VaBowHunter

Hey all, I just purchased a 1990 4runner SR5 v6 auto with 181,XXX on the ticker. This is a vehicle i bought to go back and forth to work and transport my work dog. It has a new tranny, well put in this past summer at least.
The motor runs smooth but appears to lack a little of power. I know a lot of it is probably me because the daily driver is a 2006 cummins diesel with a chip.

The issue is this: in any gear, or nuetral, the truck idles very low. Almost so low it seems like it will cut off. It cut off one time on me trying to back up and going very slow, stoppin and going. I want to say the idle is around 500rpm. Im guessing it may be the timing belt. Ive done some research that has lead me to think maybe the throttle body needs to be cleaned.

Any suggestions?

VaBowHunter

The oil pressure gauge also reads low to middle, but it doesnt leak, doesnt smoke and the oil dipstick read is consistant. incase that helps with the diagnosis

just call me smithy

Let me save you some time and $ first start off with a cheap vacuum test buy some carb cleaner and spray it on the vacuum lines while the 4runner is running if u have a leak the idol will rise with the cleaner entering the intake manifold ….if you don’t have a leak(I didn’t) move on to step 2

Step 2 do a cylinder compression check first, you can rent one from Autozone for free, if you don’t have one near you ,you can do it the cheap way, pull the plug wires off the sparkplugs one by one with the 4runner is running, if the miss goes away with a plug wire off you’ve found your problem cylinder (be sure to use gloves the spark doesn’t hurt but it startled me) this is what I did terns out I had a burnt intake valve my symptoms matched urs except I pored allot of money on parts that I didn’t need just to find out that I needed a valve job


When you find ur problematic cylinder theirs a few cheap things to fix ur miss
-new plug (gaped)
-new wire to distributor
- Fuel injector cleaner with a tank of 91oct and go for a joy ride

pb4ugotobed

First get yourself a repair manual. Second, hit it with a timing light. This is the easiest check I think you could make. You may just need to clock the distributor. The TPS may need to be readjusted. Does it just idle low, or does it have a miss? The 3.0 is notorious for valvetrain issues... Valve lash adjustments need to be at least checked every 60-75k miles. It's also very possible your dash pot is going bad and causing a lower than normal idle.

Don't ever expect the truck to idle great. They never do, they never did when they were new. Get used to that, though 500rpm is a bit on the low side.

The lack of power thing... well, you have a 4500 lb truck with an auto transmission, and a 145 hp engine. You do the math... it's GOING to have a lack of power. You won't get anywhere in a hurry, can guarantee that. You'll certainly get there, just not so quickly. I have a 91 3.0liter auto 4x4... was slow when I got it. Then I added 33" super swampers, got slower. It's fine with me, I don't think I've ever had the truck over 55mph... with where I drive on the particular roads I drive on, I don't have any need. It'll do 55 just fine (I'm sure it'd do 70 just fine if I drove somewhere I had to go that fast). It won't get up to that speed real quick, but once you get there it has no problems holding it. The best description I'd heard about the 3vz was "When they run right they still won't get out of their own way. You can tell that it wants to, it just can't quite do it".

Good luck!

VaBowHunter

Thanks guys. It will be my round town beater, i just sold my 2006 dodge ram 2500 CTD 4x4, 6" lift and 37s. I will be replacing it in a few months with a F-350 4x4 Diesel. Im a diesel guy at heart, but i live 2 miles from work. I will be using this toyota to and from work. im a K-9 officer and a big truck is hard on the dogs hips and at least with the 4runner i can keep him out of the elements as much as possible. After i get my new truck, the yota will also be hitting the trails.

As for the low idle, thats all it is. it runs very smooth, no missing on any of the cylinders. at least it doesnt sound/feel that way or idle rough. can i adjust the distributor on this motor to advance the timing and see what happens. ive always been an american made diesel guy, this is my first gasser in a while

VaBowHunter

anything guys?

pb4ugotobed

Personally, I'd say the only thing you can really do is hit it with a timing light and make sure it's all good, maybe adjust the disty as necessary. But if it idles smooth, doesn't miss, then I wouldn't get too carried away with it. Like I said, these engines never did idle worth the , even when they were new. If it idles smooth, then you're one step ahead of the game. Most idle about as well as a mildly cammed v8.

If your timing is right, then I'd just roll with it.

VaBowHunter

Okay i have an update. i didnt test drive it on the highway cause its for around town driving. i was on the highway the other day and it lurches above 55. almost like the tranny is hunting for the right gear, but i was told the tranny is new, so im guessing its the motor, especially since it also has the low idle condition. so what i have is this

1) low idle in any gear or nuetral, 3-500 RPM but still running smooth and no lurching
2) on highway at highway speeds it lurches slightly and you can se the RPMs bouncin back and forth

Kiroshu

Vaccum leak. Main intake hose leaking. Low fuel pressure. Idle set improperly. Timing incorrect.

VaBowHunter

okay thanks. i was on it hard today on the highway and it wasnt givin me much of a problem. which hose is the main intake hose? anyway to set the idle or check fuel pressure in this truck? i will check timing after i check for vaccum leaks

Jay351

MAke sure you jump the te1 and e1 connectors in the little grey diagnostics box when you are setting the timing.

THe idle should drop a few hundred rpm when you jump the connectors.

VaBowHunter

as i said earlier im a diesel guy, haha thats all jibberish to me

NYChopshop

look over your vacuum system and your EGR as well. Basically, look at every single last little hose running around inside your hood and make sure they all are well seated. Pull off your intake elbow right at the throttle body and run your finger around in there. If you have any sort of oil there, you probably need a new PCV valve (and grommet, its such a PITA to work on its not worth doing twice just because you didnt wanna shell out the $5 for the rubber bit too! I can't tell you how many times I've seen it done that way). If it idles well, its probably not the timing or compression, but no guaranties. Pick up the factory service manuals, or download them via a search here in the forums.

Kiroshu

Your main intake hose is the big hose between your air flow meter and throttle body. Idle set screw is on the throttle body. Its a flathead screw you will see it. Fuel pressure, your going to need a fuel pressure gauge and tap into the fuel lines.

VaBowHunter

WELL ITS FIXED GUYS....

I replaced the PCV valve. i capped it at the intake and ran a catch can to the end of the pcv hose after i replaced the pcv and grommet. it idles at 750 now consistantly. THANKS

VaBowHunter

I also capped the bung on the drivers side of the intake from the drivers side vent coming off of the valve cover near the oil fill cap, i put a vent filter on that bung. bad idea?