I have a 92 Prelude that originally came with a SOHC motor. Tore out the motor and swapped in a DOHC f22.

Everything was running until yesterday. Car started for 2 seconds cut out and died.

I checked the fuel pump, seems just fine.

Pulled a spark plug and I am not getting any spark.

It was originally setup for external coil dizzy, I set it up to use a internal coil dizzy that came with the engine. But, I had to splice the pig tails on the dizzy to fit the stock wiring harness.

Everything matched up fine and it worked.


I tested the pigtails going to the dizzy and there is no power anywhere.


Where do the wires run? I never chased them back to the ECM before.



Any thoughts on where I should start with this?


I found a diagram. It seems pretty simple.

 

oh man those things are fast. i have a TOHC f22z8 in mine. i crack vtech like 3 times.

 

Really? U don't say. . . .

 

bump, mods please close for stupidity

 

Really? U can't be more worthless can you?

I checked for voltage, I have power to the coil and the ground is just fine.

Swapped the igniter and coil.


What would cause it not to have a reference signal? I know of possible causes, but what can I start with?

I can't swap the complete dizzy since it does not really exist here in the US.

 

I'd start with the pinout for the ecu. It should tell you where the wires go. The harness pops through the firewall under the abs unit on the passenger side. Ecu is under passenger side floormat under a metal coverplate. The ecu will typically take things to ground, instead of sending power. On the ignitor, you should be getting +12v on the black/yellow wire with the key on. Also, the pinout for the ecu should tell you which wires for the tdc/crank pos sensor should be powered. You may, if you find the wire not supplying power, be time ahead to run a new wire from the ecu to the sensor instead of trying to find the break in the wire.

GL
Mike

 

and X01, stfu the OP at least had the right schematic and knew how to read it.

 

I kind of figured it was a wire after seeing this. . . I will look today when it warms up.


Don't know WTF happened yet though, I never seen smoke.

I somehow think the dash will have to come out. . . Boo

 

eh, if I were you I would run it on the passenger side, you can get to the bulkhead plug from under the dash and not have to pull dash. That's only if its a wire problem and you have to run a new one. BTW the plug is kinda behind the hvac blower assembly, but u can see it good from the engine bay. Bunch of wires running through hole in firewall.

 

I pulled the dash, now I see there is no way to remove the wiring harness from the car without taking down all the pedals.

I was thinking of re-running the specific burnt wires, but I can't even think of how to test the specific wires at the ECU.

 

if you have access to the specific section of wire I would start by repacing any sections that look damaged and trying it then. To test from the ecu would probably require some LONG test leads or if you unplug the remote connector you could jump it with a piece of wire there and then test between the two wires at the ecu connector with it unplugged. Good luck in any case
Mike

 

Maaaan, after getting scraped up and laying upside down for an hour or so I got to the burnt looking piece.

None of the wires look burnt through, one of them was a green with some silver dots and the other a yellow with green stripe.

I tried my best to look over the yellow with green stripe since that is the signal wire. It looks fine and has voltage all the way down to the dizzy and back to the ECU.


I don't know what else to do with this. . . . I mean what? Rewire the car?

Can it be a TDC sensor inside the dizzy?

How can I test each one? Since there is no way to swap a complete unit just to try.

 

The TDC/crank/cyl sensor is all one piece inside the distributor. You are going to have to swap the distributor if it is bad. The burnt look could just be rust from some of the other things under your dash.
GL
Mike

 

Nope, it's burnt. A few of the wires look like they got pretty warm. I can't really tell from what though.

I got it to start for a split second. . . . . We'll see more tomorrow.

 

Maybe grab a pic of the wire bundle where it looks burnt, have you separated them all out and looked at each one? There are a bunch of them in there, one probably got pinched and arc'ed to the firewall. Look for any with damaged/missing insulation; you are going to want to cut out those sections and splice in some fresh wire. One tip if you are going to have to splice a bunch of wires is to offset each splice so the butt connectors don't all line up in the same place. It'll keep the harness from getting too big around for where it goes under the dash. Oh and if that is what is causing your no-start condition it makes sense if you moved the wires around as you have been that the broken wire could have made momentary contact and allowed it to start. Regardless if you are planning on keeping the car for any period of time I think I would recommend fixing those burnt/melted wires now, since you have gone to the trouble of pulling the dash, etc.
GL

 

It looks like whatever the green wire is(real thin wire) and a yellow/black wire got hot from the inside, they did not touch any metal since they were inside the fat plastic casing. No copper is exposed, they look hot from the circuit.

I'll grab a pic, but it's a mess.

I built everything under the hood myself including the harness, but never touched the anything in the interior. We got the car as a shell, but the inside wiring seemed real good and it worked perfect after I dropped the drive train in.


Good thing this is my 4th car. . .

Update:



After studying the wiring diagram for a bit I started checking the ECU pinout.

The main relay lost power. . . . From what I can tell the power comes straight in from the fuse block/junction.

No popped fuses anywhere at all, it has to have a open somewhere. But it is such a pain to get to.

Right now I am running direct power to the relay and it's just fine. But, I'm a bit concerned about this thing cooking another wire or two.

Crap. . . . . .

Here is a good shot of the burnt wires right above the pedal. I just can't figure out what could have caused this, especially in this one spot.

 

If it wasn't pinched through, it could have been squeezed a bit in that area. In any case it looks like more current than intended was flowing through one or more of those wires. Do you happen to know what those were for? Also, with respect to the main relay, those have been known to fail, so replacing it may fix the no-start if thats still a problem. Also from the pic, the blue/white wire looks damaged, or is that just from the tape adhesive?

 

The blue white wire is for the blower motor, one other wire is power to the ECU from the main relay.

The wire's shielding looks toasted, but not through and the copper feels solid.

I re-ran everything I seen cooked and crimped it. I wanted to solder it but, this is a tight area with a lot of other wires.


Everything works, aside from the missing dash. I drove it around a bit, nothing seems to be out of wack and nothing warming up.

Even the AC works. . . .

The big gray box you see is not a stand alone or anything cool, it's a breathelizer machine.

 

Well, it could have been those wires, sometimes its hard to tell if they're messed up or not. I'd still keep an eye on that main relay, hope everything works out ok.
GL
Mike

 

I'm just keeping the dash off for a bit. . . I don't like burning wires.