During driving the car started to feel strange so i pulled over. All instrument needles peeked including the rpm and even the speedometer did not show normal reading. As soon as i pulled over the car engine stopped. i checked under the bonnet and everything looked normal so i tried to start the car again which it did. After a short ride the instruments went crazy and the engine stopped again. This time i noticed that the alternator was very hot so i thought there is the problem. When everything was cooled down after a long wait the car started and i drow it carefully home and garaged it as it was end of season and winter on its way here in Norway. I bought a new alternator during the wintar and installed it now in the spring. Battery was flat and when charging it with a gharger i noticed that it would not take charge. Kept the charger on and tried to start the car and even then it wouldn crank so i presume that the battery was shorted and completey ruined. New battery was ordered and installed today. Everything lights up and everything looks normal. Crank like it suppose to nut noth even a cough from the engine. Just like no spark at all, crank and get oilpressure but no sign of ignition. As you all know it is a pain even taking out one spark plug from the LT1 so before taking things apart i cry out here for help. For info, new MSD optispark, coil, ignition module, spark wires and an AL6 multispark module installed. So to make this short. Drove it in to the garage, replaced faulty parts and now it wont start.

Thanks and regards,
Steve

 

Do you have any codes from the ECM?

 

The opti is a prime suspect. If you are mechanically inclined, replacement is not a difficult chore. Search google for info confirming failed opti.
There is a step-by-step photo procedure for the opti replacement....
search this forum..."Replace Opti".

 

Hooked up my Tech II. No codes. Strange, checked all fuses. No fire at all when i crank, will check the fuel supply but i guess that a faulty pump or relay would give a code.

 

Replaced the old opti with a msd around 2000 miles ago.

 

Did you also replace the Opti connector harness at that time? If not, check it. I had a similar issue, replaced Opti, coil, etc, only to find out is was a loose fitting Opti plug harness. If old/original, the tabs get brittle from heat and don't click tight when re-installing.

Mine wouldn't start, then intermittently died. I could reach down to the Opti connector with a long screwdriver and get it to start.

If any doubt, consider replacing. It's a sensitive connection.

 

Replaced the harness to. Very strange, engine was running even with the battery bad when i parked it. Now after new battery and alternator its not even try to spark. Just cranking. Been sitting in the garage since September last year when i put it to storage for the winter.

 

Darn! I was hoping to have an easy solution! That is odd. Good luck!

 

Ok - You need three things for the engine to run: Fuel, Spark and compression. When you turn the key to on - do you hear the fuel pump run ??? You can hook up a fuel pressure gauge to the test port on the fuel rail, and you should see around 43 psi. If you have fuel pressure, you could then check to see if the injectors are shooting fuel out - but even if you do that test - the results won't be conclusive. If you have fuel pressure - the next thing to do is to check for spark. Cylinder 4 is probably the easiest plug wire to get - pull it off, have someone crank the motor over and see if you have a spark. If you don't have a spark - it's probably either the coil driver or the opti. The best way to differentiate is to backprobe the 4 pin connector on the right side of the intake manifold. Pull off the cover, and you should be able to see a connector that's attached to the intake manifold. In order to do the check - you'll need a meter that can read frequency or duty cycle and some kind of needle or pin - to be able to get into the connector and make contact with the pins. Many inexpensive digital meters have a frequency scale.

Pin "C" is the feed voltage to the Opti. Pin "D" is the ground. Pin "A" is the Low Res output from the Opti. And Pin "B" is the High Res Output from the Opti. While cranking you should be able to read some kind of frequency on Pins "A" & "B" when you backprobe the connector. No reading on Pin "A" or "B" - when you have power on Pin "C" means you get to replace your Opti. If you do have some kind of frequency reading on Pins "A" & "B", and you probably got lucky - you probably have a bad coil driver module. You can test the coil driver by using the digital meter - set to frequency again, and checking terminal "A" (pink & black wire) as you crank - you should again see some kind of frequency reading. If not - the coil driver is probably dead.


GOOD LUCK !!!

 

Hi. Why don't you give it a little squirt of starting fluid. If it "farts" or coughs, starts to run, then you know that it is not getting fuel, or injectors not working, eliminates spark