kylej253

i recently received a 1994 Z28. i had to put the car back together in order it get the car home. the car had no distributor in it. the previous owner put the MSD distributor in the car. it had problems being reliable. he was in the process of putting things back to stock when i got the car. it only ran for him for about 50 miles before it wouldn't start again. he said he had to put a high voltage coil on it to get enough spark to get it to fire. i re installed the MSD distributor with MSD plug wires and MSD coil. The car would turn over but not start. we have spark. i then hooked up the MSD 6A igniton box and the car fired first try. i then installed the meziere water pump and put everything back to normal drove the car home about 20 miles. it sat over night and when i went to start it the next night it just cranked and cranked and then dieseled a few times. i messed with the time screw on the distributor it then finally started after about 30 sec of cranking. Ran ok but felt like a mis fire when at low rpms. parked it and it hasnt started sense. Any one got any ideas. i have fuel pressure.

96capricemgr

iTrader: (1)

Either get a timing pointer on it and mark the damper and get the tuning software to dial in the spark so you know how to figure out what the distributor is set at, or put a stock distributor on it, take off the box.
Ignition mods on a stockish LT1 are nothing but proof of ignorance and wasting money. I say this as someone who made these mistakes.

The fact he told you it needed a "high voltage coil" proves he was an idiot, good luck with the stupidly modified basketcase, hopefully the ignition is the only place he got stupid.

The MSD distributor is no better than stock and a huge problem when people mess with the timing screw without any means to verify position.

kylej253

Do you think I can leave the msd plug wires I have a stock distributer for the car. He had a lot of money and bought the msd and when that started giving him issues he bought a stock one. I have four diff could and I few other parts. Just hate draining the coolant and taking everything off the car just to change out the distributor.

kylej253

I did find the number 8 injector was unplugged which was prob why it was mis firing. But it still won't start.

BALLSS

OP

The MSD Opti is suspect and as mentioned messing with the timing screw without any way to see wtf is going on with timing is futile.

Put on a AC Delco opti or Delphi. MSD wires and coil are OK. Ignition box really does not benefit. did a dyno test with our local club several years ago. two pulls with and 2 without and really no difference beyond normal variances you would see with multiple pulls. It did however show a more consistent graph line in the upper RPM.

I have seen Optis after 10-15 years using a MSD box. No unusual wear as a result as some claim... YMMV

kylej253

Did some more trouble shooting tonight and found I now have no spark at the coil any ideas. Had spark two days ago and now it's gone.

kylej253

I have put a new oil on and the car started with minor trouble. Any idea what would cause the car to go through coils. This is the 4th coil the car is on. Two msd coils. One has no spark the other has really lame spark. The previous guy put the accel high output coil on that lasted about a month and the spark went weak. I'm now running some oem replacement but I doubt that will last. What could cause this???

Kevin Blown 95 TA

Don't rule out bad replacement parts. It makes troubleshooting that much harder. Sometimes going back to stock helps ya get it running the fastest then gives ya time to troubleshoot all your suspect aftermarket parts.

A bad coil can be heat sensitive and run good when it is cold, then start breaking up when it is warm and under load. It can be a deteriorating condition.

The MSD adapter wiring harnesses that plug into our wiring harnesses can be faulty and cause a bad connection (in case you are using one of those).

You also need a good ground from coil to the engine - don't forget the current and voltage that needs to flow.

On our cars the ignition module can be troublesome. It gets cranky when hot. Most of us space that thing off the head to let it run cooler and prevent heat heat soak.

From past experience with ignition boxes, they can not like a coil's impedance and try to protect themselves by shutting off. I had this happen with a Crane box and MSD coil. Something about that mismatched combination was causing random stalling and hard restarts. The rest of the time it ran great. The Crane guys sent me one of their coils to try out and problem solved. Just something to keep in mind. A bad coil may have a similar effect on the box.

kylej253

I removed the msd 6a box from the loop. Just stock plugins going to the coil. The coil is bolted directly to the driver side head. On the same bolt holding the coil down is a ground strap going to the frame. I'll add another ground to the other side of the engine. To the battery negative. I'm just hoping this coil holds up. I will also try standing the modual off the head for better cooling. I did apply a heat sink paste to the coil mount to help with heat.

JOHNNYMO

iTrader: (1)

If your MSD opti is from older stock, it can have a questionable optical sensor. I had a brand new one in mine which made it about 1500 milkes and took a dump on me. Hard starting, no starting, coughing and stuttering...etc I sent the opti back to MSD and was told by the tech there were many out there with a bad run of optical sensors installed in them. I paid about $150. for the rebuild and shipping. The unit came back with new internals and cap and rotor. been great since. Id bet its the same problem with yours. Get the codes pulled using the KOEO and SES flash counts. That will help with diagnosis.

kylej253

I have to assume the guy bought guy the msd distributor opti spark in 2007 or 2008. Is that older stock.