Cold start idle

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Bram
480 Newbie
Posts: 11
Joined: Sun Mar 22, 2020 4:58 pm

Re: Cold start idle

Post by Bram » Mon Mar 23, 2020 2:11 pm

jamescarruthers wrote:
Mon Mar 23, 2020 1:30 pm
Cool, if your IAC valve seems to work id look at the little switches on the throttle valve next. I am not so familiar with the 2.0 set up but on the 1.7 there is only switch which basically tells the ECU to tell the IAC to control idle when the throttle body is closed. ‎

Put your ear to the throttle body where the switch is. Do you hear a mechanical little click when you pull on the throttle cable? It should click almost as soon as you pull the cable. And click again when the throttle is closed on its stops. 
Do you mean the throttle valve switch? Not sure where it's located on my engine but it shouldn't be far from the throttle valve :P
But I couldn't hear anything unfortunatly. I don't know how loud this click is but I listetend really good...

Bram

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jamescarruthers
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Re: Cold start idle

Post by jamescarruthers » Mon Mar 23, 2020 2:39 pm

You should be at to hear it I think. You can certainly hear the 1.7 one and the Green Book has a picture with the work "click" coming from it like a BatMan comic. 

Maybe David could see on his disc copy of these books how to set it up on the 2.0 for you?

Basically it should be easily adjustable. First adjust the throttle cable so you don't have much slack in it. Then loosen the bolts that hold the switch pack and see if you can adjust it so that it clicks again the moment throttle cable tension is applied. . 

If you can't adjust it‎ to click then I'd suggest that is likely to be your fault. With the switch broken or out of adjustment the car has no way of knowing that you'd like it to idle! This is probably also why it won't start without you helping us out by opening the throttle a little to get it started. 

You should never need to give any 480 any throttle to start it, hot or cold. 

Hopefully you are nearly there. I haven't checked but it is very likely that this switch is shared with Renault cars of the time and you can hopefully get a TPS (throttle position sensor) from somewhere French like Mister Auto. Pretty sure these bits aren't in the unobtainium bracket. ‎
1987 Volvo 480 ES, 507274, 217 - Red (Ness)
2001 Volvo C70 2.4T convertible (Olivolvo)
2008 Mini Cooper convertible (Mau)

Previous 480's:
J123 CFU -- ES
J449 MNL -- ES auto
D864 CPV -- ES
L691 JFC -- Turbo
F70 MNR -- ES
H858 FGV -- Turbo auto
E981 KHM -- ES (509849)

dcwalker
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Location: York

Re: Cold start idle

Post by dcwalker » Mon Mar 23, 2020 2:47 pm

Bram wrote:
Mon Mar 23, 2020 12:50 pm
Hi all,

I just did some checks with the IAC. Your ex-Bosch guy is correct about the little self test. The unit opens en closes when the ignition is switched to position 2.
I forgot to test what the valve does when you start the car... I disconnected the 2 hoses and then tried to start the car. The engine went full on, but thats no more than logical because it gets maximum air. At least now I know the ar is able to start correctly. And with a little certainty that the IAC is the troublemaker.

Currently I am cleaning the IAC with brake cleaner because it is quite dirty. The garage placed this one about 1000 km ago and I am not sure if they cleaned the IAC before installing it. After all it is a second hand.
But why does it get so dirty as it sucks only clean air?

Later today I will check what the IAC does when I only connect the electricity

Oh yeah, I measure 0,01 Ohm resistance on the terminals of the IAC
And it springs back to the rest position when I, manually, fully close the opening

Kind regards

bram
I'll pop outside and check in a moment, but off the top of my head the resistance across a properly functioning ICV should be 8 ohms...

Where are you Bram? I have some spare ICVs and can send you one to try if that would help.

David
Current: 1994 480 GT, 1995 480 Celebration 467/480 (plus 2004 C70 Collection)
Previous: Celebration 346 (sold to Alan480), Celebration 269 (scrapped abandoned project), Celebration 73, 1992 ES, 1988 ES - and numerous other non-480 Volvos!

dcwalker
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Location: York

Re: Cold start idle

Post by dcwalker » Mon Mar 23, 2020 3:22 pm

I will check the discs re TPS a bit later - need to be on my old desktop for that!

Have checked both Haynes and a working ICV (on the GT) and the resistance is 8 ohms. If you only have 0.01 that might be an answer?

David
Current: 1994 480 GT, 1995 480 Celebration 467/480 (plus 2004 C70 Collection)
Previous: Celebration 346 (sold to Alan480), Celebration 269 (scrapped abandoned project), Celebration 73, 1992 ES, 1988 ES - and numerous other non-480 Volvos!

Bram
480 Newbie
Posts: 11
Joined: Sun Mar 22, 2020 4:58 pm

Re: Cold start idle

Post by Bram » Mon Mar 23, 2020 3:31 pm

I will have a closer look at the throttle vale unit, see if I can manage to make things work. But the thing i am looking for is the throttle position sensor?
I feel as if were getting really close now to finding the problem!

@DCWalker I live in the Netherlands. It is probably easier for me to just look around here for a ICV?

Bram

Bram
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Posts: 11
Joined: Sun Mar 22, 2020 4:58 pm

Re: Cold start idle

Post by Bram » Mon Mar 23, 2020 8:51 pm

Okay, I noticed that I have made a mistake van measuring the resistance of the ICV. Thought it was 0,01 Ohm but it actually is 8 ohms -_-
I had put the multimeter on the wrong scale. The TPS seems to work fine as well. With the throttle closed the outpurt is 0.56V whereas with the throttle fully open this is 4.48V

Maybe the ECU is bad? Or a bad connection between the TPS and the ECU?

Bram

dcwalker
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Joined: Sun Sep 16, 2012 12:30 pm
Location: York

Re: Cold start idle

Post by dcwalker » Tue Mar 24, 2020 8:58 am

Bram wrote:
Mon Mar 23, 2020 3:31 pm

@DCWalker I live in the Netherlands. It is probably easier for me to just look around here for a ICV?

Bram
:lol: I had a funny feeling you were going to say that!

Yes, looking for parts a bit closer to home first would be sensible! However, you latest post suggest that your ICV is working fine. 8 ohms is correct. All I can suggest now about the ICV is try to ensure it is really clean.

Sounds as if the TPS is working ok as well, although I'd need to check those figures. Will try to get a chance to look at the technical info today, promise.

As you say it might be the ECU or wiring. Otherwise have you checked that everything is air-tight? If it settles down as it warms up a slight gap in any of the vacuum pipework might be sealing on expansion somewhere, hence giving you a problem when it's cold. Also, is the actual throttle housing itself clean around the butterfly valve? If that's not making the right seal when closed that can confuse things too.

Good luck - keep us posted!

David
Current: 1994 480 GT, 1995 480 Celebration 467/480 (plus 2004 C70 Collection)
Previous: Celebration 346 (sold to Alan480), Celebration 269 (scrapped abandoned project), Celebration 73, 1992 ES, 1988 ES - and numerous other non-480 Volvos!

Bram
480 Newbie
Posts: 11
Joined: Sun Mar 22, 2020 4:58 pm

Re: Cold start idle

Post by Bram » Tue Mar 24, 2020 5:31 pm

Hello,

Yes I am now in contact with someone to suppiy me with some ICVs to test. Hopefully this will help me on
The butterfly valve is clean, I cleaned it when I bought it in the hope that would fix it. But sadly nothing.
Regarding the wiring to tghe ECU how can I best test that. Are the connections on the ECU known to bad? Or is there a better place to start looking?
As far as I can see the vacuum hoses seem fine but it is hard to find a tiny hole

Bram

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