prelude85

My 3vze has been running strong for 20,000 miles so far since i put it in about a year ago. It had been running fine all the way up to the point that i got my exhaust stolen right before Christmas.

It was fine without an exhaust, besides being extremely loud. I got a new one and wrapped some tape around it. Kinda funky setup got one that was cut exactly at the same place mine was and thought I'd just get it welded. Turns out it's illegal to weld on a used cat in Cali.

I knew someone at school could weld it so i thought I'd tape it till i could get back to school. Ran good no problems it was quiet and the exhaust was working like a charm. I took it for a drive, very nice, after sitting for a bit i took off and it started hesitating like it was running out of fuel. I didn't think much of it at the time though but it got worse and worse and blew the tape away. THought it was a restricted exahaust but no, with it open it still ran bad.

Here I am a month later exhaust welded it continues to hesitate, although not as bad and very intermittent. I've looked at a lot of problems...

-New cables

-New Rotor

-Bosch O2 (yeah i know should've gone denso)

-EGR disabled makes it run WAYYYY better but the problem remains, also it's probably ruptured as it's not holding vacuum. But really could it make this big a problem?

-Timing, my initial thought which was off. The cams were off anyways, my mistake for not tightening the harmonic balancer enough had the belt rubbing hard.

-Reset distributor. The cap and rotor were rubbing...not sure how that happened, no longer rubbing.

-Manifold vacuum is at 14"...

-Compression ranges from 150-135, wasn't done in the most ideal conditions all may be higher than 135...

-Pulse Air Injection appears to be working

Weird thing right here...it runs PERFECT in the morning for a few minutes then it goes back to the same ol crap.

Gas mileage was horrible, got 150 off a tank. Last time i was back to my normal 250.

Codes!

NONE!

Except it finally set the check engine light the other day for EGR being too cold, it was disabled so yeah.

AND, ignitor to ECU signal missing 6-8 times in succession, DTC 14. So i went and looked into an ignitor, they gave me a Previa one with numbers not matching. I tried it out and i thought that fixed it. Swapped it between the old and new but in the end they felt the same so i said screw it.

Currently no codes...

I'm just about to give up here, but i don't want to I've been through so much with this truck over the years.

Brad3902

I am having the similar problem with my 22ret, it would run great cold then when it warmed up it would missfire, I am also getting really bad gas milage. then just the other day I blew my head gasket (I think, I havnt takin it abart yet, but it did the milkshake thing and i got no coolent soo...). I talked to my mechanic/boss he said that its the Head gasket or the head might be cracked or warped. did you rebuild your 3vze or is it brand new 3vze, if you rebuilt it u might have messed up th HG or your head is warped or cracked. just food for thought hope this helps.

prelude85

I got it off a 92 that had gotten a new engine through the head gasket deal. It was said to have around 40k when i got it. Stripped it down to the block and heads and threw all my old junk on it.

I was worried of something like a head gasket or something but really it hasn't gotten any worse and in fact it's only gotten better from the beginning. It used to choke out so bad the whole freakin truck would jerk me around hard, now it barely hesitates.

Low RPMs and light throttle make it happen, past 3k it's good and if i am a little heavier on the throttle it's hardly noticeable.

I haven't checked my coolant or oil in about a week or so but i will later on today. Looked alright when i took all the coolant out to check the belt and water pump when it first started though.

Brad3902

I hate to say it but I am pretty sure it's ur HG my was doing the same it would puur like a kitten at higher rpms and would misfire major at lower rpms, I didn't loose any coolent nor did my oil go like a a milkshake until after My HG blew, check ur compression

204runner

hows your fuel pressure? i had this problem it was a result of a shotty fuel pump. Also a bad distributor, wires, and plugs. replaced all of it runs awesome.

who steals exhaust? thats messed. good luck bud

jbtvt

Sounds like a possible closed loop o2 sensor problem. Checked the voltage output, no shorts in the o2 wiring?

prelude85

Well...I've been driving everyday for the past month. Probably racked up 500 miles since it's been acting up. I dunno about a head gasket. Coolant and oil are still good.

I suspected something with the O2 as well. Just kinda funky as to what, but i gotta say i feel kinda stupid.

You guys know the harness that comes up along side the 1st bank's exhaust manifold? Well it looks like it's melted itself to that manifold...and well that has the O2 wiring in it as you may know.

I tried ripping that junk out but it's a pain, I'll look into the wires tomorrow i think. Moving the wiring away from the manifold seemed to help a lot for awhile though. Perhaps it's rubbing back again to the exhaust again though. I think we've a winner here though, and it's about time because my baby needs to go out and get dirty off road again! It's been far too long since I've been out on an adventure!

jbtvt

Cool, sounds like it. Good luck with it and appreciate the update.

prelude85

alright so here's the scoop. The wires against the manifold are fine. the wires near the o2 sensor are not. Well the black one isn't.

Threw a new egr on it wrapped some wire around the ground part of the black one and still acting up.

At first i put the egr on and again, it was acting up real bad just like with the old one. Next day i somewhat fixed that wire. It runs better now with the egr connected, although not as well without it connected.

I've one more wire to check out which is the brown wire from the o2. That had about 5 ohms of resistance in it. I gotta do a voltage drop to see what's really going on.

Kinda sucks cause all my stuff is at home in central cali, I'm up in Sac for school where i can use tools but it's still a bit hectic. So progress is slow...sigh. I'm thinkin to try and get a new wire harness altogether though.

Engine vacuum seems to have improved and it's definately not running rough at idle anymore, well not nearly as bad. It's still a little off though. Off the vacuum pump it was reading around 18 inches of vacuum but bounced a little with the engine's off beat.

I'm thinkin pcv needs changing, plugs gotta go too. lucas fuel treatment drastically brought back power.