F355GTS Posted June 14, 2004 Share Posted June 14, 2004 Car is a 92 VX 2.0 injection, MBE 956 ECU I need to get to the bottom of some inconsistent running, on idle the car frequently misfires predominently though No1 cylinder (flames seen in throttle body) also on quick throttle blips flames can be seen in TB's 1 & 2 as revs drop I've replaced the plugs and after 2 x 35 mile runs today they are lighter (light biscuit colour) on cyl's 1 & 2 and darker on 3&4. I've swapped the injectors between one and two but the idle misfire problem stays at number 1. Fuel pressure appears OK with 30psi after initial prime and 70psi whilst running I've checked for air leaks and tightened everything but the problem persists also culminating in some impressive flames and pops/bangs on over run. If revs are held at say 4.5k there is a reasonable amount of popping and banging coming from the exhaust which is pushing me over 100db for track use ☹️. I'm waiting to get the Pin number for the ECU to check the Map (well read Peter C to check the Map!) but as it only appears to be affecting one or two cylinders I suspect the problem lies elsewhere Any clues? ta Mark Link to comment Share on other sites More sharing options...
stevefoster Posted June 14, 2004 Share Posted June 14, 2004 70psi. Yikes! Try 50psi. But be careful the mixture is not too lean at max power at revs. Too lean = piston melting. Check what the map in your ECU should have, they usually say 50psi. I have known of and tried a 60psi map though. Better still have you access to a wideband O2 sensor? Then you can see the mixture real time. Other than that then rough running could be a number of things.... It seems odd that it is a particular cyl though to be map or pressure related. Suspect ignition / leads / coil etc... Pin is usually 1111! Sush, that may be a secret. 100dB! I dream of 100dB! What wouldn't I give to be 100dB! What exhaust system do you have? Hants (North) and Berkshire Area club site here My racing info site here Edited by - stevefoster on 14 Jun 2004 23:04:08 Edited by - stevefoster on 1 Aug 2004 18:10:27 Link to comment Share on other sites More sharing options...
F355GTS Posted June 14, 2004 Author Share Posted June 14, 2004 Steve 4-2-1 and a 6.5" Techcraft stuffed with some strand stuff that apparently Land Rover use in their road cars Could the pressure regulator be at fault? I'm measuring hte pressure from a valve on the fuel rail with a std pressure gauge, should I be doing something different? Mark Link to comment Share on other sites More sharing options...
Peter Carmichael Posted June 14, 2004 Share Posted June 14, 2004 I had the chance to drive this car at the weekend and it isn't bad - meaning that it isn't far off at all. I suspect that the WOT mapping is spot on, but the progression has been bodged. A bit of a remap and tidy up will sort it and by the sounds of it the TBs are out of balance although this will only really effect very small throttle openings. Sahf London; every 1st Wednesday from 19:30 at The Duck just around the corner from Clapham Junction station Link to comment Share on other sites More sharing options...
F355GTS Posted June 15, 2004 Author Share Posted June 15, 2004 ! Mark Link to comment Share on other sites More sharing options...
Badger Bill Posted June 15, 2004 Share Posted June 15, 2004 That's you told then! BB 😳 😬 Link to comment Share on other sites More sharing options...
stevefoster Posted June 15, 2004 Share Posted June 15, 2004 Aha, I have the 4-1 race exhaust with 2.5" collector and that is MUCH LOUDER! Worth it though! Hants (North) and Berkshire Area club site here My racing info site here Link to comment Share on other sites More sharing options...
Red SLR Posted June 15, 2004 Share Posted June 15, 2004 Did you have the TBs off when you had the engine out? Link to comment Share on other sites More sharing options...
F355GTS Posted June 16, 2004 Author Share Posted June 16, 2004 Simon No, remained on the car Mark Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted June 16, 2004 Share Posted June 16, 2004 Alot of TB Vx's seem to soot their plugs very easily - if you your TB's are out of balance, they will soot up on half of the cylinders easily whilst idling. All sorts of misfire problems then occur. I'd clean the plugs up, put them back in (or better still, put new plugs in), crank up the idle a bit, balance the TB's then see how you get on. Do you have the original Vx plug leads? Mine started failing after about 2 years. Since used Magnecors which have been very good. Agree that 70psi is very high - mine runs at 43psi as advised by QED. Guess it depends what it was mapped on but I think 70 is very high. Mine is ok with lower preassures till you get to about 30, then it gets very lumpy. Edited by - Alex Wong on 16 Jun 2004 10:19:39 Link to comment Share on other sites More sharing options...
stevefoster Posted June 16, 2004 Share Posted June 16, 2004 Forgot to say Mr 355... If you need to borrow a wideband O2 sensor to verify mixture then pop round. Assumes you have a lambda boss in the collector of course. Hants (North) and Berkshire Area club site here My racing info site here Link to comment Share on other sites More sharing options...
Adam Posted June 16, 2004 Share Posted June 16, 2004 Steve, If you want a clamp designed to fit the sensor at the exhaust exit let me know. Its free .... Adam Link to comment Share on other sites More sharing options...
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