samuel Posted June 23, 2012 Share Posted June 23, 2012 Hope you can help? I've just completed a 1500 mile tour of France in a low mileage R500 duratec. Start and ran perfectly with one, regular, exception. Whenever I stopped for fuel or coffee etc and then restarted with the engine warm but not hot (typically 70 to 80 showing on the stack ) there was a persistent misfire / splutter and I'd find myself kangarooing my way out of town / or slipping clutch and gunning the engine to gain higher, and apparently more stable, revs. The issue would go away very quickly, typically within 1/2 a mile of driving. Doesnt seem to be an issue with that particular temperature range (except after a stop) as the car behaves well from cold and pulls cleanly throughout the rev range. Not a major problem but interested to hear if there's a simple solution? Link to comment Share on other sites More sharing options...
The Pikey Posted June 24, 2012 Share Posted June 24, 2012 Could that be something to do with heat soak effecting the intake air temp? Link to comment Share on other sites More sharing options...
samuel Posted June 24, 2012 Author Share Posted June 24, 2012 Many thanks for your input; an interesting idea which I certainly hadn't thought of. It may be that the higher average temperatures over there and the relative lack of wind compared with my native north Scotland could have a role to play! . I'll need to try to replicate domestically. Is the air temp sensor in the airbox? I presume that you are suggesting that the sensor would be reporting some form of over temperature and would be over/under dosing fuel accordingly? The technicalities are beyond me but there may be others out there can offer further guidance. Link to comment Share on other sites More sharing options...
juleslid Posted June 27, 2012 Share Posted June 27, 2012 Samuel, try a search for "duratec uneven idle", and see if the discussions on my recent problems are relevant... Jules Link to comment Share on other sites More sharing options...
Alan Reeves Posted June 28, 2012 Share Posted June 28, 2012 I had exactly this yesterday and never before, but it waqs for just a short time and seemed to clear? Definately not hot, just a short run into town and it occured when I was returning. Hopefully a one off. I couldnt find a Duratech misfire link Link to comment Share on other sites More sharing options...
FunkySon Posted June 28, 2012 Share Posted June 28, 2012 Jules means this thread here Link to comment Share on other sites More sharing options...
samuel Posted June 28, 2012 Author Share Posted June 28, 2012 Gentlemen, Thanks for all your replies - I've reviewed the other threads but dont think they really apply. i've still to check if it is a problem that occurs only in Frnace - one day it will stop raining and I can try to replicate here. It ssems to be only after hot (or at least warm) re- starting, so broken wiring loose tps sensors etc seem unlikely. When starting from cold the car behaves perfectly pulling strongly / smoothly from a cold start. Similarly when hot and running there is never an issue at a particular rev range etc. As mentioned before the misfire / splutter clears itself every time after a minute of so of running and then performs as normal even when water temp is in similar range to post (re)start temperatures (ie after long descents at near idle conditions. This does therefore sound like some kind of "heat soak" issue until air flow around the engine pulls temperature down to"normal" levles. gets more interesting - had hoped somebody would be more categoric / definitve but then is life actually like that.... Link to comment Share on other sites More sharing options...
samuel Posted June 28, 2012 Author Share Posted June 28, 2012 Gentlemen, Thanks for all your replies - I've reviewed the other threads but dont think they really apply. i've still to check if it is a problem that occurs only in Frnace - one day it will stop raining and I can try to replicate here. It ssems to be only after hot (or at least warm) re- starting, so broken wiring loose tps sensors etc seem unlikely. When starting from cold the car behaves perfectly pulling strongly / smoothly from a cold start. Similarly when hot and running there is never an issue at a particular rev range etc. As mentioned before the misfire / splutter clears itself every time after a minute of so of running and then performs as normal even when water temp is in similar range to post (re)start temperatures (ie after long descents at near idle conditions. This does therefore sound like some kind of "heat soak" issue until air flow around the engine pulls temperature down to"normal" levles. gets more interesting - had hoped somebody would be more categoric / definitve but then is life actually Link to comment Share on other sites More sharing options...
