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Help with building your Speeduino, installing it, getting it to run etc.
By zwelsh91
#57430
Hello All!

I have a 1981 VW rabbit pickup that I am going to add Speeduino EFI to. After doing some research I have decided on a configuration and have started amassing all the parts to to do so. My main objective is to modernize the fuel system that I completely rebuilt last summer and had a great time doing so while learning how simple Bosch K-Jetronic Basic really is. Simple as K-Jetronic is (mostly just a toilet bowl that constantly dumps fuel into the intake ports :lol: ), I feel it is less efficient as having the total control over fuel and ignition that EFI offers. So I am doing my conversion in an effort to increase the fuel efficiency and possibly lower emissions. While at the same time bringing myself up to speed on what EFI is, How it is configured and how it functions.

Configuration goes as such:

Stock VW EN 1700cc N/A 4 cylinder engine
Going for a "Stock" appearing conversion
Bosch Style 2 wire temp sensor (replacing CIS thermo time switch in upper rad hose inlet)
Gm Style Intake Air Temp Sensor (Installed in a custom 3d printed airbox cover)
Throttle Position Sensor P/N 3517-37100 (going to print or machine "Piggy Back" adapter to sit on top of the stock throttle linkage)
Stock VW 037133317N fuel rail with integrated 3.0 Bar fuel pressure regulator and a custom fuel distribution block for feed and return ( so I can use the factory banjo fittings to one side and barbed fittings to and from the fuel rail )
Bosch 0280156006 fuel injectors (200cc 12.0 ohm do not know the dead time will most likely have to buy a portable scope to test) was going to use 0280150955's but got the bait and switch on amazon so I have what I have now, Live and Learn there.
I will set the injectors up paired and fire them paired alternating.
14point7 spartan2 lambda controller with LSU 4.9 wideband sensor

My first thought was to do fuel-only with just the distributor for ignition but I have changed my mind.

Ignition will be:
Wasted spark using VW type 032905106B coil pack. Most Likely mounted on the front of the block where the Control Pressure Regulator is now
Brand New Modified Distributor with internal hall sensor and a custom machined 12-1 or 24-1 (haven't decided yet) trigger wheel inside and a custom 3d printed "Blank" cap. I will also "Lock-Out" all advance vacuum and mechanical
I am planning on using Missing Tooth (Cam Speed) trigger setting.

All of this will be handled by a NO2C Speeduino in a custom 3d printed case. This will most likely be mounted inside the cab under the dash.

Couple quick questions for those in the know

Does anyone know what the Hall signal on the VW distributors is? 0v-5v or is It 5v-0v? I only ask because I do not posses a scope at the moment and do not have access to one.

Also If the Hall sensor outputs 0v-5v or the inverse can I connect that directly to the Speeduino with the correct jumper settings without having to run a VR conditioner?
User avatar
By PSIG
#57434
zwelsh91 wrote:
Wed Jun 15, 2022 3:57 pm
I have a 1981 VW rabbit pickup that I am going to add Speeduino EFI to. … My main objective is to modernize the fuel system … Bosch K-Jetronic Basic … in an effort to increase the fuel efficiency and possibly lower emissions.

Ignition will be:
Wasted spark using VW type 032905106B coil pack. … Modified Distributor with internal hall sensor and a custom machined 12-1 or 24-1 … Missing Tooth (Cam Speed) trigger setting.

All of this will be handled by a NO2C …
Hello, zwelsh91! Sounds good so far. One note is that cam-speed distributor is half the tooth-count per crank-rev. I would run as many teeth as the sensor will handle. 12T (6T per-rev) should also work, but resolution is getting coarse at 60°(crank) per-tooth. That said, there are many 4-cyls out there running 4T (2T/180°/rev :shock:) with Basic Distributor decoder, but you need more teeth to remove one for Missing Tooth (Cam). Sometimes certain distributor designs had similar 6 or 8-cylinder versions that are worthwhile testing those wheels in your distributor for comparisons to your accuracy needs. It's your judgment.

Don't forget to reduce your IGN output resistors for the 106B coil pack. It needs more current to drive the old-style transistors they use. Around 75-ohms or less seems to work well for both originals and offshore clones.

