Hello all,

I am still working on getting my cat running well. Old Lucas has frustrated me at every step. From simply getting a Rotor and matching Distributor Cap through to installing a Crane Cam XR700 Ignition System.

Now I can get a running engine but cannot get more than 9 cylinders. I have opened up the Power Amplifier to find an occasional General Electric part???? Im guessing it wasn't too reliable for the previous owner.

I have trawled through much of the web and cannot find any non Lucas alternative to replacing the Power Amplifier and they are rarer than a rust free Jag new.

I am therefore looking to remove the ECU and Amplifier and put an aftermarket ECU in. This would rid me of at least all the Lucas Electronics. The ECU i am looking at is the DIY MegaSquirt from the US.

I am interested as to what others have done or even researched as its the biggest step to fully exorcise Lucas.

FYI my long term plan is to restore my cat with performance improvements as I go. Thats all in the future and Im actively listening to all the great information being passed through this Forum.

I look forward to your thoughts

 

OK.

Crane is what I used on ours, XR700, Bosch GT40R coil, universal ballast for voltage control, by-pass relay for start shunt, NEVER looked back.

The EFI is Bosch D Jetronic, and commonly known as the "grand daddy" of what we have in modern cars today, and SUPER reliable. The injectors are fired in 4 groups of 3, so 3 out is telling me you have an EFI loom issue, The fact that it is a Lucas loom, and mounted in the bottom of the "V", and is definately toast by now, and shorting all over the place.

I rewired ours in '94, fitted the Crane, and now it is sitting around 504000kms and starts on demand, stops on demand, drinks fuel, leaks a bit of oil, but NEVER fails to procede in a forward motion, EVER, and ALWAYS on all 12 cylinders.

 

Thanks Grant,

I thought exactly the same and spent countless hours wiring up a new loom. Got my soldering practice in to find the same three injectors not working.

 

Forgive my ignorance, but isn't most of the electrical system made up of Lucas components—not just the ignititon and ECU? Or have you been systematically replacing each and every Lucas component, down to the individual relays?

 

I am slowly removing the relays and replacing with modern equivalents. In time the old fuse boxes will be replaced with spade fuse holder.

 

Mmmmm, Bugga.

So same 3 injectors as with the old loom, tells me the injectors are "stuck", and bing PreHE, I would give them a good "whack" with a small hammer, or socket extension bar. I do it with the engine running, and you will soon hear them come alive as they are quite "clicky".

In case you are not aware, and if you are, sorry for repeating.

The groups are:
1A,3A,5A.
2A,4A,6A.
1B,3B,5B.
2B,4B,6B.

So if the 3 that are out are in the same group, it may be the amp (very rear), or the wiring still.

I have a PreHE injector wiring diagram on my PC, it is 3 pages of scan, and will email it if you want it, and tell me your email address. My luck at posting attachments here is dismal, coz I am not that savvy with computers, V12's are waaaay easier.

 

Unfortunately the three injectors not working are 2A,4A and 6A.

Im fairly confident its the Power Amplifier.

I opened it up and the resistance over three of the four outputs is 0.18ohm the fourth is 5.12ohm.

I have ended up buying the Megasquirt which should improve the reliability.

 

It sounds like one of the injector transistors is fried.

 

Why not spend the time and diagnose and repair the original system? Changing to aftermarket ignition and injection will not solve any of your current issues. It will give you different and most likely more things to do. You will have to source parts, make wiring harnesses and then dial it all in. The Lucas ignition is a pretty good system. The injection is a Bosch system with Lucas labels. The biggest issue with the electrics in these cars is the wiring that hardens and connectors that are not weather tight. You think factory parts are expensive, wait until you build your own injection system and then pay to use a dyno so you can dial the system in.

 

I am in agreemnet that the Lucas system in its time was reliable. However, it is 32 years since my cat was built and parts are too rare to maintain as is.

It is obvious what is wrong with my amplifier... Its the General Electrice parts that have been substituted in to the original Lucas system.

I thought to provoke keen discussion as to what all cat owners would do if money and time weren't an issue.

I personally can acknowledge that some cat owners want to maintain the Lucas soul to the car where some want a modern feel to a v12.

Im looking from guidence from more weathered owners as I personally want a reliable v12 with good performance.

 

well i use a SDS ECU system,(simple digital systems ,EFI)

and the Crane XR700 igntion, and a standard coil, like grant a by-pass relay for starting.

works for me, i have heard that the Megasquirt is a great system, and lot of backup information available.
besides being made in USA, for shipping advantages.
RON

 

Ron, how did you do the SDS ECU? Are you using two 6 cyl?

 

I am planning on using the Megasquirt already have the module for dual EDIS6 ignition control - I am so into DIY. Will be a next year job though

 

Warren, if you don't mind me asking, what did it cost for your system?
With all the injector problems I'm having, I'm considering all the alternatives.

 

I have not got the entire system yet I have been collecting bits and pieces.

here is a link to the MS website MegaSquirt Complete Assembled Units including Relay Boards and Stimulators Megasquirt Kits / Assembled Engine Management Systems, Wideband o2 Sensor Systems and tuning products - DIYAutoTune.com

You can buy completed ECU's on eBay if your not apt at soldering and building your own. IMO they are good value and even though I am an electronics tech by trade I bought the completed unit. Go for the MSII don't bother with III you don't need it. It can be upgraded to control ignition directly with the addition of drivers in the ECU, which is great - because you can basically use any ignition dual 6 cylinder or triple V8 coil packs. The Jag V12 late coil packs look suspiciously like Ford EDIS 6 coils so these do work and have been proven. Just not available in Aus - still might use them though.

I have spoken to a guy called Phil from South Africa you'll see him on youtube with a MS XJS and Cobra V12 he was very helpful as is the MS forums. Although I have not installed it yet. Need to get the rear end and the rest of the undercarriage finished first.

 

Im also a DIYer. I have just purchased the MSII MegaSquirt in the kit form.

This is my new years project. I have also bought their relay board to tidy up/replace the messy wiring in the boot.

After reading the MegaManual I am more concerned at programming the ECU than getting all the boards constructed and installed properly.

 

What are you planning on running for ignition?

 

In the very end I will have the MegaSquirt with EDIS run the whole system. Unfortunately without knowing my Power Amplifier was crook. I ended up getting the Crane XR700 which is very reliable.

Its all part of the fun. I also managed to get a new rotor with the correct magnet which according to the supplier is the last genuine one. Likely that will trigger the final upgrade.

 

EDIS is tried and proven so would be good choice. I looked at the MS and Delco 808 (commodore ECU) I was leaning to dual 808's as the EDIS 6 ignition modules were not installed in anything sold in Australia. And the 808 is very cheap and almost every tuning shop knows them. But the coil packs are very large and quite expensive so I have decided to go MSII and dual EDIS 6

 

YES as has been said, the final programming of the fuel and ignition curves, for me were the absolutely hardest part to accomplish,

i must have spent 3times the effort in programing as to the actual installation.

remember this was 16yrs ago, so a lot of information just was not easily available.

and the professional grade EFI systems ,costs, were in outta space, like Motec of the 1994 ERA, $10,000.