Lets talk 3fe Desmog.

DESMOG

  • YES

    Votes: 44 91.7%
  • NO

    Votes: 4 8.3%

  • Total voters
    48

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most issues with the idle/off idle are caused by a weak egr spring or over active egr modulator. high idle is due to a miscalibrated TPS most likely, or a dirty throttle body. going thru the FSM efi section piece by piece and trouble shoot the systems and components will narrow down where any problems are. chase the harness from each sensor to the ecu. make sure the fuse links are good and clean the throttle body. desmog gets some gear out from there but otherwise is no magic bullet. and don't forget to adjust the valves.
 
oh yeah...make sure there are no exhaust leaks near or before the o2 sensors...
 
Removed my, charcoal canister and truck runs better but that's probably due to the check valve leaking. It's super easy too. If you are interested in how let me know
 
My truck is an 89 FJ62. I've looked through these posts but can't find where it says what belt to use to run w/o the smog pump.:meh: Can anyone share a part# for the shorter belt that bypasses the smog pump please?? Thanks!
 
My truck is an 89 FJ62. I've looked through these posts but can't find where it says what belt to use to run w/o the smog pump.:meh: Can anyone share a part# for the shorter belt that bypasses the smog pump please?? Thanks!

I haven't done it, or searched the size of this belt, but yes, it looks like Dayco 22528, according to PDF document found here: https://www.ih8mud.com/tech/pdf/3FE-Desmog_Guide.pdf
 
Thanks Guys!! Appreciate that.
 
Has anyone been able to get the air injection rail off without tearing it up or taking a bunch of extra stuff apart??? I have completed every other part of the desmog but can't figure out how to get the injection rail past that heat shield.
 
Has anyone been able to get the air injection rail off without tearing it up or taking a bunch of extra stuff apart??? I have completed every other part of the desmog but can't figure out how to get the injection rail past that heat shield.

Did you read through this? https://www.ih8mud.com/tech/pdf/3FE-Desmog_Guide.pdf

I've done everything else except removing air rail, figuring it's not necessary.
 
Has anyone been able to get the air injection rail off without tearing it up or taking a bunch of extra stuff apart??? I have completed every other part of the desmog but can't figure out how to get the injection rail past that heat shield.

It only takes about 5-10 minutes to pull the upper plenum off which makes the air rail removal a breeze.
 
I removed everything and welded the air injectors s*** and reinstalled them into the head.
 
It only takes about 5-10 minutes to pull the upper plenum off which makes the air rail removal a breeze.
That's a possible solution. Though since I knew I wouldn't be reinstalling, I just undid the fittings, gripped it and ripped it. Of course it got bent all to hell on its way out, but it went straight into the recycling bin anyway.
 
Something to consider: 3FE injection is now 30 years old. But the nice thing is that the manifold nicely supports injectors and it wouldn’t be too hard to go to a system like mega squirt. You could probably run megasquirt and a nice new cat and get rid of all the ancient emissions stuff. The new efi can better support cat operation and health.
 
Something to consider: 3FE injection is now 30 years old. But the nice thing is that the manifold nicely supports injectors and it wouldn’t be too hard to go to a system like mega squirt. You could probably run megasquirt and a nice new cat and get rid of all the ancient emissions stuff. The new efi can better support cat operation and health.
Has anyone gone this route before?
 
Has anyone gone this route before?

Yes thousands of people have used various aftermarket EFI solutions on hundreds of different engines
 
These days the efi kits are quite well proven and a lot easier to install and tune. It’s been a solid 20 +years since the first standalone kits hit the market and they have gotten a lot better.
 
Honestly I'd much rather run upgraded (though I don't think any even exist that are compatible with the 3FE) injectors and convert to a direct fire DIS ignition system than bungle around with the entire fuel injection setup on an engine that most likely won't benefit from it.
 
The purpose of an aftermarket kit would be to allow you to dump all the old emissions stuff, run a modern closed loop efi system that can much better modulate fuel mixture to meet the rich/lean cycle that a cat requires to perform well and also allow you the ability to tune your fuel programs. Much like VW you could create an emissions test map and then switch to normal driving mode once past the test. And with the added bonus of keeping your truck looking 100% stock to all but the most knowledgeable testers.

Will a new system double your power, torque, and fuel mileage? Not likely. But driveability and throttle response are likely to improve. I’ve yet to read a post about a 60 owner lamenting the lack of improvement of a sniper install over a carb.


I’m suggesting the newer efi if you are faced with having to replace all the smog equipment or want to take it all of and still have a chance of passing smog checks.
 
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