More ISCV questions (sorry)

[cuh8er]

I am in the process of fault finding an idle issue with the 1UZ and have traced it back to the ISCV. I now have a few questions.

1. When I test the ISCV as per the manual (pulsing in sequence S1, S2, S3 and S4), the valve doesn't move at all. It feels like it tries to move, but doesn't. Is it a fair bet that the unit is stuffed? I have pulled it apart and it's not stuck mechanically at all.

2. How long after the ignition is switched off, should power remain on B1 and B2? When I switch the ignition off, power remains only for a very short period of time, say a quarter of a second to half a second. Is this normal? When I pulled the ISCV out last night, the valve was closed all the way and I know this isn't right....

Thanks and sorry for bringing this up again, but a search couldn't help me either.

Cheers

 

[cuh8er]

Ok having a little more of a play and it seems the ISCV isn't faulty at all.
I didn't realise you need to pulse S1, S2, S3, S4 and then repeat the process to make it open/close all the way (I had to repeat it some 15 or 20 times)

If this is the correct way it is mean't to operate, why was it closed all the way when I pulled it from the engine? Not sure if it matters, but the TPS was way out of adjustment, but I have since set it up correctly. Would this cause issues?

I'm 99% sure the power feed for the ISCV comes from the M-REL and is from the same feed as the +B1 and +B pins on the ECU. If i'm right, the ECU will then decide when to power down the ISCV like it's mean't to do....?



Cheers

 

[cjsupra90]

Yes, the sequence has to be repeated. The ISCV is a 128 step stepper motor so having 4 steps per sequence, it should take 32 sequences to go from one end (open or closed fully) to the other end.

The TPS adjustment shouldn't have an effect on ISCV opperation.

The M-Rel triggers the EFI Relay which does feed power to various idems including the +B and +B1 and the ISCV. I dont know how long the M-Rel should keep the relay energized once the ign. is switched off, but I'll check and see if the TCCS manuals specify a specific time and let you know...

Normal operation should open the ISCV all the way every time the ign. is switched off, not close it.

Is this a swap that your working on or and OEM car?
If a swap, are you sure that no ECU wiring was redone to where the S1, S2, S3, and S4 didn't by chance get reversed

 

[cjsupra90]

Ok, M-Rel should stay on for 3 seconds after IGSW signal to the ECU is lost.

So being that your not even getting a full second out of yours, I'd suspect a faulty ECU.

 

[cuh8er]

OK thanks cjsupra90.
Is the 3 second delay the same every time? ie, if I turn the ignition on and off, a few times, will it stay on for 4 seconds every time?

I have identified a wiring problem where the EFI relay was fed with ignition power instead of a constant 12V supply. When I turned the ignition off, the feed to the EFI relay would drop off, meaning it soulded like it was switching off prematurely, when it infact was losing all power.

I have now rewired it thinking that this has to fix it, but it's pretty much the same. Ignition key off, EFI relay (and power to ISCV) goes off too a moment later. Worth noting is I haven't actually tried to start the car as it's too noisy at this hour without an exhaust. Hence my initial question at the beginning of this post.

ANY help is appreciated as i'm pulling my hair out here....

Cheers

 

[cjsupra90]

Yes, it will stay alive for that for the delay period. Every time the IGSW is on then switched off, the internal timer circuit takes over to delay the shut down of certian circuits...

Are you sure you have the M-Rel wire going to one side of the relay coil and the other side of the relay coil going to ground?

The M-Rel signal is a +12V output from the ECU to drive the EFI relay. When the IGSW recieves voltage, the M-Rel supplys voltage out drive the relay coil... It M-Rel gets its voltage for the BATT signal. Which brings me to another question.

The BATT wire is going to constant power and not switched power on your setup correct?

The BATT normally comes from the EFI fuse and is hot all the time unless the fuse is pulled or the battery is disconected. If you BATT signal is dropping when you turn the Key off, then the M-Rel has no choice but to shut everthing down being that its supplied from the BATT.

