 | Home > Puma (Tdci) > over run between gears |
 
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298   
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if only......
mine seems quite the opposite (most of the time) and to be honest makes changing gear very difficult as the revs seem to drop off too much ? ARRRRRGGGGHHHHHHHHHHHHH  |
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3rd Jul 2012 6:49am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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sorry - forgot to mention that I know exactly what you mean however and have heard others mention this so I think all is good for you
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3rd Jul 2012 6:50am |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436  
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Caterham,
check if the clutch cylinder switch is not sticking. (connector on master cylinder next to the brake cylinder under the hood) This switch tells the ecu when the clutch pedal is pressed and then keeps the revs up a bit to make an easy non-cluncky gearchange. It is a NO contact, so closed loop if clutch pedal is pressed, if yours sticks or is bridged the ECU will drop revs instantly. Die-hards, or others with big knee muscles bridge this contact so the revs drop as you describe on yours. If you know how to change gear and are used to it, it works a charm or "as a classic" drivetrain reacts. The accelerator also picks up a bit earlier, reactions are more prompt as the revs do not hang. Landylad, guess that also answers your initial question, yes it is normal Also note that this "system" reduces eventual shocks on the clutch, which can be good. I drove bridged for a couple of weeks and found it "better" for all but heavy city trafic.  Last edited by tatra805 on 3rd Jul 2012 12:58pm. Edited 1 time in total |
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3rd Jul 2012 7:11am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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well
 me 
I wonder if you've hit the nail on the head with this.......I can't wait to check it out. however I'm not sure where to start 
are you suggesting I remove plug / wiring from master cylinder and check for closed circuit on the cylinder / socket - presumably not the otherway round (wiring loom) ? this may be something I need to check regularly as I'm thinking this is intermintent. Also as per Landylad is this something that operates in 4th - 6th or should it be all gears? many thanks. |
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3rd Jul 2012 7:25am |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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Yes, measure the contacts of the switch. maybe a bit of corrosion that needs to be cleaned?
I am always very cautious measuring on wiring which goes straight into a ECU, they should be protected for this but.... Depending on firmware LR can basically do anything but as i dont see how they can know in which gear you are (besides calculating on speed and RPM) nor to which gear you are changing, this "system" should do its thing on all gears If i can make a guess it is more noticeable on the higher gears as there is probably more unused mixture in the combustion chamber the moment you press the clutch during acceleration (lower revs more labour compared to low gears), this would cause the engine to surge a bit and enforce the revs-up impression. Easy to check it out by comparing what the revs do when pressing clutch while accelerating and when cruising. Good luck and keep us posted on the outcome
Edit: TD5 disables this by simply unplugging, no need for a bridge. |
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3rd Jul 2012 7:36am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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this is really sad.......
you wouldn't believe how excited I am about trying this and hopefully bottoming out the problems I've been having...... tempted to p*ss off home now and try it..... tell me is WD40 a good thing to use on electrical contacts ? one more thing.....if this connector is playing up is there a chance it wouldn't show a fault code ? |
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3rd Jul 2012 7:53am |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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ok, quick answer so you can rush home...
WD40 works I drove with and without bridge (so also with the cable unplugged without bridge) this doesnt gave me any codes on my scangauge. (ecu sees signal as being open or closed, so clutch in or out, which are both valid signals) I am sure that with real diagnostic soft you can call up the status of the switch and check if it changes when pressing the pedal but i dont see how it could be giving a fault code as long as there is no corrupted signal returning to the ECU (eg a semi-short lowering the signal voltage outside the "HIGH" signal limits in the soft of the ECU) Another thing that might give you an answer without leaving your desk... In low gear (different mapping on TDCI), when you get your foot of the accelerator, does the defender abruptly come off the gas? or does it gently lower the revs till stall-control kicks in? If it nose-dives (so abrupt), the switch is not working and the ECU thinks you are pressing the clutch all the time and reduces revs instantly. This is a very noticeable difference, so if you start looking at it, check the behavior in low range also It's quite simple, this system lowers the revs slowly when in gear/ clutch pedal not pressed down; masking clonks an slack in the drivetrain and giving a more relax / easy gearchange. The drawback is that engine braking is reduced, not as prompt. If the clutch is pressed there is no reason to hold the revs and the ecu will kind of cut-off the revs instantly. By installing the bridge you are telling the ECU the clutch is pressed and get instant reactions from the engine. Which makes for a more clonky and unpleasant drive if you have big boots or a binary driving style (1-0; on-off). You get better throttle response at the cost of fluency. Some like it more as it is closer to the older TDI, series behavior. Ok, so now you can run |
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3rd Jul 2012 8:14am |
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| GREENI Member Since: 22 Aug 2010 Location: staffs Posts: 10381 
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It makes you want go and buy a 300tdi
Technology...pah |
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3rd Jul 2012 8:20am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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I'm loving it !!!
yes mine is a little cr*p in low range ie very .....erm ......well a bit like this - vrrm vrrm vrrm and I'm hoping it should be like this - vrrrrrrrrrrrrrrrrrrrrm 
get it ? |
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3rd Jul 2012 8:42am |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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oh , i see
well... VRRRRRRRRRRRRRRRRRRRRRRRRRRRMMMMM is usualy for Gary or Pete But you could try with the WD-40 also  |
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3rd Jul 2012 8:51am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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I thought gary and pete was more vrrrrrrRRRRRMMMMMM !! |
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3rd Jul 2012 8:54am |
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| landylad Member Since: 28 Jun 2012 Location: bucks Posts: 16 
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tatra805
Ta' very much for putting my mind at rest, Great answer in detail and quick as well! I have to say it is really only noticeable from 3rd onwards and in a nice way! I also have a 300Tdi so I may have overdeveloped left leg muscles but I manage the transition from either and back again without drama ! Caterham good luck and let uis know how you get on! Cheers all fer reading and taking the time to respond Dave Landy Mad
Defender 90 XS Puma 2.2TDci Defender 90 300TDI pick up |
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3rd Jul 2012 11:20am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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hmm.
just had a quick look under the bonnet and all looks nice and clean (no need for any wd40) but given it a good blast of wd40 all the say
(it helps to keep everything nice and clean if nothing else). some how forgot to try the multimeter on it.......will go and try again in a minute. |
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3rd Jul 2012 1:30pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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right brief update until someone can help me (physically not on the web here)
just checked and the device is N/O without the clutch pedal being depressed (just need to get someone to depress and I'll chack again). in the meantime however are we sure its a N/O circuit and not the otherway round as from what you've said some bridge it out to allow revs to drop like a ton of bricks (I mean tdi) ........ wouldn't that suggest its normally closed and opening when cluth depressed to prevent the ton of bricks syndrome ? |
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3rd Jul 2012 2:37pm |
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