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EFI on the cheap

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9K views 22 replies 9 participants last post by  ALF750  
#1 ·
A few months ago I decided to have a decent crack at converting my long-term-track-car-project '77 GTV from carbs to EFI.
One of the reasons this car has been such a long term project is because I really can't justify spending money on it - and in keeping with that theme, the total cost of going to EFI has been around $250. That includes all the hidden extra costs like pumps, hoses, plugs and sensors - not just the ECU.

The ECU is a GM/Delco unit (as used in a range of early 90's Chevs etc) with modifications for realtime tuning and datalogging.
The inlet manifold is off an '85 L-Jet spider. I originally planned to use the complete plenum/throttle body/fuel rail/injector setup, but there were too many limitations so ditched all but the manifold.
The aluminium plenum I made myself, along with the fuel rail which holds Saab turbo high impedance o-ring injectors.
The throttle body is off a 3.8L GM v6, and is about twice the size of the L-Jet one.
Ignition is a Chevvy Beretta wasted spark module controlled by the ECU with a 3d advance map. The original harmonic balancer was modified with 60 degree notches, which are picked up by an ABS sensor.

There's a few things I need to finish (like a throttle cable) before I can get stuck into tuning, but it idles reasonably well already and has a much better throttle response than it did before.

It's not very pretty at this point (neither is the car in general) - but here's a couple of pics. The last one shows it's current state with a lot of bits still hooked up in a very temporary manner - I've got a bit of work to do tidying up that mess of wires and hoses...
 

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#3 ·
There's an extra notch at 70 deg ATDC that's used as the reference pulse.
The GM HEI modules all use 60 degree spacing, regardless of cylinder configuration. It makes for a very simple trigger wheel!

The modules are "smart" - up until a configurable RPM the ignition module does it's own thing, but after that the ECU takes control of advance etc.

The engine is dead stock at this point in time. I made the plenum with the idea of possibly going forced induction later on, but there's a lot to develop on the car before I worry too much about additional power ;)
 
#4 ·
A bit of an update - I pulled my finger out and finished off the last couple of things that needed to be done to get the car mobile again. You can guess from the dust on the windscreen how long it's been since it saw daylight :(

I loaded up a fairly conservative ignition and fuel map, and took it for a quick spin the other day.
So far I'm really impressed - throttle response is far better than I ever got with the DHLA40s, and it pulls very well.
It's happy to idle along in 1st gear, then floor the throttle and it immediately brakes traction without any hesitation.
But even better than that - it starts first go and idles smoothly, without having to touch the throttle once ;)

Now I'm just waiting for my wideband O2 sensor to be delivered so I can start tuning it...
 

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#8 · (Edited)
I've ordered an SLC EvK from 14point7.com.
I looked at all the various options, but didn't need anything fancy and the SLC EvK does everything I need at half the price of the others.

The ECU firmware I'm running supports a linear wideband signal input, and it can self-tune VE tables etc with a wideband connected in realtime if I want it to.

I won't be running a standalone wideband gauge because the AFRs will be captured by my datalogger along with all the engine data, and my logger displays AFR anyway.

My datalogger is still in 'prototype' stage, but here's a pic of the screen in it's current form. It also doubles as a lap timer too, that's the bottom two lines.
 

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#9 ·
Really interesting, I'm sure there would be a lot of interest by other Alfisti.
When finished, would you be able to provide a list of parts used and what car and year they are sourced from? A DIY handbook would be great, something like an e-book for purchase. I'd buy one.
 
#10 · (Edited)
So did you keep to your budget ? How much did you spend al up in the end ??

Are you interested in making another EFI kit so you can sell it to me so i can put it on my NORD turbo insted of running the carbs.

Oh i must see the circle work video, i love Alfas doing skids.

(just watched the video / ;( Grass )
 
#11 ·
Not counting the wideband kit, yes I pretty much kept it to $250.
I also sold a few spare bits that I'd made multiple sets of, so may have even made a profit from the conversion over all ;)

But I made a lot of the parts myself, and also got plenty of the other parts for little or no money.
That's why it took me 6 months to get up and running once I started - for example, I waited 6 weeks to find almost-free injectors rather than just going out and buying a set. Considering I first thought about an EFI conversion for this car about 10 years ago, a few weeks wait didn't make much difference to me ;)

I can supply you the modified ECU and software, but as for the sensors and wiring loom you'd be better off getting them yourself rather than paying me to scavange them from a wrecker for you.

