I have a 1994 Camaro Z28 that is having a problem. I know it's electrical but I don't have any idea what it is. Last week I went for a drive and on the way back home (cruise control 70 down the interstate) the car started messing up slowly at first but getting worse. Along with this problem, the tachometer was jumping around a lot. The engine wasn't actually doing the said rpms either. If I gave it the gas the tachometer would jump really fast and pretty much max out and then jump back down when I let off, but the motor wasn't, it was acting like it was going to die and eventually did and I had to pull over. After that it wouldn't start but had the check gages and service engine soon light so I had to pull it home on a trailer and let it set a few days. A few days ago I went out and it started right up. Now it won't start again. Please help. I need this car to work...

 

My first guess would be the fuel pump. With the engine stopped, turn the key to the ON position. You should hear a whirring noise coming from the back of the car. It's pretty quiet, so you'll want to do this some time when there's not a lot of background noise.

If you don't hear the pump, that's a pretty good sign that you need a new one.

 

I can hear the fuel pump fine. Any other suggestions? I appreciate it!

 

Optispark? I don't know how to check that.

 

Hi,
Check to see if the lead from the coil to the opti-spark is fully pushed on at the coil end,also check for any corrosion,just a thought.
Mark.

 

Check your grounds, as I've had the main ground cable next to the positive distribution block get loose and cause a host of issues. Other than grounds, a jumping tach I've found to be indicative of a coil issue before too.

 

I checked the PCM, even replaced it with one from another z28 with same results. I also tried a coil and ignition control module from another z28. I did find today that the car is not starting because it is not getting a spark. I checked for voltage on the coil wire to the distributor. It was about 12 vdc, definitely not even close to the voltage needed for a spark. So, the signal is getting to where it needs to be, but the coil is not stepping up the voltage near enough, however, I checked the coil in accordance with the haynes manual, which said the coil was still good, plus, I know this because of the known good coil and ignition control module I used. Also, this motor was rebuilt 150 miles ago. The optispark and pretty much everything big is new. I checked the ground wires too and they were all attached pretty well. Help!!!

 

said stupid but check fuses, sometimes in the middle of checking wires you trip them.. i did .. lol

 

I've checked them all already.

 

Sounds like optical sensor in the optispark is dead then. It is where the PCM gets the RPM signal from and gets info for timing, so if its dead then the PCM won't tell the coil to fire.. thus no spark. Or you got a wire grounding out...

 

My 95 Z28 did the same thing it was the opti and it was only a week old maybe 100 miles put on it.So I got a brand new AcDelco next it was fine.
I have heard alot of guys getting opti's that are bad.
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95 Z28 398 RWHP

 

Did you ever scan it for codes, to see why the SES light was on?

 

sounds too me like your alternator went on you, take it out and have it checked....same EXACT thing happened to me in my other camaro last year

 

I tried to scan for codes but it wouldn't work, it said something had to be repaired before it would work

 

The alternator is new so I don't see how it could be that. I just rebuilt the motor 2 months ago. Anymore suggestions I would greatly appreciate!