I am looking at buying a 1993 Z28 and was wondering if there are any common problems that I need to look for? I am not very familiar with the LT1's, only the LS1's. I am aware of the crappy optispark on these cars and that has been taken care of already. I miss my old camaro so I want to buy another one.

The car is a 1993 Camaro z28, red, cloth, 6 speed, 90,000 miles, very nice condition, new water pump and distributor. It's stock except for a stereo, K&N, and a cat back exhaust.

Does $4300 sound like a fair price? Also does a 93 have anything different from the later LT1's because it was the first year?

 

Was the Opti replacement a genuine GM/Delco/Delphi part, or some off-brand or remanufactured part? Anything other than the GM part could fail much sooner.

The 93 has major differences from all the other LT1 cars... ECM controls only the engine, not the tranny like the PCM used 94 and up (hence no "skip shift" on a 93); batch fire injection rather than the full sequential in the 94 and up; speed-density rather than an MAF like the 94 and up; AIR and EGR share common plumbing, meaning the headers will be different; T56 has totally different gear ratios and lower torque capacity, in two different versions (M28, M29) with either 2.73 or 3.23 rear axle.

There's a thread with the differences explained in detail. Maybe someone else has a link, or you can try a "search" to find it. Lot's of helpful info.

 

95's are the best, vented opti & obd1. Of course I might be a little partial. LOL.

Have fun!

 

Price sounds about right. I would take it out and test drive it and make the sure engine is still strong. I actually had the owner, who was driving it do a 0-60 run and I timed it. I also checked the transmission shifting and suspension.

 

I'm not sure on what brand for the optispark was used, but I will find out. Is the batch fire injection a bad thing?
I will eventually throw heads, cam, and maybe a supercharger on it, would it be harder to tune with the batch fire injection?
Is the different gearing in the transmission noticable? How much weaker is it? How do I tell if it has a m28 or m29? I will try and find the thread your speaking of. Thanks for the replies!

 

There should be a build code tag on the door jamb or in the glove box. "M28" or "M29" would be shown on the tag. Ditto with the rear axle ratio (it its stock), GU2 = 2.73, GU5 = 3.23.

Torque rating is:

M28 - 350 ft-lb
M29 - 400 ft-lb
MM6 (94 and up) - 450 ft-lb

The 93 has an ECM (engine management module) and not a PCM (powertrain control module), hence does not control the transmission. Only thing missing on an M6 in a 93 would be the "skip shift" feature that prevents you from shifting from 1 -> 2 at low throttle/low RPM. No big loss, everyone with a 94+ just disables it anyway.

Here's the tranny info (ignore the "GU4" for the 3.23 gears on the M29 - that is a typo):

http://www.ws6.com/faq/4_3.htm#ch4_3a

Here's the link to the entire site:

http://www.ws6.com/faq/

As far as tuning, the 93 has a removable chip in the ECM. To tune, you have to have a new chip burned. Not hard to find, just a bit inconvenient. There is a way to tune live, but its not all that easy or cheap. The 94+ has a fixed chip and is flash programmed.

The injection - batch fire vs. full sequential is relatively insignificant. I feel you can produce more power with sequential at really high HP levels, but for what most of us mortals do, there's no real difference. The 93 injectors are 22 #/HR, 94+ are 24 #/HR. Again no significant difference.

 

Hey thanks for the great info! If i can't find the build code tag, is there another way to determine what trans and rear end it has. What would the rpm be at 65 and 75 mph in both cases? Did the m28 only come with a 2.73 rear and the m29 with the 3.73?

 

Intake manifold leak.

 

http://www.compnine.com/vid.php

Put the vin code in that web site and it should tell you all your RPO codes and what not.

 

sweet thanks!

 

Well I checked the vin and it has the M29 trans and the GU5 3.23 rear so that makes me happy. I did find out that the opti was replaced about 2,000 miles ago, but with a chandler motorsprots or something like that so that sucks.

 

I will sell you my already supercharged 93 z28 wit 68k miles on it for 5k flat..its got a richmond motorsports built t56 in it and lots of other stuff pm if u interested

1993 camaro "superzee" z28