philip64

Looking for some help trouble shooting an issue with a 1993 4runner 3VZE automatic.

We recently did a headgasket replacement. After some issues with the transmission, which were resolved by solenoid replacement, we had it running fairly well with the exception of lack of power at highway speeds. A week ago the truck started to die completely with no power at all. We found a corroded ground from the battery to the passenger side; cleaned that up and the issue seemed to be resolved. Now however the lack of power issue has become progressively worse to the point that it won't get over 40 mph at full throttle. We've checked the following:

1. Confirmed no check engine or transmission trouble codes
2. Checked timing (timing does jump around a little between 10 and 15.
3. Checked throttle and transmission kick-down cable adjustment
4. Checked for vacuum leaks (found a few suspects and changed, but no difference in performance)
5. Checked remaining grounds
6. Jumpered fuel pump and ran with FPR outlet pulled - nothing unusual identified.
7. Replaced fuel filter
8. Attempted to adjust the TPS (can't say that I did that correctly). The truck runs the same with the TPS unplugged.

I've read alot about lean versus rich - how does one know if the engine is running lean or rich?
Does the fact that the TPS seem to have no effect point to that as the issue? Would a bad TPS throw a code?
Thinking perhaps checking fuel pressure is the next step. Would low fuel pressure throw a code?
Any other thoughts on what we should try next?

Thanks for the help.
PB

L5wolvesf

timing does jump around a little between 10 and 15. It should not be doing that.

How many miles on this truck?

scope103

Possible cause is bad bearing in distributor. As a very quick-and-dirty, remove the cap and try to wiggle the rotor.

The "good" way to check the TPS when you have a A340 is: https://www.yotatech.com/forums/f116...icator-303218/ (you can just use your multimeter). The setting procedure just gets the idle indication to work. The rest of what you should check is smooth change with change of throttle position (no dropouts). The cited method checks all of that.

Low fuel pressure at speed would lean out the engine, which should throw a code. (25)

Co_94_PU

iTrader: (-1)

Headgasket, lack of power..

How certain are you the cam timing is correct?

How is the compression now?

Timing needs to be done by the book, in diagnostics mode with idle switch closed. Five degrees is a lot, check for lash in the gear and bearing as mentioned also the rotor is tight on the shaft (we've seen this before with cracked rotors)

philip64

Thanks for the help.
The truck has 170k miles on it.
The rotor does wiggle a little. The outside edge of the metal rotor arm moves about 1/16". Is that normal?
Thanks for the tip on TPS adjustment - I'll order those parts this evening. We did try to set the TPS using multimeter and feeler gauge, but were not real confident in the results.
We checked the compression after the headgasket change and numbers were good and consistent. Don't remember the actual values now, but they were good at the time.
The timing was set multiple times with the jumper installed. The distributor does look to be almost all the way counter-clockwise. Is that normal for it to be that far from centered in the range?

Really appreciate the help; need to get this thing running.

The rotor and sparkplugs are new.

philip64

I spent some time cleaning up grounds on the drivers side and reset the idle and timing. The timing is still jumping around some. Now getting a code 41, looks like TPS or wiring to it.

dan1812

I had trouble setting the timing on my 4runner. Turned out to be a stripped keyway on crank..took a long time to figure that out..pulley would move so you thought the timing was set right but it wasn't.