DIY EFI

[Clamity]

I'm thinking of switching the carb on my Toyota 12R (1.6L, 75hp) motor for an EFI setup for better fuel economy and easier starting.

I've owned my '72 Hiace van for a few months now. Once it's warm it runs pretty smooth and seems to go okay. I've only just got round to working out the fuel consumption and unfortunately it's only managing 16mpg on a 100 mile run at a steady-ish 55-60mph. Obviously something's broken but it's had many of the service items replaced beforehand: air cleaner, points, dizzy cap, plugs, thermostat, so I suspect the carb has had it.

Anyhow, I'm thinking of building a megasquirt and have a fair idea of what I will need. I want to modify the existing setup as little as possible though, so ideally I'd like something to drop in in place of the old carb (which is a downdraught type). I'm thinking a swirl pot and an electric fuel pump off a bike to feed an all-in-one throttle body/TPI/injector/pressure regulator (which I'll plumb a vacuum sensor into, as opposed to getting an expensive one with an air mass sensor).

So my question is, what's a suitable donor for such a throttle body? (A Japanese car would be a bonus.)

Cheers!

[screech]

i know its not ideal but what about a single point injection set up. there essentialy one big injector inside a carb body.

now if you inject it then it will never look stock, so i would sugest doing a proper port injection job.

megasquirt is actually very easy to work with as long as you take your time with it.


now if i could just figure out why my injectors are not firing.......

[Clamity]

Okay, so I was reading this: www.302w.com/Windsor_MegaSquirt_Part2.aspx and he sourced a nice looking unit which replaced the four barrel on his V8 and has all the required parts apart from the fuel pump. To be honest, I don't care what it looks like too much, just I didn't want to start hacking the van around too much. So I'm looking for something similar to that Windsor installation, just not so big.

An Ebay search for throttle body turns up lots of cheap new ones, and a quick search for the make and model will say what the intended motor's output is, but seller's pictures don't really tell you whether they include the injector and pressure regulator or not. Just wondering if anyone had any insight into what's out there.

I know its not ideal but what about a single point injection set up. there essentialy one big injector inside a carb body.

That's exactly what I had in mind. Hope it's not too compromised.

[J1MMY]

Jan 3, 2010 19:21:59 GMT Clamity said:

I'm thinking of switching the carb on my Toyota 12R (1.6L, 75hp) motor for an EFI setup for better fuel economy and easier starting.

I've owned my '72 Hiace van for a few months now. Once it's warm it runs pretty smooth and seems to go okay. I've only just got round to working out the fuel consumption and unfortunately it's only managing 16mpg on a 100 mile run at a steady-ish 55-60mph. Obviously something's broken but it's had many of the service items replaced beforehand: air cleaner, points, dizzy cap, plugs, thermostat, so I suspect the carb has had it.

Anyhow, I'm thinking of building a megasquirt and have a fair idea of what I will need. I want to modify the existing setup as little as possible though, so ideally I'd like something to drop in in place of the old carb (which is a downdraught type). I'm thinking a swirl pot and an electric fuel pump off a bike to feed an all-in-one throttle body/TPI/injector/pressure regulator (which I'll plumb a vacuum sensor into, as opposed to getting an expensive one with an air mass sensor).

So my question is, what's a suitable donor for such a throttle body? (A Japanese car would be a bonus.)

Cheers!

I'm not familiar with the engine you are refering to but could you snoop about and see if there is a later injection engine in the family that you could purloin an intake with fuel rail etc and throttle body from, so you can make up a MS loom for it? Or even OE loom and ECU if it doesn't have inbuilt immob. in?

[Clamity]

I'm not familiar with the engine you are refering to but could you snoop about and see if there is a later injection engine in the family that you could purloin an intake with fuel rail etc and throttle body from, so you can make up a MS loom for it? Or even OE loom and ECU if it doesn't have inbuilt immob. in?

Sadly, I think the last car to use this motor was a late 80's Dihatsu 4WD, so as far as I know OEM fuel injection is out.


After trawling Ebay a bit more, I think something like this would do, if the two bodies could be separated easily. (That bike is a twin making 135bhp, so I guess one throttle on its own would be able to flow enough fuel for my engine.) Trouble is, it looks to me like the pressure regulator is half way along the rail which I think would be a problem.


I see plenty of Fiat seicento throttle bodies which appear to have all the required gubbins and are very cheap, but the rated output for those motors is pretty low. I wonder if one could be easily modified.

[RobinJI]

I think there was a 75bhp-ish 1.6l VW polo that used single point injection. Engine was in the 6n shape, and I think the same lump was used in 1.6l skoda felicia's. Might be worth a look, as the VW spi set up's tend to be very simple affairs adapted to run on engines originally designed for a carb.

[screech]

how big the engine in this bast and whats the output?

could be some old rover stuff that uses a suitable throottle/injector.

in fact a lot of post92 stuff that came with a carb pre92 came with single point in order to fit the required cat after that year.

[datman]

Some Nissan primera, micra or maybe polo, punto, fiesta/escort I think has single point. By the way I want to do the exact same thing to my Plymouth so if anyone spots a big one suitable for a V8 I would be interested.

[screech]

doh,just reread the 1.6 75hp part. try some early rovers or citroens around 92 time.

[screech]

how about an astra one, 70hp 1.6

cgi.ebay.co.uk/astra-1-6-single-point-injection-carb_W0QQitemZ110466677442QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item19b853bac2

[J1MMY]

Jan 3, 2010 22:52:48 GMT datman said:

Some Nissan primera, micra or maybe polo, punto, fiesta/escort I think has single point. By the way I want to do the exact same thing to my Plymouth so if anyone spots a big one suitable for a V8 I would be interested.

There are a few different types for V8's....ebay.us is worth a look for used SPi setups (retrotek and holley off the top of my head, pretty sure Edelbrock do them too)

Not cheap for a V8, but then it needs to be a fair sized unit!

[jo0lz]

Jan 3, 2010 20:57:56 GMT Clamity said:

I see plenty of Fiat seicento throttle bodies which appear to have all the required gubbins and are very cheap, but the rated output for those motors is pretty low. I wonder if one could be easily modified.

Fiat Sei is only going to be 45HP on a 1 litre motor
We have the same [earlier] SPI on our '93 Uno with 999cc FIRE engine . . .
totally non-adjustable . . .
so would not recommend you use it
Jo0Lz

[robg2]

You might find it easier to transfer an entire system from a different car rather than try to find a SPI throttle that will be compatible with Megasquirt.

For instance the Bosch K-Jet system in my Nova GTE would be easy, as it's:
not got a cat
doesn't have an immobiliser
has an external fuel pump rather than the more modern in-tank type with a swirl pot

Using the Nova example you'd only need to transfer the following to your car:
throttle
airflow meter
injectors
fuel rail and pressure regulator
crank sensor
ECU
...easiest if the whole inlet manifold could be transferred

If you could find a similar car with SPI then it's even easier:
throttle body
airflow meter if there is one
fuel pressure regulator
crank sensor
ECU
...and maybe knock sensor, temperature sensors, fuel pressure sensor

If you transferred a system from a similar engine then it would probably run fairly well straight away. If not then quite a lot of ECUs are re-mappable.

I'd buy a running scrapper of your donor car of choice and transfer everything from that.