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idling and hesitation
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Old 23 Feb 2006, 12:07 PM   #1 (permalink)
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idling and hesitation

hi i've got a idling problem and hesitation which only happens when the car has warmed up, the idling say if i was coming upto a roundabout to stop when i stop the idle moves up n down from say 800 to near enough stall and come back up but its never actually stall. i've check the maf by warming the car up, unplugged it and it stall which would mean it ok right guys? so what could b wrong?
now the hesitation say am on light throttle in 4th at 2600rpm and put the gas down very lightly i get no response the put down a bit more and then it responds but it kicks in rather than smooth, i cleaned out the boost solenoid so i cant think of what else it can be, mods to the car is just a exhaust not sure if its de-cat.

any advice would much be appreciate.
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Old 23 Feb 2006, 05:46 PM   #2 (permalink)
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Sounds like throttle position sensor.. it sits on top of the throttle body, take it out and clean with some brake cleaner, check the wiring.
Might be good to remove the intercooler once removed bendover engine and use a small mirror if you have one to look inside the throttle intake and you should see the butterfly, now get a rag and some cleaner and with one of your hands open the throttle (where the throttle cable connects) and give it a good clean several times inside the housing make sure all dirt comes lose, do it until no more dirt comes off, also clean the TPS

hope this helps
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Old 23 Feb 2006, 06:00 PM   #3 (permalink)
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hi mate, my be a long shot , but i had a similar promb which stockcar sorted over the phone(top man), maybe look at my thread (idle probs).This was the last post.
hope you get it sorted.
Alyn,Thanks for the advice today from our phone coversation,i did what you said & removed the BOV blanked all the holes and took it for a spin every thing seems fine, so fitted a forge bov i had kept after fitting the hks one,took it back out gave it a good hard run and as yet there seems to be no sign of the car wanting to stall when i pull up to junctions etc. gonna monitor it for a couple of days. But i think you were correct in saying the hks bov was at fault.
Thanks for the sound advice, much appreciated.

Mark.
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Old 23 Feb 2006, 06:00 PM   #4 (permalink)
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not sure if you have a after market bov ?
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Old 23 Feb 2006, 07:04 PM   #5 (permalink)
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i only have the standard re-circ on there, gonna do what bob said and hope it helps. the thing is it doesnt happen at every stop i do, it just comes and goes. any ideas on the hesitation?
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Old 24 Feb 2006, 12:13 AM   #6 (permalink)
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Uneven tickover is 9/10 the MAF. But as you also have problems with throttle responce the TPS is worth a go...
The Lambda is also another as you have exhaust mods was wondering if the Lambda was removed and replaced this sometimes messes up the Lambda sensor. I just unplug mine and run it for a day or two to see if things get better. If they do then new Lambda is require, if not then its not the Lambda...
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Old 24 Feb 2006, 05:56 PM   #7 (permalink)
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just cleaned out the sensor, and butterfly. idling seems better but now it goes to 1100 and down to 800 and back up to 1100, the hesitation seems to have got but just have to drive for awhile and see, u think i should change my maf regardless? and how bout the o2 sensor. i havent had any cel light come on.
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Old 24 Feb 2006, 06:04 PM   #8 (permalink)
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I WOULD HANG FIRE , SEE IF YOUR PROB HAS GONE .before you spend any ...........
mark
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Old 24 Feb 2006, 09:31 PM   #9 (permalink)
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Quote:
Originally Posted by lly1982
just cleaned out the sensor, and butterfly. idling seems better but now it goes to 1100 and down to 800 and back up to 1100, the hesitation seems to have got but just have to drive for awhile and see, u think i should change my maf regardless? and how bout the o2 sensor. i havent had any cel light come on.
The Maf on your car 98? is an expencive item comes as a whole unit. I would try to get someone with same year car to exchange for an hour to test out.
The 02/Lambda sensor can effect tickover as it richens or weakens the mixture. As I said I usually just unplug it for the day to see if tickover improves. I have run the car with no o2/Lambda for weeks and still never had CEL light come in..
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Old 26 Feb 2006, 10:21 AM   #10 (permalink)
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hi, been driving it about and the hesitation and uneven idle is still there, gonna unplug the o2 and see how it goes, if i get cel should i plug it back in? yep my car is on a 98plate late version 4.
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Old 26 Feb 2006, 10:38 AM   #11 (permalink)
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also should i clean the maf with some brake cleaner/ carb cleaner?
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Old 26 Feb 2006, 01:57 PM   #12 (permalink)
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Quote:
Originally Posted by lly1982
hi, been driving it about and the hesitation and uneven idle is still there, gonna unplug the o2 and see how it goes, if i get cel should i plug it back in? yep my car is on a 98plate late version 4.

When I had my mapping done the 02/Lamdba was removed for a o2/lambda used by the mapper. When removing my Lambda the thread was crossed and US. Another Lambda was fitted which had no wiring (just to fill hole). The mapper then told me. Its ok to run your car with no Lambda pluged in and it may take days for the CEL light to come in. The ECU will switch to MAP and run on that. It is a good test to see if Lambda is working ok.

I would not go racing without any sensor working ok. but as a quick test I find this method to be very good.
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Old 26 Feb 2006, 02:00 PM   #13 (permalink)
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Quote:
Originally Posted by lly1982
also should i clean the maf with some brake cleaner/ carb cleaner?
The MAF wire is clean and shiny. But the wire runs hot any oil or muck that hits the wire will bake on. turning the MAF wire a dull brownish colour. Cleaning does not usually remove this, but it won't hurt to try..
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Old 27 Feb 2006, 12:43 PM   #14 (permalink)
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hi you know the o2 thats just behind the turbo right? also was thinking about the idling, when i took it apart and cleaned it, the revs were still dropping but at a slightly different rev range could it be i might have a air leak somewhere? can i use some gasket sealer on the gaskets?
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Old 27 Feb 2006, 06:47 PM   #15 (permalink)
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o2 sensor in downpipe just after turbo... Sealer is not really required with todays gaskets. We did have a scoob with fluctuating tickover and poor BHP on the RR at Powerstation. I swapped MAF's with my car but still had the same problem. Then found a small air leak in the TPS we used a bit of sealer for temp repair and all was fine.

Try this area for leaks, this is where I found the last one.

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