FJ62 3FE EFI MAIN RELAY (1 Viewer)

[Vandyfan]

I thought I had a bad fuel pump, but before I dropped the fuel tank, I checked the EFI Main Relay. I never get 12volts from the ECM to the coil for the EFI Main Relay (checked voltage at the pig tail connector red wire and back to negative battery terminal). I am checking it with ignition switch in the “on” position. If I jumper the contacts on the EFI main relay and bypass the circuit opening relay with a paper clip, I get plenty of fuel to the fuel rail. So I know my fusible link is good.

Possibly related, my check engine light does not come on when I turn the key to the on position.

My question is what would stop the ECM from sending 12v to the EFI main relay coil? Seems like I’ve read that one of the water temp switches could cause it, but I can’t find any threads referring to it in regards to fuel issues.

When I jumper both the EFI main relay and the circuit opening relay, I can get the engine to crank but it will not fire.

 

[Vandyfan]

A little follow up: I got the check engine light on now when ignition switch is on position. Found a bad connection at the battery positive post (3 pronged pigtail connector - the 1 horizontal pin (the 2 vertical pins checked ok).

Now I will try to run a diagnostics check.

Will post results, hopefully

 

[Vandyfan]

Code 51 = switch condition signal = no throttle position sensor, gear selector sensor, or ac signal to ECM

It will turn over, but won’t crank, so I’m guessing throttle position sensor?

Any further help, would be greatly appreciated!!!

 

[tmxmotorsports]

You say you had a bad connection at the battery may have blown a fuseable link

 

[Vandyfan]

it was just a broken wire. I spliced it and got 12v through the connector now.

My question now is, will code 51 prevent it from starting or just make it run rough?

I don’t have any feeler gauges for checking the resistance measurements specified in the Haynes manual. I was wondering if I could somehow bypass the throttle position sensor just to get it to run?

 

[Vandyfan]

I found some feeler gauges, so I’m about to start checking my TPS sensor. My emissions control sticker says California compliant, and tps diagnostics says to apply vacuum to tps sensor for California models. What is the beat way to go about applying a vacuum? How big a difference does it make?

 

[Vandyfan]

Checking the resistance between idl and e2 pins with 0.0303” feeler gauges between the throttle lever and throttle stop screw, I had an open circuit (infinite resistance). I adjusted the TPS until I started getting a resistance measurement which was 40 ohms. But then I read about the same resistance with 0.0429” of feeler gauge also. It’s either open circuit with both checks or closed circuit with both checks. I can’t get it to adjust where it switches from closed to open when I change from 0.0303” to 0.0429”.

To top it off, when I finished messing with it and went to try and start. I must have blown a fuse because all my indicator lights went out immediately.

I quit for the night. Maybe somebody can shed some wisdom while I sleep.

 

[bluefish]

The code 51 wont prevent it from running. Just went through all this with my fj62 a couple weeks ago
Sounds like you have some electrical issues that are the likely cause tho, maybe ground issues. How did u end up settling on the tps as the possible culprit?

It sounds like you already moved/ adjusted the tps from where it was when last running correct?
it was extremely dificult for me to even get the feeler gauge in position with the throttle body on the vehicle. I would recommend getting a new throttle body gasket, taking the throttle body off ( takes 20min) clean it and the tps to be sure it isnt sticking. Then set it up/adjust/test it on the bench.
Best of luck

 

[4Cruisers]

Checking the resistance between idl and e2 pins with 0.0303” feeler gauges between the throttle lever and throttle stop screw, I had an open circuit (infinite resistance). I adjusted the TPS until I started getting a resistance measurement which was 40 ohms. But then I read about the same resistance with 0.0429” of feeler gauge also. It’s either open circuit with both checks or closed circuit with both checks. I can’t get it to adjust where it switches from closed to open when I change from 0.0303” to 0.0429”.

A week or so ago someone posted a question about why I used 0.043" when adjusting my TPS instead of the 0.0303". Their FSM only had the 0.0303" number (in the text), but on the same page my FSM includes a table with the 0.0429" number, along with the 0.0303" in the text. Their FSM lacked the table. So I'm not sure what the deal is. My '86 FJ60 with 3FE runs great the way I set it up.

 

[Vandyfan]

The code 51 wont prevent it from running. Just went through all this with my fj62 a couple weeks ago
Sounds like you have some electrical issues that are the likely cause tho, maybe ground issues. How did u end up settling on the tps as the possible culprit?

It sounds like you already moved/ adjusted the tps from where it was when last running correct?
it was extremely dificult for me to even get the feeler gauge in position with the throttle body on the vehicle. I would recommend getting a new throttle body gasket, taking the throttle body off ( takes 20min) clean it and the tps to be sure it isnt sticking. Then set it up/adjust/test it on the bench.
Best of luck

I settled on the TPS because when I jumpered the test box in order to get the diagnostic code, it resulted in code 51. I assumed if it was the gear selector switch input that it wouldn’t crank at all, and assumed ac switch input had nothing to do with getting it to start.

 

[bluefish]

Any progress? You're into the tps switch now regardless ey? Heres the info from my FSM

 

[red66toy]

I did both of those shim measurements with the throttle body on the bench. They list both so do both.
Also, @Vandyfan if you can't get it to read like the FSM indicates, replace that sucker. Its a critical piece for the 3FE to run correctly. Still available new from Toyota thankfully.