converting form V8 EFi to V8 with carburettors

[Smokydiesel]

I might need to replace my worn V8.

Seems that a lot of V8 engine's for sale are EFI's.

How easy is it to convert back to SU carbs ?

What do I need to replace ?

Thanks !!

[stuck]

Ehm,

I think you'd only need to replace the inlet manifold for with one with carbs but I wouldn't.

If you must fit carbs fit the original SU's and not a bloody Eddlebrock / Webber.

I assume you've heard of Megasquirt but don't want to convert the EFi for some reason?

[Smokydiesel]

I assume you've heard of Megasquirt but don't want to convert the EFi for some reason?

Hi,

Bit of a V8 -newbie here...

I want to keep the job as simple as possible, that's why I was thinking of converting back to SU's

If I were to go down the EFI-route, what would I be looking at ?:

ObviousIy I need the computer....

I suppose that computer needs input by several sensors ?

Different throttle that sends signals to the computer ?

Or is it more simple than that ?

Thanks !

Edwin

[stuck]

Have a look here Edwin

http://www.megasquirt-v8.co.uk/index.php

Hmm, wonder if Nige pays commission?!

HTH's

Mick.

[Bowie69]

Using the standard efi setup will be fine fire you, and only a couple of wires to connect up, unless you really want it, MS is not going to be for you if you think normal efi is complex

[geoffbeaumont]

Megasquirt isn't any more complex to set up than the standard Lucas Hotwire or Flapper systems - arguably easier (or at least that's what I found*) as you can plug a laptop in and see exactly what's going on. Of course if you happen to buy an engine with a complete loom, ECU, etc. then it is more expensive, but I'd never bother with the Lucas systems again. Plus you can use modern coil pack ignition instead of the distributor and have a V8 that doesn't splutter to a halt crying for WD-40 every time you drive through a pool.

As to whether you'd be happier with carbs or EFI I won't venture an opinion as I've no experience of running a carb'd land rover.

* - I gave up trying to diagnose a problem with the Hotwire system on my first Range Rover and swopped to Megasquirt, which was already installed alongside it running only the ignition - I'd spent weeks trying to trace lousy running, going through the Hotwire diagnostic routines and finding nothing. Within five minutes of getting the Megasquirt running I could see on the laptop that there was an intermittent signal from one of the lambda sensors - turned out to be an internal break in the wire, that wasn't detectable with a meter without the vibration from a running engine.

[Smokydiesel]

Using the standard efi setup will be fine fire you, and only a couple of wires to connect up, unless you really want it, MS is not going to be for you if you think normal efi is complex

Thanks for all the replies so far guys !

I'm sure MS is great but it seems far to complex and expensive for me.

Not to bothered about 10 BHP more or less, looking for a simple job that will get me on the road again in a weekend.

I'm from the TDI-planet, so a plain and basic V8 (EFI or Carbs) is heaven to me ;-)

Bowie, could you give me a step by step instruction on what to change/connect/hookup/get when I put an EFI in ?

Thanks

[stuck]

Depending upon what you take the EFi lump from you will need to connect up:

ECU obviously

Air flow sensor

Coolant temperature sensor

Lambda sensor (or tune resistor)

Injectors

The idle speed valve

Throttle position sensor

Etc, etc.

I'm sure I will have missed several things.

To be honest MS is no more complicated than EFi, some would say less so.

If you want simple & a conversion you can do in a weekend changing an EFi lump back to SU's is probably your best option

[Smokydiesel]

Depending upon what you take the EFi lump from you will need to connect up:

ECU obviously

Air flow sensor

Coolant temperature sensor

Lambda sensor (or tune resistor)

Injectors

The idle speed valve

Throttle position sensor

Etc, etc.

I'm sure I will have missed several things.

To be honest MS is no more complicated than EFi, some would say less so.

If you want simple & a conversion you can do in a weekend changing an EFi lump back to SU's is probably your best option

OK, that cleared it up for me !

Carbs is the way to go for me....

Thanks !

[p76rangie]

Using the standard efi setup will be fine fire you, and only a couple of wires to connect up, unless you really want it, MS is not going to be for you if you think normal efi is complex

Little more than a couple of wires. I am just in the process of changing a carbie 76 to a 14CUX rangie system. Even with the full EFI wiring loom it is still reasonably complex and time consuming.

