The V8 Owners Forum -

I've had running issues with my 3.9 hot wire efi for some time now (high idle speeds, difficult to start, missing/coughing at higher revs) and now it is loosing water ffs. I have here a 4.6 gems engine in a p38 rangerover I was planning to fit. What are my options for fueling this engine? I take it the hot wire system would not cope? Is it possible to fit the gems injection system? Or do I go down the carb route and if so what is the preferred setup for that?
Lots of questions I know.
Regards Alan

Obvious way (to me) would be to use an after market programmable ECU with either. Like a MegaSquirt. The software on that will show you if you have problems. But budget for a wideband O2 sensor too.

From the little I’ve read on it the gems seems like quite a good system that was way ahead of its time, probably worth using if you have it all.

Thank you for your replies. With regard to a stand alone unit does anyone know of any useful reading online? And with the gems how many other inputs do I need to run it thank you.

MegaSquirt has its own forum. With online full manuals for each type.

http://www.msextra.com/forums/index.php

Unless you have someone like Dave to set it up for you, I would stay away from Megasquirt as it is just too much hassle with too much conflicting information. Get a propriety ECU not a hobby kit unit like Megasquirt.

I would stay with your original ECU and send it to someone like Tornado Systems to set it up.

Garry

I'm very pleased with the MS2 in my SD1. Getting on for 10 years old and had been totally fault free. Unlike the Lucas injection previously fitted.

As regards info, you do need to know where to look for it, which is why I gave the link to the MS forum. And if intending DIY, learn at least the basics, so you can decide what you want. It is all freely available.

The problem with GEMS is that it needs to talk to the rest of the body electronics if the system is from a P38 Range Rover.
What you need is a 'standalone' setup, which was only found in the 50th Anniversary Defenders (which were 4.0 GEMS engines). They might have been in NAS spec Defenders too, and maybe some others like Morgans. I have an idea that Tornado Systems can do you a standalone ECU.

My intention is to use the Thor system from a later P38 Range Rover and a suitable ECU from Tornado Systems, as I believe the Thor system is more reliable.

Chris.

IIRC the Thor system is Bosch Motronic. But you'll have the same issues with it being integrated to the rest of the vehicle electronics, so may well need modifying to work stand alone. This can be done, but can be costly.

Which is were an after market ECU comes in. They are totally programmable at home using your computer. Allowing you to use (say) any suitable injectors, etc, that takes your fancy. And when you are assembling your own individual engine and injection system, it's pretty likely you'll not want to follow exactly what the maker did - even if possible.

If cost doesn't matter you could use what many of the racing types do and use say Halteck. Get it pro installed and tuned.

But if costs are a consideration, MegaSquirt is the one to go for, if you're willing to do a bit of learning.

Depending on model, MS can provide a basic fuel only system. Or include programmed ignition, getting rid of that dizzy and improving both performance and reliability. Wasted spark being the easy option. Or go the whole hog with both sequential injection and ignition. All it needs is taking care, reading things up carefully, and following instructions. If I can do that I'd say probably anyone can.

The cost of getting a Thor ECU modified to run alone is far less that the cost of setting up an appropriate Megasquirt system.

I currently have two P38's both with the Gems engines and both have Tornado chip sets and run LPG, now I know lots of people think the later Thor V8's are better, can't comment on this but I can say both my Gems engines are rebuilt top hat lined units and apart from being thirsty are reliable with only one needing a new water pump due to a weep.

I plan on taking one off the road and having Mark Adams at Tornado Chips "unlock" the ECU since it already has his chip set and use it as a standalone engine swap into either my 110 or possibly my Scimitar.

Mark is one of those guys with a wealth of knowledge and to me it is a much cheaper route to go to get a standalone system than some of the other options, plus you can get some cracking deals on P38's with airbag issues and electrical gremlins that gives you a good source of parts for an engine swap along with if your lucky enough spare parts to sell to recoup your outlay on the P38.

Worth deciding from the outset what you want. The Thor system is Bosch, so likely the easiest to get spares from and also the most reliable. But the Thor was designed for 4x4 use, so gives better low end at the expense of the top end, over the earlier Lucas plenum, etc. You also have to factor in the cost of any mods needed for standalone and having it remapped if your engine isn't standard for the injection system chosen.