FPR + Megasquirt ECU

Post by **Shug** » Wed Dec 06, 2006 12:21 pm

RICHARDHUMBLE wrote:Ta

I'm slowly pulling the data together...
The K uses bank fire 1-4 2-3 the VVC uses fully sequential. First problem solved....

Now looking at the Crank position sensor...

MEMS also times the spark (even with the dizzy - the rotor arm is a blade and it has variability in when the coil fires - the dizzy just points it to the right cylinder)

Rich H · Post by **Rich H** » Wed Dec 06, 2006 12:36 pm

OK thanks, looks like this may be a non starter with the crank position sender as the megasquirt only wants one set of missing teeth on the rotor and the k has 4...

Have posted on the megasquirt forum to see if there is a way round this. The other answer would be a second crank pos sender at the cambelt end, but I'd rather avoid that...

hiscot · Post by **hiscot** » Wed Dec 06, 2006 12:43 pm

I looked at megasquirt and was told it requires a toothed wheel and pos sensors changed , it becomes quite involved and so was not worth it in my case
however maybe things have changed by now

http://msefi.com/

http://www.megasquirt.info/PWC/wire.htm

theres a very good yahoo group also

agree with roadboy, poss over fueling any porting / cams and the map sensor takes a fit causing the ecu to overfuel in safty mode

Rich H · Post by **Rich H** » Wed Dec 06, 2006 1:04 pm

Is there anyway of monkeying with the air temp sender (Like the resistor of power!) to adjust the fuelling? Not bypass it all together but put a pot in line/parallel with it to give a bit of fine tune using this as a crude fuel trimmer? Of am I being too much of a pikey now?

I have an adjustable FPR on the way, just need to figure out how to plumb it in... Probably just end up blanking off the OE FPR and installing it into the return line. We'll see....

robin · Post by **robin** » Wed Dec 06, 2006 4:11 pm

RICHARDHUMBLE wrote:Is there anyway of monkeying with the air temp sender (Like the resistor of power!) to adjust the fuelling? Not bypass it all together but put a pot in line/parallel with it to give a bit of fine tune using this as a crude fuel trimmer? Of am I being too much of a pikey now?

I have an adjustable FPR on the way, just need to figure out how to plumb it in... Probably just end up blanking off the OE FPR and installing it into the return line. We'll see....

You can indeed use the inlet air temp signal to adjust fuelling, however in doing so you limit the temperature range your car will actually work in.

To achieve a 10% increase in fuelling you would need to pretend to drop ambient by 30 degrees IIRC. So if our ambient was 30, that would be OK, 'cos you would be telling the MEMS it's 0; but if our ambient was 0, you would be telling the MEMS it's -30 which may be below the range it strictly believes the engine should work in and so you may not get what you expected.

The megasquirt can all just be reprogrammed if you like 6809 assembler or whatever it uses, so you can use the K wheel as is.

Batched injection is fine, that's what it already uses.

The injectors are not peak-and-hold type, so you don't need the active flyback circuit; the simple flyback diode design will be adequate. Don't overspec the FETs (I think you can choose which ones to use) - you only need about 2-4A IIRC - if you use too big a FET it will take too long to switch, reducing accuracy and also making it smoke sooner

Good luck with it all - I was tempted but decided against it because I just don't have the time. I have a spare MEM socket (the thing that mates with your loom connector) if you want to use it to wire to the PCB rather than chopping up your loom.

Cheers,
Robin

Rich H · Post by **Rich H** » Wed Dec 06, 2006 5:27 pm

Cheers Robin!

As ever you are the wizzard of elastic trickery!

I am completely lost when it comes to assembly language, I have just about got the basics of PIC programming sorted, but not put it to practical use yet.

TVM
Rich

Rich H · Post by **Rich H** » Thu Dec 07, 2006 9:35 am

May have a solution, you can drive the megasquirt from the dizzy with a few mods. I'm exploring that for now as a dizzy cap is peanuts compared to a sensor, toothed wheel and fitting the damn lot and I have a spare head to play with to get the mechanical bits sorted out. I'll keep you all posted!

Rich

Rich H · Post by **Rich H** » Thu Dec 07, 2006 10:26 am

FPR just turned up and the quality is suprisingly good! It is quite heavy (~1lb time for a diet?) I think the case may be brass under all the chrome but for £34 I can't complain. Now to plumb it in... THe standard is 3 bar is it not?

Sanjøy · Post by **Sanjøy** » Thu Dec 07, 2006 10:34 am

robin wrote: if you like 6809 assembler

Painful uni flash back, aaaaargh

Rich H · Post by **Rich H** » Thu Dec 07, 2006 10:36 am

You fancy writing a bit of code for me then?

I reckon if the code could be sorted you could under cut the emerald by around £200-£250 with the right bit of software.

If the dizzy conversion works then it may be a little more expensive but not much!

Sanjøy · Post by **Sanjøy** » Thu Dec 07, 2006 10:41 am

I said it was painful and my code was some of the worst ever written.

10 print "hello world"
20 REM Above does summit refernce it by 989
30 dim var 40
40 REM I think the above is wrong but will leave it in incase it stops it from working
60 Longst c$
70 Dunno what the above does but copied it from the guy next to me
80 goto 10

Rich H · Post by **Rich H** » Thu Dec 07, 2006 10:48 am

Hey that's better than mine!

If it works it doesn't matter.... (Robin will be along soon and correct us both...Hopefully!

)

robin · Post by **robin** » Thu Dec 07, 2006 4:38 pm

RICHARDHUMBLE wrote:Hey that's better than mine!

If it works it doesn't matter.... (Robin will be along soon and correct us both...Hopefully! )

I was being slightly facetious - it's actually a 68HCS12 and there is at least one C-based software tribe out there, IIRC.

LOL@Sanjoy's code - with programming skills like that, you should be an IT contractor

Cheers,
Robin