Idling Problems

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-Nemesis-

-Nemesis-

New Member
First up, I don't condone this and i'm sure some people will tell me why my motor will die or something extreme.... :saevil:

Anyways for the last 6 months my 1UZ has been idling fast when I pull up after driving, after a while at idle it settles down blah blah blah. I knew from research on here that it was most likely a dirty ICV/IAC, but the bottom screw on the black unit is stuffed so I couldn't removed it. Okay so i lived with it...

2 weeks ago it went to the opposite, it wouldn't idle at all, it just kept turning off. Whether it was cold or i'd been driving, even in between gears. Very frustrating, especially when everyone is watching this V8 monster truck.... :rant: So I tried once again to remove the unit without taking the whole thing off (draining coolant etc) to no avail.

I had another read of the planet soarer guide to see what was inside the unit. I noticed that where the main air inlet goes (from the air intake pipe) is just the plenum type chamber where the plunger is, and what would be my guess as being the gunked up bit. Nothing sensitive, no grease etc...

So, with the engine revving (slightly open throttle) I pulled off the air hose to the ICV, it stalled... yep. Try again; I pulled the hose gently off but slid it up so it was half against the ICV intake and I could see half the opening. The revs dropped but it kept running and the ICV was sucking air through it quiet fast....Excellent.

My plan: Grab a can of quality Throttle Body Cleaner, the type that quickly evapourates. In the half hole I could see I gave it a good squirt (1 sec), waited 15 sec, gave it another.. About 4 times and then reconnected the hose and let it run for a minute as is. All up, about 3 min work.

When I pulled the chock off the pedal it immediately came to a smooth idle, wow I haven't seen that for a while. So I turned the car off and started it, perfect instant idle (no waiting for ecu to relearn or whatever.) So I let the car cool down and then started it, perfect cold start high idle and reduction as it warmed (which it hadn't been doing properly for 6 months.) It's been over a week and lots of starts and it's better than ever, like new.......

Like I said I don't condone this as i'm sure people will have problems with it. But, I don't see the point in pulling it right down and changing bearings etc unless they're actually stuffed. Happy as a poig in shoit

:Eyecrazy:
 
Yes, you've done exactly the same as removing it and cleaning it, but obviously not quite as thorough.

Carby Cleaner/throttle body cleaner is the perfect stuff to clean all the gunk out and let that ISCV reseat itself properly.

Try doing it again in a week or so, it may get even better.


As for not wanting to take the whole unit off, just do it.
When you do it, just block the coolant passages. There is one inlet at the ISCV that needs blocking, and the other that needs blocking is just behind the throttle body.
 
Well as it turns out, about 2 weeks after I did this and it was starting and idling great it stopped being good. One morning, turn the key and she's back to the same old stalling/low idle. After a few curses I took the time before work to pull the whole unit out. The plunger had some black gunk on it etc so I cleaned it all up to a shiny finish like new.

After putting it all back together and turning the key for it to stall I :censored: :censored: :censored: :rant: :rant:

So anyways, my next task this arvo will be to pull the intake pipe off and check the throttle plate. Then adjust the tps if I have too, though i'm not sure I should have to play with it if it worked fine before? In fact last year it used to idle too fast when i'd stop and take about 15-20sec to return to normal idle.

Oh and I checked all the vaccum lines I could see. I sat on the motor and couldn't hear any air, plus i put soapy water everywhere... No bubbles :boggled:
 
Nemisis,

Just keep starting it an driving it.

Given a little time it will learn the correct settings and all should be good.
 
Hey Rod,

I've been driving it for about 4 days since I cleaned it to no avail.

I just cleaned out the TB from the outside, it had a bit of junk in it. Put it all back together without touching the TPS and started it and it idled good instantly. Turned it off, waited a minute and started it again and stall... Try about 5 times, stall stall stall stall stall.

