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PostPosted: Tue Apr 09, 2013 8:57 pm 
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Car Model: ST165
OK so having some idle issues which i have had in the past as well..
This happened last year and i swapped out the isc, kicked open the T/B butterfly, adjusted the T/Body idle screw non of which helped out here..In the end it seemed to right itself?
Does the PFC constantly monitor and relearn idle settings?

My car is running a st165 isc through to the Apexi Power FC (Rev3 MR2T) but i have never been able to adjust idle speed through the hand controller, very odd!? maybe there is another wire that i missed off the patch loom?
when making the patch lead up i wired it so the isc1 was connected to RSC and Isc2 was connected to RSO, not a lot of info confirming if this is correct?
From what i have read the isc plays a big part in Decel F/Cut, is this correct?

Going on the Toyota Manual it states that with Ign Sw on there should be 9-14v between isc1 and E1 and the same for isc2 and E1.
im getting 11v at isc2 and only 0.70v at isc1!? These are done in accordance with the manual which states the ecu is to be left connected
Im assuming these terminals are Outputs from the ecu?

possibly a faulty PFC? would make sense why i cant alter idle speeds?

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PostPosted: Wed Apr 10, 2013 2:34 pm 
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The system on 185 & 205 is a dual coil setup, with one coil (RSO) pulling the valve open and the other (RSC) pulling it closed.

The drive voltage to each will depend on the RPM as it's a servo system. If the idle's too high you should see more drive to RSC to try to pull it down, and vice-versa.

I don't see why over-run fuel cut requires the idle valve, just stop driving injectors when the throttle is shut. You may be confusing with the throttle position sensor.

Try measuring voltage at isc 1 & 2 with ECU disconnected. The 12V is fed to the solenoid and the ECU pulls one coil or other down to negative to drive it. It's possible the PFC drives the idle valve differently to the standard ECU, the only way to verify is to check when it's idling and make sure that it the 'open' coil gets more drive when revs are too low and vice versa.

Check the adjustment of the throttle position sensor. I think the PFC uses the switch part of this to detect throttle closed so check the switch is closing reliably when you lift off the throttle. If you have a commander I think you can read both throttle position (analogue %) and the 'throttle closed' switch.

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PostPosted: Wed Apr 10, 2013 8:07 pm 
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Hi Chris, Once again thank you for your input on my electrical woes!

I think your right, i was thinking the isc played a roll in idle during deceleration fuel cut when actually its the TPS that controls that, my bad.
i have checked the tps settings tonight and i think it maybe slightly out, 1.245K Ohms, i haven't actually found the correct st205 TPS settings, which i believe the PFC is looking for, Did i mention im running a st165 TPS due to wiring connector and the st165 T/Body?
If anyone can point me in the right direction for these i would appreciate it, Kris site i believe has them but i found two specs which show different results?
worth noting when in sensor sw check the throttle has to be open to the tune of 1500-2K rpm before the black dot goes out for IDL!?
im 99% sure i have seen this go out soon as the throttle is touched on a st205 running a PFC?
Having set the TPS to around 0.7K Ohms the above still applies with the IDL light.


Im also unsure if the PFC needs to relearn the idle after a power interuption?

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PostPosted: Wed Apr 10, 2013 9:32 pm 
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IDl should indeed switch on once the throttle is closed as it is a switch/contact located in the throttle position sensor. Issues with this will prevent the ISC adjusting position until IDL is on. (based on experience with the PFC)

The PFC does seem to need relearning some setting such as ISC positions for normal, electrical load and AC load after battery disconnection. See the Datalogit manual for learning procedures.

I believe decel fuel cut is also linked to the IDL switch.

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PostPosted: Wed Apr 10, 2013 9:33 pm 
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It will relearn after a complete power interruption I think

Do you have a 205 ecu available that you can try? It doesn't need to run the car but it's the only way to check the disc signals are to factory spec

Also worth checking that the IDL signal from the tips is correct. There's some guidance on setting the tips sensor position in the BGB

At the end of the day if it previously sorted itself out it's probably OK and just needs to relearn


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PostPosted: Wed Apr 10, 2013 9:52 pm 
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Car Model: ST165
I will be trying a st205 ecu tomorrow evening and will take a look at the isc1 (Rsc) and isc2 (RSO) voltages with that plugged in as well, again im not 100% sure if isc1 should be wired to RSC and isc2 to RSO
Idl remains on for longer than it should imo i.e the car is revving and the pfc is still showing its at idl? i might add the car revs fine with no problems...

im looking to fit a st205 TPS and make up a patch lead to fit it to my st165 wiring harness in case this is causing the issues, again i have never been able to adjust idle speed through the PFC..
I haven't found the definative tps settings for the st205 as yet?

