3fe stumbling issue. Need some feedback. (1 Viewer)

[Azfjguy]

Alright guy’s, I need some of your knowledge. I have been lurking on this forum since October 2015 and I’ve absorbed a ton of useful information. Thank you to everyone who has contributed to this site. It’s a great resource. I have a 1989 FJ62, 3FE engine. 190k miles. My issues started after the first day of “getting it”. It’s sputtering and dies like its being starved of fuel. But fuel pressure is within spec and the return pressure is fine. It will start up fine and warm up great. But then just goes to s*** the minute I apply any pedal, will sputter and then try to even itself out. Sometime it just straight dies. Odd thing is, it’s so intermittent. I suspect that the TPS may be an issue. The odd thing is, the first day I got it we took it on a 4 ½ hour drive to a place called crown king. No issues what so ever. Ran like a champ. Now issues ever since. NO ENGINE CODES WHATSOEVER

This is what I have done so far.

Checked fuel pressure came out ok but replaced Fuel pump, sock, FPR, FPD, and filter.

Cleaned out the fuel tank the best I could also cleaned the FP / sending unit connectors.

It had some junk and rust but not too much. Old pump and sock looked stock. Old sock wasn’t to plugged up but had some specs and hairs on it.

Replaced all hoses that connect to the tank. Minus the filler neck hose.

All vacuum lines have been gone through and replaced in the engine bay.

PVC and PVC grommet

AFM tested fine but I think still may be suspect (ohmed , have yet to do a voltage check)

Plugs replaced and timing is good.

So that leaves me to check the TPS. If that comes back fine I will be back to scratching my head.

I Know I may have answered my own question about the TPS or AFM but any other suggestions are welcome.


Does anyone know if the TPS or AFM from other Toyotas may be a direct swap? We have a great parts yard up here and I really don’t want to drop new prices for those parts.


Thanks in advance for your input.

AZFJGUY.

 

[gregnash]

Don't know much about the 3FE but for advise on the parts, talk with @beno or @Sam Stewart or @mel lowe for OEM parts. The problem with replacing a part with a USED part that is still existent new is that you could possibly be running into the same issue again. I did this twice with a power steering pump before I got a GOOD one that did not wobble or leak but then again they are like $400 new and I paid $80 at the yard for it.

Anyways, if you have not go download the FSMs,look in my sig for the FSMs or go to For Sale: - 40, 50, 60, and 80 series FSM for a hell of a price.

 

[Azfjguy]

GregNash
I have the full FSM and have been trudging through it as I work to trouble shoot this thing. Thanks for the suggestions I will check those guys out. My thoughts about the used parts is, yes I will still have that factor of buying a non working used part ( the yard has a good return policy ) but if I get a hold of a good one I'll still be ahead by dropping $40 VS. New prices. I'll keep digging at it

 

[Silver City Cruiser]

Is the TPS cover stainless or black ? TPS is so critical on this model that i would spend the money on a new one if it tests bad. Original black cover TPS's are more troublesome. Also make sure you don't have a torn air intake boot= look close at the one near the throttle body.

 

[Azfjguy]

The TPS has a black body but looks suspect. For Lome reason I decided to pull back the wire loom around the TPS and it looks like a connector has been retrofitted to the stock harness. I will post some pics as soon as I can. But it raises my concern that it may not be stock. Does anyone have the original toyota TPS part number for the 3FE on their rig?

 

[Silver City Cruiser]

I have one out back still on the engine. Will check tomorrow

 

[tlin]

Did these issues start after you did any of the maintenance work noted here or before you got under the hood? Did you drive back from Crown King, get home and park, fire it up the next day/week basically untouched and then this stumbling started happening totally out of the blue?

If stumbling was noticed AFTER you did some work, I'd strongly advise looking at:

• AFM - did you get to it by unscrewing the two horizontal screws? IMPORTANT - don't EVER unscrew those screws, you only remove the wiring harness from the 3FE AFM by the two metallic clip locks on both sides of the wiring connector.
• Large air intake hoses (two pieces) between the AFM/air filter combo and throttle body - if ANY of that's cracked, it screws up the air intake and will definitely cause hesitations/stumbles
• Vacuum lines - you're positive you didn't mix any of these up when replacing?
• The TPS can definitely affect overall throttle and idle but what you're describing seems pretty extreme and sounds more like something related to unmetered air on the intake side (AFM/intake hoses/vac lines) - my $.02

Welcome to Mud! Welcome to the 3FE! Your maintenance noted above is all the right items hit for the 3FE, hoping your issue can be found quickly. I'm in an 80 ('92) but same engine/transmission you've got - running great (albeit SLOWer than I'd like).

