I'm having a very bad problem with my car, its a 93 z28. I'm a mechanic of over 13 years a thought i'd seen most everthing unitl now. My car quit about couple months ago and I've been working on it since. The problem it wasn't firing. I put a new opti spark, plugs wires the works and now I've got spark but still nothing. I've ck my fuel pressure 48psi and holding injectors spraying. The car will not hit a lick. It ran perfect befroe this and just died. In my mind if it has fire,fuel air and compression it should run. I have ck for all this and all ck good still nothing. The only thing I know now is that its firing got compression and it will not hit spraying starting fluid and my obd 1 scan tool will not connect. I would think ecm but Ive never seen 1 not do anything when spaying starting fluid to it. Any help would be great please!!!!
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Did you check compression on ALL the cylinders? My guess is no.

If you TRULY have compression and spark, then the spark is occurring at the wrong time. But not knowing the exact conditions under which your engine crapped out, one can only guess.

Get back to us on the compression of all 8. Then you either confirm what I think your problem is or you move on to something else.

 

I'VE CK ALL CYLINDERS 100 PSI OR MORE ON ALL. I'VE CK THE TIMING ABOUT 1 MILLION TIMES. IT COMES UP RIGHT IN TIME. VERY CONFUSED. THIS CAR RAN GREAT NEVER BEEN RACED PULLED IN THE STORE PARKING LOT IT DIED. BEFORE i REPLACED THE OPTI IT SEEMED TO WANT TO RUN BACKWARDS. I WOULD CONNECT MY STARTER BUTTON AND SPIN IT OVER, WHEN I LET OFF THE BUTTON THE CRANK WOULD SPIN BACKWARD AND IT WOULD SPIT AND POP A LITTLE BUT SINCE CHANGING IT NOTHING. IT IS FIRING NOW BUT I SPRAY A LITTLE EITHER AND GET NOTHING.

 

And when you checked compression you disabled the injectors and opened the throttle plates wide open too? Right?

 

No, pulled all plugs and ck 1 @ a time didnt know you had to do that. What does the throttle open do?

 

Try sucking through a straw with your finger over one end.

Do you understand what squirting injectors do?

Any way, pull a valve cover off and spin it over.

 

Ive pulled both valve covers. Everythings moving, i dont think its a valve train issue , all the rockers and springs look good, there all in place and working, dont think i would have compression if i dropped some valves. I know the injectors were disable the ignition was off when testing. I've ran several compression test and never had to open the throttle but i can its not a problem.

 

Not sure how it would fire at the wrong time, it has a distributor and it will only fire when the rotor contacts the prob in the cap for each cylinder unless it was out of time, and the opti is keyed dont think thats the problem.

 

When you say you checked the timing, how did you do it?

 

Pulled #1 plug bumped it to compreession strock rotor pointing @ 1 in cap.

 

I haven't pulled the timing cover and looked @ the cam/ crank, do you know if the shaft from the cam that drives the opti goes in the cam or is there a gear running off the cam?

 

Sorry compression stroke

 

SCAN IT FOR CODES!

Do you realize you do not need a scanner to read the codes off your 93?

Courtesy of Shoebox:

http://shbox.com/1/dlc2.jpg

While in theory the Opti splined drive shaft can only be assembled in one position, its is VERY possible to do it incorrectly. About 10% of the installs go wrong due to the splined shaft not being indexed correctly.

 

And YOUR number one contact is located at what position on a clock face?

Sorry not others but yours?

 

just about straight down I think. I could see the contact in the cap. Its a new cap and I can see it running in the cap.