Kevsta Posted April 15, 2010 Share Posted April 15, 2010 Afternoon all, I have a strange problem. It started Monday morning on my way to castle combe (typical) and was doing it at any rev range and any load/throttle. It is like the rev limiter kicks in for a split second - kind of like a cut off. This happened four times in a 40 minute journey. I then went out on track and it was much more pronounced as the throttle was wide open so it was more like a shunt (imagine fully shut throttle then back to open). I spoke to a guy there and he suggested the TPS and had a spair so I fitted it. This cured it for a 20 minute drive on the road and three sessions of 15 mins on track and then it came back. I drove it home and it was still doing it. Does anyone have any suggestions? Was it the TPS but my MEMs fried the old one and has fried the new one (I don't want to keep buying them as it was a little over £60!)? I did fiddle with a lot of sensors at the time of fitting so it may not have been this. For info, spark plugs are fairly new, as are leads, fairly new CPS. It is a VVC running Rover MEMs. Suggestions? Link to comment Share on other sites More sharing options...
Colin Mill Posted April 15, 2010 Share Posted April 15, 2010 Well, it could be lots of things but momentary loss of the crank position sensor signal would certainly do what you are getting. Link to comment Share on other sites More sharing options...
eoinmac Posted April 15, 2010 Share Posted April 15, 2010 I had this exact problem 2 weeks ago ! New spark plugs had been fitted at a major service and it turned out that one of the new spark plugs [NGK ]was faulty. This even caused the shift light to remain on Link to comment Share on other sites More sharing options...
TomGaval Posted April 15, 2010 Share Posted April 15, 2010 I had a very similar problem. A new battery cured it. Tom Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted April 15, 2010 Support Team Share Posted April 15, 2010 EU2 or EU3? IF EU2 then the coil has to be high up the list of suspects. Yellow SL #32 - member of Drowned Rat Racing Link to comment Share on other sites More sharing options...
Kevsta Posted April 15, 2010 Author Share Posted April 15, 2010 EU2, I will try one thing at a time and see what works. I have a spare coil pack so will try that first as that is cheapest! Link to comment Share on other sites More sharing options...
Kevsta Posted April 15, 2010 Author Share Posted April 15, 2010 Do keep any other thoughts coming though..... Link to comment Share on other sites More sharing options...
Frying Pan Posted April 15, 2010 Share Posted April 15, 2010 I'd second the crank position sensor - it is a primary input to MEMS and it will not fire injectors if it doesn't seen an input -----See some pictures of the build here. 18,000 miles completed! Link to comment Share on other sites More sharing options...
richard smith Posted April 16, 2010 Share Posted April 16, 2010 I had this problem for over a year. Then someone told me that its very common and I should clean the IACV with carburettor cleaner. That fixed it. Link to comment Share on other sites More sharing options...
Tim V-W Posted April 16, 2010 Share Posted April 16, 2010 Sounds quite a lot like how my epic misfire started. After changing pretty much everything I happened by chance to find that it was the Injector sub loom connector. On my car it hangs in mid air between the pedal box and the rear of the fuel rail (ex 1400 SS Forward facing ali plenum set up) and obviously had a bad connection that broke down under pressure from bumps or hard cornering. pulling it apart and cleaning it, spraying with contact cleaner and supporting it against the fuel pipe fixed a two year misfire! Link to comment Share on other sites More sharing options...
Roger Ford Posted April 16, 2010 Share Posted April 16, 2010 Has the car been standing in heavy rain at all? Water down the spark plug holes can cause symptoms like this. Pull the plug leads, blow air into the holes if possible, then remove the plugs and turn the engine over for 30 sec, reassemble. Link to comment Share on other sites More sharing options...
Kevsta Posted April 16, 2010 Author Share Posted April 16, 2010 Many thanks for comments and suggestions, all very useful and appreciated. Car has been standing but not in rain. I am going to change fuel filter incase of condensation in tank but I would have thought it would have been more constant. I have checked all the plugs and all seem fine and very clean. It may well be that I fix it without ever knowing what it was but willl try to just do one thing at a time (soooo tempting to try it all and see if it works or not but best to know what it was). 7heavensoon, when you say 'check' the CPS, do you mean remove and see how clean etc. it is? Or do you mean replace? Richard, not sure how the IACV would effect anything other than tick over? Or is there any additional feedback it gives to the MEMs? Tim, I wondered about the injectors, I looked at them (as it I literally looked at them past the plenum and thought f*** pissing around with that on a track day) and thought it maybe worth looking into. I must also add that my loom is a splice of old EU2 1400 (circa 1995) and the slightly later EU2 for the VVC. I might unravel all of my connections and re-check or remake them. Link to comment Share on other sites More sharing options...
