Hgk4life

Hello all, I had spark to the coil but not to plug wires so I changed optispark. Now after putting all together properly with a new harness for optispark new cps and new icm I am not getting any spark. Cranks over good but won't fire. Please help.

ahritchie

iTrader: (1)

I would scan it for codes and read this: http://shbox.com/1/4th_gen_tech2.html#opti_test

What brand opti did you use? A lot of the parts store ones are garbage.

Hgk4life

Not sure the brand but it came complete with everything in it. Shouldn't I be getting spark from the ignition coil to the optispark first? I have replaced optispark, crankshaft position sensor, ignition control module, ignition coil, water pump and thermostat. Really don't know where to go next with all those new parts you would think there would be spark somewhere? Please help! any ideas greatly appreciated

Hgk4life

Before I figured out the optispark was bad I had a GM mechanic bring a computer and hook up to it but it didn't show any codes at all

ahritchie

iTrader: (1)

Obviously you didn't thoroughly read the opti test posted....let this sink in:

The opti has two functions in the spark process. The first thing that happens is as the cam turns, the optical section of the optispark picks up the signals by the rotation of the shutter wheel. The pulses are sent to the PCM via the optispark electrical harness. The PCM processes the signals along with other sensor input and determines the proper time for the coil to fire.

You should be getting spark in a perfect world....but as stated most cheapo optisparks are P.O.S.'s.....how much did you pay for it? In my personal experience the cheap one only work 50% of the time first try. If you didn't pay at least $350-500 you likely have a P.O.S. opti. (Non GM or MSD). I'd test it, return it for a refund if necessary and buy a good one.

Hgk4life

It's a cheapo from eBay. Any way to test to see if it's sending signal to computer? By harness? I have been giving that change out some thought now that it still won't start. Probably go with msd but would still like to know if it's even sending signal or is the timing chain broken? Before I tear it back down? Any idea to test would be greatly appreciated. Thanks again

ahritchie

iTrader: (1)

Again, you have to read the WHOLE thing, the opti testing procedure is outlined, you need a volt meter and test it at the harness.

Ebay is the worst possible place to buy poorly manufactured Chinese made optisparks, at least the parts stores will take it back their poorly manufactured Chinese optisparks and refund you without much headaches or shipping....take this as a lesson learned. You can certainly test it it, but the source of the issues is sorta obvious to those who have also dealt with POS optisparks...

guppymech

iTrader: (7)

Do you have the old optispark? It may be a GM one and only need a new cap and rotor. With all those other parts you changed did you try them one at a time? You could've got a bad ICM or coil from the parts store.

Hgk4life

Hello, I do still have the GM optispark and the rotor was in pieces when I took the cap off. My only question now is whether to buy the GM rotor and cap for my original optispark at a cost of$353.94? Or a whole new msd optispark for $500.00? Any and all suggestions would be appreciated. Thanks in advance

ahritchie

iTrader: (1)

I would try a new cap/rotor on for sure if that was what originally broke.

guppymech

iTrader: (7)

Get a MSD cap and rotor, they're supposed to be good pieces. IMO BWD makes good stuff too. Make sure the broken rotor didn't mess up the rest of the opti before you spend the money on a cap and rotor.

Hgk4life

That's what I'm afraid of. How can I test the rest of the parts to see if they still work before spending money on new rotor and cap?

ahritchie

iTrader: (1)

If your opti worked before, then the rotor broke, the optical sensor portion likely still works fine; it's unlikely that both the optical sensor components AND the rotor self destructed at the same moment. You could try just the cap/rotor off the cheapo ebay one temporarily until a decent version arrives and see if it starts....usually it's the electronics of the Chinese ones is the main problem. I would locktite the rotor screws once you get a good cap/rotor or they might back out and you're in the same boat once again.

Hgk4life

Thanks for that info. Can I use an msd rotor and cap with my original GM optispark? Instead of paying that much for the GM rotor and cap. I can get an msd rotor and cap for $150.00 . Just asking not sure. Thanks again

shbox

Yes.

And the reason you had no codes before when you checked is because the opti was sending out the proper signals to the computer. The cap and rotor is what seems to be your failure (no codes can be thrown from that). Then you replaced the whole opti with an inferior piece that caused you more problems (not to mention all the other things you replaced needlessly).

Hgk4life

Thank you for that info. I appreciate all the great advice and schematics. I have already taken it all apart, removed cap on new optispark but didn't see any defects by eye. Have to get a smaller torx bit to fit bolts on rotor so I can interchange rotor and cap with original. Glad to know I can install msd rotor and cap with my original GM optispark. Thanks so much

bufmatmuslepants

iTrader: (3)

Don't forget to take apart any new opti and put loctite on all of the screws.

Hgk4life

Thanks for that info. Parts store said I could bring back the icm, ignition coil if they didn't work think I'll veep the cps the old one looked pretty rough with the o ring broken and all the cover plastic gone. The two parts to return would more than halfway pay for a msd rotor and cap so it will work out good I hope. Thanks again. Will locktite bolts. Any certain position I need to install the rotor at?

Hgk4life

Here's another question for you all, autozone sells the msd rotor and cap for 160 with a 1 yr warranty. They also have a dura last with a lifetime warranty on rotor and cap for 121.

Hgk4life

Online it says the msd is non vented but my original GM is vented. Which from the previous post do you all think I should get? Thanks again