Chappers Posted January 12, 2006 Posted January 12, 2006 My brother is experiencing a strange occurance with his OMEX shift lights, and if anyone on here has any advice, then it would be very gratefully received . I quote... "I am having trouble getting my new Omex sequential shift lights to work without screwing up the VDO tachometer reading on my 1800 zetec (distributorless wasted spark/coil pack). The Omex sequential is connected as below with proper crimp connections rather than Scotchlock connectors: Black Omex earth wire directly screwed to the chassis; Red Omex ignition switched 12V wire to the green ignition switched feed at the back of the tacho; and Blue Omex signal wire to the white/black signal wire from the MBE 956 ECU to the tachometer. Now the shift lights seem to work and come on at the correct revs (by ear) but the VDO tacho fluctuates all over the place and reads zero at 70mph. If I disconnect the red shift light ignition feed it still fluctuates, but if I disconnect the shift light earth, the tacho works properly. Would an alteranative be to use a coil negative connection and set the cylinders to 2 on the Omex unit, or would the wasted spark aspect mean that the shift lights wouldn't come on at the set RPM? If that would work where would the easiest place be to connect to a coil negative wire? Does one come straight out of the ECU to the coils? - in which case I could break into the harness under the dash by the ECU. Any help would be greatly appreciated, otherwise I'll have to scrap my Xmas pressie." Chappers I never knew it could be this good!
Allen Payne Posted January 12, 2006 Posted January 12, 2006 I don't know if this helps but mine take the positive from the coil, the signal from the tacho and are earthed under the dash. Has he tried taking the positive feed from somewhere else? When I connected the signal to the switched coil connection it caused a misfire when the lights came on. This is on a K-series with a vdo tacho.
Tyrone Posted January 12, 2006 Posted January 12, 2006 He doesn't have a single coil. I queried Omex regarding installation of my Speed System with wasted spark ignition and they told me to set it up as a 2 cylinder engine. Not sure it would overcome the problem your brother seems top be encountering. Failing that, email Omex direct, they are very helpful.
Chappers Posted January 16, 2006 Author Posted January 16, 2006 Message from my brother... "Thanks for the replies guys. Trying a different ignition feed didn't work and trying my brother's Omex unit also didn't work so I knew the actual Omex unit was O.K. Anyway, it all now works. I managed to pull back the insulation off the coil pack to check the wiring and found that the outer terminals are the coil negatives (white/blue and green/white - Pins 3 or 10 on the MBE956 ECU). Armed with the wire colours, I carefully cut the insulation as the wires came out of the ECU and spliced into the white/blue wire. After changing the Omex unit to 2 cylinders (since the Zetec has 2 coils in its coil pack), both the shift lights and tachometer now work perfectly." Thanks very much, Keith Chappers I never knew it could be this good!
Tyrone Posted January 16, 2006 Posted January 16, 2006 Does this mean I answered a technical question (at least partly) correctly? If so, I'm printing it out for the next club meet. otherwise they just will not believe me 😬
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now