So I adjust the TPS. Doing this I have to turn it a fair way before anything changed, the only changed was at a certain point where it would go directly from about 350rpm to about 750rpm, there's no inbetween. I got it to about where it was best and tightened it. Give it a few revs, great, back to normal idle. Turn the car off then restart, stall..... Idling to slow again.

Adjusted the TPS again, this time it had to go as far clockwise as possible to get a decent idle. Turn the car off and restart, stall.....

What could this be? Faulty TPS? There's the second TPS for the cruise control (not connected) should I try swapping that in? Hard job?
 
More info if it helps:

Remembering reading about people with idling issues etc before I just went out and started the truck abotu a dozen times to help it 'learn' what it has to do. The first time I started it it stalled, second time it just kept alive idling at about 200rpm (this is what normally does if it doesn't stall.) I let it sit there and the revs crept up slowly. Once it got to about 600rpm i turned it off and started it about 8 times, every single time it idled straight away at 600rpm. I had been only leavign it about 10 seconds between starts. I left it about a minute then turned they key, it fired and stalled straight away, second time it fired and almost stalled, then idled back at 200rpm (only just surviving), back to the way it was. :rant: :lame:


For the record it only takes a turn or two to actually fire, when it does it bursts like it should up to about 1500rpm, on the way back down from this is when it normally stalls.
The engine runs fine when driving (apart from idle) and feels like it has 100% power etc. Everything else seems to work fine.....
 
Yet another clue??? I know this is hard because it's in a custom vehicle.

When I turn the ignition to on, there is a quiet mechanical sound the goes for about 3 seconds (i assume this is the cold start timer or something?) when it stops there is a relay/solenoid style click sound from around the area of the ECU (i think.)

Now after just playing again i'm confident that: If I coax it to a good idle like in my previous posts, I can turn it off and restart it numerous times and it's all good. However if I leave it for more than say 30 seconds it stalls after it fires again.

Now this is where I discovered what may be a clue along the lines of my 2nd paragraph (relay click.) I just turned the car off after it had been idling good over about 5 starts. I was just standing there leaning in the car thinking about it after I had turned it off. After what was probably 20 seconds (at a guess) I heard the same relay style click as the one i mentioned in the 2nd paragraph. Something turning off after 20 odd seconds......? I immediately tried to start it and it stalled....
So now i'm confident that this second relay click may be a suspect, whatever it is doing seems to reset it. If I restart the car before it's been off long enough it starts great. If I leave it long enough and restart it it stalls...

I can't believe this all started out of the blue with one turn of the key....
 
When you turn the key off, does it remove all power from the ecu. This means every time its started it would have to relearn its parameters. A certain wire to the ecu needs an uninterupted power all the time, even when the key is removed. Just a thought. Kris
 
I wouldn't think so. The wiring was done by Sideshow and it worked fine up untill last month (been driving since late '05)
 
one thing you should not have touched the butterfly adjusting screw
doin that is just bypassing the problem

is there definetey no vac leaks

could also be dodgey air flow meter

i have had idle motors sieze up

like krayn said maybe the fuse is blown that supplies backup power to the ecu

and resetting all the time

just before it started playing up did u install anyhting like lights radio

half the time with some faults its something else fitted or worked on caused the prob

i can look at it if you bring car one arvo to sss automotive but not to soon
im booked out till 25th march
 
I didn't touch the butterfly adjustment, only rotated the TPS.

Can't find any vacuum leaks.

I haven't installed anything. On the way home from Holidays late January i stopped at the shop about 1km from home after a 9 hour drive. The next turn of the key the stalling issue started.....

The fuse to the back up power sounds interesting. Seeing as i've since retested it and am certain it only stalls after i've had the ignition off for more than abotu 30 seconds, if I restart it within this time it's fine.

Which leads to the question: Any idea where I find this fuse? Is it something you would have added or is it in the factory fuse location? *Goes out back to start looking for fuses....
 
-Nemesis- said:
Yet another clue??? I know this is hard because it's in a custom vehicle.

