I've just finished putting my 4AGZE back to standard - I have a bit of an idle issue that I'm sure someone would have had and can share... The car starts but wont settle back to a nice idle - it stalls, unless I caress the throttle and settle it back to the idle gently - AFM ?, TPS?, Timing is good. Anyone got any ideas ?
 
Cheers
KD
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Has the tps been calibrated?

I'd imagine you were still using TPS on aftermarket ECU, but that's the first place I'd look. Unless it's a different throttle body you were running compared to before?
 
Check vacuum lines since a leak will cause a lumpy idle/tendency to stall.
 
If it's a different throttle body, could also be the ISCV, the wax might have gotten hard so when its warming up the valve isn't opening properly.

Everything is stock. Even the ecu. I may have put the vac lines on incorrecrly.. has anyone a diagram for the 4agze? Tps was calibrated as per the book..

This is driving me mad ..
 
I have checked all the vac lines and all ok - the VSV's are all good, I've calibrated the ABV to the book, I've set the TPS to the book. Fuel pressure is 40 PSI. I've put a new O2 sensor and EFI Temp sender on, Cooling system is good. ICV is ok (I've tested on the bench and it's all operating as per the book.
The spark Plugs (new NGK as per the book), are very black after hardly any running, so it's running v.rich. The AFM has been calibrated(ish) and tested to be ok (I've also swapped it out with a spare I have). I have the std intake system (except with a new K&N filter)
 
A couple of things..
 
I have Kelford Cams 193-T which have reduced overlap. They are 262 (I) and 266 (E) degree, these have adjustable sprockets which have been set as per the book.
 
The dizzy and coil are all std, new NGK leads too.
 
SO why does this thing run list crap ?????? -why can't it idle ??? It should be Toyota reliable !
 
 

Just a thought and you probably have done this but have you set the gap between the throttle and the stop and then adjusted the idle screw on the throttle body.
 
Cheers

you have the kelford cams in?? is the engine your built motor, or one built to factory specs?? and does the head have any porting/polishing done??
if you are trying to run your motor from your previous setup, or even just a worked head, that will be most of your problems.
Otherwise, check your 12v supply is good, your grounds are good, and that there is no modified wiring left from your previous wolf install.

She is running well now ...
But to answer some of the questions before explaining what was wrong. Yes I have set the TPS. The internals/head are from my previous setup, mild increase in compression (8.5:1). All wiring has been replaced, when I put the wolf in I had a wiring loom that did not splice into the existing wiring, it used all the oem plugs so the engine loom from my half cut did the job.
 
So the cause was very much timing. I rebuilt the dizzy from my other agze engine and set all the gaps so it's perfect, this made a huge difference to the timing. I calibrated the AFM and that along with timing, and idle screw setup It's now running sweet. Although idle is a little lumpy (thanks mainly to the cams), I have it set at 900 RPM hot and that's fine. Amazed how much torque this thing has down low - I think it's better than my high HP setup, although no lifting the front wheels at 6500 rpm . the car is drivable now.
 
I've got my 3" mandrel bent exhaust up for sale if anyone is interested. It's a direct fit to any std setup, will bold straight up to the existing manifold. 4" double skin tip, stainless high flow cat with dual O2 ports. Also has exhaust heat wrap from down to the stainless flex joint. PM me..

The Fix
 
So many 4AGE/AGZE owners appear to have idle issues and I reckon not many actually find the real cause.
A high/rough idle is not a problem, it's a characteristic of a problem. The first place many look or just blame is the wax pallet idle control valve. This can be a cause of a idle issue, but there are other things that can cause idle. My AGZE had a rough/high/oscillating idle and I replaced the ICV without any improvement. I could set the idle at a sufficiently high RPM to stop the stalling on throttle release, but it was no where near Toyota Perfect (TP). Also, I wound the screw out on the AFM bypass chamber to alter the AFR on idle (the only reason the bypass chamber exists is for idle mixture control). So it appears to be running ok (ish) - but not TP.
 
The often thought about, but never really diagnosed vacuum/intake leak looked like being a culprit, but how to test? - The standard method of spraying Carby Cleaner all over the place listening for a change in engine note is pretty ineffective on these engines. The process to find all leaks is so simple and it only takes a few minutes.
 
Remove the air cleaner from the firewall entry point and block that off (I used a 500ml paint cup over a bit of 3"silicon hose to seal it and a hose clamp.
 
Remove the vacuum hose from the charcoal canister and connect up a vacuum/pressure gauge (this will allow you to measure the pressure of the intake system) - then remove the AC idle up hose from the intake and block the hose off. Then connect compressed air (through an air trigger) to the AC Idle up port. You can now pressurise the entire intake system to about 10PSI.
 
You will need a spray bottle with soapy water to spray on joints etc at this will bubble away on leaks.
 
When I did this I immediately heard escaping air - from no3 injector, the rubber seal between the injector and the head was leaking (bad too)... 10PSI of system pressure went to 0 in about 2 seconds.
 
I remove the fuel rail and injectors and replaced all O rings and seals (3 on each injector) then put it back together and repeated the processes. This time, air was leaking out the new silicon connector hoses between the top of the intake and the intercooler - they were slightly loose but I thought a good hose clamp would sort that out - WRONG!... I replaced these with the factory rubber ones and repeated the test.
 
Now the only leak is a very slight leak from the throttle body shaft, These cannot be serviced but I decided to leave it as it's now taking about 4 minutes to go from 10PSI to 0PSI - that leak is minimal.
 
REMEMBER To remove the block on the intake -
 
I started the car, immediately the difference was noticeable, a smooth idle - and that's before I had to re-adjust all the things I have played with back to standard. Once back to standard the car starts and idles at 1200 RPM before dropping back to 800 at 180 degrees F.  TP !
 
FYI - The AFM has a number stamped on it that indicates the factory calibrated setting, the number refers to the distance the top of the adjustment screw is from the top of the casting.
30 = 13mm, 26 = 12.6mm, 24 = 12.4mm  So the AFM can be set back to this.. Note this screw has no effect on the operation of the AFM, it's there for the bypass chamber air flow control for idle, this figure should never alter from factory and so the screw should never need altering (IMHO)
 
.. Hope this helps those with dodgy idle ...
 
 
 
 
 
 
 

Good job Keith, sometimes it's these minor things we forget to spend that extra time to find that can solve many of the problems we find. Injector o-rings leaking seem very common on the 4A's when they have some age on them, I personally know of 3 cars that have had this issue in 12 months.