highonpottery

iTrader: (1)

Hoping someone can help me figure out what's goin' on with my truck. Had to limp home after a trip up to Truckee this weekend.

Ok...so the truck hasn't had any work done on it in a while except for fresh oil/filter last week. Truck made it perfectly fine up to the mountains and was driving fine up there. On the trip back home I pulled over to get something out of the bed and noticed that the rpms were really really low - like 300-500 or so and I had to give it some gas to keep it from sputtering and get it back to where it normally idles around 800-900. Didn't really think too much of it, gave it some gas and it went back to normal. Problem didn't persist until we exit the freeway and the truck dies when I come to the light.

So this is what is happening: the truck seems to start up fine, but doesn't like to idle and wants to sputter out unless you give it gas. If you let off the gas in neutral, the RPMs immediately drop down to like 200 ish and the truck wants to stall out. I got it home by bumping up the RPMs to keep it running whenever I came to a stop. Upon letting the foot off the gas/decelerating, there is a strong clicking sound coming from the passenger kick panel area sort of like a solenoid click - it was never there before today. Other than that, the truck seems to run fine when accelerating.

I know that the ECU is located in that passenger kickpanel area, but not sure it would be making solenoid clicking noises and causing the issues. Also, if the ECU is bad, shouldn't it not run at all?

Any help would be greatly appreciated.

highonpottery

iTrader: (1)

ok, so i've been searching for similar issues to mine and haven't really come up with much other than it could be cold start injection but i don't have start issues, just idle. it was really cold up in the mountains maybe 10* at night but it started up fine in the mornings. could be a fuel delivery issue, vacuum issue, any number of things...anyone have suggestions? i'll try pulling codes from the engine see if anything comes up.

DYNNOMMYTE

fuel pump relay??


its in that area

abecedarian

circuit opening relay?
which could be related to the air flow meter.

highonpottery

iTrader: (1)

thanks! i think i'm going to take a spin over to the stealer and pick up a new circuit opening relay/fuel pump relay and see if that works. i took off the glove box to expose the area under the dash and drove around the block...the sound is definitely coming from that relay. i'm hoping that it's just a bad relay, not the wiring that goes to it from the AFM.

AZ89LONGBED

iTrader: (3)

When my headgasket was blown & my truck would barely idle warm, I had similar symptoms...

abecedarian

something to consider before you buy that COR- if the idle speed is too low, or there's damage to the intake duct, the airflow through the afm will be low and if it's sufficiently low, the afm vane could be bouncing around enough to be triggering the contacts that turn the COR off and on.

highonpottery

iTrader: (1)

^are you talking about the guts of the AFM under that siliconed on cover? wouldn't something like that effect ALL engine performance, not just at low RPMs/idle?

I went to Toyota today and they wanted $100 for the COR which I passed on because I was quoted $35 from Kragen, but it will take a few days for it to get here. I guess I've got time to poke around and see if anything else could be causing it.

abecedarian

the afm performs 3 functions-
1) sends a signal to the ECU regarding how much air is entering the engine
2) sends a signal to the ECU regarding the temperature of the air entering the engine
3) turns on the COR when sufficient air-flow passes through it

#3 is the one I'm addressing here.

if you were to pry open the cover on the AFM, you would find a set of electrical contacts that are held open by the AFM when the engine is off. and when sufficient volume of air is flowing through the afm, the arm that normally holds those contacts open is deflected enough to cause the contacts to close, thus turning the COR "ON" and supplying voltage to the fuel pump.

when starting the engine, the COR is turned on by the ignition switch. once the engine starts running, you release the ignition switch... which would normally turn the COR "OFF"... but since the engine is now running, the AFM keeps the COR "ON".

make sense?

thook

I second what Abe says and will add the COR is probably fine. Usually, from what I've seen, they either work or don't.....ie, fuel or no fuel.