Idle speed is spot on when all is well so not sure how its getting the info to idle at the correct speed?
The car is laid up for 6 months of the year, although it is run and moved around fairly often.

The *bleep* idle makes for a very unpleasant and embarrassing drive!
I have also noticed, what more issues!?, that when the car stalls if i go to start it again straight away it's as if the battery is almost flat i.e turns over very slowly, but if the key is kept turned the cranking speeds up and it does start up...maybe nothing to do with any of the above.

modified cars, gotta love em!

Thank you for everyone's input so far

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PostPosted: Wed Apr 10, 2013 10:03 pm 
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1 maybe minor maybe not point is that depending on who mapped it... the map could have been compensated for a out-of-whack TPS and idle switch.

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PostPosted: Wed Apr 10, 2013 11:03 pm 
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It was mapped by Ryan at 2Bartunning some time back now.
I don't think it was that far out of spec?


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PostPosted: Thu Apr 11, 2013 6:29 pm 
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My experience with PFC is very limited - to a day spent trying to sort out the running issues on Phils car (also mapped by ryan) viewtopic.php?f=1&t=5846&hilit=apexi

As far as I'm aware, the throttle switch is used to switch it into overrun / idle control mode. The upshot of this being made too high would be the ECU trying to control revs back to idle (or fuel cutting at higher revs) while you're trying to drive on light throttle - i.e. you would find the car a bit jerky on light throttles.
I suspect throttle position sensor (analogue part) is used for throttle down mixture enrichment purposes and very little else. From memory, there are some other throttle related compensation settings but they haven't been used on any maps I've seen.

Another possibility is if you have RSO & RSC swapped, then it will be closing the throttle to increase revs !!! I wouldn't expect it to idle normally at any time like this, but it is possible it has a 'dead band' where it doesn't apply any correction of RPM is within the range - this could lead to normal idling if you're lucky enough that idle speed is right with no correction.

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PostPosted: Thu Apr 11, 2013 6:33 pm 
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p.s. the slow turn over when warm is quite common on battery relocations or with old batteries / starter motors. Ezzy also did this. I found releasing the starter and then trying again normally cleared it.

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PostPosted: Thu Apr 11, 2013 9:43 pm 
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OK so have had a bit of a result so to speak this evening along with some additional info.

1) I have now checked and adjusted the TPS against the correct st205 settings and now happy, comes off idle quicker within sensor/sw check now, that they are with in spec EXCEPT for one of them..

2)Tested the voltage on a st205 running a PFC on the RSC and RSO pins and get the same results as mine, 12v down RSO only and nothing down RSC, toyota manual is to be ignored for this test when running a PFC!
I may try this test on a st205 ecu if i get a chance.

3)st205 TPS pins VC - E2 should read 2.5 - 5.9K Ohms
st165 TPS pins VC - E2 should read 3.0 - 8.3K Ohms my st165 TPS reads 7.0K Ohms which is fine for the st165 but out of spec for what the PFC is expecting to see?
Maybe not a biggie?

4)I then reset the PFC reloaded the map and went through the Idle learn process and the car behaved as it should do!? only 20 minutes as there is no longer any A/C.
I think maybe the ELS and AC wires are crossed as the engine idles up when you set the A/C rpm limit to say 2krpm and switch the rear screen on but does not idle up if the same is set for idle E/L.. TBC!

5) I noticed with the cabin fan on full, headlights on full beam, hazard lights and radio on the PFC voltage drops to 11Volts! but my standalone volt meter was still showing 13volts? Maybe another by product of the battery in the boot?
with all systems switched off the PFC see's 13volts. additional cable needed from battery to permanent 12v on the ecu?


All in all progress, I'm yet to drive the car again though, that one i will leave until tomorrow evening!

