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Power steering and AC idle up

Rob

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Mar 1, 2010
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Today I was sitting in traffic in my LC with the air con on and I thought to myself, 500 rpm is a bit low for idle :? So I turned the AC off and it went back up to the usual 600rpm so this means that the idle up function does not work any more...

I checked the idle up actuator and it is moving but not far enough. There is plenty of suction in the vacuum line so no problems there. One thing that concerns me is that it used to work fine and the actuator is solid. I have the double actuator with power steering idle up which does not work, and if I push the actuator piston further the engine reaches what sounds like the correct rpm. Seeing as the power steering idle up does not work (I think its wired up correctly) and now the AC idle up could it be the actuator or does it just need adjusting? Is it possible that the throttle linkage is not in the same place as it used to be ie the joints are wearing?

Really confused by this one as I cant see why I would need to adjust it if the actuator and bracket have clearly not moved :?

Also does anyone have PS idle up that actually works? Would be useful to have a full vacuum pipe diagram, the best one I can find is on ToyoDIY and its not clear where the top pipe on the power steering idle up side of the actuator goes...
 
it's probably due to wear/slop in the linkages. Had to adjust mine a while back as the AC idle up was barely noticable and then PS idle up had no affect. On closer inspection both actuators were working so just needed adjusting to take up the 'slack'.
 
There must be an alarming amount of slack in the linkage system for the idle up actuator not to have an effect... looks like a job for the weekend. Any ideas where I can find a good vacuum pipe diagram?
 
my PS idle up works, have to watch it when using low box to crawl along at idle in a queue of traffic and I turn the steering wheel, suddenly starts going faster!

EDIT: Doesn't RM437E have anything useful in it?
 
Jon, no that is the first place I checked. This is the best I have found:
diag_Av6VX0.png


Only issues is its not clear where the upper pipe on the actuator goes after the filter :? Will use it to see if all my piping is in the right place over the weekend.
 
possibly RM523E which is the later supplement to RM437E would cover it but I don't have that any more but I'll mention it in case your search skills are better than mine :)
 
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PS idle up? I don't think I've got one. How do I check; in neutral and work the steering?

Isn't the AC idle up a waste of time? Idon't think the engine is likely to stall? And if it were correctly set up the revs should stay the same, just compensating for the extra drag.

I might be glad when my AC idle dies. My wife jumps out of her skin every time it kicks in. She thinks the engine has gone out of control.

Surely linkage wear would be gradual, not overnight?

Frank
 
If you have PS idle up then you will have a couple of vacuum lines going to on of the banjo fittings on top of the PS pump. I assume the idle up function is operated by hydraulic pressure which would be very handy for me as I have a hydraulic winch that works of the PS pump. I think this may be a feature on the manual 1HD-FT 80s only.

AC idle up is not useless as if it's not working the engine runs very rough at 500rpm when the magnetic clutch is engaged.

They may have worn gradually, I only use the AC when its too hot inside so it was a while since I last used the AC.
 
frank rabbets said:
PS idle up? I don't think I've got one. How do I check; in neutral and work the steering?
I just went out and tried mine parked on the drive and it didn't idle up when I turned the wheel so not sure what the criteria are for it working but I'll try it some more next time I'm out and about.
 
Silly question Rob - did you not have a PS problem at Lincomb - and is this perhaps not all related? Something come adrift while field repairs were being made that's not apparent under 'normal' circumstances? If not, what else has changed recently to induce a 'sudden' fault?

Cheers
 
Jon are you sure it was not your aircon idle up that shot you down the road. Mine does that in traffic queues when idling along in 1st gear then you have to dip the clutch to avoid sctratching the front bumper.

Rob, fair point but when I start the engine when cold and then turn the aircon on it does not increase the RPM even though the magnetic clutch engages and the aircon is cold. The idle is still very smooth. Maybe it is due to the auto advance on the injection pump when it is cold. It's hot now so I'll look at RPM etc tomorrow when it's cold again.

