ChrisC Posted September 5, 2003 Share Posted September 5, 2003 Hi All I am having a problem with a misfire. It started after a track session, but only on a short drive to get more fuel, and cleared before I returned to the pits. It then ran all afternoon on the track, and also the drive home, without problem. The car has not been used for a couple of weeks, then on a run out it started again. Now it is permanent. ☹️ Its number one, and I have swapped the plugs, and the misfire still remains at number one. I have also checked with a colour tune and I can’t see a spark. I can’t swap the plug leads, because no other lead will reach. But I have tested the leads with a multi meter, and both one and two give a 2.5K resistance. (if that means anything) I have not carried out a compression test yet (need to collect the tester), and I have no oil and water contamination. The engine is a post 93 coil pack carb unit, so it does not have a distributor. Can any body offer any advise, or better still can I borough a plug lead from anyone local 🤔 In need Chris ☹️ Chris.... H15 SVN Get it ! Link to comment Share on other sites More sharing options...
ChrisC Posted September 6, 2003 Author Share Posted September 6, 2003 OK its both 1 and 4 thats down ☹️ Its fine for about 1 min when started from cold. I suspect its the coil pack, but how can i check 🤔 Anyone in my area have a VX post 93 engine 🤔 Chris.... H15 SVN Get it ! Link to comment Share on other sites More sharing options...
ChrisC Posted September 6, 2003 Author Share Posted September 6, 2003 I have spent the morning (and most of the afternoon) testing. 1 and 4 are dead ☹️ I only have a digital voltmeter, which is no good for looking at the signals from the ECU to the coil pack, so after a brain wave I plugged my DL90 datalogger on the coil pack signals from the ECU. The trace for 2 and 3 shows varying voltage dependent on revs, but the trace for 1 and 4 is flat at 12v. I think this is proof that the ECU ignition sink for 1 and 4 is duff. I have obviously checked this at both the ECU end of the wire and the coil pack, just in case the wire has broken. The ECU is a MBE 906. I think its replacement time, but I would like to test this. Dose anyone have an MBE 906 kicking around after a ECU or Injection upgrade. I would not replace it with another 906, (I am not sure I still can) its upgrade time but its to put my mind to rest. Chris.... H15 SVN Get it ! Link to comment Share on other sites More sharing options...
16vastra Posted September 6, 2003 Share Posted September 6, 2003 mbe like blowing the coil drivers, heard of this a few times now, tho i would still test with a new coilpack just to triple check similar story here http://wscc.ggr.net/cgi-bin/BB/ikonboard.cgi?s=3f5a062806bcffff;act=ST;f=3;t=7627; Link to comment Share on other sites More sharing options...
stu999 Posted September 7, 2003 Share Posted September 7, 2003 ...the output transistor had blown in the ECU, and the transistor isnt available anymore. But it was repaired using a later type transistor, which was apparently was a) a complete 🙆🏻 to fit, and b) also no longer available. *Touches wood* my engine is running sweet as a nut at present, but I fear that I am on borrowed time..... ☹️ Sex is alright, but you cant beat the real thing...... Link to comment Share on other sites More sharing options...
ChrisC Posted September 7, 2003 Author Share Posted September 7, 2003 Thanks, do you know what component was used? I assume it was a replacement for the VB020, which started life in 1984 - now long dead... unfortunately I can't seem to forget it ☹️ Chris.... H15 SVN Get it ! Link to comment Share on other sites More sharing options...
stu999 Posted September 7, 2003 Share Posted September 7, 2003 I think the replacement was a VB027....but I might be wrong. Pin-outs were different, even the transistor body had to be isolated from the original mounting. Have sent you E-mail, will try and confirm the type used tomorrow. Apparently, when I spoke to MBE about the problem, some of the reason for failure was that very often the 906 ran with a large 'dwell' which overheats the transistors at low rpm. So I keep the revs high wherever possible now 😬 Question for those who are electronically minded....Is there no way these ECU's can be converted to run 'modern' transistors? Sex is alright, but you cant beat the real thing...... Link to comment Share on other sites More sharing options...
EFA Posted September 7, 2003 Share Posted September 7, 2003 Chris, Get yourself an MBE 912 V3 for which I have a map - the 906 is hugely obselete, the 912V3 less so as it was user programable sand used on early ( pre 97) Jenvey TB setups. Wiring is a simple plug change on the loom (£20 if you diy) and a plug and play on the ECU. Bought the "Morgan" (my flared wing HPC) with this fault and it took 20 mins to get it running properly on an MBE 956 which I had lying around. The 956 and 912v3 are sa far as the car is concerned, functionally identical. Last option is to buy a new MBE 967 (you can get an ignition only for around £300, or one whhich will support injection for around £400. In both cases you will need the plug and a crimp tool, but its not too hard.... If you are looking for a new MBE unit, go to Derek Scarow at DS Motorsport [derek@dsmotorsport.freeserve.co.uk] who does discount them, unlike TBOMK SBD. Plugs can also be got through Derek or Steve Hurst at GWR Motorsport in Swindon. Fat Arn Visit the K2 RUM website See the Lotus Seven Club 4 Counties Area Website here Link to comment Share on other sites More sharing options...
ChrisC Posted September 8, 2003 Author Share Posted September 8, 2003 Thanks Arnie and Stu. OK the ECU is dead. So I am in the market for a new ECU. But this to me is the golden opportunity to do a throttle body conversion, which the wife have given the go ahead for [:]] if I keep the original look of the car ie K&N’s. From web surfing this weekend I think (and correct me if I am wrong) I can get throttle bodies which are direct replacements for DOCE carbs. I know this is not optimal because of the Caterham manifold, but it keeps the look of the car and the wife happy. I am going to check with my favourite rolling road, Peter Baldwins in Cambridge, remember I came from Minis, which ECU he prefers and this will determine the direction I choose. I know plenty of you have done this conversion, so can anyone help me compile a shopping list. 😬 Chris.... H15 SVN Get it ! Link to comment Share on other sites More sharing options...
rjc Posted September 12, 2003 Share Posted September 12, 2003 My 906 vvv MBE chip did exactly the same thing. All attempts to repair it failed. Switching to an MBE 917i 3D ecu made a big, big difference I would recommend one. Regards Rowland Link to comment Share on other sites More sharing options...
ChrisC Posted September 12, 2003 Author Share Posted September 12, 2003 Yep its going to be replaced with a 967e, I will only use 3d ignition to begin with, but later I will convert to TB's. Thanks for the Info Chris.... H15 SVN Get it ! Link to comment Share on other sites More sharing options...
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