When I turn the ignition to on, there is a quiet mechanical sound the goes for about 3 seconds (i assume this is the cold start timer or something?) when it stops there is a relay/solenoid style click sound from around the area of the ECU (i think.)

Now after just playing again i'm confident that: If I coax it to a good idle like in my previous posts, I can turn it off and restart it numerous times and it's all good. However if I leave it for more than say 30 seconds it stalls after it fires again.

Now this is where I discovered what may be a clue along the lines of my 2nd paragraph (relay click.) I just turned the car off after it had been idling good over about 5 starts. I was just standing there leaning in the car thinking about it after I had turned it off. After what was probably 20 seconds (at a guess) I heard the same relay style click as the one i mentioned in the 2nd paragraph. Something turning off after 20 odd seconds......? I immediately tried to start it and it stalled....
So now i'm confident that this second relay click may be a suspect, whatever it is doing seems to reset it. If I restart the car before it's been off long enough it starts great. If I leave it long enough and restart it it stalls...

I can't believe this all started out of the blue with one turn of the key....
Click to expand...

Does it hold fuel pressure for 30 sec or longer after you turn it off?
The relay click sounds like the fuel pump control.

If the non return valve in the fuel pump is bleeding pressure you can get stall problems on first start, second start is OK (pressure is back).

Try turning ign on till relay clicks off, turn of and back on till relay clicks, do this 3 or 4 times then start. Does it still stall ?
 
I tried that this morning thanks mate, didn't help.

Pursuing the ECU thing I started crawling all over the truck and I found something that's no doubt contributing. The ECU was mounted (quite roughly) under the front passengers feet in the foot well. I noticed up under the dash the drain plug from the A/C unit had been knocked off, I also remember the missus saying on that holiday drive that she had water drip on her feet.

Anyways I pulled the ECU out which was almost directly underneath, when I pulled the wiring plug out I found this (pic.) The two plugs that have like a plastic screw down cover over them were fine, it was just this outermost one that's corroded. Assuming this is the problem, does that mean i'm up for a new ECU? I guess they're $100,000?
 
This is my ECU type, as far as know the motor is from an Celsior. Has toyota badges, front sump and had the high flowing headers (wouldn't fit.) Most of the numbers have been rubbed off :ouch:
 
The close up pic of the one that got water in it is the plug on the far right in the second pic. I'll go count the others this afternoon..

Good chance that the water could be the culprit? If I can find the fuse if there was one for the constant supply then hopefully that's the only issue.

Any ideas where it typically is on a Toyota? Would it be inline on the engine harness (i doubt) or wherever it was for the original V6 (if there was one.) I noticed in my factory fuse panel there is no fuse where the diagram says ECU-IG. I've never known one to be there since i've owned it (5 years with the V6.)
 
Okay so I just went out to count the pins on the ECU, of which there are 40 per plug. But I found something I can't believe I missed before, in fact you can see it in the pic i've reattached again below.

On the bottom corner of the coroded plug, I think it's pins 31,32,33 that are used. Pin 33 has coroded enough to completely break off, if you look in this pic below you can see it's completely missing (top left of pic.) There is just a whole bunch of gunk where it was and the pin itself is still lodged in the plug (with lots of gunk.)

So the question is what is this pin and will it be the cause. Pin 31 and 32 which are still okay have a black with red stripe wire coming out. The one that has broken has a White with red stripe wire coming out. Anyone know by chance what this wire is? Sidey?

http://lextreme.com///forums/attachment.php?attachmentid=5280&d=1171930998

If link don't work it's the first pic I attached back up there of the corroded pins.

*Edit: Have been going through the wiring diagrams on lextreme. I can't find the pin i'm after, the only reference to a white/red (white with red stripe) is down the bottom left of this one:

http://www.lextreme.com/lexuecc2.pdf

For which it links the Main Ignition Relay and the Fuse Link Box, I don't suppose somewhere back up the chain this is my wire?
 
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