DIY EFI

Can anyone who has installed and set up an aftermarket EFI system give me a brief run down of what is involved?

I've done physical engine swaps before (Chevy Suburban small block to big block; VW Beetle Type 1 to Type 4; Porsche 912 4cyl to 911 6cyl) but everything has always been carbureted.

I'm thinking of sticking an Audi 2.8L V6 (that I scored for free!) into my 1977 Porsche 924. The bellhousing bolt pattern is the same, and the price of the engine was right! I have no idea what I would do about the EFI, though. The engine still has most (all?) if its' original (Bosch Motoronic) sensors attached but I don't have any of the wiring, the ECU or anything else from the car.

I understand, in theory at least, how EFI works and what all the sensors do. That said, if I were to buy a Megasquirt system, I would be completely lost. Can anyone who has made aftermarket EFI work comment on how big of a project this is? Will I need to use a catalytic converter and oxygen sensor(s)?

The cat question is better answered if you fill us non-Connecticut residents in on what they do there for smog checks and if this car is going to see legalized road use. I believe that you should plan on using a cat since the engine is from a time period where they were all but required, as is the car. Since they aren't all that expensive and you want to Do This Right, I'd plan on using one.

The Megasquirt & O2 sensors were discussed on this board very recently. From the discussion, I came away still believing that the use of a wide-band O2 sensor setup would make your life tuning the thing much easier. What I cannot answer is where the thing should be placed and if the Audi 2.8 has provisions for one on each bank or if you should put them farther downstream from the engine. Others will know more, but at this early date, I'd plan on having at least one wide-band on the car.

I'd like to see a GRM article that takes us step-by-step thru a carb to EFI swap, using Megasquirt or whatever. I'm totally ignorant on what needs to be done, and why.

I'd like to put an EFI on an '81 C3500 farm truck we have. It has a 350, so I'm sure this would be pretty easy and straightforward, but before I do this project (which is years away from doing, truthfully), I'd like to have a primer.

Kramer wrote: I'd like to see a GRM article that takes us step-by-step thru a carb to EFI swap, using Megasquirt or whatever. I'm totally ignorant on what needs to be done, and why. I'd like to put an EFI on an '81 C3500 farm truck we have. It has a 350, so I'm sure this would be pretty easy and straightforward, but before I do this project (which is years away from doing, truthfully), I'd like to have a primer.

http://grassrootsmotorsports.com/articles/megacapable/

That should definitely help get you started, even though it's a Volvo going from side draft carbs, there should still be a lot of usable information to get you some idea of what all is required. What might be one avenue for you to go down is to take the throttle body injection off of an 1988 & later GM C/K pickup and swap that over in place of what is currently on that grain truck.

The engine still has most (all?) if its' original (Bosch Motoronic) sensors attached but I don't have any of the wiring, the ECU or anything else from the car.

Step 1 is to pick an ECU that's compatible with your sensors and ignition. Some questions to ask on this step:

1. Is it an odd fire engine or even fire?
2. Does it have a distributor, or not?
3. What sort of crank trigger does it have? (Most Motronic systems used a 60 tooth wheel with two teeth missing.)

So you would either need an ECU that supports the stock type ignition, or be prepared to convert it to an ignition type your ECU of choice supports.

After that, wiring it up is not all that complicated; you start with the ECU's pinout and identify which wire needs to go to which sensor. You'll need to be able to make good solid wiring connections here, but this step is more time consuming than mentally difficult.

The hardest part sometimes is getting it to fire up if you are using a nonstock ECU. This can take a bit of trial and error to teach a standalone how to get an engine started. Once it starts and idles, getting it tuned is a bit more straightforward, though it's best to have it tuned on a dyno to get the most performance out of it.

Will I need to use a catalytic converter and oxygen sensor(s)?

I'll assume this is a track car and doesn't need to pass smog checks, so in that case, the answer is no. Most aftermarket EFI systems can run without an O2 sensor. It is, however, difficult to get one in tune without a wideband O2 sensor. This could be something done at the dyno shop, though, using the shop's equipment, and then you could remove the sensor for normal driving.

Kramer wrote: I'd like to see a GRM article that takes us step-by-step thru a carb to EFI swap, using Megasquirt or whatever. I'm totally ignorant on what needs to be done, and why. I'd like to put an EFI on an '81 C3500 farm truck we have. It has a 350, so I'm sure this would be pretty easy and straightforward, but before I do this project (which is years away from doing, truthfully), I'd like to have a primer.

Shameless plug: We have an article like that on our site, 350 and all.

http://www.diyautotune.com/tech_articles/megasquirt-carb-to-efi-part1-nova.htm

You guys rock!

Now I need to get a roundtuit.

Kramer wrote: You guys rock! Now I need to get a roundtuit.

http://kalecoauto.com/index.php?main_page=product_info&products_id=20

pres589 wrote: The cat question is better answered if you fill us non-Connecticut residents in on what they do there for smog checks and if this car is going to see legalized road use.

In Connecticut, emissions testing not required on vehicles 25 yrs or older.