3FE help

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ccasteel

ccasteel

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Hey guys, my sister is getting frustrated with the reliability of her '78 FJ40 with a 3FE conversion. It was originally a fun extra vehicle, but currently she is having to use it for dd. I'm considering swaping cars with her and trying to find the gremlins, but on top of not being the best troubleshooter, I know next to nothing about the 3FE. I'm hoping somewhere amongst us is a 3FE specialist that can help me work out the kinks. Any volunteers?

It starts and runs but dies most every time she slows to a stop. The po added several extra security measures that require switches and buttons to be flipped in order to run. Even the radio has some sort of a "breaker" under the hood.
 
I'm not exactly close or a 3FE guru so the only help I can assist with is track down Eric, he's sharp. If no one else local pipes up shoot a PM to Jon Held, he's owned a '91 80 series for a long time and is pretty good at troubleshooting the 3FE. Mention Kris from KS recommended him so he knows who threw him under the bus. ;)

There's nothing like having to keep a cheat sheet on how the switches need to be oriented to make the truck run. :bang: I would certainly try and figure out the wiring mess even if that's not the cause of the current issue. There isn't much convenience in having every system on the truck protected by a creative means to disable it.
 
Is this local? I was thinking it was in Texas?

There are a bunch of 3fe guru's in Austin.
 
if it's local perhaps I can help later this year(I need to get stuff finished on my ride before i touch anyone elses unless it's Sage or Colin or Eric's before the event). if it's not local perhaps I can help recommend someone in the area of the truck to help. If I recall it was in TX? there are a bunch of 3fe conversions in Tx..
the wiring is the biggest issue on a 3fe conversion. I know because i probably have over 40 hours in my wiring and i'm technically not done. I'm done for now but will finish it up after other stuff is mounted. Why someone would add in a bunch of extra switches is beyond me. one kill switch to the ignitor would suffice.
Without knowing how they built the harness or what maint is done I wouldn't know much.

slowing to a stop and dying would probably be fuel related or vacuum related. have any diagnostics to the MAF or fuel system been performed? I have spares of most things but you will have to leave a deposit. I will not ship my stuff off anymore. Lost too many things and I need my spares.
It'd start by following the FSM for the MAF, and see if there's a vacuum leak.

These things will run with minimal wiring.. to properly diagnose the wiring it would need to be totally removed, de-loomed and checked. Costly to say the least.

Regular maint? like a vacuum leak, MAF, FPR or fuel pulsation dampener can be easily checked. Other things like what fuel pump is being used and psi of that? return line? in take, out of tank? Fuel filter? etc..
I need MANY more details. Honestly who did the conversion and do you have any info on that? Did they butcher the harness or keep the 62 harness.. What year harness and engine? FJ62 or FJ80.. yes there is a difference.
Mine.. if you disconnect the harness from the engine, connect 2 wires and an ignition switch in a wagon and I'll get their engine to fire.. I tried to keep EVERYTHING intact except the smog pump and i'm still not really done.. But it does fire up.

Is it idling rough? hard to start? Lots of questions..
 
A couple quick answers before I have to get back to work. The truck is currently in Dallas. I was thinking of meeting her in Oklahoma and swapping vehicles to bring it back here. The conversion was done by someone named Randy near Dallas. He's done a few I think, but I'm not sure of the specifics. She has not been able to get in touch with him. The last time she took it to a local mechanic she's used in the past he said don't bring this one back.

Eric, all your suggestions are well beyond her abilities. That's why I thought I would bring it here where I could take my time and go through it with the help of a "mentor." If it hadn't become her only vehicle, the idiosyncrasies would be much more tolerable.
 
I'd toss a Fuel pressure regulator at it to start with.. And check the battery/alternator and look for a vacuum leak. Most shops will not touch something like this.
My $ is on a FPR.
it's hard to Daily drive a 40.. Been there done that.
 
Good call Colin!

Someone has been laying off the special sauce!!!
 
Its pretty cheap to replace all/most of the vacuum hoses w/ some high heat silicone. The 3FE has a lot fewer than the 2F, too :)

McMaster-Carr. It's PN: 5041K522. Official name is "Metric High-Temperature Silicone Rubber Tubing, Firm, 3 mm ID, 8 mm OD, 2.5 mm Wall, Blue"


Don't get me started about a EGR removal . .
 
You mean this? Laying off? That's where I get my inspiration.

image-1202980347.webp
 
A thing of beauty......
 
Update. My sister finally got in touch with Randy. Turns out this is a part time gig for him in addition to a regular 9-5. He was very helpful over the past couple days. However, having worked on this conversion for the po, the lightbulb went off today as he recalled the po was having these problems and never could get them figured out either. I will try getting in touch with Randy myself to see if we can create a plan of attack. Thanks all for the suggestions. I may be a cheaper solution for my sister, but it would take me a whole lot longer.
 
not knowing what all was "connected" during the conversion we won't be much help.. And not having mine "driving" i'm not a ton of help yet. you wait another few months then perhaps I will be of more assistance because i'll have worked out some bugs in my conversion. it's not an "easy" conversion but it's not super difficult either.. more "custom" if anything. from my research can be perceived as a VSS but most have isolated it to something else when they toss parts at it. YEah.. not really an answer but we don't have a question yet either and no diagnostics have really been performed yet. WE're here to help but not much help yet either. Gotta let me work the kinks out of my conversion first then i'll be of way more assistance.
 
She wants out

Stick a fork in her, she's done. I guess I could have predicted it would end this way. My sister is wanting to get rid of her FJ40 3FE. She's got about $12,000 tied up in it so far. Give me your opinion, do you think she can break even?

Here's a few details. I got in touch with Randy Witt who did a lot of work on it and his recomendation is to completely rewire it. Apparently the po twice removed started the conversion and had some questionalble wiring techniques which included the use of household wire nuts. Instead of starting from scratch the po wanted to patch what was there to make it work. It needs the rear quarters replaced and the tub and top resprayed to match the front end. She was getting ready to have that done, but compounded by the electrical work she's giving up. I included the build thread from the po below.

Not a bad truck otherwise. If I had the cash and didn't have a daughter in college and another project sitting outside... blah blah blah.

https://forum.ih8mud.com/40-55-series-tech/204043-3fe-fj40-rtcustoms-build.html
 
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