No start, no spark- help with wiring?

[CoreyB]

Read up, already have done that with a '91 SL to be specific, thanks though will try again. lol

This made me think you must be a 91-92. If you are 93 though the crank sensor is located behind the crank pulley.

Damn time traveling. I need to stop hanging out with those little green people. Always playing tricks on me lol. Real first post is below mine.

[onyxice]

The only reason I'm really making a thread for this is because it's intermittent, at first if I would let the car sit, it would start after a minute. Then over time it turned to moving the harness connecting to the PTU would make the rear bank of injectors "click", after doing that it would start. One day the "sweet spot" for the wiring had somehow moved to the larger bulk wiring down closer to the trans. and that time they fired very rapidly. After that it wouldn't start, my PTU was bad but not the reason it wouldn't start, replaced that, actually ran decent for a weekend (had the wire issue once more) and now it's sitting again, moved every damn wire in the engine bay and not a single noise, no luck anywhere. Not getting any spark, I'm just not sure which wire's should send which signal. In the downtime of not knowing what to do about the wiring, I'm swapping/checking ECU/PTU/thermostat/various things that needed attention due to age anyway.

Any help is very appreciated, been dealing with this for a few months now. No intentions of giving up but it's starting to annoy the piss out of me, and I miss my car. lol

[Austin@STM]

First thing is peel back the tape and look at the wires, if you had to wiggle them to get connection then they are broken or corroded somewhere, or shorted to something.

[onyxice]

I know what that means and how wires work, thanks though. More so wondering if anyone knew which one's should be supplying power to the PTU or from the ECU so I can test with a DMM (Digital Multi-Meter) without tearing my harness apart. That's a lot of tape and wire shielding to tear off accross the area of affect when I moved them. If that's not the issue I'd rather not tear it apart to be left with a taped n chopped engine harness.
Also (just remembered) when I replaced the PTU the fix to start it that time was to clean the corrosion off of the wire that connects the small cylinder on the end of the coil pack assembly, which I believe is an isolator? The plug ended up falling off though, the wires just broke at the crimp one after another, it's jumped with a straight wire now, twisted and taped until I get it back home tonight to use actual connectors.

[CoreyB]

That little canister is a condenser. It absorbs high frequency so it doesnt enter the cars electrical system. Without it you may hear some noise through the radio. Wiggling the wires to the PTU should have no effect on the injectors.
If you want to measure the signal from the ECU to the PTU do this. Disconnect the larger of the two connectors at the PTU, Using a prefferably analog volt meter connect the positive terminal to the pin that would be closest to the center of the PTU if it was plugged in. Connect the negative lead of the voltmeter to ground. While the car is being cranked the needle on the voltmeter should bounce up to about 3 volts and back to zero constantly as long as you are cranking. Thats testing one of the 3 signals. Now test each of the 2 pins next to the first one for the other 2 signals the same way.
The signal is a 5v pulse wave, when the ECU sends the 5v signal a transistor in the PTU grounds the primary windings on the coil. This colapses a magnetic field wich induces a current in the secondary windings of the coil realising the high voltage to the spark plug.

[onyxice]

Just got the car back home so if I don't have time to do those tonight I will tomorrow after work, and I've got an analog as well, actually bought it specifically for the car (CEL codes). lol
However any input to the over all problem is helpful and very appreciated, that being it won't start. If the PTU wiring should have no effect on the injectors then I'm guessing that the problem is somewhere else in the wiring, but I can't replicate that anymore, either way it's still not sparking.

[CoreyB]

You may want to check the contacts on the ECI fuse under the hood. They tend to get corroded and cause issues. What do you hear the MFI relay do when you first turn the key. This is the cycle you should be hearing.
Key on to run = 1 click frome relay
Turn over engine = Hear another click, for fuel pump
Turn key of = after about 10s you should hear a final click.

