My very own "no spark" thread.

[como]

Okay, so I've narrowed down the problem:
she ran great until I pulled the entire wiring harness and all of the body panels, windows, etc off the car.

So, I've been putting back in the wiring harness and decided that enough of it is in that the car should start and run- but she wont go.

I think it's down to my coil/ecu, though. I threw a sparkplug into the wire that typically feeds my distributor (right out of the coil), and grounded the outer edge of the plug- no spark when she turns over (which she does just fine, mind you) Now, to me, I'd think she should spark every time any cylinder was supposed to fire at that point- so lots... but I didnt get a single spark.

So I grabbed the multimeter, and checked the coil- it has 12v, so I know the inlet power is good.

This implies one of two things in my mind:
1) bad coil
2) ECU isnt telling the coil to fire

Now, I doubt its a bad coil, since it worked fine before, and I honestly didn't touch much wiring back there. This brings us to the ECU not telling it to fire- for all I know I toasted the ECU somehow. The ECU has three main plugs going into it- the two outer ones cause something to "click" inside the engine bay when I plug them in, the center one doesn't. Probably doesn't mean anything to anyone, but just an observation.

So, I'm pretty sure the problem is with the ECU, the coil, or something isnt plugged in.
Now, the only plug connection I'm unsure of leads directly into the coil, which makes me a little su****ious. It happens to be an identical plug to the one that the engine bay side vent uses, and I cant for the life of me find whatever the heck that plugs into. (anyone can tell me that'd be great); the wire with the same plug thats currently plugged into the coil leads into the timing cover, so I can't imagine its for the fan, it would make more sense to be a crank position sensor, which would make sense to be into the coil... but yeah.

What's next? I dont exactly have a spare ECU lying around

[como]

Ok, so since this wasnt getting me anywhere I decided to move along and look at other things-
I found that my plate lights wouldnt turn on.

Eventually followed the path to my tail light relay (haynes, 247) wasnt switching. looks like the coils grounding side doesnt point to ground- so ive got a bad ground somewhere... what gets me is all of the grounds around it in the inner cabin fuse area are fine.
argh.

[mr3]

I hear ya. Just keep checking. It took 2 days of thoroughly looking for the problem before I think I found the problem. I'm still not even sure if I figured it out. I know I'm close though.

[como]

I downloaded and skimmed through the electrical section of the 89 BGB, but didnt' come across anything that lists grounding points in the harness- I'm convinced that I have multiple bad grounds (the radio ground, for instance, isnt grounded- but I didnt screw it into anything since the dashboard still isnt in- but that relay ground is bad, and it must share a ground with a half dozen other things...)

Whats really pissing me off is that there are so many different colored wires and no clear "ground" color- there are entire plugs with nothing but green wires on the passenger side, and none of them are grounded- of the dozen or so green wires on that side only one seems to be a ground. Probably a problem, but I cant tell if the rest are supposed to be grounds or not- and if they were, why would there be a full plug with 5 wires that were all grounds? Doesn't make sense.

So, does anyone have a list of the grounding straps on the wiring harness for the aw11?

[Jackstand Queen]

You may have fried the ECU.

I always have the battery disconnected when installing the ECU, or removing it.

Another important item that is generally well know is . . . . for EFI car the battery is disconnected by removing the negative terminal first. It is reconnected by connecting the positive terminal first. Doing it Bass Ackwards can destroy an ECU. Don't ask me how I know this.

[como]

I think I've narrowed it down to a fried ICM, actually.

Trying to source one on the boards, since napa wants $584 for it.

[Jackstand Queen]

What is an ICM?

[como]

Little black box that sits ontop of the coil.

ECU tells the ICM when to fire the coil, ICM tells the coil when to fire, best I can figure.

has a little plug that goes to one of the plugs coming out of the timing cover; my guess is a crankshaft position sensor. ICM is supposed to have some number of ohms resistance, mines an open circuit.

[mr3]

Ignition control module?

[Jackstand Queen]

You silly Geese, no its the Ignitor. A rectangular black box that sits on top of the coil.

Used, they are a dime a dozen. I have a spare ignitor for an N.A. which I don't need anymore because I have an SC.

Ignitors are very difficult to electronically test to see if they are good. Its easier just to have a proven good spare, and swap it out.

PM me if you are interested in my spare "ICM".

[como]

Book called it the ICM iirc. I'm just going by what I read, and mine does test bad.

[espguitarist33]

i have the entire igniter/coil from an 85 for sale...on ebay their all at least 100 bucks...mines works...50 bucks sounds good to me...as long as it will work in the 89 idk if they swapped part numbers or anything

[mr3]

If they did, I have an 88 one for sale.

[como]

I'd imagine any igniter for a 4age would be identical... Neglected to grab a part number off mine today again. Sigh.

[Jackstand Queen]

20v and SC ignitors are different than USDM N.A.'s.

[mr3]

Grab the part number when you can and I'll see if I have it. I don't need the stock mr2 stuff anymore.

[espguitarist33]

his profile says 85 NA though?

what year is your car como

[como]

It's an 85, presumably na (don't know much about cars, she isn't a turbo or an sc)

Looks like MR3 has the appropriate part, and is sending it to me tomorrow (thanks man)

Can't wait to have her back on the road

[espguitarist33]

NA means it isnt supercharged or turbocharged