Idle Air Control (1 Viewer)

[RandyS]

:-\Has anyone ever corrected there rough idle by replacing there IAC. I have done everything but that. Relaced TPS, tune up with all toyota parts,the big air intake hose, adjusted valves,EGR, PVC, Could you guys let me know what the part number is for the IAC and the gasket, and if i am over looking something.
1992 Landcruiser 3FE

 

[PHAEDRUS]

Not sure as I hav just decided to live iwth the idle. have you gone through the 3FE archives on yahoo groups?? those guys are preahing th fuel pressure regulator as the 3FE gremlin of choice at the moment.
Dave

 

[Seminole]

???What about O2 sensors, clean the throttle body and intake, double check ALL the vacuum lines...??? I don't know that you will ever get it completely smooth. I 've done all that you have and above and can't get mine perfectly smooth. I just live with it. Maybe somebody else has a trick or another angle.

 

[RandyS]

:-\I did forget to mention that the throttle body and intake have been cleaned, and i had the O2 sensors tested.
It seems to run rougher when it is warmed up and sitting at a red light

 

[PHAEDRUS]

Randy seriously read throught he 3fe archives for the fpr diagnostics. the symptoms were only once warm at idle. I believe erics_bruiser changed his out on his 91 as well adn it was pretty easy.
Dave

 

[GXO]

Rough idle at temp could also be the lovely EFI Relay problem.

I have read of folks having rough idle, fixing the EFI Relay wiring, and seeing smoother idle.

I have the EFI fuse to relay replaced with 10 gauge wire as of this morning and I notice an improvement.

I haven't even done the other wire yet!

 

[RandyS]

???Dan, did you replace your EFI to relay wire, i am not sure i would feel comfortable doing that unless i had some very detailed directions. Hint,Hint

 

[GXO]

I did the EFI Fuse to Relay wire within the fuse block.

It was a pain in the arse to get a 10 gauge wire to fit into the little spaces for stock wiring.

I haven't done the EFI relay to EB1 #2 yet because I know where EB1 is, but I don't know which is #2 (there are three wires that go in there).

The swap within the block involved:
1. disconnect battery
2. Take fuse block cover off (inside engine bay, near intake cooling fan).
3. Remove 13mm bolt on the cab side of the block and slide it off of the bracket.
4. Remove the 2 12mm bolts holding the bracket to the inner fender.
5. Rotate the fuse block in the space you created by removing the bracket so you can see the bottom.
6. Remove bottom of fuse block (4 tabs to pop it, 2 on each side).
7. Now you can trace the wire from the EFI Fuse to the Relay.
8. The wires are a pain to get out, there is a little tab that you have to reach into the top of the plug to get to. Put pressure on this tab to the outside wall of the plug and pull from the bottom to get it out. Have patience, it is a pain.
9. Do this to the relay socket and the fuse socket, same proceedure.
10. CAREFULLY pry open and remove the old little wire from the connector.
11. Insert length of 10 gauge wire and crimp the connector.
12. solder a bit to ensure a good connection.

Plug it all back up and reassemble.

That is the basic process.

The EB1 connector (which is the grey connector on the first branch from the alternator going to the vacuum switches behind the fuse block) is roughly the same process if you know which wire to get after. I am assuming the Red and Yellow wire opposite the one replaced for the fuse is the one that goes to the EB1.

I am still sorting this out so any clarification would be helpful (my hint hint).

Hope this helps...may want to junkify it up to the FAQ?

 

[semlin]

I have heard much oblique references to the "EFI relay" problem with the 3FE but never an actual explanation. I thought you just needed to carry an extra fuse around. What is it and why do you need to do that Dan?

 

[GXO]

The 3FE EFI fuse to Relay and Relay to EB1 connector was made with inadequate thickness of wire such that is builds resistance and heat when it runs.

Heat makes the relays fail and can also cause the fuse to pop.

There are new relays I have heard of that have copper wire in them from autozone that are less likely to fail.

The other route is to use OEM or the aftermarket relays and upgrade the small gauge wire with some 10 gauge wire to handle the current with less resistance.

 

[cruiserdan]

The "field fix" involves replacing the 12 gauge wire(red/yellow trace) from the EFI fuse to the EFI relay and the same gauge/color wire from the EFI relay to the EB1 junction with 10 gauge wire. The relay should likely be replaced during the modification (possible burned points).

The relay is a 90987-02004-83


D-

 

[GXO]

Hey Dan,

The trick is there are two red and yellow wires going to EB1 so I can't determine which to swap out. I could cut the harness covering, but I wanna keep it purty.

Any ideas?

 

[cruiserdan]

Put a meter between the relay end and the EB1 plug end and check for continuity?

 

[RandyS]

I think i will check out my wiring under the fuse block and maybe replace the EFI relay. One other thing i want to run by you guys, in regards to the rough idle we all seem to have.
I started reading other forums, Ford, Chevy, Dodge, Honda. And what i find is we aren't alone. One guy on a dodge forum was having a rough idle and miss, so someone suggested he increase his spark plug gap from .35 to .60 and he reported back that for what ever reason it worked.
Who wants to be the first to try it and report back?

 

[cruiserdan]

Randy,

I resist tampering with Toyota's recommended settings. The main reason I do is because of my quarter century association with Toyota on a dealer level. It has been my experience that Toyota does not make decisions in an arbitrary manner. The pattern I have observed is that everything is very well thought out and almost all the angles have been covered and factored in.

If a widened plug gap really worked, I would expect a TSB stating the desirability of that change.


D-

 

[RandyS]

I use Chevron 10w-30 oil, 3000mi or less
Chevron unleaded gas
Air Filter is 1 year old Alternator output, Good
New Battery/ Cables still look good?
Pullys look good, not sure how to tell,
i do have all new belts.
AC compressor sounds fine. How do i know if the smog pump has somthing wrong with it, i just passed Wa state emissions with no problem.
I do have a new factory EFI relay comming
$8.15 do you think the EFI could be a problem, and if it was wouldn't it set a code? How about the coil?

 

[GXO]

what octane? Mine runs rough on 87

 

[RandyS]

Dan, i do run chevron 87 octane, what would you suggest i run?
Is Chevron a good brand of gas?

 

[GXO]

Run a tank of plus with some injector cleaner and see if it helps.

 

[RandyS]

Ok, i will give it a try. What brand of gas do you use?