I've been having a hard starting problem with my 94 z28, I wasnt getting any codesuntil i put the other computer i bought from a salvage yard that came out of a 94 caprice Lt1. And i got a Check engine light and acode 43 when i started it up. I thought it might have been a code stored from the other car. So i cleared it and rescanned the car and got a 43 again. Cleared it one more time and 43 again.
43 electronic spark timing failure. I checked the reference voltage from the computer to the knock sensor plugand got 4.82v. Could a bad knock sensorbe causing my hard start? Why didnt my other computer set this code?
It is hardest to startwhen hot, i can turn it over a few times and it sounds like it wants to start(kerplunk kerplunk kerplunk and then it might backfire through the intake)but it still takes about 2 turns before it starts when cold when it used to fire on the first turn.

 

Sounds like it could be an opti issue to me...Those are all symptoms of a going bad, if not already dead, opti.

 

The opti is a new msd unit. I noticed the hard starting problem the same day i got it running with the new opti

 

Make sure everything on the MSD unit is connected correctly and the pin on the cam is set at the correct lenght so the opti can pick up the position of the cam, if that pin is not at the correct lenght you're going to have issues.

 

Im 99.9% sure it is installed correctly. I have the spline drive and it fell right into place after about 10 minutes of trying to line it up. Now i cant get any spark at all from the coil. I ran ityesterday for a little while until it heated up and ishut it off and then tried to restart it.And it wouldnt start at all. That is when i checked signalvoltage from the opti to the ICM andI have 2.1v ac signal from the opti while cranking so at least it shouldnt be the distributor. Im gettingno spark from the coil while cranking so whatever was going bad has bit the dust. Imglad it died because it will help me find the problem a little easier because ican rule the distributor out.It has to be the control module or wiringor something. I just bought the control module that is on it. I tried bothauto zone and advanceautoto test my old onebut neither had a testplug for it.
This has been the biggest headache i have ever had with a car. It seems if i fix one thing something else messes up. I sure miss the old HEI ignition.

 

I found my problem, the wire on theblack plug on the coil broke off flush, it must have been just barelyhanging on not giving enough juice to the coil, giving me a hard start until it finally fell of when i wiggled the wires. I ordered a new plug for it.

 

HAHA!!The wire wasnt what caused my hard starting problem, it was just a coincidence, Im still having the starting problem... This SUCKS