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Topic: Idle Problems (Read 2836 times) |
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Fidget
Junior Member
Vox et praeterea nihil
 
Posts: 76
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Idle Problems
« on: Mar 31st, 2007, 4:56pm » |
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I've checked throught he fault finder on the site and still have problems with idle.
My idle speed is fluctuating between 995 and 1012 rpm (and is rough) and the TPS is also flutcuating between 16.9 and 17.3. These are readings with the air con off. If I push the revs to around 2000rpm, then let off the accelerator, the rpm drops tro around 1500rpm for a second then slowly drops back to around 1000 again. Gear change is subsequently 'thumpy'.
If I switch the air con on, the speed drops to near the desired 864 rpm and stays steady when the air con pump kicks in. If I rev up to 2000rpm then release the accelerator, the idle drops swiftly down to the 864rpm again, no problem.
I've replaced the IACV, checked and cleaned MAF and inlet air temp sensor. MAF is reading around 0.56 to 0.6 (with air con off) @ around 0.76v, TPS is reading around 0.85v, IAT sensor is reading 88F at around 2.56v. I've no DTCs. I've cleaned the throttle plates and body to metal with carb cleaner. I've checked for induction leaks and can find none. The car has also recently had a new cat and lambda sensors.
I'm quite puzzled right now and any help is greatly appreciated. I can provide any scan (I have the PWM ISO combo).
thanks in advance.
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Matt.
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Kjetil S
Senior Member
2001 BMW 520iat
Posts: 1419
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Re: Idle Problems
« Reply #1 on: Mar 31st, 2007, 5:04pm » |
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Still sounds a lot like you may have an air leak somewhere. Try checking for hissing sounds from your EGR valve. You might even try disconnecting the vacuum feed to the EGR valve and block off the ends.
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http://uncyclopedia.org/wiki/Norway
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Idle Problems
« Reply #2 on: Mar 31st, 2007, 5:32pm » |
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Thanks for the advice, I've run around all those connections already with a hose in my ear, can't hear a hiss at all, but I will try disconnecting and plugging tomorrow. I might still have some leak detector spray in the shed which I'll look for tomorrow too.
I forgot to mention another problem ...
I get some engine vibration between 15 and 20 mph (1st or 2nd gear) which is not there when the engine is cold. This improved slightly when I replaced the IACV. And the old girl seems a bit flat up to 30mph when it feels like a turbo kicks in.
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Matt.
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Spannerdemon
Guest
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My money is on the TPS. Exactly the symptoms that I had.
Unfortunately replacement is the only option. 
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TRACEYS_LIMO
Full Member
I'm a YaBB newbie
Posts: 377
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Re: Idle Problems
« Reply #4 on: Mar 31st, 2007, 7:39pm » |
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I have found cleaning maf doesnt always work thumpy gears are a bit of a give away, hope this helps  david
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Idle Problems
« Reply #5 on: Mar 31st, 2007, 8:04pm » |
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hi there
don't like the MAF figure, a bit high. if you send me the scan (the 3 files), i'll have a look at it for you.
hth
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Idle Problems
« Reply #6 on: Mar 31st, 2007, 8:14pm » |
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on Mar 31st, 2007, 8:04pm, scorpio_man wrote:hi there
don't like the MAF figure, a bit high. if you send me the scan (the 3 files), i'll have a look at it for you.
hth |
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Thanks!
*edit - silly me, forgot each scanlog file produces 3 files, sorry. email in the pipe sir!
Many thanks.
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Matt.
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Idle Problems
« Reply #7 on: Mar 31st, 2007, 8:25pm » |
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hi there
if you go into car code folder from my computer, then into samples. you'll then see your scan saved as 3 files. put them into a zip file and send it to me.
i need the 3 same named files or it won't work. see http://www.fordscorpio.co.uk/obdfaq.htm
hth
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Idle Problems
« Reply #8 on: Mar 31st, 2007, 8:30pm » |
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on Mar 31st, 2007, 8:25pm, scorpio_man wrote:hi there
if you go into car code folder from my computer, then into samples. you'll then see your scan saved as 3 files. put them into a zip file and send it to me.
i need the 3 same named files or it won't work. see http://www.fordscorpio.co.uk/obdfaq.htm
hth |
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Yes, sorry. I ahve sent the three files but I didn't zip them up (I hope that's not going to cause you any trouble  they should only be about 97kb all together).
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Matt.
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Idle Problems
« Reply #9 on: Mar 31st, 2007, 8:43pm » |
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hi there
i'd give the MAF another clean as it's a bit high. also check the wiring to the TP as it moves around a bit.
when you've done this, do the following scans.....
RPM
MAF
LTFT
BOTH LAMBDA SENSORS (if there's two pre cat)
run these for 5 mins at idle (a/c OFF). every minute, blip the throttle to 2k rpm. end this scan.
then do another scan, switching on and off various temp sensors. also check the tps with the engine off (ignition on). should be from 16% to 92% ish.
try not to drive it on the scan.
hth
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Idle Problems
« Reply #10 on: Mar 31st, 2007, 8:51pm » |
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on Mar 31st, 2007, 8:43pm, scorpio_man wrote:hi there
i'd give the MAF another clean as it's a bit high. also check the wiring to the TP as it moves around a bit.
when you've done this, do the following scans.....
RPM
MAF
LTFT
BOTH LAMBDA SENSORS (if there's two pre cat)
run these for 5 mins at idle (a/c OFF). every minute, blip the throttle to 2k rpm. end this scan.
then do another scan, switching on and off various temp sensors. also check the tps with the engine off (ignition on). should be from 16% to 92% ish.
try not to drive it on the scan.
hth
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Thanks Squire, I will do that tomorrow so as not to annoy the neighbours tonight. Its a 2.0 16V so only one precat Lamda.
