ShadowSix

I'm sure there are threads out there on this if I could just figure out the right search terms to use, but so far no luck, sorry!

I bought a second 4Runner a few months ago, this one is a 1994 3VZE Automatic and it had a blown head gasket when I bought it.

I did the HG job, threw some new plugs, new knock sensor and wire, new timing belt and tensioner kit, new cap and rotor, replaced some nasty old vacuum lines, ran some shiny new heavy gauge ground straps, now the truck starts and idles fine, has no check engine light, and has VERY LITTLE power past say 2000-2500 RPM's.

I gotta say, this V6 is a LOT more complicated than the 22RE in my other truck. Thanks in advance for the help!

peow130

iirc, the automatics have some ridiculous overdrive on them, which is most likely the cause of most of your problems.

ShadowSix

Ha, I haven't done a very good job of describing the severity of the problem! I'm not sure I could get the truck into overdrive because it is so slow I'm afraid to take it on the highway. It is REALLY, REALLY slow! My other truck is a 22RE, and right now the 3VZE truck makes the 22RE feel like a top fuel dragster.

An update, I realized that the fuel in the truck is at least a few months old so I'm going to go fill 'er up with some good premium unleaded tomorrow and see if that does anything.

Also, I forgot to mention that I set the timing to 10* BTDC with the diag thing properly jumped as per the sticker on the hood.

TNRabbit

USUALLY your symptom is a knock sensor not working...but I see you replaced that. Have you checked for codes?

ShadowSix

Yeah, no codes and no check engine light.

Another thing I forgot to mention, it does have an exhaust leak somewhere. I don't know if this could be messing with my (also brand new) O2 sensor?

Team420

It could...depending on where the leak is.... but more importantly... did u replace the o2 when u did the hg? could b fouled from coolant in the exhaust prior to the hg job....

ShadowSix

Yeah, when I first got the truck back together after the head gasket job it had an O2 sensor code and a seriously crusty old O2 sensor, so I put a new one in.

I don't know where the leak is coming from, the truck has an aftermarket catalytic convertor welded in right behind the O2 sensor and I think the leak is coming from there, though it could also be coming from the manifold where it was disassembled for the HG job.

How would an exhaust leak be causing this sluggishness? Is it tripping the knock sensor to retard the timing? Is it changing the reading the O2 sensor is getting just enough to slow the truck down, but not enough to throw a code or a check engine light?

I guess I'm going to have to do something about the exhaust anyway but I really wanted to get this thing running right before sinking any more money into it!

Thanks again guys! The plan for today (if I get to it all) is now to fill the truck up with some quality gas and trace down my exhaust leak(s.) I'll keep you posted.

TNRabbit

Again, check for codes before you do anything~

ShadowSix

I currently have no codes and no check engine light. I did check for codes even though I have no light and I just get the steady blinking CEL with the diagnostic box jumpered, no codes.

When I first put it back together after the HG job I had an O2 sensor code, but that went away when I replaced the sensor and reset the computer by pulling the EFI fuse under the hood.

TNRabbit

OK. My next guess would be to make sure your distributor is advancing properly. There's a distributor check in the FSM available in many places on the web.

blake.nemitz

advance your timing a little. and make sure your not running the gun off #2 cyl. done that before. only other thing i can think of is it is starving for fuel at higher rpms.

ExcessFC

When doing a HG job on my brothers 95 V6, we ran into possibly a similar issue. We had serious power for about a day, and then it has been trash ever since, with an occasional and sporadic start of decent power.

We have gone through about anything that you can think of, and the best possible candidates that we have encountered so far have been:

Knock Sensor Wire
Broken White Wire on the Dizzy
Maf Sensor
Fuel Pump

We checked/replaced each of these items, with no luck.

During the job, we sent off the injectors to be cleaned, and they tested/flowed fine there, and came back clean, but I believe that during the sonic clean process, the coils may have been damaged.

Just this past weekend we discovered 3 of the injectors were OPEN!!! Edited for clarity, open in terms of resistance, not open dumping fuel.

I hope this helps, and your issue turns out to be less of a unicorn than our quest so far.

Cheers.

TNRabbit

Don't forget TPS mis-adjusted or not functional. So many folks indiscriminately spray WD-40, etc. into the TPS & it works it's way into the electronics, ruining it.

Team420

Yup... I agree with rabbit... the tps could be off a tad (it dont take much to cause problems).... Or... u have a vacuum leak....

ebrake92

I know i'm bringing back an old thread here, but I searched my very similar problem to see what others thoughts and experiences were. I just fully rebuilt by '93 4runners engine from the ground up, and when I finally got to drive it I was maxing out at 22 mph going up a slight hill with full throttle. I checked and double checked for vacuum leaks, exhaust problems, intake blockages, anything that could be slowing it down. I got the timing to that 10 degree mark and it just sucked. Finally I called my local shop here in Seattle (Gregs Japanese auto) and he said that while I had timed it with the distributor, the ECU was doing everything in it's power to compensate for the timing that it had stored from before the rebuild. Thats where it was going wrong, he told me to use a jumper cable on to terminals of the diagnostic box but I was unsuccessful in making that work, yet. Im gonna double check with him tomorrow when I drive by their shop. What I did do, to give myself power back, was bring the distributor cap back to where it was timed before the rebuild. I could see where the washer was tightened down, and tightened it back down there so that the computer would not have to compensate and the thing runs like a top now. I hit 70 on the freeway. I will post again once I figure out which terminals to jump to reset that ecu back to base timing.

Yota Fab

Sprayed down my TPS with WD40, im retarded...

Yota Fab

what do u mean jumper cables to diagnostic box?