3FE EFI Issue !!!PLEASE HELP!!! (1 Viewer)

[ilush]

Hey guys!

Couple of weeks ago my FJ80 did not start after I turned it off, then after a while it started. Came to find out that I had a bad EFI relay (confirmed with pulling it out to let it cool off and not getting a check engine light when I turn the key). I ordered one from the local Toyota dealer and in the meantime, just yanked it out to let it cool off every time it was giving me trouble. Got the new relay, the issue went away, I thought I was good.

Couple of days ago I was on the freeway and the truck just died on me, I checked everything out, pulled the relay out and put it back in. Came to find out it was the relay again, but this time it did not seem to be an issue with it overheating. Upon inspection, I saw that the socket for the relay is broken, I think I yanked the old one in and out a little too many times and maybe a little too aggressively.

It kept dying on me, I kept throwing the relay in and out, but I was able to limp it off the freeway like that and got it towed home. It never started again after that, no check engine light when you turn the key, so I thought the connection of the relay in the socket is no good. So, after reading about the nightmares people experience with these relays, I decided it's time to relocate mine to the interior of the truck and was convinced it would get it to start again. Today, I got to it and wired everything up, put the key in, and I have the check engine light on. I was excited, I thought it was going to start, but it cranked with no start just like before. The check engine light comes on, but as soon as I turn the key to try to start it, the CEL goes away. Once I stop cranking, it comes back on.

Does anyone have any idea what I am missing here? Where do I even begin? Not having CEL gave me a clear sense of direction, but now that it comes on, I am completely lost. TIA

 

[devo]

Does the 3FE have a fuel pump relay? I had a similar issue with 1997 1FZ-FE and it was the FPR not the EFI relay. Pulling the EFI relay would rest the ECU but not relieve the issue of the FPR over heating.

Is there any help here?

3FE fuel issue

pump looks aftermarket? and no fuel sock. :hillbilly:

forum.ih8mud.com

 

[devo]

There is a lot of info through the search function on 3FE’s not starting

Down load this

General Tech - 3FE EFI Diagnostics

3FE EFI Diagnostics updated for 2020

forum.ih8mud.com

 

[jonheld]

Does anyone have any idea what I am missing here? Where do I even begin? Not having CEL gave me a clear sense of direction, but now that it comes on, I am completely lost. TIA

Couple of thoughts.
It is unlikely that you damaged the relay socket by pulling the relay. It is far more likely that there is a faulty/poor connection on one of the crimps or that one of the female relay contacts has deformed causing a poor connection leading to arcing which would melt/weaken the surrounding plastic.

EFI relays get hot. Both on a 1FZ and a 3FE. That is the nature of the beast. The issue with the 3FE is that the relay box is located over the exhaust manifold. When I took mine apart, several of the wires had very brittle insulation from being constantly baked for 30 years. I replaced the EFI relay and fuse wiring using high temperature wire with new terminals both in the relay box and up to connector EB1, which brings up another point.

Connector EB1 runs the whole shebang to/from the EFI relay and he lives close to the same location.

If you jumped wires from the existing broken/faulty relay box to the new location, it's possible that you still have poor connectivity.
If one of the crimps you made is faulty you can have poor connectivity.

If you hold the relay in your hand while cranking, you can feel if the relay is releasing during a crank. That's a giveaway.

Yes, the 3FE has a fuel pump relay, but it's called the circuit opening relay. However, I wouldn't go down that path right now.

 

[ilush]

I replaced the EFI relay and fuse wiring using high temperature wire with new terminals both in the relay box and up to connector EB1, which brings up another point.

So I bought 10 gauge wire to replace the wiring with much ticket one but I couldn’t figure out what to replace. The actual wires going to the relay are like 20 gauge and I was not gonna chase them down to fully replace them (it’s cold in Chicago) and connecting 10 gauge to 20 gauge felt like a crime.

I did see the wire from one of the pins going to the fuse, but I decided I’ll upgrade this wire when it’s warmer outside. What am I missing in the wire upgrade department?

Thank you for your response, I’ll mess w my wiring as well as try a new relay. It is definitely EFI related as I was able to jump FP and B+ and the truck ran, so at least that more or less narrows things down. I attempted to test the relay and got nothing out of it, so I’ll try a new relay and then mess with my wiring if needed.

 

[ilush]

Does the 3FE have a fuel pump relay? I had a similar issue with 1997 1FZ-FE and it was the FPR not the EFI relay. Pulling the EFI relay would rest the ECU but not relieve the issue of the FPR over heating.

Is there any help here?

3FE fuel issue

pump looks aftermarket? and no fuel sock. :hillbilly:

forum.ih8mud.com

It does, but I was able to confirm that it’s in tact after your post. Thank you!

 

[jonheld]

It is definitely EFI related as I was able to jump FP and B+ and the truck ran, so at least that more or less narrows things down. I attempted to test the relay and got nothing out of it, so I’ll try a new relay and then mess with my wiring if needed.

The B+ in the diagnostic connector on the firewall comes from the EFI relay closure.
Jumping FP to B+ simply bypasses the fuel pump logic.
It sounds like you're chasing your tail here. Do you have the Toyota EWD so you can read the schematics?
Below is the full ECU with all associated circuits.

 

[jonheld]

If the engine runs with FP-B+ jumped, then this is a fuel pump logic related issue, not EFI circuitry related.
If you read page 4 of the troubleshooting document that was posted, it explains fuel pump operation and logic.