" ... switching on and off various temp sensors ... " - I'm not quite sure what you mean by that
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Matt.
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Idle Problems
« Reply #11 on: Mar 31st, 2007, 8:56pm » |
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hi there
engine coolant temp and air intake temp. do this on the engine off scan with the TP, after the 5 min run. it's just to make sure they're working correctly.
cheers
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Idle Problems
« Reply #12 on: Apr 1st, 2007, 2:32pm » |
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Just completed the scans and sent them off.
I did notice that the TPS is still fluctuating with the engine off (16.9 to 17.3%) which kind of suggests that the wiring or sensor has a problem. Looking at the wiring, its the one sensor that I have not replaced the wiring to as yet - it is still flexible and I can't see any cracks, but the wires are bound together for some of its length. I'll get to replacing that wiring later or tomorrow I think.
Thanks again for your help Andrew.
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Matt.
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Idle Problems
« Reply #13 on: Apr 1st, 2007, 6:41pm » |
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hi there
email sent back.
cheers
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Idle Problems
« Reply #14 on: Apr 10th, 2007, 10:41am » |
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update:
Andrew, the scan was better for the IAC when running it from cold to warm (no driving).
I replaced all the cracked wiring I could find around the TPS, IACV and IAC, so its all good now, but still the problems remain...
The slightly fluctuating value (16.9 to 17.3%) of the TPS is still present, but giving it some thought (before I go shelling out on a new one) I wonder why it is that the values (Idle Speed) drop to correct values when the Air Con Compressor kicks in. I am guessing at the moment that there may be some sort of another electrical problem, but I have not yet pinpointed what other components are involved in maintaining idle speed.
The other thing I am concerned about is, whilst replacing the wiring it was necessary to remove the air intake hoses, which gave me the chance to take a further look at the throttle plates. I think they may have been disturbed at some point, there's some evidence of that around the screw heads. Then I got to thinking about the positioning of the plates themselves which are not completely closed. Now I could be wrong, but I thought on engines with engine management that the throttle plates are normally fully closed at zero throttle and the idle speed and mixture is controlled by the air bypass valve and timing. In my case there is visibly very slight opening but the screw adjuster for the throttle stop does not appear to have been disturbed. So I have been contemplating taking the stop back a touch until I get a 16% minimum reading for the TPS, but I am not rushing into that without advice first.
The other thing that is still baffling me is the slight vibration between 15 and 20 mph (which improved slightly after replacing the IACV). Switching the Traction Control on or off makes no difference and its only when the engine is warm to hot.
Anyway, being a full time Dad (I hate the expression - House Husband) to three kids I have little time to do things, but I have two days this week that I can press on with things. I think I need to find much more detailed explanations of how the fueling system functions from cold to hot on the site so I'm off to do that search now. Its so unfortunate that there is no official manual for the car, but thank god for this site.
Thanks for your help so far guys 
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Matt.
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Simmo
Administrator
I'm an OAP !
Posts: 5508
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Re: Idle Problems
« Reply #15 on: Apr 10th, 2007, 10:57am » |
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Does THIS page help a harassed father!? 
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Now I'm an OAP
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Spannerdemon
Guest
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There IS a manual for the car Fidget. Plenty of people sell it on Ebay on a CD, but there is no Haynes or similar.
You should be able to pick one up quite easily.
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Idle Problems
« Reply #17 on: Apr 10th, 2007, 11:24am » |
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hi there
i'm going to have a look at my car tomorrow (wife has it today) to be sure about the butterfly, but i do think it should be fully closed.
have a look at this site, it gives a good write up about cleaning the TB.
not sure about the vibration. strange.  i'll have a think about it.
re the manual. all the most important parts are on the site. plus you get all of us thrown in for free! 
btw, have you tried running with the tp disconneted (carefull of the wiring)? see how that goes.
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Spannerdemon
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Yes, I agree with Scorpio-Man. There is NO substitute for swopping ideas with people (US) who actually own the cars. Manuals are great, but WE are better
I am a huge believer in this Club and its great members.
Good idea to disconnect the wiring from the TPS. This was the giveaway that convinced me that mine was faulty, as with it disconnected, I suddenly had fewer problems. Might not work for everybody...but it sure did for me. They DO just fail and as it was pointed out to me, even though the readings were OK, it HAD gone faulty, and was probably 10 years old.
Since fitting the new TPS the car has been an absolute dream to drive again.
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Tompion
Administrator
1997 2.3 Ultima estate.
Posts: 2918
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Re: Idle Problems
« Reply #19 on: Apr 11th, 2007, 3:41am » |
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on Apr 10th, 2007, 10:41am, Fidget wrote:update:
So I have been contemplating taking the stop back a touch until I get a 16% minimum reading for the TPS, but I am not rushing into that without advice first.
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I would be very cautious about touching the stop screw.
I don’t know for certain but assume that the % value is set by the engine management regardless of the throttle position after a battery disconnect – meaning if you adjusted the screw to 16%, next time you disconnected the battery it would return to say 16.8% (which is what mine reverts to).
By the way I did a diagnostic on mine to check how the IAT reading compared, and it was much the same when up to running temperature, but something I hadn’t realised was that the desired idle speed control (RPMDSD) varies as the engine warms up – just wondered whether it might be worth checking this value when your engine has a high tick-over in case something is telling it to do this as opposed to a sticking throttle or IACV.
With coolant at 56 & IAT at 58 the desired idle speed 1184 RPM
With coolant at 198 & IAT at 92 the desired idle speed 864 RPM
2.3 engine
I also think it sounds like a faulty TPS.
Dave
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ABS multiplug wheel sensor pins MK IV or MK 20
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