 

[Azfjguy]

Tlin,
The issues started the day after the trip. Before any such maintenance was started. Thus my thinking I mixed up a bunch of crap in the gas tank and possibly had a clogged fuel pump sock or fuel filter. Now having been through EFI system almost in its entirety… It’s becoming annoying. I’ve been working on Toyotas for about the last 15 years but this is the first time I have been stumped on an issue that “seems” so easy to fix yet unable to do so!

The AFM was removed correctly. (By me that is) I can’t vouch for what the PO did. It’s definitely been molested before. The top of the cover to the circuit has been removed. When bench testing, it all came out within spec. Both test points came in at the lower end of the values. 130 ohms, 250 ohms. I’d like to open the AFM up and see how the sweep contact looks, but the PO epoxied the damn cover on permanently. Based on how it ran fine during the trip, I’m still leaning towards something getting jattered either electrically, or the EFI. I need to get at that TPS tonight and bench test it, and test the voltage values at the ECU.

Something else to note that wasn’t mentioned was the PO put in a new Alternator, also not sure if this matters but the smog pump does not have a belt connected to it. It ran fine on the trip without that belt. AZFJGUY

 

[jcj_78FJ40]

x3 on checking the air intake. A lot of times hard to see cracks are in the "accordion" parts.

Don't overlook the plugs, cap and wires, especially if the truck is new to you.

 

[Azfjguy]

So I removed the throttle body, cleaned it and bench tested the TPS. It tested within specs. I also took a closer look at the air intake ,around the accordion. I did find a tear in the old rubber. I'm certain that I may have done that while I was removing the throttle body. Either way it forced me to replace it and rule one more thing out. I Picked up a usable intake piece at the local yard and got her running. When I removed the throttle body the cable adjustments may have got off spec, So I will have to mess around with that. Getting closer to being able to get this FJ back on the road. Not running like I want her to, but better then before.

 

[Azfjguy]

So I adjusted the cables and she ran great. Got about 10 miles on her. Drover her to work( 5 miles) and she ran like a champ today 20 degree morning............ Not so much the story when I attempted to drive her back home at the end of the day (5 miles took me a little over 32 minutes). It was running and Acted like a TPS issue but I disconnected it and I had the same results. While limping her home and brain storming . It was acting like a vapor lock. So as I finally pulled into the driveway I shut her down and opened the tank, damn thing was ready to implode on itself. Waited 20 min and opened her up again and same thing, a large amount of vacuum released, granted she hadn't ran since it hit the driveway.

Has this been my issue the whole time

 

[SteveH]

I've never heard of/seen a vacuum condition in an FJ62 gas tank - only very high pressures. I would leave the cap loose and run the same route and see how it goes.

 

[Azfjguy]

I'm sure it sounds silly but it seems like air went rushing into the tank not out when I removed the lid. What do you know about the high pressure issues? Is it a line issue or just the way the constructed the tanks?

 

[LAMBCRUSHER]

disconnect and blow air thru the fuel supply, return and vapor vent lines. the TPS adjustment and a clean TB are KEY

 

[LAMBCRUSHER]

spray carb cleaner at all of the sealing surfaces of the intake track while idling and listen for increases in idle speed after a burst shot of carb cleaner at each specific spot a device is connected to the intake...if there are any changes in idle speed while doing this, you have found a bad seal/gasket/ aka, an intake leak.

 

[60 toy ota]

the 3fe tps is the same thing they used in one of the 4 runner generations i believe...rock doc or pappy mentioned it in one of their write-ups

 

[Silver City Cruiser]

Gas cap may not be letting air in to the tank. Make sure its ok.

 

[Azfjguy]

Fu%k me sideways.. This thing is about to get set on fire. Update since last time. Plugs have been replaced. Air intake lines have been replaced. Fuel lines have been flushed. The truck will idle fine for about the first 5-10 min... sometimes i can get 20 min of idle out of it before it goes into its sputtering and choking issue then other times I can start it after sitting for days and its right off the bat that it is not happy. By happen chance I was by the return line in the engine bay when it was doing this and I happened to pinch the line during one of its tantrums and it seemed to be a little happier. It is passing all of the FSM tests i can throw at it. But yet the issue is still around and so intermittent. Its been driven a whole 7 miles since this started in October of 2015. I need any suggestions that may lead me to something ODD. Ive been over and over the FSM and this leads me to think its either an intermittent electric or EFI issue that i just cant catch the signal while its happening.

 

[DoubleNickels]

Are you still experiencing pressure in the gas tank? This points to a faulty charcoal canister. I went through similar issues last year... my theory is the faulty canister makes the fuel pump work wicked hard to circulate the gas.

Swap the in/purge lines on the canister, see if that helps?

 

[Aseif007]

How about the ignition system? Is your coil performing as it should? Coil issues can be hard to diagnose. Just throwing it out there as another possibility.