Engine Harness and Starter Issues

Update as promised. Got the new harness in today. Connector matched to power dash. But still the same issue. Got it cranked by running through fuse box and car started running erratic.

It was in gear and started accelerating on its own. Fortunately it was on jack stands and with the ebrake. At this point it's definitely an electrical issue.



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Sounds like your on the right track.
With the car running, your ECU may be able to throw you some codes to help you.
With the wheels in the air and in gear your car may have gotten confused. The ECU uses the wheel speed sensor info and two wheels weren't spinning.
(my ABS light went off once when I did that... drove 30 feet to clear it)

Remember it revs to about 2000 RPM on a cold start.

Try to trace your wires from the ignition switch and through your clutch switch (interlock switch) the B/L and B/Y wires.
Both of those switches have been known to go bad.
 
I'm leaning toward that or the TR switch mis adjustment, but it's only a hypothesis.

It revved to 2k. I will have to find someone with electrical experience to help sort this out.


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OK duh... I thought you had a 5 speed.
You definitely want to check your TR switch...









 
Would I need to have the ECU reprogrammed or flashed for this issue?


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No... You're fine that way.
Flashing is just for performance.

Your TR switch may just be out of alignment preventing the car from starting.
It's just an on off switch that verifies that the car is either in P or N then allows the starter to engage.
The ECU still wants to know what gear it's in for other reasons but the starter circuit is quite simple.

It sounds like your car is running... Your ECU will need some time to learn but it sounds like you're almost there.
 
Sometimes if the TR switch is a bit out of alignment, you can push of pull the shifter a little bit forward or back then the switch aligns and the starter will engage.
I remember one guy could start his car in N but not P (or vice versa ?) when his switch was misaligned.
 
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I have the nonsport shifter and tried starting it in N but still same issue.


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It could be out of alignment enough that neither positions line up properly, or you may have a broken wire/bad connection between the switch and the starter motor.
 
It looks like there is two separate switches for both the P and N positions.
The H terminal looks like the one that feeds to the starter.
The other ones are for the ECU so it can switch gears and stuff.

 
If your TR switch is aligned and you still can't get the starter engaged, you can run a replacement wire from the H terminal of the connector that plugs into the TR switch right to the connector on the starter.

Edit... It might be the B terminal... It depends which terminal goes B+ when in start position.
 
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Would that bypass the TR sensor? Wiring diagrams are fairly new to me. But I do have a family member who knows electronics fairly well.


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No,... I'm thinking you've got a broken wire/bad connection going to the starter.... The wire would just replace it if you can't find the bad area of the original wire.

The other wires from the TR switch go to the ECU and don't go near the burned area of your car... And your car was working fine before it blowed up so it's hard to see the TR switch going out of alignment just sitting there.

You probably still want to check your TR switch, the ECU still needs to know what gear it's in.

OR.... You could just wire in a switch or button through the fuse box and just hit that to start the car... Not the best approach and you'd have to be careful not to hit the button when your going down the road... But it would work...
 
Maybe try holding the key to start position and going through all the gears to see if the TR switch ever lines up and sends power to the starter.
Be careful of course... It could startup in gear again.

The power (B+) goes from the key in start position into the TR switch on either the H or B terminal then out the other,then to your starter.
 
OK... So I've been thinking of a way to systematically diagnose your wiring...

With the help of your mechanic or family member,... With everything connected, including the battery and your wheels in the air on jack stands.,... check for +12 V at both the H and B terminals of your TR switch while your key is held at start position.

You can probe the back of the connector while it is plugged in. (remember, the terminal order will be mirror image from the back of the connector, check your color codes on the wires coming from it)

Be careful of course, the starter may just decide to kick in...

If you are getting +12 V at both terminals, it proves that power is getting to the TR switch.... And it would also be getting to the PCM (ECU) and cruise control because it feeds both of them on it's way to the TR switch.
(according to the wiring diagrams)

You probably are getting +12 V through because your ECU (PCM) was happy enough to allow your car to start and run.

Then, unplug the TR switch and check both the H and B terminals of the connector to see which one is +12 V with the key held at the start position... That is the power feed into the switch.

Then cut the other wire (the switch output) about two inches back and splice in a new piece of wire and run it straight to the starter.

EDIT... I forgot about this...



 
So...

This is the start fuse and the circuit that I am confused about...




So I went to my car and did this...






There is no power going to that fuse until you turn the key to Start position.

And the power comes in on the top right corner terminal, goes through the fuse then down through the terminal below it then off to the PCM where it has something to do with the brake circuit ??? I dunno ???

The weird thing is, my car started with this fuse pulled out ??

SO... Go and test for +12 V at that fuse... You don't have to pull it out, there are little metal test points on the top of the fuses.

 
If you are getting +12 V (when your key is turned to start position) at that fuse then you can use it feed to your signal input for your starter.

If you are not getting +12 V at that fuse (key at start) then your wiring harness is not delivering power to it.

That's when you go back to the TR switch, splice in a wire (from terminal H or B,.. whichever is the output) and feed it into the fuse box at the start fuse (#12).

This way, your starter safety stays intact (only starts in P or N) and power is fed to the brake circuit inside the cluster to do whatever the hell it's doing ??
 
We tested that fuse and no power was being delivered. The mechanic ended up using that fuse to bypass the signal.


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OK... So if it were me, I'd check for power at the TR switch on terminals H and B (which I'm assuming you have because your car starts and runs). And string a wire from the output terminal (H or B) then to the starter as well as the fusebox. Run the wire through a ten amp fuse then into the lower terminal of the fuse holder.

You could bend the wire around the blade of the fuse (the top blade) and plug it in... But that can expand the connector in the fuse box though and could make a bad connection.

I took apart a fuse (removed the plastic) and used one of the blades as a connector.... You could do the same and solder the wire to a blade to plug into the fusebox.... It would make a better connection that isn't quite so cheesy.

Like this...



Another option is to remove the fuse box and splice into the wire underneath that feeds the fuse.

And the best option is to trace the wire all the way from the TR switch or even from the ignition switch if power isn't getting to the TR switch itself,.. And find where the break is and fix it , but that can be a pain because the wire goes through a bunch of different harnesses and connectors and the wire changes colors along it's journey.

You'd probably still have do some splicing anyway my way just does the entire length.
 
You will most likely need to supply +12 V to the bottom terminal of the fuse holder (the one below where my probe is) but only when the starter is engaged... Even though my car started without the fuse.



I figure the microprocessor in the instrument cluster does some sort of test while most circuit are shut down during start.. Like testing the brake light to make sure they're working ??

If it doesn't get that +12 V during start it might get pissed off and retaliate in some unforeseen way.
 
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