My 3FE into FJ40 swap (1 Viewer)

[Curtice]

How do I check for power? I know I have continuity in the B-L wire from the battery connection to the relay pin, so I assume it is sending power. Is there a better way to verify?

 

[Stumpalama]

OK, if you have continuity, which you checked with the wire disconnected then you should have power as well. But just to verify, use the voltmeter function on your multimeter. You should have constant power from the wire from the battery (B+). Connect the positive (red) lead to the (B+) wire and the black lead to ground to verify voltage.

 

[Curtice]

thanks again...i'll give it a go tonight. You guys are awesome.

That is the only wiring issue I noticed (right away anyway), so once I get that working, will pull the harness, get the new gauges integrated, do some clean up and repair on the old 40 harness, and wrap it all.

 

[73tlcv8]

Post up what yo are using for a relay so we have the full picture of what you are trying to make work. Thanks.

 

[73tlcv8]

In my view, the Toyota engineers likely provided a second switched 12v contact on the ignition switch for the ecu to minimize noise and voltage fluctuations in that circuit since it can impact ecu function and injector pulse duration. The relay provides that second switched contact missing on the 40 ignition switch. It may work without it and you may or may not notice anything, but you know there was a reason for it.

 

[Curtice]

That is a picture of the relay. I double checked tonight and realized I did have the wires backwards (I had the battery cable and the B-L wire on the 1 and 3 terminals, when they should have been on the gated terminals (2 and 4). But when I corrected it, still having the same problem.

I did check the voltage and it is sending 12 volts.

I suspect my ground might not be good. My ground wire is spliced into a wire which grounds at the fuse box bolt. But not sure how to test this.

 

[Stumpalama]

To check the ground, set the multimeter to ohms and put the red probe of your multimeter in the 1 or 3 slot of your plug, whichever is your ground circuit into the relay, then put the black probe on the ground bolt you mentioned. resistance should be 0 or damn close.

 

[pappy]

Probably not related, but I'll toss it out there. Make sure the bracket on the coil/ignitor is grounded. I ended up running a wire from the battery to the bracket, because of this issue.

 

[Stumpalama]

That relay could be baD too... you can test it by making some connectors and hooking up the 1 and 3 terminals on the relay to a battery and listening for a click. while that circuit is energized, plug your ohm meter probes into the 2 and 4 terminals and check for continuity. It should be 0 when energized and 1 when de-energized.

 

[pappy]

That is a picture of the relay.

OK, I get why the relay. I guess I wouldn't trust old FJ40 wiring either. I used all FJ62 wiring from the dash so I was good without the relay.

Question, why not use a regular Bosch relay? That way you can get one anywhere if it goes bad. Easy to wire too.

 

[Curtice]

OK, I get why the relay. I guess I wouldn't trust old FJ40 wiring either. I used all FJ62 wiring from the dash so I was good without the relay.

Question, why not use a regular Bosch relay? That way you can get one anywhere if it goes bad. Easy to wire too.

I just re-purposed a relay from the 62 harness...seemed easiest. I have two of them so if one goes bad, I guess I have an extra.

Incidentally, I have tried using both relays and get the same result...so I don't think it is a bad relay. Will try the suggestions above. Coil bracket isn't really grounded well...its just sitting on the frame. But the fact that I can start it if I jump the wires to bypass the relay tells me that isn't the problem. I will ground it better though.

 

[73tlcv8]

you probably thought of this but try a temporary ground wire to your relay to rule that out.

 

[Curtice]

Yup. Ran the temporary ground and it fired right up.

So I guess I'll re run the ground wire. It might be my splice, but a bunch of my dash stuff (hazards, brake, fan) is not working either. Didn't notice before cause I was focused on the ignition. If that is all the same ground, that might be my problem.

I'll need to consult my wiring diagrams on that.

Thanks for the suggestions.

 

[Curtice]

So the ground wasn't working because I didn't have the light switch hooked up. I guess the circuit runs through that. Hooked it up, and the engine fired right up using my original ground. So all is good!

 

[pappy]

Enjoy.

 

[Stumpalama]

Glad you got it figured out.

 

[Curtice]

Me too. I will probably run into a few more wiring issues, but really glad I wasn't chasing stuff down forever. Considering I knew next to nothing about this I am very pleased. Thanks for everyone's help.

Goal this weekend is to get the harness wrapped, along with cleaning and repairing the old stuff. Fuse box is in kind of bad shape. Also need to get the new gauges from Amaurer in and wired.

At least the end is starting to be in sight.

 

[73tlcv8]

Way to go. I know about this time in my swap I was wondering "what else could go wrong?" Its a wonder they make thousands of new cars a day and they mostly work when they go out the back door.

 

[Curtice]

I was in the same boat, 88 engine harness with two plugs and an 89 cowl harness with one plug. The 88 engine harness was pretty rough so I just went with a 89 engine harness and solved all the issues. I went out and looked at my partially disassembled 88 engine harness and came up with this:

Two conductor plug
G-R = VC to TPS and AFM
G = ?

Five conductor plug
B-R = Ign switch to Starter Solenoid/circuit opening relay/start injector
B-Bu = Ign switch to igniter/injectors/efi computer
R-G = FP power to check connector
Y-R = +B to ISV and O2 sensors
B = Tach signal to check connector

How'd I do?

ok, bringing this back up again. On the two conductor plug, unsure about the G wire:

I believe it goes to the water temp switch on the picture below. I have a green wire already plugged in to that switch.

But where does the other end go? There is nowhere on the ECU for it that I can see. Is it unused in my setup? I don't think it goes to the gauge, because I believe that is what the temperature sender is for.

I guess the question to go along with this is what is the different between the water temp switch, sensor, and sender?

 

[pappy]

That was one of the bridge connectors on the 1988 harness that connects the engine harness to the cowl harness. From my notes:

• To: Water temperature gauge (G)
• Bridge: AFM to TPS (G-R)

And that looks like my picture. Where is my copyright attorney?