Idle Control Valve S4 - Page 2 - Alfa Romeo Bulletin Board & Forums
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post #16 of 40 (permalink) Old 11-08-2018, 09:18 AM
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all the AFM numbers above look good to me!

by the by, has your car ever idled and ran well?

I was wondering if some PO was messing with the 2 wire Bosch plug to the ICV, maybe replacing a broken plug and mixed up the wires? I realise you cannot put it on upside down, but you could put the wrong wires into the plug.
Now I do not know what effect that would have (would it work opposite/backwards?)

on mine, if you peel back the ICV rubber boot the pin with the orange wire is on the left (faces back of car)
I know it should be numbered 1 & 2, but I didn't find any numbers on mine, unless they are underneath, and I didn't want to remove the whole thing.

just a wild shot.

don't forget (also) the code 1222 - "Output stage of ECU for Idle Speed actuator" - could also be a dodgy ECU.....

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.

Last edited by spiderserie4; 11-08-2018 at 09:21 AM.
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post #17 of 40 (permalink) Old 11-08-2018, 10:21 AM Thread Starter
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by the by, has your car ever idled and ran well?
Hell naw!

Bought it in summer - maybe temps matter.

Part of the deal was changing the engine mounts (ie. remove lots of things on the intake side) and clutch. The shop that did the work was sloppy, if not incompetent. They left the Oil Vapor Sep. hose disconnected, shift lever was uncentered, inner boots torn, and overall the car felt worse than when I agreed to buy it.

It was idling, although it was hunting a bit and there was some stutter when the fans came on - that was my first post regarding this. From what I understand the ICV is supposed to compensate for the load placed on the system.

I did find multiple stored 1222's so I'm guessing it happened before I bought it also.

The stalling issue started after I cleaned the Oil Sep, ICV, throttle body, VVT, changed the plugs.
It was kind of intermittent. As it got colder it went from intermittent to constant.
Would that point to a leak? Bad electronic part?

On another car I had an issue with a TPS that was acting up in colder weather.

Honestly, the car feels pretty good otherwise, much better than when I got it.
There are a couple of other issues but they're unrelated.


Quote:
on mine, if you peel back the ICV rubber boot the pin with the orange wire is on the left (faces back of car)
I know it should be numbered 1 & 2, but I didn't find any numbers on mine, unless they are underneath, and I didn't want to remove the whole thing.
Alright, I'll check this.


Quote:
don't forget (also) the code 1222 - "Output stage of ECU for Idle Speed actuator" - could also be a dodgy ECU.....
Yep. I'm gonna order some replacement relays for the ones behind the parcel shelf.

And I guess I'll check for leaks with the air compressor method mentioned on the BB.
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post #18 of 40 (permalink) Old 11-08-2018, 10:35 AM
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Voltage also? I thought it was just for resistance.
With a high-impedance DVM the risk is low, BUT it's best not to tempt fate. I mean, if you slip and touch the probes together you've just shorted the ECU, and that's not good.

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1963 Giulia Spider (1750 engine)
1974 GTV
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post #19 of 40 (permalink) Old 11-08-2018, 10:51 AM Thread Starter
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on mine, if you peel back the ICV rubber boot the pin with the orange wire is on the left
No luck there. Connector looks like it hasn't been touched.
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post #20 of 40 (permalink) Old 11-08-2018, 11:22 AM
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From what I understand the ICV is supposed to compensate for the load placed on the system.
correct.

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It was kind of intermittent. As it got colder it went from intermittent to constant.
Would that point to a leak? Bad electronic part?
a leak not really, you'd feel that whether hot or cold...
BUT, as you are saying it is sort of temperature related, now I am suspecting the Motronic temperature sensor, the CTS (the blue sensor near the injector).......this one sensor is the most important on the whole system.
Either check it out,check the plug pins are good, or replace it....the ohms tests are not 100% proof it is good, as the probe can get crudded up and under operating conditions sending false info to the ECU.

