acerbis

i have the same problem but with a 22r. Just no power. It revs pretty slow and doesn't have much power. Although mine is running super lean. I'm going to try and go the "not enough fuel route". Keep this thread updated.

tomasp

Update:

The new exhaust sounds good, still no power if it down-shifts while going on the motorway, just sounds like it is going harder but it doesn't. Also I noticed if I drive with O/D off, reach 80km/h and push the O/D button then for a moment the engine revs up before the overdrive engages. Now I think the major issue has to be the slushbox - it looks like I will have to drop the pan, replace the filter and probably pay the garage to do a full flush and oil replacement.
Still have to measure #6 clearances but I just don't think it would be impacting things that much (lower compression, that is).
Just a few days ago I checked oil (after a long time, shame on me) and it took 1.3 liters of oil before it was back to FULL mark.

tomasp

Not sure if anyone is following this or not.
Just replaced my original 1992 spark plug leads and I can tell that the old ones WERE leaking under load - there is a difference in sound and power over 3000rpm.
I've been researching my pinging issue further and today bought spark plugs one unit colder than stock ones, will try tonight what happens.

mattches

So how is the fuel consumption going? Still around 9-10?

I am having similar issues. But am still attempting at diagonising. Sorry for the stupid question, but what is AFM & VF? What terminals on the diag board are they?

SEAIRESCUE

Put a vacuum gage on the engine and see what it reads. A steady 19-20 inches means all is in order.
May be your transmission torque converter is going bad. A stall test is in order here.
The reading on #6 is of concern. That is the cylinder that typically dies due to the crappy exhaust on the 3.0 and the induced thermal load that is not removed by the cooling system. I seriously hope Toyota fired the SB that approved that exhaust design.
Your CAT may be clogging from age. I have cleaned one of those out and there is a ton of honeycomb in there with really small passages.
I don't think you have a fuel delivery issue.
I think you would benefit from a good quality, TRD, set of headers.

Report back on the vacuum check at hot idle. Hold the brakes and stomp the gas to the floor and tell us how many RPM's you see on the tach for the converter stall test.

tomasp

It is around 14-16mpg on the highway but still around 10 in the city.
I am thinking that given that I have heads machined and higher than standard pressure, maybe the knock sensor detects it and ECU retards timing killing performance and mpg....

tomasp

Thanks for the tips. I will try to get hold of a gauge, I don't have it. Just from observation I'd say the vacuum is fine, I say this comparing with other cars I had and also the "feel" - if that means anything.
I don't have cat anymore, so that can be ruled out. A freeflow exhaust is in place. I used butane around the intake, no leaks detected.
Will try the converter test and report. Tried it some time ago, it revved up to 3500 or so, but then my tires started skipping (rear brakes were not adjusted properly).

JCM4x89pu

burnt exhaust valve

forby4

Hi all, first time on any forum for me. I'm not a mechanic but i learn from others so i can do my own work.
Unfortunately i have my own similar problem/s. I appologise for the length of this post but i don't want to leave anything out...and i'm tired as hell.

In AUG'07 I bought an auto 91 4Runner 3.0L V6 3VZE with a big-end knock - i didn't pay full price. 300k on the clock and head gasket recently done (another fault with these things is the gasket going at around 300k).
The "mechanic" who did the head gasket hooked EVERY frikkin hose up wrong - including all vaccum hoses. He even had the cannister hooked up to the wiper jets...

obvious signs it had got hot under the bonnet with melted sensors and brittle rubber
I (with help from others) got straight into re-building the V6.
Replaced basically everything, except only cleaned the heads, but had them checked for warping, valve clearances and seats. Cleaned the injectors (not sonar, just got all the crap off/out of them),
replaced all hoses and eveything else that was damaged/melted.

while re-building V6, we inspected the first two clutch packs of the auto gb (special tools needed to inspect gb further than first two packs), but the person who put the gb back together jammed the first clutch pack in.

