wildwestsydney

You do not need a crank sensor. You do need a way to tell ms that a crank revolution has occured. With my bike this was somewhat troublesome due to the fact that it was a true CDI ignition and that had no signal or pulse that i could directly feed to the MS. I used a mutli meter and found a post on the back of printed circut board for the tach that gave the signal I was looking for. I don't think find a pulse to send to MS will be a problem. I will think about how I would look for one.

hacker-pschorr

Um, the crank sensor is what tells the computer a crank revolution has occured

On 78-84 cars that is what the green wire is for. It tells the ignition brian, L-Jet brain and tach the speed of the motor. So your example of using the tach signal would be using the green wire like I suggested. Not the best method, but it should work. This would limit you to using the stock non-twin dizzy distributor.

I was originally going to install EZF and keep L-Jet for a while, then eventually convert over to LH. One problem that was discovered is the frequency from the LH / EZF cars is half the signal coming from the green wire. This means that even if I installed a 928 crank sensor, it was the wrong signal to trigger L-Jet and I would also need a new tach or install some sort of frequency adaptor to convert the signal. These devices to exist, I didn't want to go that route so I scrapped the project for now.

wildwestsydney

Here are a few pics of my bike conversion.

Jim bailey - 928 International

Just need to mention ..."I'm already inclined to do a quick driveway hone and re-ring " Using anything in the Alusil block other than the special paste will kill the bores. Hit it with a bottle brush hone and you have destroyed the finish and will likely seize a piston.

L8 APEKS

Yeah, forgot about that. I'll just de-glaze it. No worries.

Jim bailey - 928 International

I would rather mention it to people BEFORE they do it rather than AFTER

McLovin

Is this "special paste" still available from Porsche? Is it available elsewhere? What makes it so special?

Jim bailey - 928 International

Here is a link to more than you ever wanted to know about Alusil bores..www.sunnen.com/NewsDetails.aspx?NewsID=11 - 59k

L8 APEKS

It's called Soylent Green.

And it's made from PEOPLE!!!

plastex

You should be able to get the signal from the coil. I did a Megasquirt conversion on my 76' 911 this way.

I am doing my 83' 928 this winter with Megasquirt and am wondering how to do the fuel pump cutoff. Anyone know how to hook this up to the megasquirt?

Thanks,
Oscar

Larry928GTS

The fuel pump cutoff in an '83 is done by the fuel pump relay. The fuel pump relay receives an RPM signal on pin 31b. It's the same RPM signal that the tachometer gets. If there's no RPM signal received on that pin of the fuel pump relay, the relay doesn't supply power to the fuel pump.

Lance J

best computer for diy efi projects are computers from GMC cyclones or Pontiac sunfires. you can solder in from 4 injectors to 8 injector drivers. the support on this ecu is the best i've seen and you just mount obi senors for your inputs

wildwestsydney

MS will fire the fuel pump relay when it is powered up, I think a 2-3 second span, and when it sees an rpm signal. This initial running of the fuel pump is the priming pulse which if I recall correctly is user definable for length. This is cool if the car has sat for a while, the fuel pressure will be up to where it needs to be when you go to start it.

plastex

Yeah, the Megasquirt has a wire to the Fuel pumt that let's it start for a few seconds prior to starting the motor, I can't remember which wire on the harness. That being said, how would I hook this wire up to the car. I am going to be hooking up a jumper from the LJET plug over to the megasquirt. This way In a pinch I can go back to the LJET. I will need to know what wire on the LJET plug is the one that hooks up to the fuel pump shutoff.

Thanks,
Oscar

Bart-Jan

I just finshed building MSII on my '85 S. In the beginning it looked difficult, but it turned out to be quite easy. I used the standard fuel system with the standard injectors of the LH-Jetronic. It actually is easy because they are high impedance injectors, not requiring extra tuning.

I also use EDIS, which defenitely is a great improvement over the standard dizzies. For the crank signal, I put an extra trigger wheel at the fan side of the crank pully. Here's a picture of it:

And a picture of the complete setup:


The Ford coils hanging under the intake pipes:


I used 95% of the standard wiring sysytem, but had to reconnect quite a lot. I Changed the schemes and will draw the up nicely, later:


For the TPS, I used one of a Saab 93. It has the same plug as the Porsche one, only two wires had to be swaped places. The temperature sensors are standard Porsche. One of the most expensive investments was a wideband Lambda sonde. But I would defenitely recomend it to everyone!

That's all there is to it! Just do it!