New car - temp worries.

[CubanGav]

Hi folks. Had the new car for a week now and loving it.
I've been searching the forums and google and am looking for a couple of answers. Any help is much appreciated. (I'd have foned Allan but we all know about his accident. If you see this Al - I should be up to see you tomorrow with Cheese.)

Ok: 1: The engine temp fluctuates wildly from 88 to 104 degrees when sitting in traffic. I can hear the fan kicking in but this seems really high. I did read that it’s a pressurised system and it won’t boil before 120. Still - is this normal? No issues when driving.
2: When idling it bounces rhythmically from 800 to 1000 rpm. Again - normal?
3: The rubber seal for the window where it meets the roof on the passenger’s side has came away from the window over about 5 inches. it had been glued back down but has came away. Is there anything special required to stick it back? Is a new seal a better option?
4: Steam coming out the bonnet when it rains. (assuming this is just water hitting a hot radiator though.

Many thanks,

Gav.

[alicrozier]

1 and 4 sound perfectly normal Gav.

2 not so. Maybe a sticky IACV (Idle Air Control Valve), try cleaning it with carb cleaner (quite easy wee job)
http://wiki.seloc.org/a/Idle_Air_Control_Valve

[cla5h]

1. At this time of year when ambient temp is high, that sounds quite normal if sitting in traffic for a while after the car's been driven.
2. I see small fluctuations in mine too. If it gets too rough then it might need looked at (Idle Air Control Valve can sometimes need cleaned out.)
3. If the rubber is OK then just glue it back
4. Correct - rain turning to steam on the hot rad. Perfectly normal.

[r10crw]

With Ali as regards 1,2 and 4. Since its a digital temp gauge you tend to "rely"on it too much. An analogue gauge would hardly move.
No 3. Try and stick it back if you can as official replacment rubber is a fortune. You get alternative types of seals which can do the job and cost pennies if you must replace. If you choose this route someone on here will give you details or I can try find out the book.
Cheers Craig.

[robin]

Rythmic change in idle speed can also be caused by dead or dying lambda sensor.

Temperature should not "fluctuate wildly" but rather in slow/stationary traffic it should increase to 104, then fan cuts in and it reverts to 90-something. Repeat. If average speed gets above about 30mph then it should sit steady-ish at mid-to-high-80s.

Is it S1 or S2?

Cheers,
Robin

[CubanGav]

Robin - 2002 S2

Cheers folks. So 1 and 4 are me being a worry head. Its funny having a car where there are so many little noises and things right in your senses. I like it. I went for a good run after work and the temp stayed within the range. Very different looking at a readout that says 100C rather than a little needle moving up and down which really means nothing.

So the rubber round the window looks in good nick and hopefully I can glue it back down. Seeing as it pissed rain all day I came back to a wee swimming pool, I'm going to see to that first. I am assuming I just need to source a sealant that will bond the rubber to the window surround/plastic stuff. Google is my friend.

As for the idle I think I'll have a go at cleaning the valve. Doesn't look too taxing for a second job. (Lambda sensor however - Yikes) The other thing it does is blips when I'm off the throttle when stopping at a junction. It'll drop to 800ish then blip to 1200 before settling down again to the smaller variations. I'll get it done at the weekend end and scream for help if I get stuck.

[Rich H]

Get it idling and fluctuating then unplug the IACV - does it keep hunting?

[CubanGav]

Hmmm. Dunno. I'll go try. Is it cool just to unplug it when the engine is running?

[Rich H]

dunno but I did

Its just a stepper motor in a fancy case

If you worried then unplug it first and then start it. It'll still run OK but the idle should be stuck high or low, if it's still hunting then your problem is elsewhere.

I'd unplug the lambda next but I don't know what that will do, best ask Robin, but it should fail safe....

[CubanGav]

Ok got it warm and unpluged it. No change. Is it wise pulling the lambda sensor?


Gav.

[robin]

OK, so with the IACV disconnected, the idle is still hunting?

It's worth noting that on the S2 the idle speed is 1,000 RPM when rolling (the ECU sees the wheel speed sensor) and then it drops back to 800/850 (cannot remember which) once the car has been stationary for a few seconds. So you should do your testing stationary and once the idle speed is sorted, check it out on the road again.

The ECU has to control the idle speed by adjusting the IACV and the ignition timing; once warm it probably only uses the ignition timing - hence unplugging the IACV at this point has little impact. At the same time it's trying to keep the emissions under control, hence the impact of a dodgy lambda sensor on idle quality.

If you unplug the lambda sensor it will turn on the MIL but it's otherwise safe. The MIL will go off if you turn off the igniton and reconnect everything - you might need to turn the engine on/off a few times for the ECU to decide that everything is back and working OK and thus turn off the MIL. The ECU will ignore the missing lambda and just run open loop using best guess fuelling - it won't adjust fuelling for emissions any more and so it might stop hunting ...

I would still remove and clean the IACV though as the ECU can cope with wide variations in air flow and so it might be compensating for stuck open IACV with more fuel and less ignition advance (more fuel required to prevent it running lean and producing yucky NOx compounds).

I would also be looking for an air leak into the inlet manifold if none of the above reveals anything.
Cheers,
Robin

[CubanGav]

Ok - got it started with the IACV already out. I heard the wee motor in the valve wind right up/down till it hit full wind and stopped. The hunt went to almost nothing. A very small movement, maybe 50rpm wiggle. I'm gonna clean it when I visit my folks on Saturday.
What it did do when I turned it off, plugged in back in and started it again was stall a couple of times before settling back down. I am assuming this was because the valve was waaaay out of normal when starting again. After a couple of restarts it ran fine.
I'll let you all know what like after I clean it out.

Buenas noches, muchas gracias.

[Rich H]

That sounds about right Easy fix.

[CubanGav]

Fiddley did you say? Not half. Thought I was going to have to learn how to take off the under tray at one point because a bolt made a bid for freedom.

Took it off and gave it a thorough clean. Very sooty and now pristine. Idle is solid as a rock. Happy days.

Thanks again folks. I'd imagine I'll have another question up here shortly.....