Hi,

I have posted this before: At very low rev and engine tends to shut down (e.g. when parking) I sometimes hear a sound like pinging (detonation). In that case the engine is shocking. The dealer couldn't find anything.

At all driving speeds and loads in all gears there is not a sound of detonation (like it should be).

What could be the origin of this detonation sound (< 800 rev) under load and shocking engine?? Could it be the motor management software?

Who has an idea?

Greetings,

Dutchman

Also for your info:

Bulletins for 2001 Volvo S60 2.4 L5-2435cc 2.4L DOHC VIN 61 B5244S

General Recalls

TSB Number Issue Date TSB Title 89103 MAY 01 Campaign - Lug Wrench Revised

Service Bulletins

3370014 OCT 01 Headlight Bulb - Replacement
00202 JUL 01 Policy - Service Upgrade Campaigns
2250023 JUL 01 Electronic Throttle Module - Uneven Idle
8850018 MAR 01 Whiplash Protection System (WHIPS) - New Test Method
4430017 FEB 01 A/T - Diagnosis & Check List
8512 JAN 01 Interior Door Panel - Repair Kit
0097 JAN 01 Lemon Laws - Repeat Repair Procedures
2230052 NOV 00 Fuel System - Quick Release Connector

Rene
S60 2.4M

Hey Dutchman,

I don't think rpm's are supposed to go under 800. On mine idle is 850 and it never goes under that.

Does it make sense?

Rene
2001 S60 2.4M

Hello Rene,

It indeed is idling very nicely at exactly 850 rpm. The sound occurs when, for some kind of reason, you shift down too late to first gear at vey low speeds (<10 km/u or so) or during a parking manoevre. Remember I have a MT.

All the new Volvo models have indeed anti-knock sensors. But, could some error in the motor management cause detonation at such low speeds??? (it really sounds like that, and not like the exaust is hitting something).

Anyway, next monday the car is at the dealership. But if anybody has an idea, that would be helpfull!

Thanks,

Dutchman

Dutch, is the motor rocking at all when it is doing that? 10 kph is about 6 mph right? (close enough). It's hard for me to say because I own a turbo automatic car, so the torque converter is putting less load on the motor. Think it is possible it's transmission noise? Does it only do it in first gear, or every gear under load?
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2001 S60 2.4t~82 242 Turbo 5spd~87 244 (nothing special)

Hi EgS60R,

Thanks for your concerning questions.

Today I was at the dealership and I was convinced that there is nothing wrong: When the engine is at too low rev the flywheels (and/or other parts) may produce the metal sound, as was explained to me. However, for the behaviour at low revs there was an official report (although I don't think that is the origin). Thus I received an updated software. Actually my 2001 S60 now received 4(!) software updates.

Greetings,

Dutchman

Thats true. Did you mean 1800 rpm? Cause, your idle shouldn't be dropping under 800 rpm for any reason. If it is, then you really do have a problem.

LOL, bunch of help that was.
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2001 S60 2.4t~82 242 Turbo 5spd~87 244 (nothing special)

Man, dutchman you have just the WORST luck w/ cars dont you?

Well, are you running premium fuel? If you are then I would say a problem w/ the engine management. If the timing on the fuel injecting is off a bit I suppose it could be causing that problem. Try a throttle control module, not sure if they use one but I've had other cars do similar problems to that.

Good luck,

Doug
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2001 S60 2.4t~82 242 Turbo 5spd~87 244 (nothing special)

Hi EgS60racer,

I use the adviced octane rate. The sound is only there at very low rev, also sometimes when accelerating from second gear when you should have shifted down to first gear (alsmost zero speed). At all other speeds there is no sound at all and it drives fantastic!

Can detonation be heard at such low revs as < 800 rpm???

Hi,

It may not me engine knock. The engine could be hitting something due to close tolerances. Or the exhaust pipe could be hitting the body. Check the top engine mount for cracks.

Good Luck,

Steven---

I don't think so. Is it a low fq type thing, cause mine makes a sound at the same rpm that I always assumed was a turbo thing. Yours is NA though right? Happens when you get back in the throttle at low speeds (ie 10-15) mph?

Hmm, sounds interesting but I've never attributed my sound to detonation. I've heard that before (on my old 'bird) and I would say that all new cars have knock sensors. Not sure on Volvo's but I HIGHLY doubt they dont.

Good luck,

Doug
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2001 S60 2.4t~82 242 Turbo 5spd~87 244 (nothing special)