EFI relay - tip for quick diagnosis.

[IdahoDoug]

The 93 would not start out of the blue a few days ago. No hint. Engine simply turned over but did not even try to run. Luckily it was in the garage. Starter fluid made it hit, so had spark. I opened the fuel pressure reg - fuel pumped out. Opened the fuel line on the left inner fender - fuel again.

On a whim, I put in a new spare EFI relay. Started right up. Put the old back in - no start. In the process, I noted that with the old in when I turned the key on, the "check engine" icon (amber engine) did NOT light up. Put the new relay in, and it does.

So, that's my quick field diagnosis tip. If your 93-97 turns over but won't start and the check engine icon is NOT lighting - suspect the EFI relay without screwing around. Hope this helps someone.

DougM

PS - that is the first ever no-start in 19 years and 235,000 miles!! Dang it!!

 

[autobon7]

Lucky you had a spare. My 95 has 218XXX.....relay is prolly cheap insurance. Guess I will pick one up. Thanks for the tip.

 

[half k cruiser]

That was pretty observant of you. Thanks for the good tip Doug.

 

[ttubb]

Anyone know the part number and cost of an EFI Relay for a 95 FZJ-80?

Question, is this more of a problem for pre-95 FZJ-80s due to under-hood heat issues?

 

[LandCruiserPhil]

Anyone know the part number and cost of an EFI Relay for a 95 FZJ-80?

Question, is this more of a problem for pre-95 FZJ-80s due to under-hood heat issues?

90987-02004

The same relay you remove with the LCP window mod

 

[CJF]

Starter fluid made it hit, so had spark.

Doesn't dead EFI = no spark?

 

[Godwin]

So, that's my quick field diagnosis tip. If your 93-97 turns over but won't start and the check engine icon is NOT lighting - suspect the EFI relay without screwing around. Hope this helps someone.

And not just for 93-97 but also 88-92 FJ62 & 80.

 

[Rwhat]

How would you jumper the relay in a pinch without a spare?

 

[LandCruiserPhil]

How would you jumper the relay in a pinch without a spare?

Term 2 - 4 just like the window mod or use the window relay

 

[ttubb]

How would you jumper the relay in a pinch without a spare?

Per Phil's excellent write-up on the window power mod here:

https://forum.ih8mud.com/80-series-tech/612856-window-power-without-key-made-ez.html

You already have a spare onboard! Now we know. Thanks Phil.

 

[jonheld]

No CEL=No Start. Where have I heard this before?

On a 3FE, the lack of the +12 tally back to the ECU will kill spark and fuel delivery. Since Doug says he was able to make fire with starting fluid, I would suspect that the 2 ECUs differ in that regard.
I'll have to test this on my brother's LX450.

 

[Tapage]

small hi jack ..

where is the fuel press regulator .?

 

[CJF]

I'll have to test this on my brother's LX450.

Please do.

If it's controlling neither spark nor fuel pressure, what's left?

Firing of the injectors is the only thing that immediately comes to mind...

 

[jonheld]

It's not really controlling anything, just enabling certain circuits.

The EFI relay feeds power to almost every sensor and the secondary coil of the fuel pump relay. The fuel pump primary is fired by the starter circuit while cranking the motor, however the injectors shouldn't fire without the EFI relay closure.

So even if Doug was able to get the motor to fire briefly, the fuel pump wouldn't have run and the injectors wouldn't fire.

I like playing with my brother's truck. He freaks out when I start pulling things out of the engine bay. Good times.

 

[Michael Hanson]

I suspect if he got it to fire briefly, the efi relay had cooled down just a bit. Mike

 

[jonheld]

After looking over the ECU circuits from a 96, The fuel pump management is very different between the 3FE and 1FZ motor. The ECU runs the whole show on the logic side. So it's possible that in one error condition (EFI relay open) the fuel pump would never run even when cranking. Of course this would differ from the EFI fuse being open. I need to verify both error conditions.

In any case, the 2 ECUs and subsequent design of dependent circuits are different in many ways and similar in many ways. The injector circuits differ and are individually controlled by the ECU as opposed to the 2 groups of 3 on the 3FE.

I'll stare at the squiggly lines some more when I have time. I'm sure that the 2 flavors of 1FZ (OBD1 vs OBD2) are different in certain aspects as well. I don't have an OBD1 version of the electrical FSM.

Bottom line on both motors, No CEL=No EFI Relay closure=No Start.

 

[IdahoDoug]

Cool - might be a field test if you susspect the EFI relay then. Time shaver for sure

 

[tmsimonson]

IdahoDoug ---- Are you still taking orders for your DVD?

IdahoDoug,

Sorry to hijack this thread but have been unable to reach IdahoDoug regarding the head gasket DVD. Are you still shipping these? I have sent paypal payment about 10 days ago but have had no communication regarding order or status. Again sorry for hijack but a bit frustrated by zero feedback.

Thanks....