[FridgeFreezer]

To switch back to carbs is not hard, it's just the inlet manifold to swap over although there may be plumbing issues as there are numerous variations of heater plumbing / front cover etc., not such a biggie if you can transfer bits from your old engine.

Flapper EFI is dead easy to get running, it's very basic, only needs ~5 wires (power, ground, fuel pump, revs from the coil -ve) and the rest is self-contained. However, if you don't like electricals and just want to get back on the road you're probably best off sticking with what you know for now and pursuing the parth of enlightenment at your own pace

[Bowie69]

As above it is just 5 wires, and a high pressure fuel pump, water plumbing shouldn't be much different, but as above you can use bits to make it fit... as you don't seem scared of mechanicals it shouldn't be a problem for you

In case you didn't know, the EFI loom is completely separate from the rest of the car, connecting in just a few places, everything else just plugs in, and you can't really get anything in the wrong place, all the plugs are 'coded' to the socket.

I would say 5 wires is far simpler and cheaper than getting a working Lucas EFI setup working, especially the hotwire.

don't get me wrong, I love my MS to bits, but for a stock engine and if you are a bit hard up like most of us it's a bit overkill.

[Smokydiesel]

Fridgefreezer: yes, I think you're right, the best and fasted way to get going again is with Carbs !

Bowie: let's see if I understand what you are saying:

So there is a difference between a flapper EFI system and and Lucas EFI system ?

Flapper is much easier to hook up compared to Lucas....

How do I recognise a Flapper from a Lucas ?

[Bowie69]

Both Flapper and Hotwire are Lucas, I was just using 'Lucas' so I could refer to both at the same time

Arguably, Lucas Hotwire is the better system (it is later after all), and found predominantly on 3.9s, 3.5s got the Lucas Flapper system, idnetifying between the two is pretty easy on the engine, the Flapper has a 'ninth injector' on the RHS of the plenum, the Hotwire doesn't.

3.5 on carbs = ~135BHP (depending on carbs.... if you have the resticted ones it is just 90!)

3.5 on Flapper injection and no other changes = ~155BHP

3.9 on Hotwire injection = ~185BHP

3.9 on carbs.... who knows (never factory fitted), but I'd wager not much more than 160BHP.

I think I made a mistake in my last post, it meant to say 'I would say 5 wires is far simpler and cheaper way of getting a working EFI setup, than Megasquirt in any flavour'

Oops

[muttleyd]

Have to say I have a 3.9 on carbs and it runs badly and only 8mpg. Admittedly there may well be something else amiss that I am yet to find but all the usual checks have turned up nothing.

I am hoping MS will help improve the rough running and the fuel economy. And whilst buying SU,s will be cheaper if you have to refurb or gaff with them it's never going to be as economical or smooth as efi.If you decide to go for a weber or edelbrock it's not much cheaper than the MS kit and you already have most of the engine bits.

Anyway good luck with the motor.

[p76rangie]

As above it is just 5 wires, and a high pressure fuel pump, water plumbing shouldn't be much different, but as above you can use bits to make it fit... as you don't seem scared of mechanicals it shouldn't be a problem for you

In case you didn't know, the EFI loom is completely separate from the rest of the car, connecting in just a few places, everything else just plugs in, and you can't really get anything in the wrong place, all the plugs are 'coded' to the socket.

I would say 5 wires is far simpler and cheaper than getting a working Lucas EFI setup working, especially the hotwire.

don't get me wrong, I love my MS to bits, but for a stock engine and if you are a bit hard up like most of us it's a bit overkill.

There 40 wires going to the ECU and you have to figure them all out to fit them into a pre-EFI system.

You have the problem with it requiring a electronic speed signal from a transducer to know when it is stopped to adjust idle and when it is moving to cut the injectors under deceleration. If you grab a wiring loom from an EFI car you will have all things not related to the EFI system integrated into the wiring loom that is not directly related to the EFI system and you have to get rid of them.

Then you have the issue of whether the wiring loom as O2 sensors wired in or not that you have to pull out. Then change the tune resistor to suit a non-cat vehicle.

Then there are the wires to do with controlling the air-con, heated window demisters, etc, that you need to get rid of. Wires to connect for the coil, check engine light, fuel pump relays, main relays, Ignition supply, battery supply, speed transducer, etc, etc. There is also the issue of them using a number of black wires for anti-theft reasons, so you cannot work out what they are for without stripping the wiring loom.

