I have installed a new engine. Its taken a few weeks on and off, since I work night crew and sometimes very long hours. Today I got to the point where it was time to crank it. I hooked the stock ECU back up, and turned the key to on, and realized none of my guages bounced like they did a month ago, the radio didn't come on, the odometer didn't light up. I checked every wire I could, I checked over the ecu several times, all 4 connections are in and snug. The black connector for the control box on the back of the ECU is fine. Everything seems to be connected, but I'm getting no start.

Powered:
Windows
Headlights
A/C Fan
A/C recirculation button
starter

Not powered:
Guage cluster
A/C button
radio
dome light
ecu(?)
hazard lights
blinker
brake lights

Went through and checked all the fuses and they all visually passed inspection. What fuse would cause something like that? Couple of friends said that the ECU was blown. But I don't see how it could've been blown. I unplugged it, sat it on the passenger seat, then a few weeks later, plugged it back in. I'm stumped.
Any help? I want to get it running tomorrow morning if I can, so I'll be checking the post all night ..

 

Try swapping the TNS relay and the headlight retractor relay next to it and located in the relay box, on the front of the car, next to the passenger headlight. Both relays are blue. I've had a blown TNS cause no instrumentation or parking lights.

Also check the engine harness connectors from the ECU upwards. There is a white 16(?) pin connector that is way up under the dash, just before it goes through the hole in the firewall.

 

Missed the white connector at first, went back through and found it. It is connected now. Have to wait till morning to try swapping those fuses, but will give it a try.

Any other ideas?

 

You said visually check fuses? You really should get a continuity tester ($7) at any autoparts store. It looks like a screwdriver handle with an icepick point. The handle has a light in it and a wound cord with a clip on the end. Clip it to a ground and touch the point to the metal tabs on each side on top of the installed fuse. The light should light up on both sides when the key is on. If not, blown.

 

I had the exact same thing happen to me a while ago. I went to a friends house, then when I came back outside to drive home, it did what you described. I got home and looked at all the fuses and they looked ok. Then I took each one out and put it back and everything worked again, go figure.

 

Heh, I know what a continutity tester is, I was just pressed for time. The Auto shop on base closes early on saturdays, which is incidentally the only day I have all day to mess with stuff. I kept telling myself it was something simple, but I just couldn't pin point it.

 

Any more ideas?

 

Did some testing today. Put a new terminal on the neg side of the battery. Redid the ground, sanded the contact patch on the wire, and on the chasis. Still no good. Switched out my ECU with a friends, and my ECU works in his car just fine. His ecu made no difference in my car. Also swapped out the TNS relay with the retractor relay, and made no difference.

So what now?

 

Did you mess with any of the grounding points on the engine or points that mount to the car? Make sure you have the one of the battery harness, the 2 white flat sensors up front, the 2 on the engine block from the harness, one from the UIM to the firewall, one down by the ecu inside the car.

 

I'm not sure what you mean by the two white sensors up front .. do you have a picture?

 

You did check that big white 120 Amp Main Fuse right?

 

I looked at it, and it looks fine. How else could I test it?

On second thought, I could swap it out with my friends ......

 

Can somebody give me an idea of where all these grounds are so that I can check them? A physical description would be nice ...

 

take the fuses out and put them baack in. it worked for me. worked for me.

 

The 2 white ground "things" are bolted up to the front crossmember. If you havent taken off your front bumper then chances are you havnt messed with those. If you have they are about 1.5"x1" with a metal tab for grounding coming out of it.

 

Ok tested all the fuses. They all work. I tested them by placing on side of the tester on a ground, then touching both sides of the fuse, it lit up on both sides therefor its good... Right? On some I had to touch a hot wire, and touch the fuse.

I got a difinitive list of what is powered and what is not:
Powered:
Wiper
Headlights
A/C Recirculation switch (lights up)
Windows
Starter
Headlight pop up
A/C Fan will come on

Not Powered:
ECU
Brakes
Turn Signals
Hazard
Dash
Dome Lights
Mirrors
Greddy Guages
Coin Tray Light
Radio
Locks
Running Lights
Cig Lighter
Fuel Pump? (Can't hear it priming when ignition is left in "on")

I've been looking through all of the wiring diagrams for the car. And it seems that all of the things that don't work go through the 60A Btn relay, 40A B1, 40A B2 and of course the ignition switch. Some of then things that DO work go run through the B1 and B2 relays, but all of the things that DO work do NOT go through the BTN relay. So I'm thinking that maybe thats the problem, even though I got current on either side of the relay when I popped off the little plastic cap. I also took the neg. side ground off, put a new terminal in, sanded the connections on the ground, and sanded the chasis where it connects. Hoping that would ensure a better ground. Also, today I went through and pulled EVERY fuse and EVERY relay, then put them back in. Made no difference.

So .... anybody have any ideas? Could the relay be good even though I get a good connection on either side of it?

 

Guys,

A relay is a four connection device. Two of them provide power and return (ground) and two are the switched contacts (unless it is a multiple pole relay). The relay could fail to function if any one of the four paths and connections are bad. I don't have my FSM here at work, but will look tonight and see if I can help, I'm an electrical & mechanical engineer, so I should be able to pick common paths for the device list you have.

Mick in San Diego
'93 R-1 with bad EGR valve

 

That would be awsome. I don't really understand how any of the fuses or relays could've gone bad when they weren't even attached to anything. But I'm hoping its something as simple as that.

If not, then I might just have to get a new wiring harness, but up to this point, any attempts to find a vendor have been worthless. Anybody have any idea who sells one?

 

Ok, went through today and replaced all the fuses with known good ones. I also used my fuses in a running FD, and they all checked fine. Which leaves me to believe either:
1) A wire isn't connected
2) A wire got fragile and broke in the harness that I couldn't see

Either way I'm going to have to tear back into the engine to find it, so while I'm at it, I might as well replace the whole damn harness. Right?
Where can I find a new harness, and can any of the electrical guru's out there give me a hint or clue as to which wires are suspect?

 

Ray Crow at Malloy Mazda in Virginia is the only discount harness source I know of and he wants $750 or so.

Restate your problem again. The car cranks but does not start or does nothing at all when you turn the key?

 

nm

 

Problem is, I put the key in, switch to run. Nothing comes on. I can turn on the headlights and the rest of previously mentioned "powered" items, but nothing else. The Starter will turn the engine. But there is no spark or fuel pump, so no fire. Not to mention guages don't turn on, ecu doesn't get power, etc etc.

Heh, mad_7ist, I was about to say, the spark plugs aren't on the same side as the passenger. Is there a ground on the passenger side?
I redid the ground from the battery. Put on a new terminal, sanded down the chasis where the wire is connecting, sanded down the connection on the end of the grounding wire. The ground coming off the upper intake, onto the firewall is clicked in. I sanded the connection there down too just to be sure. Those were all the grounds I could find. If I'm missing some, please enlighten me.

Man $750??? thats crazy. I was expecting around $300. Looks like I better find the problem with the current harness.

 

there is a ground on the driver's side by the plug wires. verify that the circuit opening and the main relay click when you turn the key on. the fp is powered from the circuit opening relay

 

I agree with Mad 7tist. The most obvious answer is a relay. Check your relays before you start hunting for a harness problem.