homebrewed electronic fuel injection photo journal

was wondering how you set up your ecu and how it was wired what did you use to set all the electronics up i have 2 sets of itb's and an extra manifold would love to do this set up also .thanks

 

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I don't get to this site very often, so I just happened on your build recently. VERY nice work, and I'm glad to see you've persisted in seeing it through to a working system.
I built my setup for a Caddy Northstar powered bucket T a couple years ago and have been very happy with it. in many ways mine was easier than yours because I started with an EFI engine, but I can certainly relate to the many bridges to cross. I also fabricated my own air filter system and thought you might get some ideas from it for your project. just some mandrel bent ex tubing, sheetmetal and some hammer work.



Cheers,
Russ aka Northstar T

 

Thanks guys! Alex, I ended up buying another MIG welder, but thanks for the offer! Are you going to be at any shows in the near future?

I would love to answer any questions about EFI.
lorodz, here is the diagram of the wiring.

There are alot of options when setting up Megasquirt, so a little planning is needed (which I did not do the first time!). First you need to decide if you want fuel or fuel and spark control. I am using only fuel control. When using fuel control only, you still need an rpm signal to the computer. I am using a solid state pertronix, but if you want to keep points, you still could do it.

I am running the megasquirt 1 v3.0 board and bought it unassembled. If you dont want to solder tiny resisters and such(although the instructions are simple to follow, alot like a plastic model kit) you can buy a pre-assembled unit. The advantage of soldering it yourself is that the instructions show you options for circuits you might want or not want (kinda like plastic model kits, you can build the stock or custom version, or somewhere in the middle). This was helpful to me because I didn't want to run an Idle Bypass valve, so I left the circuit off.

Next you need to wire the computer to your power and hardware. you can use the diagram posted, but frankly, Im not an electrical engineer and didn't want to calculate fuse and relay sizes. I would recommend you buy the relay board kit from diyautotune.com though. Its like 65$ for an unassembled kit.
you also need to get the 37 pin pigtail that connects the ECU to the relay board. The board has all the fuses and relays ready to go and even has all the terminals labeled so you just route your wires to it. the cool thing about megasquirt is that its configured by default to run common GM sensors. also I would recommend using a fuel pump from a 1986 460 ford truck. I have heard this pump is good for 400-500hp, and it works well with my system. I am also using an adjustable regulator, but you could probably find a junkyard piece that fits your set up.

I hope that answers some questions! and If anyone has anything to ad or correct me, feel free. I hope more people start doing this, as the possibilities are really limitless.

 

Whoa!! those tb's look familiar! what are the filters from?

 

I'll probably go to the Wishbone or lil Anthony's in the next couple of weeks.

I sent you a P/M...

 

Hi Ramaro

First off congrats on the success of you efi!
I have been watching a couple of threads regarding stack injection and I love your approach.
Did you research the throttle plate diameter(or bore dia.) and are you running your M.A.P. sensor to the vacuum manifolds you fabed. Some guys are using the sensor on board the ecu to only adjust for atmospheric pressure.
I have a vintage S.B.C. Kinsler M.F.I. with 2 1/4 throttle plates that I want to reduce. I also just purchased a Megasquirt II 3.57...what do you think?

Thanks,
Doug

 

Ramaro, that engine sounds fantastic.

 

Ya. I thought the TBs might look familiar to you . GSXR600s with a spacer between the middle pair and extended throttle shafts. My injectors are in the fabricated manifold and I use the old TB injector holes for IAC ports.
I originally had a bit of an issue with gaining a strong vaccum signal to the MAP which left me with a very narrow range of values on the base map to work with. I finally realized that the TBs were robbing vaccum from each other between pulses so I installed a check valve in each line except one. the one without the ck valve gives a bleed off when the throttle is opened. You may not have this problem, but something to think about if you find you can't get a large enough vaccum signal at the MAP.
The filters are from a 280 ZX as I recall. I just picked a set from dimentions in the book. 16 x 5 x 1 3/4 if memory serves.

Russ

 

Check valves are an interesting idea! what is your range like with them? my manifold idles at 65 kPa and goes to atmospheric, which is 91 kPa here, better resolution would be nice, as I'm running an 8x8 table. what sort of check valves should I be looking for?

 

Yeah, I've been told that for a good midrange powerband, you generally go with a throat size the size of the intake valve. Maybe smaller. the 600 GSXR tbs were the smallest, cheapest option, and since Im not really aiming for big power (yet) , I was ok with them.

megasquirt gives you the option of two different methods of calculating the fuel required. Some guys run Alfa-n tuning algorithm, which is to say, the only inputs that have the most effect are engine speed and throttle position. I run speed density algorithm, which mainly uses rpm and MAP, (also uses throttle position to create an acceleration enrichment, like a power valve on a carb). This algorithm business should not scare anyone off though! I've had success with both, but find the speed density algorithm to be more intuitive.

Megasquirt II is great because the have a much better resolution (16x16 i think?) for the fuel table, so the problem Old Crow was talking about might be less severe.

Two other things that I have found to make your tuning MUCH easier would be a Wideband o2 sensor(with gauge or not)(200$) and a subscription to TunerStudio(50$). I would recommend struggling with megatune for a while just to get an idea of how it works, but these two things work great. tunerstudio lite is free and can be downloaded, but the subscription enables you to allow the program to tune itself as you drive. It's not really the be all end all but very close.

2-1/4 throttle plates sounds a little big on a motor like mine, but I would be interested in seeing how you bush those down. A problem I encountered on my twin ford throttle bodies was the extreme sensitivity of the throttle. But I think its all in the design of the linkage. you could make something that barely changes throttle position off idle, but increases in angle speed as your foot goes down, if that makes sense. that way its not as touchy and would be livable in traffic.

a good, well rounded itb design would be the off-topic BMW e30 m3 (like any of this stuff is trad any way ).

Ahhh sorry this is soo much info, but I'm lovin this stuff. I think bridging the gap between computer "voodoo" and good old fashioned shade tree hot rodding is very important!

 

It's been a wile since I was down that road, but as I recall, the ck valves added about 4-5 inches of vacuum. it was an imediate improvement in the drivability, mostly due to better enrichment control under acceleration.
these are the ck valves I'm currently using:
http://www.usplastic.com/catalog/item.aspx?itemid=38670

Russ

 

have been running twin throttle bodies on my Y-blocks for the last couple of years controlled by a gen 7 DFI Accel computer. Lots of low end torque. Way more drivable then the twin holley Teapots. Will never go back to carbs again. MIKE

 

famdoc3, that sounds like a cool setup. post up some pics if you can.

 

Good to see this thread pop up again. I agree on the TunerStudio.... great program! I've got mine dialed in pretty well, plan to swap out the distributor and see if it gets even better. I'm running a Unilite with no vac advance, want to find something with vac advance.

Send me a PM when theres an event going on, want to see this car!

 

pm sent

 

Here are a few pictures of the engine with the fuel injection in my t'bird. with the air cleaner on it's invisible. When you take off the air cleaner it's just cool. MIKE have tried multiple times to up load photos not currently working try this link www.y-blocksforever.com/forums/Topic60885-4-1.aspx