I'm having some crazy electrical issues with my build. I picked up the car as a shell in March. It was FWD.
We did the AWD conversion, fuel senders rewired as the diagrams on here suggest, etc.

We got the motor in the car and yesterday went to connect the laptop to test the fuel pump. Two separate laptops would not connect. We also noticed the MFI/Pump relay was not clicking so we tried jumping the relay and the fuel pump kicked on although still the laptops would not connect. This morning we went to the local pick and pull and grabbed two replacement relays for the car, hooked them up and still have the same results. No ECU power, No turn over, No fuel pump turn on. The relay works and you can hear it click but the only way the pump kicks on is if you jump the relay.
There is no voltage coming from Pin 12 and 25 on connector B-53 (Power Supply) even after swapping in the new relays. We tried my 95 Eprom with DSMlink V3 installed and then the 97 ECU that was in the car so we don't think it is an ECU problem.
Also I noticed when you turn the key on the odometer goes up without the car even running or moving yet. There must be a short somewhere, but I'm not sure where to begin. Does the odometer tie into the engine harness somewhere and causing the other problems? Please someone help.

In the engine bay. In the upper left corner of fuse panel is two fuses. One is 100 and another is like 60 or 80 can't remember but they're the two biggest fuses. Also check the 30A fuse labeled 'moteur', that is the specific one to said circuit

Also want to add that the car seems like it had an alarm system at one point I see some wires cut in the drivers side kick panel area and also some wires that were spliced into the ignition harness to the lower left side of the steering column at one point. I'm about to post up some pictures of that wiring.

Here is the kick panel area wiring. Probably an alarm at one point?

This is the other wiring to the left the steering column. I believe the ignition harness?

I don't know those wire colors off hand but could be. Could also be turbo timer or some other crap.
Did you check the fuses?

Checked the fuses all look to be physically fine.

Upon removing some electrical tape from one of the ECU harnesses this is what we found.

This is connector B-56. Pin 78 (Pin out info I'm looking at states this pin is for the knock sensor for 95-96s. My car is a 97)

It looks like he has 4 different grounds tied into Pin 78 and they run through the harness. Also pin 79 "12 pin connector (drag) is tied into for some reason

I'm not sure what he has going on here or why, but it was all taped off as if it wasn't giving him any issues the way it was so this likely isn't my problem?

I'm getting some suggestions from a couple people about adding some grounds. There is no battery in the car, we're using one of those large battery chargers/starters to supply power to the car with the negative cable attached to one of the strut bolts. I don't have any grounds in the engine bay attached other than one connected from the starter bolt to the firewall so I'll add one maybe from the engine block to the chassis. Hopefully it is a grounding issue?
I'll check back with results later.

TSiGoesPsSsSst said:

(EDIT)There is no battery in the car, we're using one of those large battery chargers/starters to supply power to the car with the negative cable attached to one of the strut bolts. I don't have any grounds in the engine bay attached other than one connected from the starter bolt to the firewall so I'll add one maybe from the engine block to the chassis. Hopefully it is a grounding issue?

Click to expand...

Edit: I read that you checked the fuses under the hood.The grounds could most definitely be your issue. Once you connect your grounds, you could hook up your negative cable to the negative terminal. A battery would be better especially if your going to try and start the car. Have you noticed if the check engine light comes on when you turn the key on? If it does not check the main engine fuse under the hood

That wiring is stock. That's how factory does it. It's reliable, just doesn't look pretty. And FYI the green cables are stock too. Green cables are shielded cables, so the braided silver should stay grounded.

I'll pop back in later with a diagram of MPI relay.


If he has no power to ECU there won't be a check engine light. Also just said he checked the fuses?

NHerron said:

If he has no power to ECU there won't be a check engine light. Also just said he checked the fuses?

Click to expand...

Yeah I edited my post, somehow I missed his reply about checking the fuses.

With the key ON, check for +12V on pin 82 of ECU connector.
http://www.dsmlink.com/images/forums/2GECUPinout.pdf

That +12V input tells ECU to 'wake up'. With + there, the ECU then grounds pin 38, which grounds MFI relay and causes MFI relay to close and send +12V to pins 12 & 25 of ECU.

Well....



We have connection!

I added another ground from one of the top transmission bolts to the firewall, mounted the negative cable to the firewall which has two grounding points of its own, then put an old battery in the car that we had kicking around in the garage. The battery is junk and doesn't keep a charge but I charged it for a few minutes with the same charger we were using to power the car with before and then hooked up my laptop. Opened up ECMlink and it connected. At that point I yelled "YES!!" and a huge amount of relief was felt. ::
Fuel pump works, fans work, odometer no longer has a mind of its own so I think I'm in the clear. I attempted to see if the car would turn over a couple of times but nothing happened..like I said the battery is pretty much dead that I threw in it to test. It probably doesn't have enough juice.
This weekend I'm going to pick up a Miata battery and go from there. Hopefully with more juice it will crank over.

Sweeeeeeeeeeeeeeeeeeeeeet