just_some_guy

1986 4runner, 22RE, 5-speed, DLX

Fittingly, this happened two days after I posted how reliable my truck has been. I know there are threads on this, and I've read through them the best I can. Hoping someone might have some insight, though. Currently at a loss.

Yesterday, out of the blue, the truck started bucking slightly, primarily in 2nd and 3rd gear, but also a bit in 4th. It would only do it on flat ground or going uphill. Downhill was ok. Later, I noticed the problem was exacerbated when I turned the lights on or off, the high beams on or off (not just on), and when I used the turn signals if the high beams were on. There's a significant idle drop as well, near to the point of stalling.

Things I've done:

• I replaced the spark plugs, and #3 was a little corroded but not too bad. Problem persisted. (I have spark plug wires on order. Replacing those tomorrow.)
• Unplugged the throttle position sensor (TPS) and checked the resistance. I think it needs to be replaced, but when I unplugged it, the problem persisted. The idle increased significantly, but it would still drop when I messed with the lights. The exhaust started to smell rich.

Other info:

• I'm missing my battery clamp and had been using a rubber tiedown. The battery came loose on a hill yesterday and had nicked the hose between the idle-adjust screw and the AAV, but there doesn't seem to be any kind of leak. I'm suspicious of this in particular because this happened the same day the problem started. I have a battery clamp on order.
• All engine bay fuses and fusible links are good.
• New battery with 12+ volts
• Voltage stays above 14 when running, even when lights go on. Only drops by 0.10V or so
• I have a code 52, presumably because the PO removed the knock sensor. Didn't know that and assumed it was the O2 sensor (never assume). The truck has driven fine without, and I have one on order. No other codes.
• The idle did start changing when using the headlights after I replaced them about three months ago; however, the manufacturer said the ones I bought shouldn't draw much more than stock. And the bucking only started yesterday.
• There's a significant amount of water coming out of the exhaust when I first start it, but I haven't really driven the truck and I don't smell coolant. My coolant level is also good.
• I have no info on timing chain replacements for this truck. It's now at 211K and change, but a mechanic I trust put a stethoscope to it 3,000 miles ago and said it sounded fine.
• My hazard lights don't work, even though I know the flasher relay is good.

Help?

Edit: Update—the TPS seems to be within spec. The prongs on mine were in the reverse order of what I had expected.

Paul22RE

I'd say fuel pump based on your symptoms.

wallytoo

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Co_94_PU

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Should of, would of.. Been interpreted as a code 25 then not 52. It will output codes from low to high numerals.

wallytoo

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just_some_guy

@wallytoo, you're right. I mistyped that because I was reading codes for a later model, then backtracked. It's a 12, so knock sensor, which is a 52 for other models. I just purchased one and installed it, but it's still throwing the code. I'm suspicious of the wiring. That's the next project. I'm not a natural mechanic and wasn't really taught when I was young, so I'm learning as I go.

As for the bucking itself, it was an extremely stupid thing. I finally went back to a KISS mentality and went over everything with a fine-toothed comb. Apparently when my battery came loose, it loosened up the ground to the body just enough that the corrosion on the connector and the body prevented a connection. I sanded some more paint off the body, sanded the connector clean, sanded my battery terminals while I was there, and put some dielectric grease on all of the ground's surfaces. Bucking is now gone.

I give myself a C–, and only that high because I didn't compulsively spring for a new TPS.

jakey poo

Make sure the threads that the knock sensor goes into are nice and clean. I had the same KS code because the PO was running it without the sensor. Used a spark plug brush to clean up the threads and my code has been gone for almost a year.

just_some_guy

I'll do that. It's only measuring resonance/vibration, right? I don't need to worry about any kind of electrical transfer? Also, do you have any kind of torque info? I was assuming hand tight, but I have no way of actually knowing that.

jakey poo

I believe the sensor grounds through the block. I just snugged it up, not sure of a torque rating on it.

just_some_guy

Awesome. Thanks. Do you have a thread for your pickup build?

scope103

There's no torque spec in the 1993 FSM, but as Jakey_poo points out, it's just an electrical ground connection. "Snug" should be good enough.

The part you DO need to worry about is the "electrical transfer." The sensor does only measure vibration (with a peak at a resonant frequency), so the signal is very weak in a very (electrically) noisy environment. The sensor itself is very tough and unlikely to fail, but the wire connecting it to the ECU is shielded, and in a very harsh environment. I don't know if your year/engine has the "pigtail" connection from the sensor to the rest of the harness, but in the 3VZE especially that is the weak link (and should always be replaced when uncovered).

Look carefully at your wiring.

just_some_guy

The '86 22RE goes right into the harness; it's not separate. I purchased a new harness off of ebay just for the hell of it because the price was right, and I figured that even if mine wasn't broken, it eventually would be. I'm going try jackey_poo's spark plug brush thing to see if that helps. If it doesn't, I'm going to dive in next week to go on a little "fix everything you've been neglecting" adventure, including brake pads all around, brake bleed, clutch bleed, and T-case gear oil.

just_some_guy

Holy tamales, Batman. I knew the engine wasn't performing up to its full potential, but I had no idea how much that missing sensor was screwing me. She runs like a top now and even shifts better. And I drove up to San Francisco and back to see the coast, and my gas mileage was noticeably better. Plus, I feel like I gained 5 or 10 horses back. And that's a lot for a 22RE.

jakey poo

cblackmon1

Hi Paul22re. The radio works. I think the horn maybe the contact on the back of the steering wheel but I am certainly not sure about that. I just read about the contact last night.. If the radio works. i guess the blue yellow wire cant be it. Do you know where the flasher relay is located on my truck? I have read alot and cant seem to find it. Thank you for your help.

wallytoo

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