Constant Idle Speed System

lookforjoe

lookforjoe

True Classic
Started installing the Volvo CIS system today.

system overview

CISw-iring.jpg


Has provision for AC step up, which is a compelling reason for me - as it stands, the stock AC stepper makes no difference - with AC, the idle drops to the point where it barely charges, and eng temp increases....


ECU (VO 1317499 Bosch 0 280 220 005) & harness routed through firewall through stock ECU harness port

IMG_8874.jpg


braised a 12x1.5 bung onto the water housing

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Volvo/Bosch 026 sensor

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I'm gonna put the OEM T/stat back in - the stant one I installed made no difference, and I like the brass better

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Tomorrow I should be able to wire the sensor, TPS, coil feed, etc & get the t/stat housing on.

EDIT: have to confirm pin 3 on TPS grounds above idle.
 
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Long day at work - didn't have the energy to drain the coolant & deal with the housing, so I worked on the wiring. The stock TPS only has idle & full load contacts, so I had to add another switch that will ground the CIS off idle.

X19CIS0007.jpg


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Next I will get the housing done, and then figure out the best way to mount the CIS motor.
 
Your grounding switch, isn't that normally a WOT switch on a VW or Volvo with Motronic?
 
kmead said:
Your grounding switch, isn't that normally a WOT switch on a VW or Volvo with Motronic?
Click to expand...

No, it's from a '85 240T, K-jetronic. All the Volvo LH variants use a TPS just like the X1/9 - idle & WOT signal - Motronic uses the variable resistance TPS pictured in the MegaSquirt thread.
 
ECU

Hi Joe,
Is this system a replacement + improvement for the std ECU ir an addition to it?
Excuse my ignorance...

Enjoy -
 
htfx19 said:
Hi Joe,
Is this system a replacement + improvement for the std ECU ir an addition to it?
Excuse my ignorance...

Enjoy -
Click to expand...


This is to eliminate the stock Aux Air Slide, and provide better/more stable idle speed control. It is separate from the std ECU used for fuel management.

It also eliminates the AC idle step valve, which does a very poor job

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Also removes the need for this idle adjuster

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which I don't have, since I bored out my throttle body & used a Volvo butterfly of larger diameter when I did head/cam work last summer

X19225Throttle0003.jpg
 
Installed the housing & the sensor, IAC valve & hoses today. Short IAC hose is from a '92 960, long IAC hose is from a 200/700 B230F. Powered the system off the pnk/black wire that feeds the dual relay.

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Why another switch?

lookforjoe said:
Long day at work - didn't have the energy to drain the coolant & deal with the housing, so I worked on the wiring. The stock TPS only has idle & full load contacts, so I had to add another switch that will ground the CIS off idle.
Click to expand...

Was just interested why you need another switch? As you point out, the existing TPS has switches for idle and full throttle. Pin 10 from the ECU provides power, so you will get a voltage on pin 2 at idle. You can use this to power a transistor that in turn powers a relay to ground your CIS.

The advantage of this approach would simply be fewer mechanical components, but I suppose that now that you have your switch in place it isn't really worth the extra work.

Cheers,
Dom.
 
dcioccarelli said:
Was just interested why you need another switch? As you point out, the existing TPS has switches for idle and full throttle. Pin 10 from the ECU provides power, so you will get a voltage on pin 2 at idle. You can use this to power a transistor that in turn powers a relay to ground your CIS.

The advantage of this approach would simply be fewer mechanical components, but I suppose that now that you have your switch in place it isn't really worth the extra work.

Cheers,
Dom.
Click to expand...

Hi Dom

I had thought about using a relay w/diode to reverse the ground - I need the ground off idle - but the manual doesn't explain how the (Fiat) L-Jet uses the signal - if it grounds, it does so internally. The CIS uses a 'hard' ground, not a floating ground within the ECU

Picture2.png


So, as I understand it, I would need to power a normally-closed relay from another part of the system, then use the ground of pin 2 * the TPS to keep the CIS ground circuit open, allowing the CIS ECU to ground off idle when the contact in the TPS opens. It was simpler to just add the second TPS :)
 
!

This is a fascinating project. The stock idle control is a crude and silly thing. I just removed the whole mess.

I hope it works!
 
eflexter said:
This is a fascinating project. The stock idle control is a crude and silly thing. I just removed the whole mess.

I hope it works!
Click to expand...

It's working very well. No more idle issues with lights or AC engaged. Stable idle, no stumble/drop when decelerating & coming to a stop after highway driving. No more extended high idle when cold, and so far, better cold starting (that could also be 'cos the ambient temp is now over 70ºF)
 
lookforjoe said:
Hi Dom
So, as I understand it, I would need to power a normally-closed relay from another part of the system, then use the ground of pin 2 * the TPS to keep the CIS ground circuit open, allowing the CIS ECU to ground off idle when the contact in the TPS opens. It was simpler to just add the second TPS :)
Click to expand...

Actually, you would probably need to control the relay from a transistor, to be on the safe side. I'm not sure that the sense voltage that the ECU feeds to the switch on pin 10 would have enough current to drive a relay directly.

The relay contacts would then be used to ground the CIS. Have a look at the instructions here.

I'd agree that it is potentially more work than to add another TPS as you have done, but I'm always happy to swap mechanical complexity for electrical complexity...

Anyway, good to see that you have it working!

Cheers,
Dom.
 
looking for the CIS ecu

wow this wold work on my carb'ed project, I just can't seem to find a part number for the ecu or any other refference to it for sale...


Please help!!

Jeff
 
Volvo Service Manual CIS

Jeff,
There is the Volvo CIS service manual.
That a good reference document if you want to implement CIS.
 
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