Go to u-pull-it and find an N13 pulsar or LD astra, and grab the complete loom plus MAP sensor (you'll probably need a 2 bar sensor though), IAT sensor, Coolant sensor, and O2 sensor (if you're not going wideband). The ECU is under the passenger's seat (grab it as a 'spare' if it's cheap enough) and the engine harness runs under the carpet, along the sill and out a grommet in the firewall.
Unplug the two ECU connectors and cut all the cable ties until you can feed the whole harness out through the hole into the engine bay.
Then, just follow the harness bundle and unplug everything that connects to it. That's how you find the sensors - you pretty much want to take anything that's plugged into the harness (except the windscreen wiper, not sure why it's in this loom?)

Also grab the fuel pressure regulator, and the fuel rail if it fits your plenum.
The injectors probably won't be any use to you with a turbo though, but they'll get you started if you don't have better ones on hand.

If you're going to run a distributor, grab the dizzy and the coil.

Otherwise if you want to run coil packs, go find a V6 commodore and grab 2 of the coils, and an ABS wheel sensor (this can come off any car just about, I use a late 80's saab one on mine).
You'll need to machine 7 notches in your harmonic balancer too, and fairly precisely positioned. If you can't get that done locally I might be able to help with that.
You'll also need to get hold of a D1927A ignition module that was used on a bunch of 4cyl engines in the US (but we never got them here) - turn to ebay for that. The Commodore coil packs fit this module.

The v6 commodore throttle body is a nice size, so if you can make it fit then grab one of those from the wreckers too. If you're going to use a Camira plenum then you might be stuck with the Camira's throttle body unless you can make some sort of adapter plate.

The pulsar harness went straight into my '77 GTV with almost no modifications. I think I had to cut 3 wires for the coil pack setup, and just supply a battery and ignition feed to the correct wires after plugging in all the sensors.

Apart from fuel lines and pumps, that's about it.
If you're serious about doing a conversion, sort out your plenum and inlet manifold first - the rest is easy ;)
 
#12 ·
Cool, if you can modify the loom and just label the wires accordantly, such as power and sensors. All the sensors etc i can just go get from U-PULL-IT many commodores and n13s there etc.

How much would you charge to get the complete loom,ecu from the wreckers then modify it for the Alfa engine and just label all the wires and kinda write up a list of parts i need to complete it.

All the mechanical stuff i can do my self and i will sort out intake injectors etc.
 
#13 ·
There's no loom changes necessary! And no need to label any of the wires, everything has it's own unique plug so it can't really go together the wrong way. It's "plug and play" :)

If you go distributorless, it's just a case of cutting one plug off the loom and replacing with another one to fit the ignition module. I think there's only 3 or 4 wires involved, so not rocket science.
I can give you all the wiring diagrams and loom colour codes too, but it's as simple as cutting a hole in the firewall for the harness grommet, run the harness areound the back of the engine along the firewall and plug everything in. Most of the plugs are on the inlet side, and everything reached fine without any modification.

Do you know BradGTV? I don't know if he has actually done his conversion yet or not (he changed his mind a few times on what he was going to do), but certainly has most of the parts already and knows how straight forward the wiring is.

The only bit you can't just grab from a wrecker or ebay is the modified ECU, and I'll pm you about that.
 
#14 ·
sounds pretty easy.

Yes i know Brad, i seen his camira EFI set up and its basicly sitting at the back of the shed hiding. I sold him a sr20 engine and he is installing that into his GTV at the moment. I havent seen him in about 2 months but i will see him soon as he has a few parts of mine he was borrowing.
 
#18 ·
Here's a pic I took a while ago, showing one of the (very few) good points of the Bosch Spider inlet manifold.

To try and explain it, this is looking down one of the inlet runners with a mirror. There's a pencil in the injector hole (upside down because of the mirror) showing how the nozzle sprays straight at the back of the inlet valve which is where you want it going.
 

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#21 ·
No problems with tuning for E85 with that ECU.
With the spider inlet manifold, it does bolt straight up but you'll need to cut reliefs into the top of your head's inlet ports or the injectors will spray into metal. Have a look at the difference betweek a spider and a alfetta inlet gasket to see what i mean.

@BradGTV: is this what you need?
 

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#23 ·
Just wanted to say I love your work Festy. This info is just what some of us need to make the conversion doable. Keeping the smoke in the wires has always been a problem for me! Appreciate your efforts on the 75TS/ECU et al thread - I wish I had all this info when I owned my TS 15 years ago.