Anyway we put the motor back in with a y-pipe under the gearbox - looks ok and sits about the same height as the gearbox cross-member.

took some stuffing around but we managed to take it for a test run. but because the clutch pack was jammed the thing ran like it was pulling a semi.
we pulled the gb back out and the first two clutch packs were fried (the rest of the gb couldn't be inspected). we replaced them, plus the gb filter and shift solenoids (solenoids packed it in as a result)

finally, after we broke the engine in i took it up the freeway about 20mins round trip. had no guts after about 70kmh (43mph). While driving engine light came on and gave me a 'knock sensor' error code. when i got home i popped the bonnet and just about burned my hand on anything i touched - the brake lines and master cylinder, battery, air filter box, even the starter-motor wire insulation was smoking. 3hrs later everything was still burning hot. but the temp gauge was showing correct temp while driving.

we decided to only take test drives at night (being cooler) but on the first run we pulled over on the fwy, popped the bonnet and saw both exhaust manifolds glowing ~HOT~orange!
the engine light (knock sensor error) was coming on and off every now and then but we could only check the sensor lead and plug for the time being.

we spent hours/days checking everything and taking test runs. some things we tried were:
advance/retard timing at increments
remove exhaust after cat
remove exhaust before y-pipe (the more we removed pieces of the exhaust it seemed to increase the speed and length of the glow - maybe due to increased flow it allowed the heat to travel along the exhaust quicker?)
we also found the exhaust wouldn't glow below 70kmh (43mph) which is about the same as whe noticed the loss of power.
basically we tried just about everything we could, then the knock sensor error finally became permanent.

we replaced the sensor (buried deep in the heart of the 3VZE - genius idea) and lead which fixed the error problem. re-checked everything as we put it all back together then the o/2 sensor gave out so we replaced that. but nothing made any positive difference to the glowing exhaust.

after 2 months (OCT '07) i gave up and sent it to a well respected mechanic/auto gb specialist who ran defferent tests and had it on the dyno several times. He said the gb was operating normally.
After they tinkered around with various things (mainly the timing) they put a hi-flow cat on it. The mechanic said the passenger's side stopped glowing after that, but the driver's side glows under load or if you put your foot into it. he said it's ok to drive around town, just don't give it to it until i fix the exhaust.
(when i removed the cat before it seemed to increased the glow, but maybe it was a combination of things i didn't try)
he seems to think the driver's side glow is caused from restrictions in the y-pipe. so he said with a set of extractors, a larger exhaust system, and a better made y-pipe this should solve the problem.

i have only just picked the runner up two days ago after 4mths (MAR '08)...but the short 15min run home to me it still feels just as sluggish as before (i know it's a runner)...but the engine bay was just as hot. i haven't had a chance to look at extractors yet.
after i drove the 4wd home i parked it and i've been deciding whether to get rid of it or keep spending.
I paid (AUD) 3000 for it, i've spent about another 3500 on it, but it's insured for 9500 so i'm still in front.

My concern is the heat under the bonnet is the same as before - before i bought it, before i took out the pipe on the back of the manifolds and put a y-pipe in, and before we cooked the packs in the gb. there is so much heat under there i've even put a scoop on the bonnet to increase air-flow into the bay.
the engine itself is not hot on the temp gauge - sits just under half way but it reaches half temp in about 3 mins of driving (is this normal to be so quick?), just everything within 2feet of the exhaust has a tendency to want to melt. will extractors and hi-flow exhaust really get rid of all that heat?

I appologise again for this thread being so lengthy and all over the place (i'm extremely tired)
i hope this helps or someone can help.
cheers

forby4

sorry, another thing - i can only get about 130km out of a tank of fuel. avg about 1ltr per 2km or 46ltrs per 100km.
and yes we have checked the fuel system...

tomasp

Gidday Forby,

Sounds to me that you have fuel dumped/burning into the exhaust, quite likely leaking injector(s). This would explain both your mileage and glowing manifolds. When you had injectors out, it was a good idea at the time to get them not just cleaned ultrasonically but also leak and flow pattern tested and rebuilt. Doesn't cost a lot, a performance garage should be able to do it if they have a machine.
I also have heat under the bonnet, I'd say hotter than your average car but they say Toyotas run hotter generally so what do I know
I am very dissapointed with my 3vze+auto combo, especially auto gearbox. I have ability to build a custom ECM for it or just manual shift but I am nearing the end of my patience with this truck. It costs arm and a leg to drive it, I am talking about petrol.
BTW, if you still have a cat - does it smell like rotten eggs? Should do if you have fuel dumped into exhaust. Also - does it glow in the dark after driving?
I get around 350km from the tank for mixed, which is similar what others get (as I hear, but for city only) and which is appalling.

MonsterMaxx

forby,
Check your timing. Sounds like it's very retarded. Try it at 15deg and see how that runs. Up to a point, adding more timing will reduce exhaust temperatures and often give more power.

Easy way to check a cat is to take it out and hold one end up to the light and look thru the other end. If you can see thru easily, all's good. If you can't or it looks all crappy - replace.


I turned one into SLAG (exhaust was nearly completely blocked) and it ran very much like you describe. We believe the cause of slaging the cat was retarted timing.