3.9 carb to efi conversion

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bendelaurence

New Member
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234
Right, I've finally made the decision to get rid of my holley carb and make the switch to efi.

My engine started out life as an efi, then was converted to holley carb. But now i own it, i want the fuel econ back.

So what i need is a comprehensive list of parts required so i can get to work.

Also do i have any options to consider....? Some mentioned the megasquirt ECU insted of the standard landrover one

Also, if anyone is on efi and fancys the switch to carb get in touch, maybe we can do some kind of trade. Wouldnt mind working with someone to get them swapped too.

DISCUS!!! :D
 
well if you buy a rotten scrapper you will have all you hotwire bits there, plus I will buy the interior bits off you to fit into my 72 RRC :D
 
sounds good , I would have looked on ebay , one went for about £400 the other day.

What have you found and where?

PM me if you want.
 
Not forgot about u mate. Just reasearching a couple of things. Apparently the cam shafts in the efi are different to the cams in the carb motor.

Just need to find out which I've got. Hopefully they didn't bother changing them when they first concerted it to carb.

Also apparently the gearboxes are geared differently.......

Anyway, once I've got the job planned and finalised I'll find one and get in touch.

If u find anything good in the mean time let me know mate
 
So have you finally finished the job? What are the results? Any better fuel economy? Where did you get the spare parts? That old truck you bought?
I've read a thorough report from some guy who installed an EFI system from 3.9 motor to his 3.5L engine. As far as I know he hadn't swapped or altered the camshaft - it was a standard 3.5 engine. BTW, there are two different models of 3.5L engines - with different compression ratios. May be that's the trick? Thinking of completing the same job.
 
Hi guys, yes finally finished the job. I was short on cash (bleeding recession!!) but a guy offered to swap his complete hotwire/manifold for my holley/manifold as he needed it for a hotrod he is building. Strait swap, no money involved :).

I currently have it setup with no lamdas and i have to say it's great, but very different. Loads more talk/power, no flat spots,correct mixture, idles better, starts better, smoother. My only problem is stalling pulling up to junctions. But i'm pretty sure i have this sussed.... My gearbox currently has an analog speed cable going to a analog clock, these need to be swapped out for the digital ones, then i can supply the ECU with road speed date i.e. it will know when it is coasting in gear, or idling out of gear. Once thats done it should be fine.

I have to say though that it's not all positive with efi. It all depends what you want. My Holley sounded better, alot better!! It was way more exciting to drive, even though it was slower.

Summing up i'd have to say, if you're looking for performance, reliabilty, and fuel economy go with EFI.

If you want a gas guzzling bundle of fun, excitment, and noise go with a carb.

If anyone needs any advice on the conversion feel free to contact me. I've done it from start to finish, overcome alot of problems, and know the system pretty well now.
 
bendelaurence said:
My only problem is stalling pulling up to junctions. But i'm pretty sure i have this sussed.... My gearbox currently has an analog speed cable going to a analog clock, these need to be swapped out for the digital ones.
Click to expand...

Not necessarily!! I am reasonably confident that if you get hold of an early speed transducer you can have the cable up to the older analogue speedo head because the transducer has drive cable connectors at both ends, as long as you have got the wiring harness in place, it should be reasonably straight forward.
 
Really? So there's a speed transducer which take the analog speedo cable aswell? That would be perfect! Just need to find the right one for my gearbox now..... This could take a while. Any ideas?
 
bendelaurence said:
Really? So there's a speed transducer which take the analog speedo cable aswell? That would be perfect! Just need to find the right one for my gearbox now..... This could take a while. Any ideas?
Click to expand...

As far as I know the standard transducer will take the drive cable at both ends. Go and fin yourself a late '90 RRC or a '91 and look at the transducer. One end is connected to the gearbox, the other has a blanking nut on it. Remove the blanking nut et voila there is an identical cable drive as found at the other end!

A new transducer is however quite expensive. Might be worth looking on fleabay (and buy 2!!)
 
yes my transducer has two drives one either side. Its off a 93 3.9 RRC. I curently have the gear box to transducer connected so have no stalling issues but have not re connected the speedo side.
 
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