If you are running a manual you need to put a resistor on the transmission signal wire.

As already stated, I have just finished this week wiring in the EFI system for a 76 Carbie Rangie and it is certainly not as simple as connecting 5 wires

[Bowie69]

I'm sorry, but I really think you are over complicating the issue rather, you certainly don't need to know where each of the 40 wires going to the ECU go, the other ends of them are coded plugs as I said, so very hard to get in the wrong place, the only one I can think of is the CTS and FTS which can be swapped accidentally.

Hotwire certainly runs absolutely fine with no speed sensor, fuel cut on decelleration works, IIRC, from the TPS value going to virtually nil, and uses the engine RPM to decide when to turn the injectors back on afterwards.

The wiring loom from an EFI RRC for example is completely separate from the rest of the truck, it literally unplugs.

Very few Hotwire trucks came with lambdas, if it has got them then you just unplug them and don't connect, change tune resistor to a suitable value, the info for this is on the web and in the workshop manual.

There will be a wire for the aircon, if fitted, but I expect it exists on the truck even if it's not fitted, no need to remove, just leave in place and insulate off if you feel necessary.

Ignition supply/battery supply and earth are all readily available on any LR product, so once you know the wire the loom expects to find ignition live, permanent live and ground just connect them up. Relays are all in separate holders and you don't need to touch them.

Take the white/purple from the fuel pump relay and use this to feed the HP fuel pump and connect the white/black wire from the AFM part of the loom to your coil negative.

No realy need for a check engine light, in fact the earlier Hotwire RRCs didn't even have one.

If a manual you will need to connect together (or leave unconnected, I forget) the start inhibit switch wires.

As for black wires for anti-theft, this is more likely to be aftermarket, but actually very easily bypassed, just trace the wires and match insulation colours and resplice, job done. It is likely you will find that most only cut the starter signal (both of mine did this, and a mates).

Wiring diagram, looks bad, but you are only interested in the bits around the ignition switch, and fuel pump relay. Learn to read the wire colour codes and you are set.

I have a mate with this setup fitted and working in a 90, adn is perfectly easy enough to work on, and a complete electro-phobe managed to fit it no problem.

[p76rangie]

I'm sorry, but I really think you are over complicating the issue rather,

You have obviously done it a few times and have worked out a way that suits you. We will leave it at that.

[Cynic-al]

Assuming there is nothing wrong with your carbs and inlet manifold i would just bolt those onto the new engine, I owuldn't go from carbs to flapper EFI if you don't like electrics. It is a very simple loom that you just plug in, I took mine out whole when I did the MS and from memory there was only one 5 pin plug under the dash but you need to add other sensors ie the flapper which means altering your inlet.

However whilst the engine is out and especially if you couldn't run it before you bought it I would be tempted to inspect timing chain, oil pump, bottom end, gaskets etc. You could easily throw another couple of hundred quid at it as they are generally pretty tired.

[iomlt]

I have done two efi hotwire installs into my landrovers and its so simple. al the wiring for the engine side took about 1 hour. the longest bit of time for me was choosing where to mount and mounting the ecu and the two relays. its all plug and play. off the top of my head, Constanst 12 v, ignition 12 volts, Wire to high pressure fuel pump, earths. think thats about it that i had to join up. I choose a hotwire system without lamba sensors. touch wood never had a problem in 3 years and have been in some mighty pounds in the challenge tuck.

My 90 used to be a carbed V8, so i thought the same as you to start with keep it simple. but its not that simple when it comes to balancing carbs and the likes. fit the Hot wire off it goes. if you have a problem loads of spares and its a very simple loom to trace wires.

just my experience

AL

[iomlt]

Oh the wiring diagram above all be it true does make it look awful scary. Its not.

[p76rangie]

Oh the wiring diagram above all be it true does make it look awful scary. Its not.

Firstly the colour codes in wiring diagram do not apply to many of the looms out there.

Secondly, there are two plugs in the wiring diagram that plug into other looms. These plugs are 32 and 12 on the wiring diagram. These two plugs have 12 wires as a minimum that you need to work out where they connect into you old wiring loom.

