GregStevens

I've searched through a lot of threads and I've not really found a solution. I hate to post another thread about what may be (at least I hope) a simple problem that I'm just overlooking.

Here are the symptoms, please help me if you can... This has been going on for about 3 days now...

3VZE has about 125k on it. Never had any problems with it, nor have I had the HG replaced.

Starting the rig, cold or warm or hot, the idle and rev'ing up to about 1500rpm is rough...the whole rig shakes somewhat, it's obvious something is wrong.

I almost hear an exhaust leak...it just seems to sound different.

There are no metal sounds like a bearing or something spun inside the engine. No ticking of valves, either.

From a dead stop, the roughness is noticeable as I get off the line. It starts to go away as the revs get higher, but there is 'significant' power loss.

Fuel mileage is down the tubes.

Significant power loss throughout the band. It's dogging REALLY bad (and a dogging 3VZE is really nothing short of a road hazard )

Starts up fine, no problems there.

Doesn't stall, but it feels weird, so I put it in neutral at stop lights. And keep the revs up a tad to avoid the 'rough idle range.'

Transmission shifts fine, no issues there.

Oil is fine and clean.

Haven't check the coolant for oil.

I made no changes to the engine when the problem started...it just seems to have 'happened.'

I put new plug wires on early last Fall...never any issues with them since.

There is no smoke from the exhaust, but the exhaust comes out in puffs, not a (more or less) steady stream.

Seafomed the crankcase a couple of weeks ago. Love that stuff...


What I've done to try to figure this out has been:

Make sure all plug wires are secure. (they were)

Carb cleaner to check for vacuum leaks...none found.

Cleaned the already clean TB.

Checked belts and they are fine.



So I'm really stuck trying to figure this out...any ideas? Clogged cat? Head gasket? Plug wires? Coil? Dist. cap? Like I said, whatever it is, it starts as soon as I crank up the rig. Doesn't go away. It's not like pressure is building up (as in the case of a clogged cat) and then it starts to screw up...it's right off the bat.

Any help would be great appreciated...thanks guys and gals!

ctcost

Any cracks in the intake or air silencer? If you've removed the siencer for the mod did you make sure it's all tightened down and not leaking there?

GregStevens

Good idea there...I will have to check that over tomorrow. I don't 'think' there are any leaks in there, as I made sure it was all snug when cleaned the TB thinking that might help it. I just now replaced the dist cap and rotor...thinking that since they were original, that may be the problem. While it may be SLIGHTLY better, the underlying issue is still there. Rough idle and stumbling off the line.

I'm going to see about the timing tomorrow. That's something I haven't farked with at all. I'll just see how it sound by ear and get a better idle and if that seems to do something, I'll take it over to my guys and see if they can set it for sure (with the right equipment).

I don't 'think' it's anything serious. The engine sounds fine, no clanging or banging, etc. It's got to be something relatively simple...I'm just about out of ideas, so if you good folks have been through similar things or have any advice, I'm ALL EARS!

Thanks...!

Bigblock

check the PCV hose,and there are other vac leaks you may not reach with a spray can.

Bigblock

oh yeah;have you ever replaced the timing belt?

Bumpin' Yota

Check your codes.

Sounds like your VAFM is shot.... Check the VAFM and the TPS.

(Vane Air Flow Meter and Throttle Position Sensor) Also make sure that both plugs are plugged in securely. If either of those are the culprit, you will need to pull the EFI plug

Fink

Check/Clean your TPS, replace fuel filter and 02 sensor, run injector cleaner through, have injectors removed and professionally cleaned, replace plugs, cap and rotor. Have exhaust checked for leaks, although that would not cause your problem. I'm trying to think of all the things that I had done when my 2nd gen did this...AgRunner may have some ideas as he had the same problem, may want to check the cat to see if its clogged. Thats really all I can think of.

If I think of anything else I'll let you know, try doing a search for one of threads about all of this, just search for my threads and go to some of the very first ones and you should see a fairly large one about my engine hesitation and such.

Good luck!

Fink

Blair

Sounds like you've done a very thorough job of troubleshooting.
How about this...pull each plug wire, one at a time. If nothing changes when you've pulled a particular wire, that's your source. Using this method, I found a plug wire that had come in contact with the EGR tube, burned right through. Replaced the wire, and the 'miss' disappeared.

GregStevens

Blair, good idea on taking off one plug wire at a time. Tried that a bit ago. Each wire made a difference, albeit slight, in the idle...so it appears that all cylinders are firing.

And oh, I got shocked TWICE...man, I HATE getting shocked! It's not much current, but still...ARGH.

I still don't know what it is, though. There is no smoke out of the exhaust, no clunking around in the engine, etc. I'm going to look into the other things you guys suggested though...I have some research to do.

Any more ideas pop up, please post...!

