Clarksaver

New member needs help. I was driving my 4runner up a hill and lost engine power in half. Barely made it to top of hill. Had to trailer home. Pulled it in shop today to troubleshoot, it is acting like the left side of the engine is not firing. I have removed plug wires at coil on 2, 4, 6, cylinders with no charge to rough idle. I have voltage to injectors with key on. And have over 100psi compression on that side. Should be higher but it’s probably my tester is seen better days. Please send help!

maxvp01

You said “it barely made it up the hill” the first thing i think of is fuel filter, air filter, or fuel pump.

If it has a rough idle, try spraying carb cleaner in the intake tube and see if your idle changes at all.

What makes you think it is the left side not firing?

Have the injectors ever been replaced or serviced?

Clarksaver

I removed the air cleaner and no change.
I sprayed cleaner and no change.
I replaced all injectors when I rebuilt engine last year.
the reason I believe it’s the left side is due to no change in idle when those plug wires are unhooked

2ToyGuy

Did you try holding the spark plug end of the wires you suspect, the even numbered wires, near the metal of the head to see if spark jumps out of them? Alternative method: Put a spark plug in the wire while it's off, and hold the plug so it's touching the metal of the head. That way you can SEE if there's spark from those wires or not.

Be forewarned: Use insulated tools, and wear gloves. If there is spark going through the wires, it can bite the heck out of you.

If you suspect no spark, you can trace it back through the system. No spark, try replacing a wire to see if it improves. Then the distributor cap and rotor, then the wire to the coil, then the coil...
Since the odd numbered cylinders are firing normally, apparently, I would bet that the coil, etc are all ok. Something downstream. Distributor cap/rotor, wires, plugs. And don't forget the head's ground. I'm going to presume that both heads are grounded somehow. I don't have the 3VZE, so I'm not familiar with the electrical system, but I know the plugs get their ground through the head. If something happened to the way the even numbered side is grounded, it can interfere with the spark. No ground, or weak, corroded ground, no spark.

Alternatively, could it be a set of bad plug wires? I wouldn't think that half the wires would go bad and not the other half, but stranger things have happened.
Could the even wires be too close to metal someplace? IE: Is the spark going to ground instead of the plugs?
Again, I don't know that half the plugs could go bad and not the other half, buuuut....

Could the fuel supply to the even side be not what it should be? Low pressure or low volume?

I'm just throwing out possibilities that I can think of. I don't "think of" so much as I used to...
Pat☺

Clarksaver

Yes I checked spark at distributor and at spark plugs. I also pulled the plug and checked spark through them.

scope103

Firing-on-one-side but not the other sounds like an injector issue. All 6 injectors open at the same time, but they are driven by two signals, divided by bank. "#10" (W, right side) and "#20" (W-R, left side) at the ECU. Note that the ECU opens an injector by grounding the terminals; the B-R wire to all injectors is battery voltage with key-on.

My guess is that you've broken the W (White) injector wire somewhere between cylinder 6 and the ECU. You can use a "noid" light to check for the pulse at the injectors, but if it were me I'd start by confirming the (ground) pulse at the ECU (pin C-25 on a '94). Then you'll probably have to remove the plenum to get access to the injector connectors, to check there.

Clarksaver

Thanks for the information on wiring and signals. I will look into this tomorrow or Tuesday and reply with my results.

Clarksaver

I am thinking I need an ecu. Do you guys have a definite way to troubleshoot?

scope103

Well, you can drop a couple hundred on a junk ECU. When that doesn't work, then what will you do?

Clarksaver

I was hoping for some help troubleshoot before I spend money on an ecu. I checked ohms out on the signal wires to the injectors and had good continuity. I have a hard time believing that I had 3 injectors go bad at the same time. That is why I believe the ecu is bad. I like to verify problems before buying parts. Thanks for helping.

Clarksaver

I wired an LED light at my injectors and they flash so now I am not sure where to look now. I just have a tough time thinking that those three injectors quite at the same time. Guess I will try replacing them unless you guys have a different idea?

Clarksaver

I still had my old injectors so I changed the three in the left bank. No change.

Clarksaver

The left cam gear jumped two teeth not sure how it’s possible. It is all back together and running strong!

87-4runner

Glad you found it and got it fixed.
thank you posting your conclusion.
How did you find that it had jumped
Time on one side?

Clarksaver

I knew that I had spark and compression. The injectors were getting signal from pcm so I was out of options. Still don’t understand how only one side was out of time.