Then it is going to come down to what type of job you are going to do. Are you going to leave all those plugs, relay mounts, and extra wiring in the loom and leave it to future people who may have to work on or own your car to figure it out. Or are you going to get rid of all the stuff that you are not going to use and simplify everything so someone might be able to sort it out in the future.

Then you have things in the wiring loom that have nothing to do with the EFI, like sensor wires for your gauges and tacho, alternator wiring, etc. When you are fitting it to an older motor, such things are often in different locations. Again are you just going to leave such wiring hanging out of the loom, put it to the right location, or remove it.

As previously stated, the main thing missing is a speed transducer on your existing carbie vehicle. It will run without it, but you will have **** idling and lack of engine braking off-road.

To me it seems to defeat the purpose of attempting to improve your vehicle with EFI if all you are interested in is the quickest and dirtiest way of putting it in.

[Bowie69]

Wires that connect to points 27,28,29,30,31 on connector 32 can all be ignored, these are to do with the aircon, so unless fitted are not required. It's a loose plug so leaving it in situ is not a problem.

Connector 12:

Top pin: ignition feed

Next: out to fuse, inertia switch and fuel pump

Next: Out to EFI warning light (not required or fitted in many cases)

Next: Permanent live

Next: Neutral/Park switch for auto box -not required is a manual, but very easy to fit if it is an auto

Next: Heated screen input -not required if not heated screen is fitted, but easy to connect up if needed.

Then you just need to ground the obvious points and job done.

Alternator IND wire, tacho and main battery charging wire is part of a separate loom, so you can leave your existing wiring in place with no duplication.

Speed sensor makes very little difference in my experience, but there is of course nothing to stop you fitting it anyways.

[iomlt]

Firstly the colour codes in wiring diagram do not apply to many of the looms out there.

Secondly, there are two plugs in the wiring diagram that plug into other looms. These plugs are 32 and 12 on the wiring diagram. These two plugs have 12 wires as a minimum that you need to work out where they connect into you old wiring loom.

Then it is going to come down to what type of job you are going to do. Are you going to leave all those plugs, relay mounts, and extra wiring in the loom and leave it to future people who may have to work on or own your car to figure it out. Or are you going to get rid of all the stuff that you are not going to use and simplify everything so someone might be able to sort it out in the future.

Then you have things in the wiring loom that have nothing to do with the EFI, like sensor wires for your gauges and tacho, alternator wiring, etc. When you are fitting it to an older motor, such things are often in different locations. Again are you just going to leave such wiring hanging out of the loom, put it to the right location, or remove it.

As previously stated, the main thing missing is a speed transducer on your existing carbie vehicle. It will run without it, but you will have **** idling and lack of engine braking off-road.

To me it seems to defeat the purpose of attempting to improve your vehicle with EFI if all you are interested in is the quickest and dirtiest way of putting it in.

without sounding rude,

But most of what you have highlighted there makes little or no difference. both my cars run perfectly. idle perfectly and ones manual and one is auto. engine braking is as you can imagine slightly better in the manual.

Mine is a very clean install. done around 25 thosand miles with no problems at all.

Maybe and likely if you have had trouble in the past then maybe there was a undelining issue that cause you so much grief and is maybe whey it has made you with the mind set you have. But there is aleast two of us here that have not had the trouble you seem to highlight.

I'm about to do my 3rd , 4.2l auto in a 90. i'll be sure to left you know how that goes

[p76rangie]

But most of what you have highlighted there makes little or no difference. both my cars run perfectly. idle perfectly and ones manual and one is auto. engine braking is as you can imagine slightly better in the manual.

The ECU does two main things related to speed that cause issue without a transducer. Firstly, throttle off and car near stationery, it will attempt to adjust the idle. With no transducer it will think that the vehicle is stationery all the time. So whenever you back off the throttle it will attempt to adjust the idle. So when you actually do stop it has attempted to switch the idle right down and easily could stall. This means that you will be mainly relying on your base idle settings, which will still cause the motor to idle incorrectly until the motor reaches running temp.

Secondly, the ECU will cut fuel to the injectors when you take your foot off the throttle and are still moving. It will not cut the injectors when you are not moving. So with no transducer it will never know you are moving and it will never cut the injectors. Therefore, engine braking is affected.

These affects are not imaginery. You can check in any literature on the 14CUX and they will confirm the effects.