Kevsta Posted April 28, 2010 Author Share Posted April 28, 2010 Odd update, have tried a few routes and so far to no avail (MFRU, coil packs,). Yesterday was MFRU, went for drive, nothing for 20 mins then it did it 4 times in quite close succession. Got home and put away. Today is MOT (not actually due til 20th May), get car out, fire up...and it won't start! Bonnet off, swap to old MFRU and quick look at wires, try again and it starts! Bonnet back on, sit in car - cuts out. Try cranking - one cough then just cranking and nothing. Bonnet off etc. - does it three times until I give up (comically it was every time I sat in car - so I timed it and was 30 seconds...last time (number 4) I didn't sit in car...still did it. All I can think is maybe if it is the 5AS immobilising? Maybe it is dropping the live or the code thingy while driving and this is why it 'misses'. I have standard immobiliser fob etc. and know this to be working re the clicking etc. Not sure if anyone else has had this before? Don't you just love electrical gremlins!?! Link to comment Share on other sites More sharing options...
Adrian Williams Posted April 29, 2010 Share Posted April 29, 2010 Could be a poor connection in the loom giving an intermitent fault. I had a dodgy pin within the plug that goes to the cut out switch that took a while to track down. It didn't manifest intself as a misfire it just wouldn't start, then you fiddle with all the plugs and sensors and it works. Adrian Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 29, 2010 Share Posted April 29, 2010 Is the power delivery to the engine loom via the infamous spade connector (purple to brown). This tends to get loose over time and crimping it together helps. Just adding to the list of various things to try, seeing as nobody has mentioned it yet. Link to comment Share on other sites More sharing options...
Kevsta Posted April 29, 2010 Author Share Posted April 29, 2010 Hi Adrian, Yes this is similar to what I had yesterday, wouldn't start and a fiddle meant it would. I think it is best I go through it all and check/redo connections I have made in the past. Peter, yes I was looking t it yesterday as a potential, I will add it to the list of wires to go through. Many thanks Link to comment Share on other sites More sharing options...
jradley Posted April 29, 2010 Share Posted April 29, 2010 You mentioned it is a fairly new CPS and plug leads - did you keep the wiring to the coil and CPS in the same position as it was before, ie not too close to the coil HT ? Also, do you have the old CPS that you can try, just in case the new one is faulty ? Good luck finding the issue. John Link to comment Share on other sites More sharing options...
charlie_pank Posted April 29, 2010 Share Posted April 29, 2010 ISTR that someone had a weird fault like this when the crank position sensor or cam position sensor wiring ran too close to an HT lead, which interfered with it. Just worth a try... back here because I want to be. Link to comment Share on other sites More sharing options...
Kevsta Posted May 1, 2010 Author Share Posted May 1, 2010 Good point, I willlook to ensure they are all separated. Will look for CPS to fit too. Got to find this! Driving me mad! Link to comment Share on other sites More sharing options...
jingars Posted March 13, 2011 Share Posted March 13, 2011 Thread Resurrection!!!!!! Kevsta, did you track down your issue? I have a similar problem, have changed the TPS and still misfired most of the way back home from a Pistonheads meet at Gaydon. I guess that a CPS is next... Link to comment Share on other sites More sharing options...
Kevsta Posted March 13, 2011 Author Share Posted March 13, 2011 Hi Jingers, Yes I did, it was the fuel pump. Once changed all sorted...mine let me know it was the pump by eventually completely failing while I was searching for the problem (and after having taken a LOT of it apart). Hope this helps. Kev Link to comment Share on other sites More sharing options...
jingars Posted March 13, 2011 Share Posted March 13, 2011 Thanks, Kev - I will give that a look-over. Did you get the part from Caterham or more locally to you? I ask as my works head office in in High Wycombe and I am down there on Wednesday. Link to comment Share on other sites More sharing options...
Kevsta Posted March 14, 2011 Author Share Posted March 14, 2011 I bought a second hand pump on here but it didn't work (I don't doubt the pump was fine - rather the connections in the housing were at fault) so I then bought one from Caterha,. Not too cheap but fixed it. You'll also need the gasket seal ideally. It is a pain to get out (easier to take the tank out) and to get back in but all good now. Drain as much of the tank out before hand as you can!!!! And have someone to help you plus cover your roll bar as it is a tight fit and needs rotating, dropping down a bit, wiggling etc. etc. Good luck! Link to comment Share on other sites More sharing options...
jingars Posted March 14, 2011 Share Posted March 14, 2011 Thanks, I am going to need it Caterham don't show the uprated pump in stock on their website, so will probably follow Mankee Cheng and Dave Jackson's advice and go for the pump from Merlin Motorsport; I spoke to John there earlier today and it looks like they can get one to me for Thursday. Gasket also ordered locally - three people have advised me to get that, so I have done as instructed! Sod's Law - filled up en route home yesterday.... Link to comment Share on other sites More sharing options...
Kevsta Posted March 14, 2011 Author Share Posted March 14, 2011 If your pump is still working then you could use it to pump the fuel into a fuel can or two?! I did the same - as you say - sod's law! [8) Link to comment Share on other sites More sharing options...
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