Motronic CTS (Coolant Temperature sensor): Bosch 0 280 130 026
Ohms test:
@ –10C the resistance should be 8.3 to 10.5 K.ohm
@ +20C should be 2.2 to 2.7 K.ohm
@ +80C should be 0.28 to 0.36 K.ohm

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #21 of 40 (permalink) Old 11-08-2018, 12:09 PM Thread Starter
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Can you bench test the ICV with a 12v battery and test wires? This may help to settle if you have one, or two good-bad ICVs.
Just checked and they're both moving with a 9v.


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With a high-impedance DVM the risk is low, BUT it's best not to tempt fate. I mean, if you slip and touch the probes together you've just shorted the ECU, and that's not good.
Good point. I had a cloth between the paper clips back-probing the MAF connector today.


This idle issue is mentioned quite a few times on the BB, but generally there's no follow up.

https://www.alfabb.com/bb/forums/164...ty-signal.html
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post #22 of 40 (permalink) Old 11-08-2018, 01:10 PM Thread Starter
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Originally Posted by spiderserie4 View Post
Motronic CTS (Coolant Temperature sensor): Bosch 0 280 130 026
Ohms test:
@ –10C the resistance should be 8.3 to 10.5 K.ohm
@ +20C should be 2.2 to 2.7 K.ohm
@ +80C should be 0.28 to 0.36 K.ohm

2.5k at 15c



This is the thread where it ended up being the fuel regulator.

https://www.alfabb.com/bb/forums/spi...circuit-3.html
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post #23 of 40 (permalink) Old 11-09-2018, 12:02 AM
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This is the thread where it ended up being the fuel regulator.
easy enough to check....pull off vacuum hose from plenum and suck through it, if you can suck through it (or there is petrol in the hose) the diaphragm is split...make sure though, the hose itself is not split.

you could also clamp off the fuel return hose from bottom of FPR, see if your idle improves

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #24 of 40 (permalink) Old 11-09-2018, 07:28 AM Thread Starter
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Originally Posted by spiderserie4 View Post
easy enough to check....pull off vacuum hose from plenum and suck through it, if you can suck through it (or there is petrol in the hose) the diaphragm is split...make sure though, the hose itself is not split.

you could also clamp off the fuel return hose from bottom of FPR, see if your idle improves
Looks like the FPR is fine. I had already changed the small hoses.
Clamping the bottom hose - no change.

Guess I'll check for leaks again - although I already sprayed all over.
If it was a leak big enough to stall the car wouldn't it also be noticeable when the ICV was disconnected?
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post #25 of 40 (permalink) Old 11-09-2018, 08:48 AM Thread Starter
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Is the O2 sensor involved with the idle when the car is cold? For example 1st start of the day.
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post #26 of 40 (permalink) Old 11-09-2018, 09:56 AM
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Before it started doing this, there was some hunting at idle, and some stumbling at idle when the fan kicked in, heater was on.

At that point I cleaned the ICV, throttle body, Oil Separator, VVT, and changed the plugs from Golden Lodge to NGK BP7's. The car felt much more responsive etc, but it started dying at idle.
Thanks
when you cleaned the throttle body, did you notice if the butterfly was closed?....my photo shows a throttle body off the car and you only see the tiny gap because I shone a flashlight behind for the photo.
I can imagine if the butterfly is not almost closed it would cause all sorts of idling problems.

The throttle stop is factory set and capped off, but some PO mess with them when there is a problem elsewhere, like a bad ICV or bad TPS etc.

check the throttle stop is just in contact with the throttle mechanism and not so far screwed in it is keeping the butterfly open.
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Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #27 of 40 (permalink) Old 11-09-2018, 01:08 PM Thread Starter
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when you cleaned the throttle body, did you notice if the butterfly was closed?....my photo shows a throttle body off the car and you only see the tiny gap because I shone a flashlight behind for the photo.
I can imagine if the butterfly is not almost closed it would cause all sorts of idling problems.

The throttle stop is factory set and capped off, but some PO mess with them when there is a problem elsewhere, like a bad ICV or bad TPS etc.

check the throttle stop is just in contact with the throttle mechanism and not so far screwed in it is keeping the butterfly open.