[GTwizard]

Our wires are old. And they were crap to begin with. The wires ar oxidzed, but you can make some simple repair. Just use Asid flux when soldering to old wires. The acid brakes the oxidation and cleans the wires. Pulling the bundle apart to look for bad spots can be a pianfull Job to most. The main harness has what I call the Mitsubishi Braid. If you cut and un-braid the lines first, you can really change the path of part of the harness, the lengths, and their location. I try to route lines so they will end up a bit more hidden. I run no wires across the front of the engine and as many behind the motor as I can. Not hard to do. Just takes a bit of time. I also hard wire the rear injectors just like the fronts.
http://i498.photobucket.com/albums/rr343/GTwizard/S6305398.jpg
http://i498.photobucket.com/albums/rr343/GTwizard/S6305400.jpg
http://i498.photobucket.com/albums/rr343/GTwizard/S6305402.jpg
http://i498.photobucket.com/albums/rr343/GTwizard/S6305404.jpg
http://i498.photobucket.com/albums/rr343/GTwizard/S6305405.jpg
http://i498.photobucket.com/albums/rr343/GTwizard/S6305788.jpg

[GTwizard]

Not sure if he is first or 2nd gen? Did not say. But never heard of a 2nd gen having Cap issues. Only 1st gens, Just an FYI. The service/repair manual is a must for most any electrical issues. In fact cake with the manual. No harder than making toast. Just takes a little longer.

[GTwizard]

No. You are wrong about that totaly. Yes, all cars get old and thing can go out. That is not the case with the first Gen cars at all. Do your home work dude. The specs for those caps on the first Gen board were correct. But the board supplier never followed those specs and used cheap as infearior parts. Strait up wrong parts on the boards. This was a manufacturing issue from the supplier and this was corrected before the 2ND gens were out. That is the issue.

[onyxice]

There are no fault codes, I've checked the ECU already, will do again though. Swapped in three different PTUs, a friends ECU, something I don't even remember what it was, fuses, coil packs.... about the only thing I haven't are the plug wires. Gonna' buy a new set soon I guess.
Also I took two years electronics vocational school, and a year of Airframe and Powerplant school. I know how to cut/check/patch wiring, I was just asking for someone who's familiar with the harness and plugs to give a little guidance. I'm considering doing what GTWizard (seems?) to be doing and just making a new one but yeah those pics confirmed my thoughts that it was some crazy shit.
And I have the service manuals, but honestly I don't what it is but they make me retarded. I get lost in them most of the time.

[onyxice]

Read up, already have done that with a '91 SL to be specific, thanks though will try again. lol

[onyxice]

I'm really glad I decided to run through checking things again, because I'm gonna' look like a dumbass right here. lol Okay, when it was running the CEL was off, I never paid attention to it staying on when the key was "on" because of the four or so other lights that are on (batt, brake etc). But anyways, I checked it's codes again with an analog meter and it's #8 on the first page http://www.stealth316.com/2-diagcodes91-93.htm (two long, three short- top dead center sensor) Next problem is I have no clue where that is? Looking through the service manuals now, which btw I can read, I'm not sure what the hell I was thinking last time I tried. lol

[onyxice]

I've swapped all these parts in and out of that 91 SL, the kids practically my brother he lets me work on them if I need something. lol
Why are you so confident I'm going to make things worse by doing what YOU'RE telling me to do eh? I'm unsure of my knowledge and don't want to do that, I'm not retarded and I'm capable, thanks.
It's not getting harder, it's been months and I've not fixed it the same issue.

[CoreyB]

Top dead sensor or other wise known as crank sensor is attached to the end of the intake cam on the rear head by the throttle body. On your car this sensor is the cam sensor and crank sensor in one unit.

[onyxice]

Edit: Had I mentioned before it's a '93? Dunno' how you knew. lol
Thanks though, very much. With different codes I never would've figured they were the same part.

[Mike-92RT]

If you have a 93 model, you more than likely have the 1st gen ECU, which the capacitors are junk. You can check to see if they have done damage, by just pulling the ECU out, and open it up, check the motherboard for a black substance, that you KNOW shouldn't be there.