 

[cuh8er]

Cheers for the help CJ, to answer your early question, yes this is a swap, but the ECU-engine wiring was untouched, as per factory.

I have double checked the wiring and i'm sure it's right.

After work I put everything back together and fired the engine. The engine now idles VERY low and runs on when I turn it off, which it didn't do before. HOWEVER, the EFI relay stays on for 3 seconds after I switch the engine off. I get the delay only after the engine has been running.

I now know the TPS is right and i'm pretty sure the ISCV is ok, but still a crap idle. Just because the ISCV opens and closes freely, is there a chance it's still stuffed? If the engine idles low for long enough, it bursts upto 1500-2000 rpm all of a sudden, but then drops away to nearly stalling again.

What could cause it to run on now....?

 

[cjsupra90]

What all items are you feeding power to from the EFI Relay???

Where is your injectors and ignition power suppy coming from???

Sounds like you have injector power and ignition power coming from the EFI relay and it shouldn't it normally comes from the ignition switch or you could wire in a relay... If you are infact running the injector power and ignition power from the EFI relay, then that explains the run on that you getting now...

 

[cuh8er]

More ISCV questions (sorry) **NOW GENERAL IDLE ISSUES**

Ok small update.
Fixed run on problem. As CJSUPRA90 said, the ignition and injectors were frd from the MREL.

I still however have a dog of an idle problem.
Starts fine first time, but immediately falls into a very low idle. after it goes too low, it seems like it's trying to correct itself because it spins up suddenly to 1500 odd rpm.
I have tried 3 different ISCV's with no change.
I have also changed the 'temp sender' right under the drivers side ignition coil. Still the same.

Occasionally after playing with the ISCV it'll idle awesome, but not for more than about 2 mins.

Not sure if it's related, but there is no exhaust on it, and it smells like it's running uber rich.

Belled the ISCV out and there is 0.5ohms resistance back to the ECU.

Anyone with info, even if it's basic stuff, i'm getting desperate now.

Thanks

 

[cjsupra90]

cuh8er, The sensor that you changed out is the cold start time switch. This will have no effect on idle as it is only possible active during cranking and even then only is the coolent is under a certian temp while cranking. As soon as you let get of the key, it looses voltage supply as it recieves its voltage suppry from the STA leed.

You what to try changing or atleast checking the regular coolent temp sensor that is for the ECU. It is the two wire one that is on the far right side (left if your look at the front of the motor) of the front water bridge. That is the one that supply the ecu with coolent temp info.

 

[cuh8er]

Cheers.
I have changed the coolant temp sensor now with a new one from Toyota.
Old one was reading 1700ish ohms and the new one measured 1400ish ohms.

Fitted everything to the engine again and it's the same.

Injectors have been cleaned with new o-rings and i'm sure there is no air leaks anywhere.

A few other possibilities.

Would dirty fuel be a possible issue when idling? I cleaned the tank out (as this vehicle was originally a diesel) but maybe not well enough? It purrs when you rev it, only at idle does it struggle.

I have a Bosch 044 feeding the engine, is there a chance i've damaged the fuel pressure regs/pulse dampners?

Ever feel like it's just getting too hard....? Well i'm just about there now....

Thanks again.

 

[cjsupra90]

I dont see it being a fuel supply issue cause that would tend to get worse as you try to rev it and your saying that its runs great when you rev it.

Are you 100% positive without a doubt sure that you have the TPS set correctly???

 

[cjsupra90]

You did set it with taking the TB off and using a feeler gauge to make sure that there was and was not continuity between IDL and E2 with the correct feeler gauge inplace right?

 

[cuh8er]

Set the TB by removing it and turning the TPS till it was open circuit between IDL and E2. Didn't use feeler gauges as 1. I don't have any and 2. the Toyota tamper proof paint was still intact.

I am going to head out now to try it again though, just to be sure....

