Lot of work, but you have a 4th gen.
If it was my car, I would pull up the carpet and cut holes in the hump and have a screw on plate siliconed every time I put it back on so I could get to those plugs, I'd do it even if the car was new. Some people can't handle that though but I'll modify something in a heartbeat if it makes things easier on me.

Z28500

Those optispark's I would get a spare and keep it in the glove box or maybe you have the original one you could use in a pinch, kind of like a spare tire