[onyxice]

Well the ECU has been checked, it's throwing a code pointing at cam/crank sensor, also I just finished testing all the wires and they're all fine for both of those. Gonna' replace the sensor(s) and see if that works I suppose.
And don't you have to have a 1g ECU in a 1g car?? lol

[Mean Green]

What's your fuel pressure doing?

[Mike-92RT]

1993 3s were frankenstein cars lol.. they are mixed with 2g and 1g parts

[onyxice]

The fuel pressure I'm assuming is normal, haven't checked it as I can feel the relay, hear the pump, and my injectors were just tested a few months ago and fuel delivery seemed to be fine.
Either way, as for now I need to know why it isn't sparking.

And yeah, I seem to pick whatever I can that'll make it a little more difficult or confusing. ha.
Thanks for the replies everyone.

[Mean Green]

1993 3s were frankenstein cars lol.. they are mixed with 2g and 1g parts

yea, tell me about it...


The fuel pressure I'm assuming is normal, haven't checked it as I can feel the relay, hear the pump, and my injectors were just tested a few months ago and fuel delivery seemed to be fine.
Either way, as for now I need to know why it isn't sparking.

And yeah, I seem to pick whatever I can that'll make it a little more difficult or confusing. ha.
Thanks for the replies everyone.

Have you checked the resistance from the PTU connector back to the ECU connector?

[onyxice]

Nope, haven't checked the PTU wiring yet because someone reminded me to check for codes and I got that cam/crank code so I focused on those and other misc things I need to do. I can go through the PTU wiring tomorrow though.

[CoreyB]

Seems I had a post disappear. I saw you used a 91 SL ECU so I assumed you were a 91-92 car. Seeing how you are a 93 the crank sensor is mounted behind the crank pulley. Sorry for the confusion.

[onyxice]

Actually I was going to ask you about that Corey, because I had gotten the notification email, but I couldn't see it... well, it's the first post.
I don't know how you did it but you jacked my thread, and posted that in 1969, seriously, go check it out. First post of the thread. LMAO
Awesome.

So I guess I'm just on a dumb streak and am asking before I look, my apologies to everyone, but I'm a computer tech. not a car mechanic, just not 100% confident I'm doin' stuff right. Anyways, timing jumped, figured I'd have to take it to a shop but I guess I'm just gonna' get all the rest of the tools I need and take my time and do it myself. After I fix the timing/cams, and that sensor (and replace the outer belt on the harmonic balancer) I'll post back with update if all my problems are fixed. I've been dumping money into this misfire/sputter/randomly running like crap... I'm guess my timing has been slightly off since I bought it and I've just been knocking it farther out, guessing from the distance off, and that my belt has all it's teeth. Sometimes I wish I didn't always learn things the hard way... lol

And whoever said I was gonna' break stuff, I take back my comment and admit you're right. I guess I shoulda' checked that long before, possibly could've avoided a few issues (or fixes that didn't fix).
Anyways thanks a lot for all the help, any hints/tips on the timing? Reading old posts on the old site, seems to be fairly straight-forward.

http://i133.photobucket.com/albums/q63/JimJim420/10201920-TIMES.jpg

[onyxice]

Bump- Updated post above. (Pics and the bit about how dumb I can be lol)

[CoreyB]

Valves are going to be bent.

[onyxice]

Ah, thank you sir. I thought that something got trashed when the timing jumped, I couldn't remember what it was though as I had no real reason to until now.
Spent plenty of hours reading the old forum, wish I would've retained more of that info. And at that I apologize again if I've annoyed anyone, I've kind of annoyed myself with the content of the thread. But thank you very much to anyone who posted and tried to help aside from how dumb I'm thinking I look at this point.
Well, I guess now the real fun starts, and I really experience what it's like to be broke.

[CoreyB]

No worries, you dont look dumb. Shit happens, we learn and move on.

[blindmist]

Just saying, I KNOW what I am doing, and I have been all of my intake valves twice. :) Don't feel so bad. Some how I can't even seem to get the exhaust to bend? Non-interference exhaust valves?