John Vine Posted June 28, 2012 Share Posted June 28, 2012 Hmmm...could it be as simple as a dodgy plug? JV Link to comment Share on other sites More sharing options...
samuel Posted July 6, 2012 Author Share Posted July 6, 2012 Hi to all contributors. Spoke with my "local" Caterham approved garage (Dreadnought in Callander) today on another issue but discussed the above as an aside. They (like Jason Fletcher) suggest heat soak but this time are suggesting vapourisation of the fuel in the rail. This would make perfect sense and would explain the recovery after a short period of running (vapour is purged by liquid fuel entering the rail. I'm very impressed with this garage - they know their stuff inside out and are very customer focussed. p.s I was out this evening in a damp 10 degree evening and its happens here too so my initial thoughts re higher ambient temperatures in France are not relevant. Now that I've had a satisfactory explanation I'm not concerned anymore and will merely let the system "recover / purge" after a hot -restart. Thanks again Link to comment Share on other sites More sharing options...
John Vine Posted July 7, 2012 Share Posted July 7, 2012 Do R500Ds tend to suffer from fuel vaporisation? It's not something reported much on Techtalk. JV Link to comment Share on other sites More sharing options...
samuel Posted July 7, 2012 Author Share Posted July 7, 2012 Hi John, As I'm a very new owner of an R500 and an even newer "member" of blatchat I cant really comment about the prevalence or otherwise of fuel vaporisation issues on the R500. My last post was more based on a feeling that it seemed to answer perfectly the symptoms and their complete absence under any other conditions. Similarly the garage that made the suggestion merely suggested it as a solution rather than making any categoric diagnosis - the most they could do having never seen the car or the symptoms first hand! I'm sure there are other reasons that could also explain - perhaps ECU derived fuelling or ignition settings that are appropriate for a given water temperature but less so where the actual engine and / or exhaust temperatures are cooler than when in running mode? I somehow feel that a dodgy plug would manifest at other times other than for 1 - 2 minutes only after a hot start? I don't however profess any great knowledge and stand to be corrected! Thanks for your continued interest and input Link to comment Share on other sites More sharing options...
Jason Plato Posted July 7, 2012 Share Posted July 7, 2012 Gregg and I are on your around Switzerland . we both have duratec and his is a 2011 R500. he suffers from lack of response and power after a stop with a hot engine. I think this is due to the air temp sensor - shared with the MAP sensor on the airbox. I think the air temp is soaring on standstill and this confuses the ecu on startup. if Gregg only uses light throttle it clears after a 30 seconds. this could be due to the air then being refreshed and cooled . dj Link to comment Share on other sites More sharing options...
samuel Posted July 7, 2012 Author Share Posted July 7, 2012 Hi to Dave (and Gregg). Hope you're enjoying your tour in Switzerland as we did in France and the Pyrenees. It sounds very much like Gregg's issue is the same as mine - hardly symptoms to impress the locals as you attempt a "spirited departure from the local cafe (as you cough splutter and kangaroo your way out of town)! Maybe taking the bonnet off when you park or sitting an ice pack on the sensor might help (or perhaps more practically trying something similar to see if it cures the problem. Thanks for the pointer - the rain continues here so a test will have to wait Link to comment Share on other sites More sharing options...
John Vine Posted July 8, 2012 Share Posted July 8, 2012 I think DJ may well have the answer. JV Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 8, 2012 Member Share Posted July 8, 2012 Quoting Dave Jackson: I think this is due to the air temp sensor - shared with the MAP sensor on the airbox. I think the air temp is soaring on standstill and this confuses the ecu on startup. if Gregg only uses light throttle it clears after a 30 seconds. this could be due to the air then being refreshed and cooled . Don't know anything about these systems. How do you test ideas like that? Could you test it by measuring that input value and comparing it with what ought to be? Or could you rig a faked input value and see what happens when you vary it under the conditions that cause the problem? Jonathan Edited by - Jonathan Kay on 8 Jul 2012 16:16:56 Link to comment Share on other sites More sharing options...