Decide now what your tuning goals are, and how to get there. For example, peak power efficiency in one area and peak economy efficiency in another are clear goals. But general emissions reduction can be by reducing fuel consumption, or it can be to target specific emissions with specific Lambda/AFR to feed a specific type of catalytic converter, and so on. Clear goals get clear results.
zwelsh91 wrote:
Wed Jun 15, 2022 3:57 pm
Does anyone know what the Hall signal on the VW distributors is? 0v-5v or is It 5v-0v? I only ask because I do not posses a scope at the moment and do not have access to one.
Hall is simple to test with just a multi-meter or LED. You don't need an O-scope for that. Power the sensor and test the output with and without a vane in the sensor slot. Typically, Hall vane sensors ground with a vane blocking, but you should test that, then also decide if you want-to or should read the leading or trailing-edge signal.
zwelsh91 wrote:
Wed Jun 15, 2022 3:57 pm
Also If the Hall sensor outputs 0v-5v or the inverse can I connect that directly to the Speeduino with the correct jumper settings without having to run a VR conditioner?
Correct, digital signals are direct if the signal is <=5V, or is float/ground with a <=5V pullup. Most Halls use the pullup jumper, but again, test your output. I don't have your distributor here, and one example is the popular LSx sensors that are powered-by and output a 5V or 12V signal with no pullup. Always test your signals. ;)
#57435
Thanks for info on the trigger wheel and tooth count. I own and operate a manufacturing business, so I don't mind brewing up any size and tooth count trigger wheel and machining it. (I recently made some Type 1 and Type 4 VW Fan Pulleys with integrated trigger wheel on the back for a customer ) Truth be told the options are endless :D As you stated resolution is important. Best I can tell the higher the resolution you can manage to better (to a point). I have been reading through this thread: https://speeduino.com/forum/viewtopic.p ... R&start=10 and it also has good info about cam speed trigger wheel, coming from no other than you PSIG. In the thread you are discussing using a trigger wheel that is missing a tooth in a distributor (ex: 24-1) that rotates at cam speed rather than crank speed. So that is the flavor I am going for. I would say physical count for my needs would be 24-1 at minimum but I'll make a 36-1 to try as well and if things go sideways well go for less.

My main goal is fuel efficiency and drive-ability. I daily drive the vehicle at the moment and would like to get better than the CIS can provide. So my statement about emissions is fairly mute, I am looking more for fuel economy and drive-ability.

I did not realize that there would be a need to change resistors on the board to run the 106B coil. I'll have to look into it and dig through my electronics stash to see if I have a few resistors on hand to do the modification.

As long as the weather holds out I'll do some testing on the distributor later tonight. I live up in Washington and it has been monsoon season lately here :roll:
#57438
Just to clarify. :)

The number of teeth needs to divide into 360/720 without remainder. 360 for crank and 720 for cam.

this is why 30, 36, and 60 teeth are common. On a cam though, you also have the option of 48 teeth if you can squeeze them in.

What ever you choose, you need to ensure the sensor you use, can clear a tooth before beginning to read the next one.

Watching :)
#57631
I have been busy at my Machine Shop but have steadily been making progress on this project.

Made some hardware changes to the NO2C board as advised by PSIG for the ignition output for the 106B coil. Made up a 6' pigtail and populated the connector so that i can install and trim it to the final length. I have also started making wiring diagrams and documentation so that everything will be easy to service in the future.

Ended up buying a cheap import distributor to modify into a cam speed decoder. I have decided to start with 16-1 trigger wheel using the missing tooth at cam speed settings in tunerstudio. I have tested the output from the hall trigger and with a clean voltage divider circuit I get a nice 5v square wave signal that is easily seen on a scope. I found a datasheet for the hall trigger that is in my distributor and feel that 16-1 is a good starting point. here is the data sheet for the 2AV53 sensor in the setup https://www.datasheets.com/en/part-deta ... l-31248074. I am also going to try 24-1 later down the road but i think the resolution may be too fine at that tooth count.
Heres a couple pics of the final product:
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Last edited by zwelsh91 on Thu Jul 07, 2022 4:53 am, edited 2 times in total.
#57632
I have also printed my TPS sensor mount and adapter. Installed them on the intake manifold and got it all squared away. For now it is just a "dummy" setup for testing against engine bay temperatures. I ended up using Black ASA filament and printing everything at 100% infill. Had to make some steel bushings to go under the bolts so that the plastic didn't squish and split. I am eventually going to make this bracket out of aluminum plate (the joys of being a manufacturer).

Here's a couple Pics of the install:
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Last edited by zwelsh91 on Thu Jul 07, 2022 4:54 am, edited 3 times in total.
#57633
Also got my airbox and fuel block squared away. Printed at 100% infill like the TPS bracket. Had to print it in 3 pieces because my printer is too small to do it all in one shot. But it should work well all things considered. I intigrated the IAT into the top with a boss and also made provision to mount the fuel delivery block as well. The block is designed to use the stock feed and return line banjo fittings from the K-Jet setup and I'll just use high pressure rubber line from the barbed fittings to and from the fuel rail. I am going for a stealthy "Stock" appearing install and I really feel this part ties the theme together quite nicely.
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Last edited by zwelsh91 on Thu Jul 07, 2022 4:55 am, edited 2 times in total.
#57634
Last but definitely not least I made some conversion Injector cups from Delrin for the fuel injectors. Since my truck is early 81 with CIS the Injector cup bores are larger than the late model K-Jet Lambda and Digifant heads. So I was not able to just order and use Digi injector cups. I will need to fabricate or print a rail support bracket eventually though. but first things first.
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Last edited by zwelsh91 on Thu Jul 07, 2022 4:56 am, edited 2 times in total.
#57635
For your viewing pleasure. Here are a couple shots of the truck and engine bay as Before shots.

Enjoy
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#57788
Made some progress over the last week or so. Machined up a nice coil bracket that uses 2 unused holes on the front of the block to mount it. turned out slick.
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