I'd test the AFM. Sounds like what I've been through before. Search "AFM testing" using "thook" under threads started by. Anyway, run that little test gone over that the FSM doesn't go over.....hehehe. I'm guessing you'll find your problem there.

highonpottery

iTrader: (1)

ok, so today i had some time to tinker and see what i could do...

didn't seem to find a vacuum leak anywhere, but who knows.

tested the AFM with the Ohm meter and everything seemed to be within spec of the FSM.

pulled engine codes got a 24 - intake air temp signal, and a 31 - AFM signal/Vacuum sensor signal.

started it up just fine and it idled for a few minutes perfectly, even revved it up from TB and seemed to be ok. took it for a spin around the block and it showed same symptoms of sputtering idle with clicking COR at idle and when shifting between 1st & 2nd.

came back and hit the search button again. found thread by Jay351 regarding his TPS on his 3slow...made me think about the idle adjust screw for some reason.

turned the screw 360* counterclockwise and now she seems to idle just fine now. drove it around the block a few times stopping randomly and i don't seem to have the problem anymore at least not that i noticed, might have to drive it around some more. pulled codes again and got the same codes, might have to clear them and then try again.

so my question is this: how easily should the "black screw/idle adjustment screw" turn? i turned mine with my fingernail and it didn't give too much resistance for something that i'm assuming would be a stiff screw to keep from moving. i do recall that the day before i had my issues i had driven down alongside some RR tracks in the gravel...could the gravel road caused the screw to vibrate itself out of spec?

highonpottery

iTrader: (1)

alright, so i guess the idle tweak didn't really do much - i'm still having the issue. when i tweaked the idle the truck was warm and i was driving around the neighborhood with no problems so i thought it was all good. decided to take the truck to work today and problem started up again after i got off the freeway.

after doing some homework i've concluded that it MUST be something with the vacuum lines or the AFM. I've kinda ruled out the fuel filter since it runs fine at higher RPMs.

tonight i'm going to recheck the vacuum lines with some starter fluid/brake cleaner or some soap water which i should have done instead of a visual inspection. Somewhere i read that i should pay special attention to the master cylinder area and see if that is where the leak is at - i guess that is where some vac leaks commonly occur?

I've already tested the AFM with an ohm meter and it was fine, but i still get the code 31/AFM signal. i think i'm going to try to find myself a used one to swap in and see if that helps.

abecedarian

the idle bypass screw should have some resistance to turning. being able to move it with your fingernail sounds a bit loose to me. if I remember correctly there is an o-ring around the screw to seal it and that's what causes the resistance. it takes a fair amount of torque to turn the screws on both my trucks- no way I could do it with a fingernail. if it's that loose, it's possible engine vibrations are turning the screw down and lowering your idle speed enough to cause the afm to bounce shut.

if you disconnected the afm with the engine running, that's likely what's caused your codes. Have you pulled the efi fuse or disconnected the battery to clear the ecu?

poynter

I posted this same problem just a few days ago. Exact same sputtering and the relay clicking whenever I let off the gas. I ended up turning the idle screw around a full turn counter clockwise and it seems to have fixed the problem but I'm sure it will come back since yours did. My truck will still bog down sometimes when I'm sitting at a light, sometimes down to 200rpms but it works itself out and it hasn't died on me for a few days now.

Might be unrelated but I noticed my tach jumping around this morning at idle when the RPM's of the motor weren't bouncing so maybe its an electrical short somewhere.

poynter

I turned the screw on mine with my thumbnail so maybe its just the screw?
PO also said the screw was black and I think mine is gray, maybe I turned the wrong one.

abecedarian

mine did the same thing a few days before the ignitor started acting up. may be related, or just may be an issue with the tach or the signal wire to it.

abecedarian

it's the one on the top of the throttle body, to the left of center. the other screw is underneath the throttle next to the accelerator cable cam.

highonpottery

iTrader: (1)

first of all, thanks for the help abe.

that would make sense. i had the (-) terminal of the battery disconnected when i tested the AFM, but i forgot to plug the AFM back in when I started it the first time. i'll try clearing the ECU again and see what comes up. i do remember pulling a code 31 before i disconnected anything at all.

what's the "other" screw? the idle screw that i messed with was the one on top of the TB that is dark gray/black. it did have 'some' resistance to my fingernail but it was nothing that required a screwdriver. i'm going to put a pencil mark on it and the TB to see if it moves on my way home. only reason why i thought it might have moved while driving was because the day before it all started i drove a short trail that had about about a mile long stretch of deep, chunky gravel next to a RR track - but then again the rest of the trail was fine and I didn't have any issues at all.

abecedarian

the screw underneath the throttle body is the throttle stop screw, used to set the base angle of the throttle plate.
there's also a screw on the dashpot on the side of the throttle body.
neither of those are used to set the idle.

toyotastupid

2 weeks ago my 91 22re 4runner started doing the same thing. i messed with it for a day or 2 then just parked it. i have been doing alot of looking to see what it might be. this is the best info i found yet. we have the same problem down to the tee, clicking and stalling. it will alway start back up though. i have a bunch of afm's so i will put one on tomorrow and see if it works.