Jason Plato Posted July 8, 2012 Share Posted July 8, 2012 either read the ecu live with a laptop if you have the software or simply move the sensor outside of the airbox and see if the problem persists . I have already moved my air temp sensor in this way to a point on the chassis rail that better represents the real air temp entering the trumpets .but my sensor is a rover item not the ford one Gregg has. it is greggs plan to relocate the sensor on return to the uk Link to comment Share on other sites More sharing options...
samuel Posted July 8, 2012 Author Share Posted July 8, 2012 Gentlemen, Sincere thanks for your continued input . I get a sense that were getting close to an explanation. The suggestion of moving the inlet air temp sensor to a less "heat - soakable" area seems excellent but I think I read the in the case of R500 this sensor is combined with the MAP sensor and therefore relocation would seem problematic. Could a new dedicated temp sensor be fitted elsewhere and the wiring modified so that the MAP could stay where it is and the input from the new remote sensor coupled. Or is there commonality of wiring? Has anyone tried the bag of ice or cool air blower to reduce the post rest temperature before re-starting? regards Link to comment Share on other sites More sharing options...
Jason Plato Posted July 8, 2012 Share Posted July 8, 2012 the air pressure in the airbox is the same as outside the airbox so moving won't pose a problem. you could splice the wires and relocate another second combined sensor to just measure air temp - sensors are only about £20 on eBay etc. 4 wires I recall. earth, 5v from ecu, two sensors - map and temp. Edited by - Dave Jackson on 8 Jul 2012 17:01:51 Link to comment Share on other sites More sharing options...
7 wonders of the world Posted July 8, 2012 Share Posted July 8, 2012 Whilst heat soak could vapourise the fuel, the prime cycle of the pump is sufficient to re presuurize the rail. The dead end rail set up is used on thousands of cars many of which live in hotter climes than you've experienced. Heat soak on the air temp is a factor which can be massivley reduced by isolating the temp sender form the alloy backplate in the air filter, make the hole oversize so there no metal to metal contact then using phenolic / thick fibre washers front and back to isolate the sensor from the alloy. My K had the same issue, this cured the problem Link to comment Share on other sites More sharing options...
samuel Posted July 8, 2012 Author Share Posted July 8, 2012 Its getting ever more interesting. I like the idea of twin / split sensors particularly because I'm concerned that air pressure inside the air box will surely be typically lower than atmospheric (as measured some distance away on a chassis mounted location) given the vacuum created on induction and perhaps to a lesser extent the flow resistance provided by the air filter (thus depressing air box internal pressure still further below atmospheric? The airbox backplate on the R500 is carbon fibre so I suspect the thermal conductivity will be much lower on this than with an alloy backplate. Link to comment Share on other sites More sharing options...
Harry Flatters Posted July 9, 2012 Share Posted July 9, 2012 Definitely move the air temp sensor out of the airbox. I have a 265bhp VX and used to have a similar problem on a hot restart. The sensor is supposed to read ambient inlet air temperature but when stopped the temp in the air box soars and gives a false reading for the restart. I moved my sensor to the bottom chassis rail so that it is always in the ambient air flow. No problems since. Link to comment Share on other sites More sharing options...
Alan Reeves Posted October 10, 2012 Share Posted October 10, 2012 Samuel did you sort this ? I have picked up an intermittent mis fire and CC thought it might be the throttle sensor wiring . away to Richard ... alan Link to comment Share on other sites More sharing options...
Smiffy69 Posted October 10, 2012 Share Posted October 10, 2012 Just to add another example ...... I had the same problem on mine during the (short / non existant) summer- long blat and left it sitting in the sun whilst I had a lovely pub lunch. On restart the engine would cut / stall but after a few seconds settled down and ran fine. It does definitely seem to indicate some sort of temperature issue? BTW mine's an R300 Duratec with the stage 2 mod i.e. roller barrels and trumpet intake etc so I assume its a similar config to Samuel. Link to comment Share on other sites More sharing options...
Alan Reeves Posted October 10, 2012 Share Posted October 10, 2012 Mines not heat its breaking down, Link to comment Share on other sites More sharing options...
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