I'm new here and apologize for starting off asking for info. I have read through many of the posts to see if my question has been previously answered but did not find anything directly on point. So here goes and thank you in advance for your time & info.

I have a 1992 C4 LT-1 6 speed which has 55k miles. I am the 3rd owner and the car appears to be stock. Last December I had my local dealer replace both clutch (master & slave) units and when the car was returned I had the following problems:

1) Under acceleration (not real hard) in 4th, 5th & 6th gear the car feels as if the clutch is slipping. The battery cable was loose when I first picked it up. After the dealer tightened the cable this problem persisted although not as bad.

2) When applying the brakes, (harder than normal but not a panic) the "service SRS" & "service ABS" lights go on. After killing & restarting the engine the lights go out.

3) Upon cold start, the "low oil" light comes on after the engine is started although the pressure is fine according to the gauge. If I kill the engine and restart immediately, the light does NOT come back on ??? This only seems to be a problem upon the 1st start up after sitting for several hours and occurs say only 7 times out of 10 starts ....

From reading various posts it appears the ECM is linked to the ABS / SRS systems. I am wondering if the loose batter cable has caused some kind of malfunction in the electical system which is causing this problems. The oil light problem I have no clue about ??

Thanks for the help and I hope to be able to contribute in the future.

Thanks,

Carl

 

The only one I can help with :

3.

My '92 does that when it is a 'bit' low on oil. Either add a 1/2 a quart or get an oilchange and fill it up to the required amount and it should be fixed.

Otherwise, welcome to the forum.

 

1) There are known problems with the slave units on clutches. I don't have any first hand experience but a search on the subject will show you what I mean.

2) Check your brake fluid level. If it gets low it can cause this problem.

3) If your oil level is good then it is most likely a sensor problem. The FSM can show you have to verify this.

Welcome to the forum.


Dave

 

Thanks for the great input. My slave was leaking which caused me to take it in .... Is my Clutch slipping or engine lugging possibly an ignition problem ?

Seems like all of this started when I picked the car up w/ the loose battery cable ??

Thanks again !

 

1 – The master or slave would not cause the clutch to slip. If anything, it would cause you to have a problem getting it into gear. If for some strange reason the clutch was not releasing all the way caused by the hydraulic system, it might cause that but it is a far reach for that to happen. A huge screw up would have to happen in the installation. Most likely the clutch is just bad as you indicted. The battery cable is not going to effect the clutch operation either.

The clutch problems referred to on the Forum in the last months were master clutch cylinders where the rubber ‘o-ring cups’ were installed backwards. This caused soft pedals and problems bleeding the air. It came from the manufacture like that.

2 – Your service ABS light is probably caused by a low fluid level in the brake master. It may look full but it probably has to be topped off a bit higher. This may have set a code and should be checked out and cleared if set.

3 – I agree with the 2 suggested oil solutions so far. Another thing to try would be to disconnect the battery cable for a few minutes to clear the computers. A glitch may have occurred setting a code and starting with a clean slate may help..…I agree, this suggestion is a stretch.

 

mid-repair update....

Dealer diagnosis:

Oil light - unknow but believes pressure is fine ... will check level be completing oil change.

ASR & ABS Service Lights - exactly what you guys thought. Fluid low due to brake wear. Brakes down to 10% / 20% therefore will do the brakes.

Lugging - Engine lugging @ 1600 RPM which causes feeling that clutch is slipping. Bad Optispark. Will replace w/ new water pump, gaskets.

Once Optispark is in they will determine status of plugs & wires (could be expensive from my reading of other posts).

Will check S belt & coolent while apart.

So far $2,200 ... ouch ... but you just gotta love your vette !

More to come ....

 

Picked up today .... plugs, wires, hoses & belt not needed. The car runs great and idles much smoother w/out any lugging ! Thanks for all of the input !

Carl

 

The engine lugging sounds like an optispark problem.

If you're on the highway, have it in high gear, and go to floor it and it just stumbles every once in awhile. -Or- as I experienced, if it wont go any faster than say 115 MPH. Your optispark is bad.

If you are on a hot acceleration run,gun it, and it bucks and kicks at some point during the run, your optispark is bad.

Buy a book and do the work yourself. Dealers will rip you a new one and usually mess up the job anyways -at your expense. The optisparks are down to $300 or so dollars. Dynaspark makes a better than stock replacement unit. The newer (95-96) models have vacuum venting to suck out any moisture that may get into the unit. I retrofitted the new one with a 95-96 cap and vacuum venting.

Very very common problem on LT1 C4s.

When I bought my creampuff 93 vert ZF6 in 2001 (26k miles), I thought theres no way that can be bad. Boy was I wrong. The whole rotor was rusted, rust flakes inside the optispark, etc.

 

you will quickly learn that the dealer is not your friend. It just takes a while.

 

As im reading i was getting nervous. Just glad all worked out.