Thanks mate.

 

[cjsupra90]

Have you tried pulling codes to see if any are showing up?

 

[cuh8er]

OK.
Threw the following codes.
14
24
41

I am searching at the moment to try to find out what they mean. Engine is from UZZ31 soarer.

 

[cuh8er]

Ok, according to this page
http://www.lextreme.com/Lex DxCode.pdf

Code 14 means IGNITION No1
Code 24 means INTAKE AIR TEMP SENSOR
Code 41 means THROTTLE POSITION SENSOR.

No idea what 14 means. I'm assuming the igniters are wired correctly as it runs with a bit of revs under it's belt.

I was under the impression the air temp sensor was part of the AFM? There is 2 wires (white-black and white-red) running up past the AFM, maybe i'm missing a temp sensor....?

The way I set the TPS is as follows. 1. Loosen the screws and wind the TPS all the way counter clockwise. 2. With the throttle closed I slowly wound the TPS clockwise until I lost resistance between IDL and E2. Incidently, with the TPS unplugged, the car starts the same, and then returns to a crappy idle. Haven't been able to check it with feeler gauges though.

I have tried 'resetting' the ECU by powering down for 5 minutes, but the codes remain.

 

[cjsupra90]

The code 14 is the the first one you need to be paying attention to here...

Code 14 = No IGF1 detected in 8 consecutive ignition events.
When this happens, the ECU cuts fuel.

The first thing I would try is flip-floping the left and right coil and see if the 14 changes to a 15 if it does then the one coil is the problem sorce.

If the code change doesn't happen, then try the same thing with the two ignitor plugs and see if the code changes then. Like before if it does, then you've got a problem with the ignitor. If it doesn't then its probably a problem in the wiring...

What doesn't make sense with that though is that when you rev it that the problem seems to go aways... That makes me think that its a problem in the #1 coil and when higher inductance loads are needed, it states to fire correctly..
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For the 24, yes that is the IAT (Intake air temp sensor) and it is part of the AFM. The code is there if there is an OPEN or SHORTED circuit... The ECU defaults to a fail safe fixed value to represent 20*C (68*F)

This wouldn't be causing your idle problem so I wouldn't worry about it too much for right now.
______________________________________________________________________________________

The 41 is for the TPS and its usually there if an open or shorted circuit in VTA signal is present.....
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First and formost, you really want to get rid of that code 14 as it is a good possibility of where your idle problem is coming from. After that, worry about the the 41 then and lastly the 24......

The way that you are setting the TPS is kinda wrong cause you do want continuity between IDL and E2 while the throttle is closed and from what you said, your setting it to where there is no continuity. When you set it, with a .40mm feeler gauge between the throttle stop screw and lever, you want continuitu and with a .65mm feeler inserted, you do not want continuity so the change over for continuity to no continuity should accure some where between .40mm and .65mm

The last thing to check also is that the E1 terminal at the ECU has good continuity with Ground... I dont really think that this is an issue though cause your not getting a Code 22. If the was a problem with the sensor ground circuit, you would get a 22, 24, and 41 which you are getting the 24 and 41, but you didn't say that you were getting a 22....

 

[cuh8er]

Ok code 14.
I swapped igniter plugs with no joy.
I ran a dedicated earth from the battery to my earth point up behind the ECU and have now swapped the coils. When I was swapping the coils I noticed this device had been broken and stuffed up behind the coil. No idea what it is, possible issue?

About to try firing it up again after the coil swap now. They have to be bolted in to work properly right? I can't just let them sit there....

Cheers

 

[cuh8er]

Ok, after some googling, the above part is a condenser for the radio, so that's not an issue.
I swapped the coils, ran a dedicated earth to the battery, reset the ECU (again) and the problem remains.
HOWEVER, the ECU isn't throwing any codes anymore. The CEL flashes rapidly, one flash ever half second or so.

Still idles like a dog though :34:

Maybe time to look at the TPS....?