OutlawMike

Mine still runs great, no problems at all. Idles nice, issue has not cropped back up.

Brad.

OK thanks, I just gotta work up the know how to dissect the TPS, I am more of a musician than a mechanic. However I can't afford not to do my own work.

headstomp3

i am going to see if i have the same problem and try your fix, i will post my results as well

airkewld4life

Could this potentially fix a low idle problem? After my motor is warmed up the idle drops to about 400-500 RPM.

OutlawMike

I don't think so. If you have low idle, you can adjust the idle screw on the throttle body. You can unscrew it to increase the idle speed. Just make sure your timing is set correctly ahead of time. And it is always a good idea to check the TPS while you are in there.

Mike

dgrewhl

I'm thinkin of forgettin the impact driver and just using the hammer. Seriously you guys rock, newbie here and damn glad I aint the only one with issues,lol. will let ya know if the
thermo valve is my culprit, or at least show the pieces. best wishes !

OutlawMike

Welcome to Yotatech and let us know what you figure out with your problem.

Mike

arielb1

Hey, finally found the exact same problem I am having now. EXACTLY!

Do I have to disassemble the back plate with the plunger off and clean it? I prefer not to have to mess with the screws.

From what I understand, I have to take the TB off the engine and run hot water through the ports. Does it matter which side I run the hot water through?

Third, I just installed my TB a week ago. I installed a new paper gasket I picked up at the dealer. Can I still use the same gasket?

I plan to change out the TPS as well. At 119K miles, I will just purchase a new one. I only get 14mpg and I was told this can be a culprit.

Many thanks...Im still learning.

arielb1

Well, took me 20 minutes to get the TB (I works slow).

Water runs through the TB ports with no resistance.

I am going to replace the Throttle Positioning Sensor.

OutlawMike

I just replied to your TPS post. It appears you have a TPS problem.

But, one thing to makes sure of is that the rubber coolant lines going to the TB are not clogged. I hit mine with compressed air to make sure they would flow coolant. A little messy as it comes out somewhere, but it is good insurance to make sure the coolant can flow.

Good luck.

ethanmc

I have a 1994 with the 3VZE and it idles between 1500 and 2000 RPM all the time. The check engine light is on for the O2 sensor running lean. Is O2 sensor the problem here? It runs fine just idles super high.

pholife

O2 sensor does not run lean. I think you coolant sensor not senderr is malfunctioning causing your ecu to make your engine run rich not lean.

As a result, replace or check your coolant sensor.

good luck

phildelfino

[QUOTE=OutlawMike;51228632]Those screws are a bear. I used a tool that you smack with a hammer and it rotates at the same time. Impact screw driver? I don't know the exact term. I replaced them with torx head M4's so that I could get them out easier.

QUOTE]

i bought one of these many years ago as a phillips head stripped screw remover. came with a few different tips and seemed they were shaped a little differently to accomodate the added pressure when smacked with hammer. works great.

EPrice88Yota

I have been having the same issues. 88 pickup 3vze with a high idle

Idle screw is all the way in
I have taken the TB off (1 thousand times!!!) and cleaned it and boiled it out
checked that air and water flowed through the cold idle valve... it flows freely
replaced TPS and got in specs
replaced water temp sensor
I checked for diag codes... nothing

I have just about given up on the ole truck.

It all started when I was out riding one sunday. I was driving around the edge of a really big mud/ water hole and low and behold I was not far enough away. I fell in. I shut the truck off. Got pulled out drained the water from the intake hose. And since then I have had the problem. There was no vacuum leaks before so that can be ruled out. The truck has been babied all its life never seeing above 65 or the off road. Until I got it and that was the first time I had it out riding off road.

Can anyone help???!!!

