**SOLVED** Rough Idle, less responsive, CEL codes 25 and 26 less power 1FZ-FE 1994

[Desert Dino]

@landtank is there a way to force the fuel pump to run at full speed under 2000 RPM just for diagnostics?

Maybe I got junk in the fuel system or the gas pump filter that is inside the fuel tank is bad, and running it in low speed dose not produce good flow and pressure?

 

[Irish Reiver]

Not yet They are in the OEM position In the long run I will move the O2 sensors to the PAIR location
in 2017 I got from Toyota Japan a recall campaign from 1995 that was preformed by a local Toyota dealer, although this rig was not imported to Israel by Toyota Israel and all was free of charge.

When you move the O2's to the exhaust manifold you will will only be 60cms away from the ECU. You likely will only need to shorten one of the cables and it is fairly easy to do.

@Irish Reiver we do not have the same problem I have issues you had bad signal or short disconnections between O2 sensors and ECM

Not sure if it is the same or not. I had the same the codes as you, both my O2s showed as working on Toyocom. The only thing I didn't have was the vibrations.

 

[BILT4ME]

@landtank is there a way to force the fuel pump to run at full speed under 2000 RPM just for diagnostics?

Maybe I got junk in the fuel system or the gas pump filter that is inside the fuel tank is bad, and running it in low speed dose not produce good flow and pressure?

Yes. You can pull the relay and short across two connections.

IDK which ones. I think @jonheld has a diagram.

 

[jonheld]

Yes. You can pull the relay and short across two connections.

IDK which ones. I think @jonheld has a diagram.

The 1994 EWD is in the resources section available to download free-fer-nothin'.

 

[BILT4ME]

 

[landtank]

To jump to high it’s 3-5. But looking at the diagram I’d suspect the open circuit relay as well. My daughters 93 Camry had hard starting and running issues and the open relay was the problem.

 

[TomH]

You should be able to jump +B and FP at the data port in the engine bay and provide 12V to the fuel pump. Please double check my work but I just went through this on my SC400.

This is from the 1994 EWD. My 1997 is different.

 

[Desert Dino]

Making the story short, it was the VAF sensor, replaced it with a used new one it solved the problem. I'll post later the long way we did until we found the problem.

 

[GertB]

Had perfect time 4 days crossing the Negev desert from the Jordanian to Egyptian border. No gas station on the way.

View attachment 2990568

on the last day i was driving very low on fuel, the last hour the red low gas light was on and the road was very bumpy. we arrived on the pavement, stopped to rest and make some coffee.

I never cleaned my 25 years fuel tank! I was lazy, I read in here that I should do it, but never got to do it.

When I started the rig it was vibrating rough no power only when in high RPM it worked without vibration, when coasting around 2000 RPM it was vibrating and I got check engine ON

View attachment 2990566View attachment 2990565

I added 5 gallon gas, drove 20 miles to gas station got 40 gallons of fuel and 1 fuel additive and drove home it didn't help.

At home changed Air filter and plugs and more fuel additive still its very bad

Any Ideas?

Hi!!
I

Had perfect time 4 days crossing the Negev desert from the Jordanian to Egyptian border. No gas station on the way.

View attachment 2990568

on the last day i was driving very low on fuel, the last hour the red low gas light was on and the road was very bumpy. we arrived on the pavement, stopped to rest and make some coffee.

I never cleaned my 25 years fuel tank! I was lazy, I read in here that I should do it, but never got to do it.

When I started the rig it was vibrating rough no power only when in high RPM it worked without vibration, when coasting around 2000 RPM it was vibrating and I got check engine ON

View attachment 2990566View attachment 2990565

I added 5 gallon gas, drove 20 miles to gas station got 40 gallons of fuel and 1 fuel additive and drove home it didn't help.

At home changed Air filter and plugs and more fuel additive still its very bad

Any Ideas?

Hi Guys,
Just read through the post.
Lots of good information.
I bought a 1994 LC a few months ago, very clean and low km on for its age, 190000
Then two weeks ago went out for run around the dunes around riyadh, and blew something in the gear box. All ATF out in minutes.
Long story short, had the gearbox rebuild.
Had it back now a few days, all gears shifting well.
However now i notice it has a bit of a low idle issue!
Specially in the morning when the car is cold.
Few times it even stalled.
Any comments on what i might look for?

 

[Malleus]

You should probably post this in a new thread, since your problem isn't likely the same as the OP's.

Check the idle air control valve. There are two checks to make, one mechanical and one electrical. You have to check both and you have to remove it from the throttle body to make the electrical check. Removing the throttle body is the best way to do it. The instructions are in the service manual, which is in the Resources forum.

If it fails the tests, you can try to polish the plunger bore with very fine sandpaper. If that doesn't work, you'll have to replace it with part number 22270-66011. The one for your year is no longer available, but this one (for the 3rd generation 80 series) is a direct replacement.