sb5walker

It means air is either getting past the throttle valve (butterfly), or there is a vacuum leak. Hold anything flat against the opening of the throttle body to completely cut all air going into the TB, and if it still runs, you know there's a vacuum leak. On the other hand, if it immediately stalls, then it may be the throttle valve, perhaps as thaddeusss described in post 11:

Good luck! Keep us posted.

Operator

Had a similar issue once. When it is warm and idles high, can you move the butterfly valve by hand right outside the throttlebody and push it further back to idle? My solution for me was to just WD 40 the whole thing. Also the dashpot assembly could be sticking. That is the little container that sits on the side of the throttlebody underneath where the throttle cable attaches and slows down the closing valve at the very end. If it is stuck it will not let the butterfly close all the way.

DupermanDave

I just tried oiling the butterfly valve and letting it warm up. No go. while it was warm and before it was warm, I tried to measure the gap with some feeler gauges. It's a pretty tight seal. I eventually started using a slice of printer paper to gap it. Almost tore the paper it was so tight.

Tried blocking off the intake and starting it up. The truck stalled immediately.

Windsor

Haha, sorry, didn't mean to outright conflict with your post.

I saw the cyan-color and largely bypassed it, so I missed your reference to an unlit torch.

I don't have a propane or MAPP torch (close, I have a butane torch I used once), so I guess it depends on what you have available.

DupermanDave

I've also rechecked all the hoses. There are a few cracks in the tips of some of the hoses, but the hoses are so deep onto the nipples that stick out that the cracks aren't a problem. I looked in the middle of each hose and couldnt see or hear any signs of holes.

DupermanDave

I THINK I GOT IT!!!

I don't want to jinx it. Last night while laying in bed I was running through the whole intake system wondering what else it could be. It couldnt be a vacuum leak, because all the hoses are new and I just re verified they're all tight. No hoses are cracked or had leaks. Next, I figured the throttle body wasn't leaking through the gasket because I changed that out twice. Marks that off. Wasn't a leak with air getting past the idle screw because I blocked that off temporarily. I burped the system one more time (making a total of 5 times). NOTHING.

I remember looking at the dashpot and throttle stop screw. I hadn't adjusted the screw, but it could still be a problem. I figured maybe the gunk I cleaned out of the Throttle body had somehow prevented the butterfly from closing all the way, so now that the gunk is gone, maybe the throttle stop screw was too tight (and wasn't noticeable before because of the gunk.)

So I got out of work early today and checked the truck's throttle stop screw. As I began to remove it, the idle went down and down and down. I removed it entirely, and adjusted the idle screw all the way down and got the idle down to about 900 RPM. Still can't get it any lower, but this is a good sign. So I think I fixed it.

Right now, the TPS is loose on the screws so I can adjust it again with a multimeter. Could the disconnected TPS make the idle as high as 900 RPM? Or should I continue the search for something affecting the high idle?

Anything above spec 750RPM is a "high idle" for me. 800 Isn't too bad, but this is at 900 and can't get it to drop.

-edit-
got the throttle stop screw back in. It's idling now at 1000 RPMS, no lower. I'm still not happy :-(

DupermanDave

so throttle stop screw is back in and idle screw is all the way in. I checked spark plugs and hoses again. Still idling at 1000 RPM. The throttle stop screw used to be pulled out 2 full turns, but now it's in all the way.

Anything else I should check?

Junkers88

Man this has got to be the longest problem in history. I have to keep re-reading the entire thread(s) just to remember what you've done with it.



I don't have any advice at the moment but will keep searching for you. Good luck!

DupermanDave

Yeah, the other thread is for what I thought was a TPS issue. I figured this thread is for a totally separate problem.

I took the truck for a drive again and when I pulled into the parking lot it idled down to 500 RPM. After parking in a space and letting it sit for 10 seconds the idle climbed back to 1000 RPMS.

Take note that I still have the TPS unplugged and very loose on the throttle body. I'm adjusting it tomorrow (maybe)

any other tips?

sb5walker

Yes, my tip would be not to bother trying any other troubleshooting until you've got that tps connected and properly adjusted - as mentioned, the computer needs to have that IDL grounded so it knows the motor's at idle! Otherwise, it's injecting too much fuel and also probably has the timing advanced too much.

If getting the tps squared away doesn't solve the problem, I would try taping over the top of the adjusting screw - sounds like it might be leaking some air. See if that affects the idle speed.

Double check that the throttle position when idling is in the same position as the throttle when the motor is not running.

Pinch the vacuum tubes attached to the top of the throttle body, one by one, while the motor is idling, and listen for a drop in idle speed - if there is a drop, that could be your culprit. Use something that won't damage the hose - like the flat part at the end of a pair of pliers.

One of the vacuum tubes attaches to your fuel vapor recovery canister, the other two to your EGR vacuum modulator. Maybe one of the three check valves in the charcoal canister has failed, or the modulator has sprung an air leak.