Is the cold idle air valve itself available at a parts store? I have even tried another throttle body (that I spent money on) IDK I need some help before I go mad! Also, if and only if this can't be fixed would it hurt to just screw the cold idle air valve all the way in to close it off and just not have that?

turo

i had the same problem and didn't know what to do since I looked everywhere for leaks and adjusted the idle always... thanks

88MemphisBlues

Did you ever figure this out? I posted yesterday asking what I think no one has mentioned before about the IACV, which is when testing it off the truck with boiling water, and after it seeing it successfully moving to what looks to be a fully closed position, it still does not block air flow through it as tested with pressured and metered air. Mine blocked about 75% of the original force of 30psi, all the way up to 90psi, which scaled at any pressure I tried.

I found after putting it together again that the valve must block ALL air, sans any vacuum leaks which I and my neighbor (he has an 86) have thoroughly checked off as correct.

This is a great fix for most, but I guess I have to figure out now what to do when the valve is worthless, and the only TB one can buy these days are as old as the trucks we need them for. Frankly, I have trust issues now given my truck's history, and the lack of success I've had hunting junkyards.

olivermeyer

IACV FIXED

Ive had the same problem with a very high idle on cold start, around 2000rpm.
The good news is it was the IACV not closing all the way and its completely fixable.
The thermostat is pressed into the TB and over time the rod that expands pushing the plunger up to close the vacuum wears away. (i found metal shavings in the bottom)
The threaded cap at the top that helps create the seal is removable but you will have to make a tool to remove it. I used a key for a dremmel and shaped it to fit.
Remove the top cap and remove the large spring and plunger.
Thoroughly clean everything.
Now for the hard part. As explained when the coolant is hot this valve must closed all the way. To assure you screw the cap down far enough you will have to run hot water to the thermostat and create a seal. i suggest an extra turn to be sure. you can test its sealed by blowing air through the port at the front of the TB.
This dropped my cold start down to 1300rpm.
I also replaced my TPS and put a new O ring on the throttle screw. (do not buy aftermarket TPS they are junk)
When its all put back together run the engine warm and adjust the throttle screw to achieve idle of 800-900rpm

88MemphisBlues

I'm on my second additional throttle body from a salvage yard and still I'm having the same issue where as the truck warms up, the idle speed actually increases from the idle after start (about 950 or 1k,) as though my IACV is opening while I'm driving instead of staying closed.

With the idle screw in all the way, again it starts and runs at about 1k then creeps up to 1200-1400 (it varies with driving, but not quickly,) and it's high enough that I get the fuel cut when applying braking (as mentioned in other threads given high idle.) I've mentioned before, but what stumps me the most, is that when I park the truck for say, running into the grocery store to pick up some things, when I come back out to it and crank it, it barely runs at 400-500 rpm. I believe this is because the IACV is actually closing given the underhood temps cooking it closed by radiant heat alone. This alone is what makes me think it has to have something to do with the IACV, or the coolant somehow doing its job so well that its keeping the valve open because it's not at a high enough temp to close it. I have no clue. I've changed the coolant, and it flows through those hoses when I check them, or so there is fluid in them when I pull them off when the truck is stopped.

olivermeyer, I may try to replace the o-ring on the throttle screw just for good measure, but given two throttle bodies are doing the same thing, I believe the problem lies somewhere else that I hadn't been able to check much more thoroughly yet. Originally I thought it could be a vacuum issue, and hell still may be, but I've replaced all the hoses with silicone and the seals are tight. I, along with two different shops whom I paid, couldn't seem to find vacuum leaks either using smoke and whatever else tricks they tried, such as I did with carb cleaner and later brake cleaner spraying. I am not dismissing the making of a key that would unscrew that wax seal valve chamber for a much more effective cleaning, but the valves are working in both my TBs when off the truck (boiling water tests) and are obviously having an effect on the truck when it sits and the sitting engine heat soak obviously closes them for rough restarts about 15 minutes later, to then idle back all the way up, by more than a thousand once the coolant starts, I guess, cooling the whole thing down again.

Updates when I can... for giggles if nothing else.

hwehrman

Have you checked your coolant temp while running? May need new thermostat, these things like to run pretty hot.
.