MSD Ignition Module ....

[ultimarich]

Dear all,

Have just taken the car for a Spring tune ...

A couple of queries arose around the dizzy and coil. Most notably it appears the MSD dizzy requires a version 5/6/ or 7 control module to run properly but I couldn't locate anything in the engine bay or in the bulkhead pods.

Apologies for the dunces question but have I missed any other obvious place that it may be housed ??? or is it possible the car is running without and is simply over juicing with a permanent 12V.

Any help, as ever, would be much appreciated.

Cheers

Rich

[bigmack]

Ugh...it should be a red box that says MSD on it. More than likely, if they did use an MSD box, it would be a 6A or 6AL. I don't think the MSD dizzy requires an MSD brand box. They could have gone with another brand. Just a side note, I prefer to mount mine behind the seats down low on the rear bulkhead. The engine bay gets too hot. You should see some kind of ignition amplifier box somewhere. Keep looking and let us know how it goes.
Cheers!
-Mack

[davefiddes]

I believe that you can run with just a MSD billet dizzy. It behaves like a GM HEI dizzy which is basically a simple (these days) transistor ignition module. A lot of people hook them up to MSD 6AL or some other flavour of capacitive discharge ignition box to get a more powerful spark particularly on cold days or at high revs. It is not an absolute requirement though.

[ultimarich]

Thanks guys.

Will phone the factory on Monday as the mysterious red MSD box is nowhere to be seen. The car is now starting okay but I'm told that running a permanent 12V through the dizzy is not desirable.

Am going to replace the dizzy on the car for one with a vacuum advance. Am hoping that amongst other things I can get the car to behave a little better at lower revs and improve on the truly awful fuel consumption I'm getting .... or is that just due to a heavy right foot

Will report back on Monday.

[davefiddes]

Note sure what you mean by running permanent 12V through the dizzy? The standard Ultima wiring loom hooks switched 12V into the dizzy which is then directly connected to the coil. This should be a perfectly acceptable setup. An MSD box fits between the dizzy and the coil and requires a permanent, high current, feed of 12V. A modest amount of rewiring is required to do this neatly as has been discussed in the past...

I'm with you on the vacuum advance. I'd guess you've got an American Speed engine as well. I'm not quite sure why pretty mild engines like my 425 bhp one (13" of vacuum at idle) are shipped without vacuum advance. To the best of my knowledge the MSD P/N 8360 comes with a vacuum advance kit...which American Speed probably have either turfed or added to the spares drawer. Should be possible to get a replacement part from your friendly neighbourhood Chevy V8 bit supplier.

I don't think that this will fix your fuel consumption a huge amount (but will probably be great for low rev driveability). A few weeks ago I got myself a wideband oxygen sensor from TechEdge in OZ. Haven't had much of a chance to play with it yet but did get 15 mins to stick it in the car in the driveway (i.e. no load - YMMV). What it showed me was that the Holley carb as supplied produces an almost perfect Air/Fuel ratio of 12.5 from idle through to 4k (wasn't happy to rev any more on the drive). This should be perfect for max power. Absolute pants for getting decent economy on cruise though where you are looking for 14.7-15 (slightly lean off stoich). I think that this is where the real gains in fuel consumption are to be had.

If I could have another go I'd ask Gail at American Speed to build an engine with better road manners...or given the exchange rate ATM just get it with Holley EFI.

There's some interesting reading I found a few months ago on how to tune Holley carbs that you might find useful. They apparently can be made to cruise quite well but still have all of the fueling capability needed to run at full power and not go lean. Not planning to go that way myself...am hoping to go down the EFI route later this year in the search for better driveability (if in doubt apply a sledgehammer to crack the nut ).

Course if you are having the same problems as me with the odometer then try dividing your fuel consumption by 0.8...it might make it a lot nicer than you originally thought

Apologies for the inordinately long post()...

[steve_D]

ultimarich said:

....Most notably it appears the MSD dizzy requires a version 5/6/ or 7 control module to run properly but I couldn't locate anything in the engine bay or in the bulkhead pods........

As you have not see an MSD 6AL a word to the wise....It's bright red and only slightly smaller than a house brick. There are few places on an Ultima you can 'Hide' one.
Steve