AMMO Posted July 24, 2002 Share Posted July 24, 2002 My car has developed a fault. It misfires in every gear at 4,200 rpm. You cannot drive through it. After checking various components by replacement the fault was traced to the positive feed to the MBE 3D ECU (car is on carbs). If I connect the ECU directly to the battery problem goes away. The positive feed is taken from the old coil feed wire from when the car was Crossflow powered and has performed faultlessly for around 4,000 miles. It tried feeding the ECU via the fuel pump positive feed but problem is identical. The strange thing is that the voltage in the original feed wire seems fine and volts rise with rpm and is regulated to around 14 volts. As I cannot drive it with an unswitched positive feed from the battery I am trying to find a solution. There are no other switched positive feeds in the vicinity and even if there were I'm not sure this would solve the probllem. I'm thinking that the ignition switch is at fault but am reluctant to buy a new one in case it doesn't solve the problem. Anyone encountered this before? Anyone got a spare ignition switch I can borrow to see if the problem goes away? Thanks for any help or advice. AMMO Link to comment Share on other sites More sharing options...
philwaters Posted July 24, 2002 Share Posted July 24, 2002 Do you have a Vecta immobiliser on the car? When mine was x/flow it used to cut out on me and I traced it back to the Vecta cutting the ignition circuit feed, whilst the starter circuit was fine, so it would just turn over with no spark. Could the Vecta be failing and adding interference? Failing that, can you not run the power from the ignition key. This is how mine is done, just find the terminal that comes 'on' on the last turn of the key (before the final twist) and connect it there. Or will that give the same problems? Phil Waters Zetec is in and running Edited by - philwaters on 24 Jul 2002 08:38:50 Link to comment Share on other sites More sharing options...
AMMO Posted July 24, 2002 Author Share Posted July 24, 2002 Phil No imobiliser fitted. I assume that the feed to the coil (white wires) come directly from the ignition switch. It may possibly go all around the houses through various multiway connectors. Didn't think of wiring directly from the switch. I will try that next. Thanks for that suggestion. I'll let you know what happens. AMMO Link to comment Share on other sites More sharing options...
Paul Turner Posted July 24, 2002 Share Posted July 24, 2002 Ammo I have an ignition switch off a 88/89 chassis if you need one. Paul Link to comment Share on other sites More sharing options...
AMMO Posted July 24, 2002 Author Share Posted July 24, 2002 I have wired the ECU directly off the back of the switch. Problem still present. As it looks like it is definately the switch I may just get a new one. Anyone know what it's off? Thanks Paul. Mine is also an '89 chassis. If I cannot get a new switch I may take you up on your kind offer. AMMO Link to comment Share on other sites More sharing options...
philwaters Posted July 24, 2002 Share Posted July 24, 2002 Sorry that it didn't fix the problem.. Sounds like a good chance to go to a nice flip-covered igition toggle switch and a push button starter... I bet it is a lot cheaper as well! Phil Waters Zetec is in and running Link to comment Share on other sites More sharing options...
AMMO Posted July 24, 2002 Author Share Posted July 24, 2002 Paul Have sent an email. AMMO Link to comment Share on other sites More sharing options...
AMMO Posted July 24, 2002 Author Share Posted July 24, 2002 Mis-diagnosis of the year! Found the problem to be a broken spade connector on the back of the alternator. Sheared off but still touching as retained by plasic sleeve. It was the first thing I checked and it appeared to be secure. I was also thrown as the alternator was putting out 14 volts. Anyway, problem solved. Thanks for your help Phil and Paul. Paul ignore my email and thanks again for your offer of help. The big stupid grin is back on my face after an extensive high rpm road test. AMMO Link to comment Share on other sites More sharing options...
philwaters Posted July 24, 2002 Share Posted July 24, 2002 Nice one.... Glad is all ok again. Phil Waters Zetec is in and running Link to comment Share on other sites More sharing options...
Graham Perry Posted July 24, 2002 Share Posted July 24, 2002 Ammo, You were lucky to find that so quickly. Thats exactly the sort of fault that would frustrate an expert for hours. Link to comment Share on other sites More sharing options...
AMMO Posted July 24, 2002 Author Share Posted July 24, 2002 Graham I think you're right, a certain amount of luck was involved. Could have been messing around for ages. Luckily found it quite quickly. Just goes to show what one poxy duff connection can do. How's the Crossflow? Did you get a smaller battery? AMMO Link to comment Share on other sites More sharing options...
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