Bumpin' Yota

check your codes!!

Blair

Only twice?
It's got six, you know?
And each one got me when I did it.

AgRunner06

Two words: spark plugs.

I wouldn't go any further without checking those first.

You engine is misfiring. That's why the exhaust is the way it is and you have a rough idle. If the spark plugs are fine (and I bet they aren't since you only replaced the wires), I would then check the distributer cap and rotor.

GregStevens

WARNING....WARNING...WARNING...!!!

MORONIC POST AHEAD!


Geez, I swear, I'm such a putz sometimes. All freaked out about my rig and everything...nightmare scenarios running through my head and all.

OK, so after all the BS I went through troubleshooting, I took it to my guys who I trust at the shop near my place. Turns out that when I put the new plug wires in last Fall, I missed one of the looms and the #5 wire had gotten too close to the EGR sensor and had finally burned through it. After he figured it out, he pointed it out and it was even arcing! Cool that they didn't charge me for that, though...

On the one hand, I'm THRILLED that it was so simple. On the other, I feel like a complete idiot for not seeing that...or noticing when I pulled each plug wire while troubleshooting.

But at the end of the day, it only cost me 55 bucks for a new set of wires. I replaced the #5 and the coil wire (just for kicks, as I didn't feel like doing all of them) and she's back to her good old slow-ish self!

Thanks for the ideas guys...what I have found in all of these things is that it's often the most simple explanation out there. Check the easy crap first (like I THOUGHT I was doing) and you'll be back on the road...

Man, I amaze myself sometimes...

Blair

Well, here's whi I didn't notice, when I was pulling wires...I pulled from the distributor side...no change, because there was no contact ANYWAY!. I'll bet you did the same. Mine was the #5 as well. Found it myself, though.

GregStevens

Blair, that's EXACTLY right. I hadn't thought of that before now. But yep, that's why I didn't notice it. Thanks for the insight.

What I wish I had actually NOTICED was the arcing, though! It was so obvious once I saw it...

The rig is running great now...well, as great as a 3-slo can. At least it's back to normal. heh

fsbii

So after numerous searches your post caught my eye. The problems i am having on my '94 3vze match your rigs' symptoms to the 'T'. I'm hoping you and any others who helped with your situation could shed some light on a few things.

The first thing i did was replace the fuel filter, air filter, spark plugs, wires, rotor and cap. Still had the same problem (although it ran a little better for a day and the CEL even went out during that time)

But the problem came back and i took it in for a diagnostic checkup today. Two things came up: 1) The CEL was throwing a lean code and that i needed to have my fuel injectors serviced (650$) 2) One of the new spark plug wires was jumping (or arching?sp?) somewhere and that i needed to have the brand new wires, cap and rotor replaced (375$)
----------------------------------------------

Now the questions for ya'all...

Greg you mention arcing of your #5 wire. What does this term mean. I do recall that my #5 wire does make contact with a metal part. Could it be coming in contact with the EGR sensor? What is the EGR sensor? I understand contact by the wires are bad so do i just get more plastic spacers?

Just to clarify, in checking the spark plugs while its running, i should pull the wires from the plug ends rather than the distributor cap ends, correct?

How daunting of a task will it be getting those fuel injectors out on the 3VZE? I will be reading through the chilton in a few minutes but any tips/hints would be most appreciated.
-------------------------------------

If its still running rough after all this i plan on replacing the pcv valve (somehow - tough to get to) and the O2 sensors.

Well, i think thats all i've got for now. I apologize for the long post. Have been using this site as a resource for the past couple days alot and its been great, helped alot with all my initial replacements and self diagnosis...look forward to contributing and helping out in the future.

Steveh29

I had a similar set of engine symptoms and it ended up being a bad temp sensor on the block. It was sending all sorts of screwy temp readings to the computer. So checking the engine codes is always a good idea!

axon

I was throwing a lean code a few months back, a new Oxygen sensor fixed that problem. If you dont know where it is, its right in front of the Cat.

12residing

I found this form and it describes my exact problem. It's currently throwing problem code 24. From the research I have done, this is the iat sensor/ maf. My question is, do you think a bad maf would cause the high rough idle(1500 rpm). The replacement part is $200... Don't want to spend the money if it won't fix the issue.

I have a 1993 Toyota extended cab pickup 4x4 5 speed with a 3.0 3vze.

Any help/advice is much appreciated!

xAusteh

i have a 1994 pickup 3.0 and with all regular maintenance throughout these years and with all the reputation these engines have built being notorious for blowing headgaskets my has been nothing but butterflies and rainbows until the beginning of the pandemic. like i mentioned all regular maintenance was applied and the truck ran great for all these years then the headgaskets blew and the water pump went so i had those fixed now im running into this problem and have tried almost every solution on this forum nothings worked