matman88

So I'm not getting any spark from my coil in my 93 and I'm trying to decide what the problem is. so far I've ruled out the coil (replaced it) and now I'm trying to figure out if there is no signal from my opti to the computer but I'm not sure which of the 4 wires to check here is the diagram http://shbox.com/1/93_ign_system_schematic.jpg what should I test to hopefully rule out my opti as the problem?

Gojira94

iTrader: (4)

You were almost there:

http://shbox.com/1/4th_gen_tech2.html#opti_test

Big Al

iTrader: (1)

First check for the pulse on terminal "B" of the ICM while it's cranking. What test gear do you have? Something like this will make it a lot easier.

http://www.amazon.com/Elenco-Logic-P.../dp/B0002E7X5O

They're all over eBay for about $10. Some DVM's have logic functions.

Al 95 Z28

matman88

so I have all of the voltages that I am supposed to have going to the ICM. a 3.7 Volt AC signal from the computer when cranking (indicating my opti must be working), I also have 2 ~10V DC signals from the coil as well as a good ground. so I figured the ICM must have been bad but after replacing it and the coil I still have no spark from the new coil. how is this even possible unless either my new ICM or coil are shot?? I am so confused right now I thought I had a good understanding of how this works but I must be mistaken... PLEASE HELP!

matman88

could my battery be too dead to send a spark? the starter just started clicking after charging it for 15 minutes from my buddy's neon. seems too dead to take a charge i haven't got a battery since may '08 and I have some amps hooked up. but it seems like the starter would fail before the spark would?

Big Al

iTrader: (1)

What you let a Neon jump your Z28! Expect lots of trouble now

Don't take much battery for the ignition system to function. If it cranks it will spark. I'd bet the jumper cables you're using are too small to crank the engine with a dead battery.

Al 95 Z28

matman88

does anyone have any ideas as to why my coil won't fire if all of the proper voltages are measured going into it? the only I could think of other than my brand new ICM and coil being bad is if the 4 volts AC going in to the ICM not be timed right?

I also got a code 16 at some point but I think that was from unplugging the opti's harness to trouble shoot it as this code was not seen before I took everything apart. I reset the battery and tried it again but it only gives me code 12 now which is impossible because I have an A/C and an EGR delete so those codes should at least show.

Big Al

iTrader: (1)

First, you're looking for pulses, not voltages, from the PCM to the ICM. That's the "B" terminal on the ICM. So you're not troubleshooting in a sensible way. You need to figure out what's happening on that line, and insure the ICM has ground on "C" and 12 volts on "A." If you're using a DVM, you may be fooled. Use a 99 cent test lamp to check A and C. For the pulse signal you need to use something that shows the pulses. DO NOT try to check "B" with a test lamp. The test lamp will also show the activity on "D" if there is any. It should blink on and off when you crank it. If it does, the pulse IS on the "B" terminal so that may be a better test.

Al in Tucson.

matman88

well looks like I give up I've been in denial for too long but I've just replaced my ignition switch, coil and ICM in the past week soooo... here comes the new opti. these stupid unvented ones aren't made for Florida rains. it's only 15k miles young too. what do you think? have people had luck with the vented MSDs? is it worth springing for or is it doomed to be eaten alive by my next water pump too?

Boman6760

iTrader: (1)

Did you test the opti harness when unplugged? If so plug it in and test the red wire with key on. It should be close to 12v. I had a bad experience with this. Unglugged everything was fine. Plugged in, I got less than half a volt passing through. Dead opti. Swapped it out and test showed fine. Avoid AIP opti's. Ebay seller. I am running the LTCC conversion now but have heard good things on MSD units.

gatorhead

iTrader: (4)

Do a search on ebay for delphii opti. They come up and are selling for @ 300. That is a factory made opti with the mitsubishi sensor.

BEFORE you buy an opti make SURE you are testing everything correctly. I have gotten both a bad ICM and a coil brnad new outta the box dead. I make them test the ICM's now before ever leaving the store. You should test your new coil as well it is easy to do.

To me everything you listed was within spec. A bad opti would never pulse 3.7 v AC. They either wont send any signal or they won't send enough.

If I were a betting man I would say your problem is a bad ground. You should have two tans a black and a bare strap ground located behind your coil/ICM mount. Make sure they are all there AND inspect each one of them. I have never worked on one of these cars that didnt have bad ring terminals on the grounds due to their mounting location.

Where in Fl are you?

matman88

I'm in Melbourne. what is the best way to go about testing the ICM and coil? my friend has a 95 vette. can I plug it in to that or is it a different set up because I have an ECM?

gatorhead

iTrader: (4)

Take the ICM off and take it to Autozone, have them run the test 5 times in a row.
The test for the coil is on shbox.com.
While you have those off look at your grounds

matman88

the terminals on my coil show about 9600 k ohms which is 1100kohm more than expected is this too much of a variation?

gatorhead

iTrader: (4)

its ok.

02v8ta

iTrader: (8)

Just wondering why? Where/what are the best opti to buy I know an original is the best but where? I Couldn't find a delphii opti?

matman88

well I don't have a car to go get the ICM tested hahaha so just thinking ahead here... if my opti does need to be replaced I want a vented and well sealed one. is the delphii one sealed or is the msd the only vented one available for 93?... and no, I don't want to modify a stock one

Boman6760

iTrader: (1)

I only say avoid AIP from my experience with them. They first one they sent me had a sensor missing the top off of it. After sending them photos they sent me another sensor. It wasn't three months of driving it started throwing codes and missing. Then after some emails they just stopped responding. As for the best of vented I'm not sure. I switched to the LTCC kit. It still requires the sensor but you can remove the rotor as its not needed. Removes the bad atmosphere that can harm the sensor. Then you can fully seal everything up. For me it was the way to go and I couldn't be happier. Like I say as for the Msd unit, I've heard great things. Never used it myself though. Only other way I know is mod to a vented.

gatorhead

iTrader: (4)

I amnit going to list any names, just got to ebay in the search bar enter Delphii optispark and it will come up. They sell for @ 300. Anything less is a fake........when I say less I mean alot less lol