dmahonec

I recently purchased a 1990 4Runner with a 3VZE motor from a 1993 4Runner. It is an automatic, 4WD. It runs great with the exception of this low idle problem that mine seems to be having. Upon startup, it runs at about 1100 RPM, and once it's warmed up completely, 300-400 RPMs...I honestly have no idea how it stays running at these speeds. It also sometimes stalls when I hit thick snow or rough terrain and let off the gas. After it stalls I start it right back up, and rev the engine a little bit before letting it idle again, otherwise it stalls right off the bat. The only solution I can think of is to back off the idle screw, but I wanted to get some other opinions before I do anything, as I am new to Toyotas, and new to the inner workings of cars in general. Here is a video I took with my phone of the exhaust sound, the tachometer, and the engine as it's running. Sure, I may be asking a stupid question, but any and all input is appreciated! Thank you

P.S. - The rattling in the beginning is the fender on the exhaust tip; I hold the fender still so you can hear the exhaust note.


http://www.youtube.com/watch?v=O8_On...aBK39DdAEow%3D

McKenna

I just adjusted my idle after fixing bad valve cover gaskets (Vacuum leak), and installing new plugs/wires/cap/rotor. Warm up your truck and then turn your idle screw counter clockwise one full turn at a time to increase your idle and clockwise to bring it down. If this does not fix the problem it may be a TPS issue, you could unplug your TPS and see if the truck jumps back to the factory idle zone.

dmahonec

Thanks I will definitely try that. New spark plugs have been on my to-do-list since I bought the truck last Sunday, as well as an all-around tune up. Do the 3VZE's have multiple idle screws (one for cold idle, one for warm idle, etc.)? Or is it just one "master" adjustment screw that adjusts everything around it?

aviator

Just one screw... there is a vacuum driven pot that activates for cold start/idle...
iirc as you look at the throttle lever on the engine you will see a set screw near the top which seems to ride against a silver/gray piston in a @1" round black pot {this is the cold idle up dohicky} you want to adjust the screw so you get 700-750 idle warm...
you may see the cold idle very high after you make this adjustment but don't worry the ecu will correct that once it adapts to the proper idle setting restoration.

does'nt hurt to lube the throttle linkage/idle up with a white lithium grease or other quality lubricant...

hope this helps

dmahonec

I will definitely try this! I'll be sure to post back with an update and a new video of the corrected problem if it works. Thank you.

AZSPEED

Have been having lots of problems like that found my cat about 90% clogged .

dmahonec

Just a quick update on what's been going down this past week...got all new spark plugs (NGK V-Power), wires, distributor cap, rotor, air/fuel/oil fliter and swapped em all out. When I took off the Tubing (or whatever you would call it) that is connected to the throttle body, there was some oil built up in there and a little bit in the throttle body itself, so I scraped it all out, and when all was said and done with, and the tubing was put back in place, it idled a little higher (500-600ish). I also checked the codes that the check engine light was throwing at me, and it says that the knock sensor was bad and that there was an issue with the idle (obviously). I'm guessing that the knock sensor going bad would send a signal to the ECU, and the ECU would cut horsepower, idle lower, and cause stalling like it's been doing. So my next step is to replace one of the knock sensors (there are 2, idk which one it is) and see what happens to the idle. Thoughts on this, anybody?

Kiroshu

Faulty knock sensors retard timing... thus low idle... thus low power... More than likely your majority problem. A very very common problem with the 3VZE. Lots of threads.

dmahonec

Indeed there are a lot of threads lol. My apologies for posting a seemingly useless thread, but I had no idea where to start with the idle problem and was just looking for some answers since I'm new to all this. Many thanks for all the help everybody gave me! Once the problem is resolved, I'll post here for informational purposes, whether it's the knock sensor or not. Cheers everybody

dmahonec

So here's the deal: Knock sensor and knock sensor wire were replaced, as well as the EGR (which was rusted out) and the intake manifold gasket (snapped off while trying to remove it). However, it still runs rather rough and idles low, but not as low as it used to, since I changed plugs, wires, cap, rotor, etc. The usual stuff you do when you first get a used car. It threw a CEL code saying knock sensor faulty, and bad TPS. I tested the ohms from the knock sensor, and it read fine, and I also tested the TPS, which was also fine. I've come to the conclusion that when the previous owner swapped in the 93 block, he kept the stock ECM and harness, and because of that, it doesn't properly mate with the engine, and throws random codes such as knock sensor and TPS in this case. (the knock sensor wire was actually bad, and did need to be swapped out.) I'd much rather not track down the proper harness and all that, as there are tons of variations, depending on what you have (auto, 4x4, what kind of O2 sensor, etc.). I've decided to just sell it and buy something that isn't a conglomeration or parts poorly assembled lol. Thanks for all the help though guys, much appreciated.