Discussion
last night I was coming home and the idle speed was fine when I started up.
drove about 5 miles, then realised the car was 'pushing on' a bit. I dipped the clutch and the idle was at around 1700rpm.
it stayed at 1700rpm for ages. once clear of houses, I gave it a good blip (up to about 5500rpm) and that cleared it - idle returned to normal.
Something stuck in linkage? I WD40'd the cable not that long ago and it it clean but well greased.
Idle control valve thing?
throttle body? I think this is less likely seeing that the problem cleared and if it was the body it'd still be happening.
any thoughts?
drove about 5 miles, then realised the car was 'pushing on' a bit. I dipped the clutch and the idle was at around 1700rpm.
it stayed at 1700rpm for ages. once clear of houses, I gave it a good blip (up to about 5500rpm) and that cleared it - idle returned to normal.
Something stuck in linkage? I WD40'd the cable not that long ago and it it clean but well greased.
Idle control valve thing?
throttle body? I think this is less likely seeing that the problem cleared and if it was the body it'd still be happening.
any thoughts?
I'd have said that it would PROBABLY be the throttle body.... it's only happened once so far but if it continues then it could eventually turn out to be this.... pulling the intake gibbins off to have a look at it certainly can't hurt... check for signs of wear and fouling, and at least you can then rule that out..... could be the idle control valve though...
Could be the start of the throttle body going although when mine it strted sticking around 2.5k - 3k rather than that low so unless they are all different i'd thought it would be something else.
One way to tell, does it do it while driving and not using the clutch, as i would brake in mine and it would accelerate back up to 3k, which in traffic scared the hell out of me first time round! lol
One way to tell, does it do it while driving and not using the clutch, as i would brake in mine and it would accelerate back up to 3k, which in traffic scared the hell out of me first time round! lol
Replacement throttle bodies are around £140 (get the Sport 160 version - no point in anything else), but prices vary, so shop around.
Fitting is a ten minute job; maybe 20 minutes if you are the sort of person who needs to read the instructions before changing a light bulb.
edited to add: ...except be a bit careful not to drop the bottom screws, else they end up rattling round on the undertray somewhere (undertray off or 10 minutes fishing around with a magnetic pickup!).
>> Edited by Mutant Rat on Friday 8th July 10:32
Fitting is a ten minute job; maybe 20 minutes if you are the sort of person who needs to read the instructions before changing a light bulb.
edited to add: ...except be a bit careful not to drop the bottom screws, else they end up rattling round on the undertray somewhere (undertray off or 10 minutes fishing around with a magnetic pickup!).
>> Edited by Mutant Rat on Friday 8th July 10:32
Mutant Rat said:
Replacement throttle bodies are around £140 (get the Sport 160 version - no point in anything else), but prices vary, so shop around.
Fitting is a ten minute job; maybe 20 minutes if you are the sort of person who needs to read the instructions before changing a light bulb.
so 15 mins then!!
Yep sounds like sticky throttle. The 160 one is from the Rover MGTF I think, and is a trohpy throttle-body not a Sport 160 one.
If you've only got a 48mm one then you can always replace with an ally version. IIRC the 52mm one won't change anything for the better unless you're car's modded anyway. Don't forget to reset the ECU after you've done it.
If you've only got a 48mm one then you can always replace with an ally version. IIRC the 52mm one won't change anything for the better unless you're car's modded anyway. Don't forget to reset the ECU after you've done it.
I stand corrected...throttle body from the MGF Trophy, not the Elise Sport 160. If you are ordering from the Eliseparts website, they refer to it as the 'Sport 160', though, and other places just call them 'big' or 'alloy' throttle bodies.
I don't think they make a massive amount of difference to the power output, anyway, so the critical thing is to make sure you get an all alloy one instead of the satndard plastic-bodied jobby which has a well known tendency to stick.
And don't pay that much for one!
You can buy a second hand ally 48mm one for about 20 quid on eBay.
HTH
Dan
Jude Performance Services Ltd
www.judeperformance.co.uk
You can buy a second hand ally 48mm one for about 20 quid on eBay.
HTH
Dan
Jude Performance Services Ltd
www.judeperformance.co.uk
djroadboy said:
And don't pay that much for one!
You can buy a second hand ally 48mm one for about 20 quid on eBay.
HTH
Dan
Jude Performance Services Ltd
www.judeperformance.co.uk
cool. dan, do you think it will be the body or just something in the linkage? It's the fact that it cleared as soon as I blipped the throttle which is making me think it's not the body. It's fine so far today.
I had similar problems but it was the IACV. It's worth taking it off and giving it a clean first (carb cleaner or similar). Ignition on/off will function it. Do you also have a slightly dodgy/fluctuating idle?
On light throttle openings the IACV will normally open to smooth overrun etc. but when mine was sticking the vacuum drawn in the plenum would pull the throttle butterfly against its seat and stick it slightly open - enough for 4K rpm under no load.
On light throttle openings the IACV will normally open to smooth overrun etc. but when mine was sticking the vacuum drawn in the plenum would pull the throttle butterfly against its seat and stick it slightly open - enough for 4K rpm under no load.
alicrozier said:
I had similar problems but it was the IACV. It's worth taking it off and giving it a clean first (carb cleaner or similar). Ignition on/off will function it. Do you also have a slightly dodgy/fluctuating idle?
On light throttle openings the IACV will normally open to smooth overrun etc. but when mine was sticking the vacuum drawn in the plenum would pull the throttle butterfly against its seat and stick it slightly open - enough for 4K rpm under no load.
Hi Ali, I did reset the IACV when I put on my K&N noisemaker a couple of months ago. The idle is generally steady, at most it fluctuates a few rpm but not a great deal.
The throttle hasn't stuck the whole weekend so maybe it was just a one-off? If you're at Alford (I'll marshal/commentate) could you maybe have a wee look at it?
tuscan_thunder said:
I had similar problems but it was the IACV. It's worth taking it off and giving it a clean first (carb cleaner or similar). Ignition on/off will function it. Do you also have a slightly dodgy/fluctuating idle?
On light throttle openings the IACV will normally open to smooth overrun etc. but when mine was sticking the vacuum drawn in the plenum would pull the throttle butterfly against its seat and stick it slightly open - enough for 4K rpm under no load.
Hi Ali, I did reset the IACV when I put on my K&N noisemaker a couple of months ago. The idle is generally steady, at most it fluctuates a few rpm but not a great deal.
The throttle hasn't stuck the whole weekend so maybe it was just a one-off? If you're at Alford (I'll marshal/commentate) could you maybe have a wee look at it?
I'll be there and happy to have a look.
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