19 replies to this topic

[tony kenobi]

Ok, so here my current situation. Ive an SPI Jap spec but the previous owner did the unthinkable and tampered with the idle screw.

The car has never idled properly since and it wasn't until I bought an ACR4 that I could see the stepper is WAY out...

The range is supposed to be 31-40 steps but mine is around 100!!!

 

I have had the car off the road for 4 months and have checked, double checked and again that Ive no air leaks, vacuum issues etc

 

So today, I started it up and it's still sitting around the 100 mark when I run the ACR.

Other values are....

 

Idle switch- Off

P/n switch- on
Map sensor- 28 to 30
E.c.t- 83
I.a.t- 19
Ambient air temp- 200
Battery volts- 13.9
Throttle pot- 0.36
Lambda sensor- 215 to 800 changing every second

 

I'm using a multi pod (no.30352800) on the ACR4 which gives the option to adjust the stepper BUT...

 

HOW?

 

It gives me the following instructions....

 

"Adjust the stepper motor position by adjusting the throttle stop screw. The value displayed will stop flashing when the stepper is within tolerance 31-40).

 

Once i start to adjust the screw the idle increases or decreases, but the stepper value goes from 100 to 107 and up.

Obviously I want this to go down but if I wind the screw inwards it decreases but the car is on the verge of stalling!

So I'm standing scratching my head without any idea how to adjust this within tolerance!

 

I have PM'd Flyingscott several times in months past regarding this (thanks for your help so far mate) but we haven't had any success.

So I'm asking for any SPI/Stepper wizards to step in and help if possible. I'm in Western Australia so struggling to find an injection mini mind locally.

 

Any help is greatly appreciated, regards, Tony.

[minisilverbullet]

if it were me I think I would be interested to see what the stepper position is with just the ignition on. 

[tony kenobi]

Thanks Minisilverbullet....

 

The position pior to starting is normal. Ive spent the last hour moving the screw slightly and turning the car off and leaving it, then repeat.

It's down to 60 now!!! But I can't get it beyond that.

 

I'll be honest, I'm not sure how it decreased but the ACR is displaying 60 steps at idle.

 

I'm going to keep do the same thing see if I can get it towards that 31-40 bracket.....

[minisilverbullet]

. Ive spent the last hour moving the screw slightly and turning the car off and leaving it, then repeat.

It's down to 60 now!!! But I can't get it beyond that.

 

 

that was young to be my next advice. 

[tony kenobi]

An update....

 

Using the ACR4 plugged in for the last few days, Ive managed to get the stepper adjusted down to 30 steps on idle.

The last motion gap has been set to the middle and the car no longer hunts at idle...

 

BUT

 

It sits at 956-961RPM when warmed up at idle. Ive been told that this should be 850RPM

 

The Map is showing 28-30 so thats all good

Lambda has been replaced and moves up and down no issues

Ive this morning replaced all the front vacuum/breather pipes (made no difference)

 

So is the stepper possibly at fault? (test on ACR passes)

Im at a bit of dead end with this idle and lucky have taken a week off work to fix this before summer in Australia.

 

Has anyone any other ideas? It's been suggested that the PCT sensor might be letting some air in, but while I'd the manifold off all looked good.

TPS is moving smoothly (tested with ACR & multimeter) from 0.38 up to 1.1 at full throttle)

 

Any pointers are much appreciated! Regards, Tony

[FlyingScot]

Nice work Tony. Sounds like more likely an air leak with everything else checking out. What about the fuel evap system hoses and the charcoal canister (if it's fitted) these can also perish or get pin holed or cracked at the charcoal can end (under the wing).

FS

[tony kenobi]

Hey flyingscot, I had the canister off and spent 5 mins looking at it, seemed fine!

I've kept the k&N on and properly sealed the red vacuum nipple from the inlet (a screw and some liquid weld) so that can't be leaking.

I've tightened all the manifold and inlet studs to make sure

It idles exactly on 956-960rpm
In stepper adjust mode on the computer the idle hunts up and down, I'm assuming this is it trying to settle within a range? The idle can drop but shoots up again 25-47steps is what it shows.

I've gotten it to mid thirties, have hose clamps on every hose. Tested the purge by blocking it off with my finger made no difference.

Replaced entire exhaust with mani flow system (was doing that anyway)
New lambda fitted and computer shows it moving no problem.

If it's an air leak it's microscopic as I've spent 2 days going over it.
I tried fitting the old air box but made no difference.
I just need it down an extra 100rpm!!!!
Seriously pulling my hair out

[tony kenobi]

So, question....

Mine is an spi/mpi mix (being a jap spec) it's running a single point injection system but has mpi coil, relays and a strange ECU. It's still got the map inside it though.

Looking around the standard mpi idles at 950rpm. Maybe mine should be also?

to be honest I think I know the answer....I'm just clinging to hope lol

[FlyingScot]

Tony, I think if you have checked everything I would leave it.....

Sounds like she is running perfectly except being a few rpm high, there is a tolerance to the idle speed anyway.
Last thought does it have aircon and is it on? My Japanese SPi bumps up the idle as it detects the load of the air con (or any other load)

FS

[tony kenobi]

It has air con but I never use it (thinking of removing it to be honest)
Only thing on it the radio.
Yeah I think I'm gonna leave it. Good advice.
I've run outta ideas.

[tony kenobi]

I took the mini out for a short blast last night.
I discovered a few oddities...

While the car idles it warms up as normal with the temp gauge just below half. But while driving and at high rpm the gauge moves up just slightly above the black line.
It's never done this before.

I've a new mini spares rad, new thermostat and flushed system. Now I'm wondering if my CTS is faulty?
Anyone seen this before?
The sensor was replaced under 12 months ago so I've never questioned it.

[tmsmini]

Just trying to get my head around testing the temp sensors. I just received a new Intermotor sensor and a new Rover sensor. I would like to test them side by side, but need something more scientific than my finger for heating and maybe a stable voltage source.

 

https://www.youtube....bed/9NSrClF0MNQ

 

Terry

[FlyingScot]

Pan of water with a thermometer and a regulated 5V supply?

FS

[tmsmini]

That is what I need, plus the time. I have an old color process thermometer that should be very accurate. The power supply could be an issue, unless I can use a 12 volt supply with a variable resistor to bring it down.

Terry

[tony kenobi]

What brand are the sensors Minispares sell?
The lambda I got from them was not a Bosch, so I've ordered that from another website.
Think I'll take FlyingScot advice and go back to the original air box with a KN element, see if that helps.