 | Home > Td5 > td5 flat spot |
 
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16945   
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Throttle position sensor perhaps, though I'd expect a logged fault.
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20th Sep 2014 1:07pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558 
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possible , will try if the flat spot is in one position of pedal movement , might have bad segment of sensor
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20th Sep 2014 2:41pm |
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| Anderzander Member Since: 08 Feb 2011 Location: Lancashire Posts: 999
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They do have a flat spot ... ?
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20th Sep 2014 3:38pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16945
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When the TPS started to fail on my TD5 Disco it developed a monster flat spot. IIRC, the faults were cleared when the ignition cycled so it took me a while to identify. If I jiggled the accelerator I could generate faults quick enough to cause the MIL to come on and put the car in limp mode. Switching the ignition off and on would clear it (I became quite adept at doing this on the move).
It's a pig to change on the Disco unless you have a three-armed double-jointed mutant infant to help, but easy enough on a Defender. When I had the oil-in-the-harness problem it caused a general random misfire rather than a flat spot. |
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20th Sep 2014 3:47pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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I would go with monster flat spot , I know they a bit flat as standard but its a fault it never had before, ok maybe try a pedal
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20th Sep 2014 3:57pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16945
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The potentiometer on the TPS has three tracks (two on the very early ones) and a comparator on the ECU compares the voltage from all three to ensure an accurate reading. As the tracks wear or get dirty it sometimes happens that at one point an erroneous reading is given by one track. The default action in this case (as a fail-safe failure mode) is to shut the throttle and put the motor to tick-over.
The result is that as you press the pedal the revs increase, then drop to tickover at the faulty instant, then come back when the fault is passed. Just like a massive flat spot. Good luck with it anyway! |
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20th Sep 2014 4:14pm |
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| bob neville Member Since: 30 Apr 2009 Location: Marbella Posts: 3247  
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Sounds a bit like my TD5 last year.
Took a while to find but it was the crank position sensor - it was missing the spacer. Strange thing is I had not noticed the flat spot but as the indie was sorting other problems out it actually got worse. Worth checking. Bob 2015 Jaguar XE240 R Sport - goes like ....... !! 2013 Defender 90 CSW - sold 2009 Defender 110 Double Cab - sold 2001 TD5 90 CSW - offroad project - sold to a forum member 2011 Porsche Boxster - for the sunny days ! |
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20th Sep 2014 6:46pm |
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| muckybeast Member Since: 07 Mar 2014 Location: kildare Posts: 13  
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I had the same problem ,it turned out being the MAF meter
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20th Sep 2014 8:55pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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tried unplugging maf , but didn't make any change to it . but worth another look
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20th Sep 2014 9:08pm |
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| Paddie42 Member Since: 24 Apr 2014 Location: Hamphire Posts: 230 
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Mine had a complete lack of acceleration and then picked up well (if that's what you mean by flat spot). I unplugged the MAF sensor and it was a lot better. My test was the journey home from work which is about 35 miles. Just testing in the car park I couldn't really tell.
Worth a second look and a reasonable test drive. |
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22nd Sep 2014 12:05pm |
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| kevinf Member Since: 12 Apr 2011 Location: sheffield Posts: 55
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sorry to hijack this thread but!
whats this spacer fitted to the crank position sensor, ive read about a few times now on different posts i have a 52 plate td5 that i have had for 8 yrs and have had the c.p.s out a couple of times for various reasons and i dont have a spacer fitted is it something introduced to later models? cheers kevin |
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23rd Sep 2014 12:19pm |
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| mk1collector Member Since: 17 Sep 2009 Location: West Yorkshire Posts: 6769 
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Also does anyone know the oe manufacturer? Some people say intermotor and some say Lucas.
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23rd Sep 2014 12:48pm |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6492 
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Intermotor is an aftermarket supplier, not original.
 1988 90 Td5 NAS soft top
2015 D90 XS SW |
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23rd Sep 2014 12:57pm |
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| bob neville Member Since: 30 Apr 2009 Location: Marbella Posts: 3247
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Kevin
This is the shim - http://www.brit-car.co.uk/product.php/1265...ion_sensor Mine is a 51 plate TD5 and should have been recalled years ago to have the shim fitted as it was missing from new. Needless to say the owner at that time never took the vehicle in ! The symptoms on mine were a massive flat spot at just under 2000 rpm apparently caused by the sensor losing the signal. Above and below that rpm the vehicle was fine. Once the shim was fitted problem solved
Bob 2015 Jaguar XE240 R Sport - goes like ....... !! 2013 Defender 90 CSW - sold 2009 Defender 110 Double Cab - sold 2001 TD5 90 CSW - offroad project - sold to a forum member 2011 Porsche Boxster - for the sunny days ! |
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24th Sep 2014 11:43am |
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