High Running Idle - Page 2

loki_the_glt · Feb 3rd, 2021, 08:41

If you're stuck I can supply a Code Reader.

https://www.volvoforums.org.uk/showt...+reader&page=9

Contact details (email) and price are in the thread. Delivery would be a day or two after payment, dependent on my shift pattern and whether or not I've actually got one sitting around

There's a separate link to the codes and meanings elsewhere on the forum.

Rversteeg · Feb 3rd, 2021, 09:29

Just thinking out loud, couldn't it be the temperature sensor? If the ECU thinks the engine is cold, it will inject quite a lot of extra fuel on startup, which would flood the engine on hot start. Cold start will of course be no problem. Once running, the ECU will have the engine run at high idle to compensate for additional friction of a cold engine. A hot engine will be harder to start and run on high idle after that.
Do you smell petrol on a hot start?
Rob

Laird Scooby · Feb 3rd, 2021, 11:02

Quote:

Originally Posted by Rversteeg

Just thinking out loud, couldn't it be the temperature sensor? If the ECU thinks the engine is cold, it will inject quite a lot of extra fuel on startup, which would flood the engine on hot start. Cold start will of course be no problem. Once running, the ECU will have the engine run at high idle to compensate for additional friction of a cold engine. A hot engine will be harder to start and run on high idle after that.
Do you smell petrol on a hot start?
Rob

The other thing along similar lines is that when cold, the ignition advances more because of a high resistance from the CTS so you could be on to something there.

PurpleTurbo · Feb 3rd, 2021, 15:41

Just checked today I use 95 octane fuel, its the highest octane fuel around me so I always try to stick to that.

Laird Scooby · Feb 3rd, 2021, 15:46

Quote:

Originally Posted by PurpleTurbo

Just checked today I use 95 octane fuel, its the highest octane fuel around me so I always try to stick to that.

What is the brand? Also what other brands do you have nearby?

PurpleTurbo · Feb 3rd, 2021, 20:27

Quote:

Originally Posted by Laird Scooby

What is the brand? Also what other brands do you have nearby?

Gulf, only other near me is tesco and they dont have their premium brand

Laird Scooby · Feb 3rd, 2021, 20:47

Gulf is better than Tesco at least, shame you don't have a BP nearby. That said, i'm guessing the being 95 octane, it will also be E10 fuel?

PurpleTurbo · Feb 5th, 2021, 11:45

Quote:

Originally Posted by Laird Scooby

Gulf is better than Tesco at least, shame you don't have a BP nearby. That said, i'm guessing the being 95 octane, it will also be E10 fuel?

E10 is right yeah

TonyS9 · Feb 5th, 2021, 12:03

Still its not going to cause high running idle at 1500 or 1800rpm, is it?

AFAIK it caused by deliberate intervention with the IACV by the ECU because of inputs which it doesn't think are correct (eg high air flow with no vehicle speed reading), or by increased amounts of air leaking in.

There might be other error conditions that respond in this way and this is why you need a code reader.

2 more issues I have seen is adjustment of the throttle body, especially if its been off for cleaning, there is enough play in the bolts for it to go back on in the wrong place, and (possibly) false triggering of auto drive select or AC on (in a manual these signals should be grounded to avoid false triggering).

Turning off and on again should reset any false reading.

PurpleTurbo · Feb 6th, 2021, 21:51

Quote:

Originally Posted by TonyS9

Still its not going to cause high running idle at 1500 or 1800rpm, is it?

AFAIK it caused by deliberate intervention with the IACV by the ECU because of inputs which it doesn't think are correct (eg high air flow with no vehicle speed reading), or by increased amounts of air leaking in.

There might be other error conditions that respond in this way and this is why you need a code reader.

2 more issues I have seen is adjustment of the throttle body, especially if its been off for cleaning, there is enough play in the bolts for it to go back on in the wrong place, and (possibly) false triggering of auto drive select or AC on (in a manual these signals should be grounded to avoid false triggering).

Turning off and on again should reset any false reading.

I have a couple broken broken clips on the airbox, this would cause excess air leaking in i guess.

Feb 3rd, 2021, 08:41	#11
loki_the_glt Torquemeister Last Online: Apr 17th, 2024 16:24 Join Date: Dec 2004 Location: Asgard, Cheshire	If you're stuck I can supply a Code Reader. https://www.volvoforums.org.uk/showt...+reader&page=9 Contact details (email) and price are in the thread. Delivery would be a day or two after payment, dependent on my shift pattern and whether or not I've actually got one sitting around There's a separate link to the codes and meanings elsewhere on the forum. __________________ loki_the_glt - Skipper of the Exxon Valdez, driver of Sweden's finest sporting saloon - and pining for another Slant-4.

Feb 3rd, 2021, 09:29	#12
Rversteeg Master Member Last Online: Yesterday 14:06 Join Date: Feb 2006 Location: Amersfoort (NL)	Temperature sensor Just thinking out loud, couldn't it be the temperature sensor? If the ECU thinks the engine is cold, it will inject quite a lot of extra fuel on startup, which would flood the engine on hot start. Cold start will of course be no problem. Once running, the ECU will have the engine run at high idle to compensate for additional friction of a cold engine. A hot engine will be harder to start and run on high idle after that. Do you smell petrol on a hot start? Rob

Feb 3rd, 2021, 20:47	#17
Laird Scooby Premier Member Last Online: Today 07:47 Join Date: May 2012 Location: Lakenheath	Gulf is better than Tesco at least, shame you don't have a BP nearby. That said, i'm guessing the being 95 octane, it will also be E10 fuel? __________________ Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........

Feb 3rd, 2021, 15:41	#14
PurpleTurbo New Member Last Online: Nov 29th, 2023 16:33 Join Date: Jan 2021 Location: Caithness	Just checked today I use 95 octane fuel, its the highest octane fuel around me so I always try to stick to that.

Feb 5th, 2021, 12:03	#19
TonyS9 Premier Member Last Online: Apr 9th, 2024 21:44 Join Date: Jul 2009 Location: Holywood	Still its not going to cause high running idle at 1500 or 1800rpm, is it? AFAIK it caused by deliberate intervention with the IACV by the ECU because of inputs which it doesn't think are correct (eg high air flow with no vehicle speed reading), or by increased amounts of air leaking in. There might be other error conditions that respond in this way and this is why you need a code reader. 2 more issues I have seen is adjustment of the throttle body, especially if its been off for cleaning, there is enough play in the bolts for it to go back on in the wrong place, and (possibly) false triggering of auto drive select or AC on (in a manual these signals should be grounded to avoid false triggering). Turning off and on again should reset any false reading.

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