As I recall the butterfly looked 'closed'.
This was messed with, however, I doubt that's the issue because I backed it off completely
and there's no change. I set it to touch + a tiny bit.

Plus, if I keep it running for a few minutes until it warms up,
it will idle with the ICV connected. It hunts a bit, but it won't stall.

It only stalls with the ICV connected when it's cold.
If that was the problem it would persist when it was warm, no?



To back up to the beginning:

When I first got it in summer, when the ambient temp was high, it idled with the ICV connected.
It was oscillating between about 900-1000, but it didn't stall.

It started stalling as it got cooler outside.

If I warm it first, either by keeping up the RPM's or disconnecting the ICV, it idles like before - some hunting but it doesn't stall.


When I first start it, it smells rich. About the time it warms up a bit and stops smelling, it will idle with the ICV connected.

So what controls the idle if the ICV is disconnected? With the ICV disconnected the idle won't drop below 1k even with the throttle stop backed up all the way.
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post #28 of 40 (permalink) Old 11-09-2018, 01:19 PM
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So what controls the idle if the ICV is disconnected? With the ICV disconnected the idle won't drop below 1k even with the throttle stop backed up all the way.
There's a rotating vane valve in the ICV. When the ICV is unpowered, it rotates to a fixed opening point. So it still flows air, it just doesn't control the flow. When you power it up it actually rotates to close that baseline opening and opens a gap on the other side of the valve.

I'm probably not explaining it well, but if you look at an unpowered ICV you'll see the opening where the air flows. The rotation of the valve is in the direction of making that opening smaller, not larger.

The throttle plate isn't supposed to be completely closed. There's a calibration to set the correct air flow at idle, but it requires Alfa flow tools that you don't have. Since it's been messed with anyway, maybe try *opening* it a bit more using the adjustment screw? It sounds like you're not getting enough air at idle, and if the throttle plate is too closed that might be part of the problem.

I would try progressively opening the throttle adjustment until it'll idle cold with the ICV connected, see if that makes a difference. Note that you'll likely need to adjust the TPS in parallel so that the idle switch is still closed at idle.

Tom

1963 Giulia Spider (1750 engine)
1974 GTV
1991 Spider
Former: 1987 Milano Gold
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post #29 of 40 (permalink) Old 11-09-2018, 01:43 PM Thread Starter
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There's a rotating vane valve in the ICV. When the ICV is unpowered, it rotates to a fixed opening point. So it still flows air, it just doesn't control the flow. When you power it up it actually rotates to close that baseline opening and opens a gap on the other side of the valve.
Alright.


Quote:
The throttle plate isn't supposed to be completely closed. There's a calibration to set the correct air flow at idle, but it requires Alfa flow tools that you don't have. Since it's been messed with anyway, maybe try *opening* it a bit more using the adjustment screw? It sounds like you're not getting enough air at idle, and if the throttle plate is too closed that might be part of the problem.

I tried this before but I didn't change the TPS because the idle was quite high so I thought it's pointless.

However, it sounds like the ICV might actually be less open when connected than when disconnected - that's what I didn't account for.

I'll try increasing it by about 100-200 RPM and then adjusting the TPS so it knows it's at idle,
and if the ICV is less open that might actually drop the high idle.

But what I don't understand is - why is it Ok with the current settings when warm and not ok when cold.

Is the O2 sensor active immediately or only after it warms up?
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post #30 of 40 (permalink) Old 11-09-2018, 01:52 PM
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But what I don't understand is - why is it Ok with the current settings when warm and not ok when cold.
When the engine is cold you need a more open throttle to maintain the same idle RPM. The L-Jetronic manages this through the AAV, that lets in more air when cold and closes when the engine heats up. The Motronic does the same thing through the IAV.

In both cases, though, the throttle plate (and idle air bypass in the case of L-jet) need to be set right or there still won't be enough air to cold idle.

Tom

1963 Giulia Spider (1750 engine)
1974 GTV
1991 Spider
Former: 1987 Milano Gold
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