shn7 Posted February 24, 2007 Share Posted February 24, 2007 1.8KSS. On boxing day my car developed a mis-fire about 10 miles into a blat. Yesterday I finally got round to trying to resolve the problem by fitting a new set of HT leads, Dizzy cap and Coil. I also checked the plugs which appeared to be in good condition and so were replaced. Just been for a test blat and the problem persists. It occurs on part throttle between tickover and about 4000rpm. When it occurs the shift lights also flicker. These are set to start coming on at 5000rpm. Above about 4500 rpm and full throttle everything appears to be fine. I've checked battery voltage with everything off at 12.56v and engine running at 14.nnv so don't think there's a problem with power supply. So what's the next step in diagnosising the problem? Steve. West Sussex AO Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
Rob Walker Posted February 24, 2007 Share Posted February 24, 2007 Sounds electrical , I would disconnect the shift lights and try again. Then try replacing the coil. Link to comment Share on other sites More sharing options...
noddy Posted February 24, 2007 Share Posted February 24, 2007 Potentiometer 🤔 Just had the same sort of issue, tickover fine, part throttle big misfire - flames etc, full throttle OK. see my post (process of elimination) from a few days back. R400 BYEeeeeeeee .......... I love it Link to comment Share on other sites More sharing options...
shn7 Posted February 24, 2007 Author Share Posted February 24, 2007 Hmm wondered if the shift lights could be related. Problem started not many miles after they were fitted. Already done the coil. Noddy, Throttle pot is also a possible. What I'm really looking for is a method to eliminate likely causes without buying one of every sensor and finding it's the last one to be replaced that was the cause. Steve. West Sussex AO Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
Allen Payne Posted February 24, 2007 Share Posted February 24, 2007 My (Omex) shift lights caused a horrible misfire when they were connected via the coil. Connecting them via the tacho solved the issue Link to comment Share on other sites More sharing options...
shn7 Posted February 25, 2007 Author Share Posted February 25, 2007 My Shift-i ligths are connected to the spare tacho feed that would be used for a stack dash. So std part of the loom under the dash. Power from the back of the ignition switch and earthed at one of the scuttle mountings. Steve. West Sussex AO Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
philwaters Posted February 25, 2007 Share Posted February 25, 2007 That's similar to how I ran my Shift-i lights - I piggy-backed the tacho feed, power and earth similar to you - I had no issues at all. Still worth removing them to eliminate another possible cause though. Phil Waters Link to comment Share on other sites More sharing options...
shn7 Posted March 1, 2007 Author Share Posted March 1, 2007 Hoping I may have just found the problem. Went to remove the scuttle so I could disconnect the shift lights and found the scuttle mounting nuts all loose 😳 😳 😳. The under dash wiring and the shift lights are earthed opn one of these and so I'm hoping this was the cause. Will find out at the weekend en route to Goodwood. Steve. West Sussex AO Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
Unclefester Posted March 2, 2007 Share Posted March 2, 2007 Steve, The symptoms sound horribly familiar to me, only difference being yours is an EU2 engine, mine's EU3....check here I tried everything, during the summer, and though changing both coils worked, strangely, for a while, the problem was only solved finally by changing the ECU. I suggest you borrow another ECU and test this. Good luck! Lucy in the Sky with Diamonds..ooooh hooo hooo!!... 😬 😬Abbey Road Time-Machine *eek* Edited by - Unclefester on 2 Mar 2007 14:06:54 Link to comment Share on other sites More sharing options...
willie pascoe Posted March 2, 2007 Share Posted March 2, 2007 have you changed the distributer rotar arm This is a common fault willie pascoe Link to comment Share on other sites More sharing options...
shn7 Posted March 2, 2007 Author Share Posted March 2, 2007 UF & WP, Have you not noticed that I said: I may have just found the problem 😬 However, rotor arm was check when I changed the dizzy cap and appears to be in good order. Steve. West Sussex AO Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
Unclefester Posted March 2, 2007 Share Posted March 2, 2007 Steve, Sure, I noticed that, but I've said the same thing myself....kept doing things which probably caused some slight change in voltage levels or summat in the ECU which jolted it back into behaving normally for a while, but it always started to misfire again. Have you in fact sorted it? Lucy in the Sky with Diamonds..ooooh hooo hooo!!... 😬 😬Abbey Road Time-Machine *eek* Link to comment Share on other sites More sharing options...
shn7 Posted March 2, 2007 Author Share Posted March 2, 2007 Will find out on Sunday when I head gor the Goodwood Breakfast Club meeting. Steve. West Sussex AO Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
shn7 Posted May 1, 2007 Author Share Posted May 1, 2007 Well time has moved on and a day spent with the ever so persistent Pater Carmichael may have got to the bottom of the problem. On the way to see PC it was mis-firing quite a bit. After some initial investigations and a few re-starts the engine would fire, run for a second or two and die as if the immobiliser was arming. I had had this occur a few times in the past and always got it going again by resetting the immobiliser and/or removing the FIA key. However on this occasion we couldn't get it to run. PC's Rover Testbook though not a huge amount of use on my EU2 engine confirmed that it was indeed immobilising. What we couldn't manage to do was unset the damn thing. Though somehow by chance we did manage to 2 or 3 times during the whole day but it wouldn't restart. Suspected the immobiliser to be at fault we scavenge a matching ECU and immobiliser off Gridgway's Seven (thanks Graham). Same symptoms 🙅🏻♂️ So off came the scuttle and out came the test meter. We checked voltages and continuity on numerous circuits all of which seemed ok. Finally we wired in a new heavy duty battery to chassis earth (something this car has run without for the last three years). Turn the key and it runs. Switch off, restart and it still runs. Disconnect the new earth strap and it fires and dies. So the conclusion, and this isn't a 100% guaranteed cure and is pending more use to confirm it's fixed, is that when the car got a soaking at Goodwood in November last year and was put away wet until Boxing day something has suffered in the electrical department. Adding the new earth strap, which really should always have been there, has resolved the problem. TBH as long as it now runs ok with no misfire or starting problem I'm very happy. Two problems not thought to be related fixed by one modification . Steve. Sussex (West) AO Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
Peter T Posted May 1, 2007 Share Posted May 1, 2007 Great, good to hear that it is finally fixed. For Peter C. R500 260 BHP Mango Madness CAR NO-37 Link to comment Share on other sites More sharing options...
Alan Bowler Posted May 1, 2007 Share Posted May 1, 2007 *thumbup* (nips out to garage to check earth connections again) AB Link to comment Share on other sites More sharing options...
Mark Durrant Posted May 1, 2007 Share Posted May 1, 2007 Steve Looks like we both fixed our electrical problems on the same day Mark D Comp Sec Link to comment Share on other sites More sharing options...
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