FraggleRock

I've got a '93 T/A that threw a SES 36 and 41 before dying. Car stalled two or three times a week apart and then just wouldn't start anymore. Preliminary diagnostic were pointing to the original opti (117k) or Ignition Control module. I ended up replacing both parts along with the coil, plugs, fuel filter, water pump (just to be safe), and opti-pigtail harness. The spark plugs I had put in six months prior along with new wires were black... I tried using a spark tester from autozone--a little tool that I just clipped to the coil pack output, set a gap of about 1/3 of an inch and then attached a wire from the other end to a ground point on the car. No spark was produced (assuming I did it right).

I've run voltage tests on the connectors under the dash (red, pink, yellow, brown, and orange wires) and the voltages all appear correct when I turn the key to the various positions. I checked the connector that has been known to melt under the dash and it's perfect and the dash lights up and the security light goes out after 3 seconds.

I've got voltage on the A & D (outer) pins on the Ignition Control Module harness and on the C pin on the opti-harness connector. The only voltage I wasn't able to verify was a pulsating test light when cranking, but again, all of the ignition components are brand new and behaving just like the old ones

I've tried checking my grounds--the negative battery patch ground up top on the passenger front, the ground to the block just under the coil, and the flat braid wire ground to the side wall under the antilock system. I do have two connectors that I still want to replace, the MAP connector and the 4 prong connector going into the throttle body which is pretty hashed. I don't know if either of those are the problem, but I wouldn't think so.

Back before it all happened I was worried that I got some water in the gas from the winter with a near empty tank for a couple of weeks, but I got it running later and put some HEET in the tank to deal with the water, not to mention running another tank of gas through it, so I think it's good.

I'm really at a loss now other than either an open circuit I can't track down, or possibly the PCM, which I don't know that I can test without taking it to a dealer, which is exactly what I'm going to have to do unless someone reading this has other suggestions I can attempt tomorrow. If I could just get some dang spark I'm sure it would run. If you've made it this far and have any suggestions to help put a little spark or bang into my 4th of July tomorrow I'd appreciate it Thanks.

FraggleRock

Well, I took the '93 T/A in for a diagnosis at the dealer after replacing the ignition coil, ignition control module, optispark, spark plugs, fuel filter, and water pump and still having a no spark condition. The dealer thinks it's one of the following:

1) Bad optispark (It's a brand new AC Delco off of ebay last week)
2) Incorrectly installed optispark (I don't see how this is possible on the '93... 3 bolts, 1 keyed pin that only goes on one way)
3) Problem with the timing chain.

Given that the problem existed before any of the above parts were replaced, I doubt it's either 1 or 2, so perhaps it is the timing chain... I didn't pull the cover when I replaced the opti. Dealer wants $600 labor and diagnostics already done thus far, plus parts if necessary. Any thoughts anyone? I guess I should have pulled the cover...

Speedy

If you're having a 'no spark' condition then your problem is purely electrical, so where do we get the timing chain bit from? This should be a simple diagnosis starting at the plug and working your way back.

Check the current running into the optispark unit. If you have current, then you know you have a problem with your optispark unit. One common problem that gives the codes you got is a loose or damaged rotor, another is a damaged opti unit. Did you check the tightness of the cap before you installed it?

I'm not sure what your experience is with engines. With $600 in the can already, you might want to just get the dealer to do the job and be done with it. Chalk it up for experience.

thesoundandthefury

iTrader: (3)

Unless a previous owner had done a vented optispark conversion, you should have the style that has a splined drive that fits into the camshaft hole. This can definitely be installed more than one way. This photo might shed some light:

http://shbox.com/1/93-94_opti.jpg

Might want to double check that you have the spline indexed correctly. If it's off by even one tooth you'll have problems.

FraggleRock

I checked the current going into the opti and I was getting voltage in but nothing out when cranking. The tech at the dealer was also able to invoke a signal on the high and low rez signals from the PCM to opti and had current going in but not out. Given that the same problem existed with the old opti in before I replaced it, it seems like it would be less likely the brand new opti is bad, but it is possible. It was one of those on ebay (AC Delco) for ~200 a couple of weeks ago.

The timing/timing chain theory came into play by the tech if it he pulls the opti and it is in fact good an not installed incorrectly. I really thought I lined up the spleened drive as mentioned above, as at first it didn't want to go on after my first attempt to line them up, so I turned it slightly once or twice and then it went on without much force. The theory was that if the timing is off or the opti is on wrong, the optical sensor will never send a trigger signal to fire the coil.

I didn't check the tightness of the cap on the opti since it was brand new... I'm definitely not an expert on the engine... I did rebuild the top half of the block a year ago--pulled the intake, heads, etc, but that is about as far into the motor as I've ever been. I contemplated pulling the timing cover and swapping out the front seal, but was having difficulty getting the harmonic balancer shaft bolt off so I bagged it. The bill is probably going to be painful by the time the tech figures out what's going on (he'll start monday), but like you said, I may have to bite the bullet and chalk it up to lack of experience

FraggleRock

Thanks. I really thought I got them lined up, but I guess I'll find out for sure on Monday. That little spline really seemed to prevent it from going on any way but one, but maybe not...

Speedy

The spleen can definitely be deceiving as soundandfury said. Check it out, but you should do it all by the book. Check for top dead centre, mark everything and be sure you've lined the rotor up in the correct firing position. Don't rely on the spleen by itself, because it will sometimes slide into the incorrect position - probably why they changed the design in '94.

thesoundandthefury

iTrader: (3)

When installing this style of Opti, a paint marker is your friend.

FraggleRock

Well, now for the conclusion to the issue, but first thanks to everyone in this thread for your suggestions. Okay, so it wasn't the chain and there was no need for the tech to go there and he never ended up trying as it didn't make sense... In the end it turned out that one of the parts I replaced with the new optispark, ignition coil, and ignition control module was the pigtail harness. I ordered a brand new one from a company called Ledfoote via ebay. After a few more hours of diagnostics, it turned out that this brand new 4 wire harness was wired incorrectly! Two of the pins were switched!

So while I would unplug the pigtail at the connector on to the side of the intake and check voltages and be good, the harness was swapping the signals into the opti and thus no spark or output from the optispark. I never suspected that such a simple, brand new wiring harness would be wired wrong. That junk harness has cost me the original $38.95 for the part, plus $60 to tow it to the shop, plus 3.5 hours of labor and diagnostic ($353.44) put my total bill at $452.39!

I've emailed the seller and am awaiting a response...

That said, the car starts right up and passed safety and emissions with flying colors...

FraggleRock

Here's the exact diagnosis from the dealer invoice:

"117049 Run Diag. And Isolation Tests, Charge Battery No System Voltage, Run Isolation Tests, Test Pcm Output And Inputs, All Outputs From Pcm To Dist. Tests Okay, No Output Detected From Dist To Pcm No Low Or High Reference Voltage Signal Present, Test Circuit Continuity From Dist To Pcm, All Circuit Tests Okay, Access Dist. To Test For Cause Of No Signal, Customer Has Replaced Dist. Upon Inspection Detected Connector Harness From Dist To Computer Jumper Harness Ignition Circuit Are All Misswired (backwards) Pull All Pin Connections And Rewire Correctly. Reassemble Vehicle And Verify Proper Operation, Ok. Fill And Bleed Cooling System. Ok. 3.5 74"

Speedy

Luck it didn't damage your optispark. Man, if that doesn't get you angry I don't know what will. At least you're up and running though. Have fun.