There are some fuel vapor canister troubleshooting hints (not great ones) in the fsm:
http://personal.utulsa.edu/~nathan-b...17evaporat.pdf

Since the motor was still running with both air bypasses taped, (which it DEFINITELY should not have been) the air is either getting in via a vacuum leak, or getting past the throttle plate, or some combination. Since it stalled immediately when you blocked the end of the throttle body, a vacuum leak, if there is one, could not be that great.

So somehow, somewhere, your throttle body is leaking air. If you taped up all the air bypasses inside the throat of the TB, then it seems some air MUST be getting past the butterfly. At this point I would try removing the throttle body and trying to shine light past the throttle plate area. Remember to look on the sides also - not just top and bottom.

Good luck, man! (And get that tps connected!)

DupermanDave

I already did that last night before I found out the idle screw was part of the problem. I didn't use tape, though. I used some old gum as sort of a putty to block it all off completely. Didn't affect it any.

I doubt it will still idle with both of those taped off. When I taped them off and it ran, that was before I discovered the throttle stop screw was opening the throttle a little bit. Now that I've backed out the stop screw, I have a feeling it might stall out.

When I'm setting up the TPS tomorr, I'll also retape those holes and double check it again so make sure it's all correct. I'll even mess with the stop screw some more to make sure I have it backed up all the way. Do I even need the stop screw? It doesnt seem to be serving any purpose that I can see.

DupermanDave

GRRRRRRRRRRRRRRRR. I HATE SENSORS!!!!!!

So I went to adjust the TPS. Turns out the multimeter is broken. To make matters worse, one of the screws for the TPS unscrewed itself and fell out onto the highway. So I had to improvise and use a wood screw in place.

I started the engine and tried adjusting the TPS by ear. I sat there for about an hour hunched over the engine slowly rotating the TPS and checking the RPMs. They don't change at all with the TPS plugged in. So I swapped using feeler gauges and rotating the TPS. Still no change.

I discovered something new. When I shut off the engine and turn it back on immediately, the engine idles at about 500 RPMs for about 20 seconds and then climbs to 1000 again.

I jumped the diagnostic connectors and started the engine and it seems to idle good with those jumped. However when I rev the engine and let it idle down, it only goes down to 1000 again.

I got the throttle stop screw back in as well.

I'm stumped. Anyone want to buy or trade for a 22re?

Another quick question. What size allen screws should I get to replace the one that fell out of the TPS? 4cralwer suggests swapping those screws for some allen heads, but when I go to Ace hardware what size am I looking for? I don't trust myself at this point to eyeball it.

-edit-
I'm still not dismissing the TPS, but I'm going to purchase a new one before I mess with the TPS.

socal_style

According to the 4crawler website, the screws are 3mm. I tired checking at Home depot, but they did not have screws in that size or thread. Good luck finding them. It may just be worth buying them for the $5 that 4crawler offers them for.

I have a problem similar to yours, but not exactly. My problem is that after running my truck for a while, the engine will rev high. I just received my TPS and I am ging to try to install it after dinner. I hope it solves my problem.

dntsdad

If you have an Orchards Supply around you, they have good selection of machine screws. So does Lowes actually but you have to look in the pull out bins.

DupermanDave

I'll check around for the orchards supply and other places. There's 3 industrial fasterners and supply shops right next to my apartment, so I'll try those.

Good news. After taking off the throttle body and reassembling it, my truck no longer smokes at startup :-)

Still looking to fix the idle issue. Still idling at 1000 RPM. Anything else to check besides TPS?

sas'd22re

i replace mine with the allen head screws. while i was in there, i also did my idle stop screw and dashpot adjustment screw since i was starting from zero anyways. it looks pretyy cool with the black allen heads all around the tb. i took an existing screw out of the tps, and its the same pitch screw for all of the locations listed above, and i took the screw to canadian tire and matched it up. good luck

DupermanDave

Just to update the thread, I changed the EGR gasket last night. Still no change in the idle. I found another thread over at toyotanation. http://www.toyotanation.com/forum/sh...d.php?t=273253

After he cleaned the TB, his idle was really high. He fixed it by replacing a gasket and the TPS.

I still have a hard time believing it's the TPS because even with it unplugged and the diagnostic terminals jumped, wouldnt the engine idle and rev to a default RPM? TPS never affected idle before whenever I unplugged it numerous times. Why would it start affecting it now?

TNRabbit

I doubt very seriously it's the TPS. You have a leak somewhere~

Did you ever try the gas/WD-40/etc. thing for a vacuum leak? I'm TELLING you, there can be cracks you can't see. I had one that was HUGE on the underside of a medium-size vacuum line on the passenger side fender. Didn't find it until I used the torch...

dntsdad

I agree you have a vac leak. I would borrow, rent or steal a torch or get a huge can of wd-40 and start spraying everything and anything and take your sweet time doing it!!!

CHAUCH

how do you do this wd-40/ torch test......? I think I may have the same issue with my truck