A technical question for Chris W.

I think the coil pack on the Sunbeam is dead but just want to be sure that there's no was ity could be the ECU.

I have a weak spark on 2 & 3 and my understanding of wasted spark coils is that they fire on 1 & 4 and 2 & 3. Three wires go to the coil, Drive 1, 12v feed and Drive 2. am i right in thinking that the drive wires signal the coil to spark on 1 & 4 or 2 & 3 and would not be able to cause a weak spark, only a loss of signal would create no spark?

The coil is a Bosch unit as used on 2000cc Vauxhall XE engines. The ECU is an old MBE 912.

With just the ignition on, you should get a good 12v supply to the positive lwire of the coil. That only leaves the coil and leads.

Well that method worked for Col and myself this weekend.

Sorry,head down doing the finishing bits to the mag.Some of the Vauxhall coil units used to be driven by an ignition module and not so much the ecu,and yes you are right in the fact that wasted spark would be firing on the exhaust stroke on the opposing cylinders.If you can give me a rough idea on age of the ecu and wiring colours at the coil pack I might be able to find a wiring diagram and values you might expect at the coil unit.Three wires at the coil give me a clue,I will check autodata tomorrow.

Thanks Chris,

The ECU is nothing more than an electronic ignition module. It was made by MBE as a competition unit.

I just wanted to get my head around whether the strength of the signal from the MBE unit would affect the output of the coil given that the coil has a continous 12v supply. Do you think it could case a weak spark?

I'd guess it's possible. The ECU will have driver transistors to do the job previously done by the points, and (unless they've done some extremely clever circuitry) a couple of condensers to do the job once done by the condenser. If one of those starts acting up, the result could be a weak spark on one side, although I think it's more likely for one side to pack up completely. You'll need an oscilloscope to check it though.

O.K. I have tried to find it and have come up with an ecu that may be similar,I have emailed you what should be the pin out of your ecu and the connections at the coil pack.What you should have is either a 3 or 4 connection at the coil pack,the extra wire is an earth (used for screening as well),between the positive connection at the coil pack and one of the trigger connections (the primary resistance) you should have around 0.5 ohms and that should read roughly the same for both trigger connections (one trigger for one & four and one trigger for 2 & 3) if the resistance is not the same if they then you should suspect the coil pack.Bobs idea of an oscilloscope or wave form viewer would be favorite for checking the signals from the ecu or module.

Isn't technology wonderful - I remember when a 12v bulb and bit of wire sorted out wiring problems - now you need a wave form viewer (I bet there not cheap) or a sillyscope - I'm still getting to grips with Office 2007 and transferring dvd's to my Ipod

Whats an Ipod

An iPod is a portable device for storing and playing audio files encoded by MP3 or AAC compression algorithms. Designed by Apple Computer

I knew you were going to ask that - MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression and AAC, Advanced Audio Coding, is a technique for compressing digital audio files - ok now?

















Sorry James for hijacking your post - hope you get it fixed.

What he means Rob is..."imagine a gramaphone....but really, really small.... that you can put lots of 78s on and runs on funny little tubes containing elektrikery..or summat"

Hope that helps.

Mk3rob wrote:MP3....AAC

AAC is easy. American Auto Club.
MP3 is a little more more dificult. Could be something to do with forthcoming elections.
(Possibly total number of MPs who are trustworthy)
I did a search on Yahoo but as there are about 3,050,000,000 entries, I gave up.
Try asking a five year old i'm sure they could help

Thanks Chris & Bob,

Bob you get the prize, it's one of the drivers in the ECU that's packed up. I spoke to SBD (really helpful as always ) and they were amazed that my MBE 912 ECU had lasted this long. usually one driver packs up but occationally they will partly pack up giving a weak spark on two cylinders.

The MBE 912 unit is over 10 years old (apparently) so I've had to order a new one & a loom for £550!!! but i can't sell the Sunbeam without it. SBD are mapping it for me using the spec i've given them (it's only a electronic dizzy so not rocket science) so all i'll need to do is plug and play, I hope!

A good guess!

Incidentally Martin, my own 'scope cost me all of £2 - they had clearouts from time to time at work and flogged off the surplus stuff. I missed out on the good 'scopes at £10 a time and got one that had been dropped on the floor, but apart from the broken handle it proved to be OK. After 20 years though, it's probably out of calibration.

One of the drivers has packed up? what and gone home? I'd sack him if I was you James - you could get a Scamp with an MOT for £550 - by the way OS maps are now free to download but that sort of mapping won't be of any use to you I suppose - lucky its not the Shuttle or the ISS your trying to fix - I don't suppose you can get Eastenders on your scope Bob now wev'e gone digital - was going to get a 60" HD ready tv but now saving for a HD 3D ready one now - now where did I put those cardboard 3D glasses I had in 1971?

We used to have a digital waveform viewer and that got us out of the cack on many occasions(we've recently sold it on ebay),only thing was it was not fast enough for digital systems so we have just invested on a new piece of kit(just got to learn how to use it now!!). Incidentaly we had an 04 plate Fiesta ecu go down on a signal lead and that was caused by a spike up the low tension side from a faulty coil,so make sure you check that as well.

Incidentaly Martin,you'll find your 3d glasses along side of your flares,your medalion and your chest wig.

Don't you mean "loons"