Serious first gen 3rz problem.

Okay tacoma world, in need of some serious need of help with this damn truck.
I have a 95.5 3rz 4x4 5 speed, I got rid of the truck to a kid I know awhile ago, well I just got the truck back on a trade, and it has an issue that I cannot figure out for the life of me. I'll go into detail on the problem/symtoms that the truck has, and what I have done to try to diagnose it...

It takes awhile to start, and when It does decide to start it has a dead misfire on cylinders 1 and 4 and it will only accelerate if I barely press the petal. It breaks up and back fires through the intake as if its out of timing or something. And it will not run if the mass air flow sensor and/or the tips is plugged in, it will only run if they are unplugged.
Now on to the list of new parts and things I have done to try and fix it.

It has a new mass air flow
new tps
new distributor
New distributor cap and rotor
New fuel pump
New fuel filter
New spark plugs
New crank position sensor
It has good compression across the board
I noid lighted the injectors and they all fire fine
To eliminate a dirty injector, I sprayed some ether in the intake while giving it a little gas to see if the misfire cleared up, yet nothing.
I've scanned it for codes and all that keeps coming up is a crank shaft position code.
But it throws that code with the old sensor and the new one as well.
I've even went as far as swapping the ecu with a "known working" ecu from a friend's truck and the problem is still there... I'm sure there is more information I am forgetting but this is all I got for now. Any ideas? I'm growing tired of this problem already and loosing hope for this truck. Someone please help! Lol thanks for any info!

 

Bad injectors would be my guesstimate.

 

Bad injectors would cause a crank position sensor code?

 

Hmm. I missed that part.

I’d be looking for a poor connection at the sensor or damaged wiring between it and the ECU.

 

What's the exact code, P0335 or P0336?

P0336 could be the distributor not installed correctly, like off by a tooth and the computer detects the difference between the crank position sensor and the cam sensor built into the distributor on 95.5-96 models. This would also cause an early spark and explain the backfiring.

Use an old school timing light to check the timing at the crank pulley or just try reinstalling the distributor one tooth over.

 

Forgot to mention that, I have also used a timing light on it, lol

 

I suggest before reloading the parts bazooka doing a leak down test with the engine cold.

 

Have you checked the coil? 3rz’s share coil packs between 2 cylinders. I can’t recall if 1 and 4 are shared, but worth a check.

 

It's a 95. It has one coil for all 4 cylinders. I wish that were the issue.

 

One thing I was thinking about was the reluctor ring on the crank shaft is maybe missing some teeth? The fire to those effected plug wires seems to be some what intermittent, but from what I can tell by having the motor out of my other "98 tacoma 4x4" the timing cover has the oil sump pick up tube on it which means I will have to pull the oil pan, and that looks next to impossible unless I ether lift the motor or pull the motor. So I was leaving that for last. But is it possible that if it were missing teeth, it would cause an Issue like this?

 

What was the code?! Fallow the test procedure in the repair manual for that particular code.

The computer will try to adjust the timing as much as possible, but if the distributor is off by one tooth it can't adjust it enough to fire the spark at the correct time under all engine conditions (RPM, load).

What was your timing? Timing should be 3-7° BTDC @ idle with TE1 and E1 jumpered in the data link connector.

 

I've tried it 1 to 2 teeth in ether directions. I'll look further into that tho

 

Possible the harmonic balancer has failed and is allowing timing to jump around?

 

Ehh I was thinking that but I have rechecked the timing a number of different times and it is always dead on.

 

Checking base timing with ECU jumped out?

 

my wiring manual is for a 96... maybe this helps, maybe not. All of those components listed are grounded through a splice that ultimately ends up on the engine block ground. Disconnect the battery and the CPS see if there is an open between the "E" brown wire and the engine block ground. Have someone wiggle the harness at various places to see if it is an intermitent.

 

Plug wires in the correct order?

 

Yeah I believe they are. I've tried about 3 different firing orders that I have found online and only one of the ways work to let it run. So I believe it's right.

 

I will check this out tomorrow. This is some great information. Thanks a lot man!

 

If you unplug the MAF or TPS then the computer goes into fail-safe mode and it will run like crap even if everything else is working. Without the MAF the timing is fixed at 5° BTDC, so it's hard to do any meaningful timing checks with a timing light this way.