Okay, as the title says, car won't start and I'm at a loss. I've replaced the optispark, plugs, wires, ignition coil, battery, and fuel filter. The Ignition Control Module tested good, fuel pump is priming and pumping, and I even checked to make sure the computer chip is connected securely. Can any give me ideas for what else to check? The car cranks, but just won't turn over. I'm looking for any idea, even the simplest I might have overlooked. Thanks...

Oh, despite the sig, it's no longer an MSD coil or Opti...so it isn't something MSD specific...

 

Are you getting spark from the coil AND out of the plugs?

Did you do a proper fuel pressure test?

 

I'm not getting spark at the plugs or out of the coil. Since posting this, I've tried the multimeter test on Shoebox's page and got matching voltage at all the connector's leading from the opti plug to the ICM and coil. The "voltage while cranking" test showed .1, but I'm not sure what setting that was on now, so that very well may have been a full 1 volt (I'm actually pretty sure it was, but the meter is digital and isn't marked well). Putting a spark plug tester between the coil and the opti, I got no light on the tester at all. I'm kind of thinking ECM at this point, but I'd really rather be certain before dropping that much into what may be a useless replacement.

Forgot to add that no I haven't done an actual fuel pressure test because the pump is cycling, and I'm 99% positive the problem is no spark getting to the cylinders...just not sure why it's not getting there. Also, I did go ahead and replace the ICM just to rule that out.

 

Have you checked for codes?

 

The battery was dead for the last six months, so any codes stored prior to the car dying are long gone. I just went out and checked it (by jumping the A & B terminals) and no codes, just diagnostic 12. One thing I did notice though that I never did before (although it's been about 3 years since I've done it) is that the fans came on as soon as I turned the key. Not sure if that's normal so I thought I'd mention it.

 

Its normal for the fans to come on when you short the ALDL pins.

I would also check the fuel pressure. Just because the pump runs for a few seconds doesn't mean its pumping fuel at the right pressure.

 

This is really weird...

According to the test on this site: http://www.mainstreamtopics.com/foru...p?showtopic=78 it's a bad optical sensor.

I just replaced the opti last weekend with a Summit opti. I took off the MSD opti because when I originally installed it, it ran for 2-3 weeks and then died because of the red powder contamination problem. After sending it in for warranty and reinstalling it, it ran for another 2-3 weeks and died again. I naturally figured it was the MSD opti again, as it died the exact same way, sitting at a stop light. So I was rather surprised when I opened the MSD opti this time and found it to be in pristine condition. So it seems a little odd that it could be the opti again, unless there's something that could be frying them.

[EDIT]

Okay, rented a fuel pressure tester from AutoZone ($150 ) While pump is priming, pressure is 45psi, then slowly (very very slowly) it drops to about 42-43 psi, but as far as I can tell it held there. I assume therefore that everything fuel related is ok, so I'm back to the electrical.

[RE-EDIT]

Okay, so it isn't exactly holding steady at 42-43. After about 20 min I went back out and it's down to around 39.5, so there's some drop, bet extremely slow.

 

The pressure drop on shutoff is not important at this point. Its holding well enough.

If you lost the output from the optical sensor, it should set DTC 16 and 36. Also not so sure about the test procedure you linked. According to the pinout data on Shoebox's site, the red wire from pin B14 of the PCM should supply the optical sensor with 12V (B+), not 5V. B3 pink/black wire is the ground from the PCM. The two signal wires (red/black = low res signal to pin B2; amd purple/white or blue/black wire = high res signal to pin B20) should have a voltage that is either 0V or 5V, depending on whether the slot in the Opti "disc" is in front of the optical receptor or not. As you slowly rotate the engine, the low res should vary from 0 to 5V 4 times in one crank revolution, and the high res should vary from 0 to 5V much faster (180 times per crank rev).

Loss of low res pulse will prevent the engine from starting.

 

First off, thanks for helping with this so much. Especially after your last post I get the feeling I'm getting close to at least one answer.

I have a shop manual (the big 3000 page one), so I didn't go by the color that page referred to but by the description in the manual. I just redid the tests and both red/black and blue/black showed 4.5 volts. The red wire showed 11.95 (it was 12.75 earlier, but many crank attempts later... ). The last wire, black/pink, showed between 0 and 0.2 volts while the engine was cranking. I realize that last one is extremely lower than the 0-5 volt range you said, but could that be just that the meter couldn't keep up with the speed of the engine (digital meter)? It would seem to me that the opti then is not the problem right? Or is that 0.2 volt reading significant?

 

A DVM isn't going to indicate the swings between 0-5V on the high res signal. Its changing too fast. You will read some sort of "average" voltage, limited by the speed of the meter. There are 360 light slots on the Opti disc. It turns once for every 2 crank revolutions. that means you might have better results measuring the frequency on the wire. That would read 180 X engine RPM. e.g. at 200 RPM cranking, you would see 200 x 180 = 36,000 cycles/min = 600 Hz.

If you don't have a code for the Opti, its not likely to be the optical sensor. But... there are no codes related to the high voltage section of the Opti (cap/rotor). Is is possible the rotor fell off? Very common problem. What kind of Opti did you get to replace the MSD? Did you examine the rotor screws and loc-tite them? Is it possible you incorrectly indexed the splined shaft that drives the Opti?

 

I replaced the MSD with a Summit opti, and I actually didn't even open it before I mounted it. I didn't force it onto the shaft though, I lightly pushed the opti into the hole, and when I felt resistance I took it back off, turned the gear a tiny bit, then tried again. After the third or fourth time, it slid right in with no resistance at all, so basically I found the keyed slot and mounted it.

How do you measure frequency on a wire? The meter I have only has volts and ohms, no Hz.

Does the simple fact that the voltage does change indicate that at least the optical sensor is picking up movement/reading something? That would imply it is working, right? I mean, it isn't showing the specific voltage because the meter's too slow, but the fact is is changing means something's passing in front of the sensor, and the sensor knows that...at least I would think so.

 

You need a digital multi-meter with a frequency scale. I was in Sears the other day, and they have that on their $30 multi-meters.

 

Well, I officially surrender. A tow truck is on the way now to take it to the shop, where they'll probably find that it's a fuse or relay that I somehow missed. Actually my bet is that it's the ECM, but for future searches I'll post what it turns out to be.

Again, thanks for your help Injuneer, it's much appreciated.

 

Okay, so apparently it was the ECM and the PROM. I'll be getting her back from the shop Friday, then on to the myriad of other things which needs to be fixed/replaced. I forgot how fun this can be...