Chris, worth knowing about the slow turn over after it stalls, the starter is relatively new, all be it maybe 10 years old? there is a relay in the system to take some load of the solenoid.
TBH having the battery in the boot is probably the worse mod i have done to the car!

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PostPosted: Thu Apr 11, 2013 11:46 pm 
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3 - The throttle position sensor is acting as a full potential divider rather than a variable resistor, The value of the resistance of the whole track is therefore second order, what matters is the ratio of resistance from wiper to gnd vs wiper to supply. If the 165 is a different resistance potentiomer then the above readings are meaningless. I doubt this would affect idle anyway, only throttle response.

5 - The voltage at the engine bay end is mainly going to be driven by the alternator. At idle with a heavy load, the alternator won't cope so the voltage will drop to what the battery can supply, minus the drop along the cable. At higher RPM, you will probably see over 14 at the ECU. Not ideal to have this much swing as you're relying on the dead time settings for the injectors vs voltage being accurate otherwise fuelling alters - one of the biggest hurdles to smooth / predictable idling. This MAY be your problem.

What size cable are you running from your battery, and how long is it ?
Where is the battery Earth connected, and have you removed paint to ensure a good Earth to the body ?
What have you done about earthing engine to body ? Ideally use the large cable that used to go from engine to battery and link instead to a good earth point on the body.

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PostPosted: Fri Apr 12, 2013 1:41 pm 
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If you have a commander or datalogit you can look at TPS % and make sure it goes 0-100
It's only used for a fuel trim afaik


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PostPosted: Fri Apr 12, 2013 7:29 pm 
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Nibbles wrote:
3 - The throttle position sensor is acting as a full potential divider rather than a variable resistor, The value of the resistance of the whole track is therefore second order, what matters is the ratio of resistance from wiper to gnd vs wiper to supply. If the 165 is a different resistance potentiomer then the above readings are meaningless. I doubt this would affect idle anyway, only throttle response.


So, having driven the car etc this evening i can safely say the car can still be revved to around 2300rpm with the pfc thinking its still on IDL!?
maybe this is down the the st165 TPS? i will try and swap this out still i think..
The car drives fine other than this.

Nibbles wrote:
5 - The voltage at the engine bay end is mainly going to be driven by the alternator. At idle with a heavy load, the alternator won't cope so the voltage will drop to what the battery can supply, minus the drop along the cable. At higher RPM, you will probably see over 14 at the ECU. Not ideal to have this much swing as you're relying on the dead time settings for the injectors vs voltage being accurate otherwise fuelling alters - one of the biggest hurdles to smooth / predictable idling. This MAY be your problem.


Measuring the voltage at the battery with the engine off shows around 11.90-12.10v and again similar figures with all electrical systems on, this is echoed as the same in the PFC 'Batt voltage' monitor.
same can be said for testing voltages at the ecu connectors.
There is a big fuse holder under the bonnet where the original battery cables attach to one side and the other side and runs back to the battery.
I swapped out two relays, Main & EFI relay to ensure these weren't causing any issues, dirty contacts inside (Read clutching at straws here) no difference.

Nibbles wrote:
What size cable are you running from your battery, and how long is it ?
Where is the battery Earth connected, and have you removed paint to ensure a good Earth to the body ?
What have you done about earthing engine to body ? Ideally use the large cable that used to go from engine to battery and link instead to a good earth point on the body.


The cable running from engine bay to the boot is around 5M long and is 20mm2, thick enough?
There is two earth's for the battery both terminated in the boot area, one goes to a rear suspension top mount stud...as i type this i realise that is a terrible earth point as the top mount is mounted in rubber, no paint has been scratched off from the turret area..
The other from memory is using the same earth point as used by the ABS unit just behind the rear seats..
I think this is an area that needs further attention!

Engine earth points.
one from the inlet manifold to bulk head.
one from alternator bracket to suspension front turret, fairly small being held in by a 10mm headed bolt.
There is a couple of others on the N/S of the engine bay but can't remember exactly where? TBC

Again Thank you for your continued input and advice :)

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PostPosted: Fri Apr 12, 2013 7:30 pm 
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two_OH_five wrote:
If you have a commander or datalogit you can look at TPS % and make sure it goes 0-100
It's only used for a fuel trim afaik


I have a commander plugged in but couldn't see anywhere that showed a TPS percentage?

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