Incidently I took it for 140 mile run today as we are off for 2500 miles in France and it has not done a long run for 12 months. I had worried that the aircon was not working fully but this was because it was cold dry weather . In todays' heat it was fine and cooled the interior well. Also a nice big puddle under the drain pipe proving that I just did not just imagine it was cold.

She returned 29 mpg after brimming at the same pump and has not used any oil or water so is fine for a long journeY

Frank
 
frank rabbets said:
Jon are you sure it was not your aircon idle up that shot you down the road. Mine does that in traffic queues when idling along in 1st gear then you have to dip the clutch to avoid sctratching the front bumper.
I will check next time I get chance, certainly doesn't do it on the drive.
 
Gary Stockton said:
Silly question Rob - did you not have a PS problem at Lincomb - and is this perhaps not all related? Something come adrift while field repairs were being made that's not apparent under 'normal' circumstances? If not, what else has changed recently to induce a 'sudden' fault?

Cheers
Not a silly question at all Gary, this is the first thing that crossed my mind. I did have a power steering hose failure (winch feed) and I had to bypass the winch and put it back to stock which meant moving around the PS idle up valve on the power steering high pressure banjo connector. This has 2 vacuum pipes attached to it so I wanted to check it against a vacuum pipe diagram to see if its all connect properly.

frank rabbets said:
Rob, fair point but when I start the engine when cold and then turn the aircon on it does not increase the RPM even though the magnetic clutch engages and the aircon is cold. The idle is still very smooth. Maybe it is due to the auto advance on the injection pump when it is cold. It's hot now so I'll look at RPM etc tomorrow when it's cold again.
When cold the engine will be running at higher rpm so the AC idle up actuator will have no effect.
 
I am trying to work out why my ac has packed up, no its not low on pressure before you ask, been regassed!

Compressor wont 'kick in' & I wondered if it is the idle up valve that is faulty, where is this valve located on a 12v 1994 80 series?

The air con gets cold if I put 12volts straight to the compressor, but the engine doesn't idle up at any time.

Any thoughts???
Andy
 
Could it be the pressure sensor that's packed in? When the aircon is turned on and the pressure sensor sees enough gas (pressure) the compressor should kick in. The idle up servo at the IP throttle linkage then opens the throttle slightly. If this doesn't happen the AC should still work. I had a similar problem where the idle wasn't increasing even though the compressor kicked but this turned out to be a split hose to the servo/actuator.
 
Last edited:
Thanks for that, but I have tried bypassing the low pressure switch ( the switch by the passenger side battery).

i guess I was just hoping it might be the idle up servo really. Can't see how that would stop the compressor kicking in.

I'm not to good on the electrical fault finding & will check the obvious first , like dodgy connections behind the dash panel, but when it comes to the tech electrical stuff I am a bit lost, Had enough trouble finding the location of the relays & not found the a/c ecu yet!!!
 
Frank,
I can only find the a/c fuse in the fuse box in the cab by the steering wheel.....that's ok, and when I switch on the a/c button, the button illuminates & blower blows, but the mag clutch on the compressor doesn't get any power, & no idle speed increase.

is there another fuse anywhere??

andy
 
My AC triggers the idle-up (even though the AC isn't working now:icon-evil:) but the PS doesn't seem to make any difference. I need to get someone under the hood while I operate the steering to check for activation.
 
Hello.

To bring this back to life my vacuum pump has good suction, my linkage is nice with no play, the solenoid valve that is used to actuate the diaphragm that then increases rev's is working well as i get the right amount of increase in rev's when the AC is switched on BUT when i turn the steering i get nothing.

I know there must be a switch/sensor that activates the solenoid valve but am not sure where it is or is it the first solenoid valve following the pipework up from the vacuum pump that then activates the next solenoid valve that increases revs.

Hope that makes sense
 
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