924Board.org

[safe]

OK, I dont understand how EDIS work in relationship with MS.

Another thing I thought of. How have you wired up the power for the ECU? Do you power it from the ignition barrel?
I EFIed my car earlier this year and had problems, found out that the barrel cuts power from the "ignition on" while cranking. One wire from the barrel have power while cranking but that gets cut between the on and crank position so the ECU restarts just at the moment the engine gets going.
I ended up having to use a separate start button to crank the engine.
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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe

[924RACR]

That all seems reasonable to me, matches what I've seen in the documentation. The composite logger data would seem to suggest that you have functional crank sensor data coming from the EDIS unit... but maybe it's not putting out a solid spark for you to work with?

Looking at timing light output for the limp-home mode should give some idea - though make sure to plug the battery in to a boost starter when you try this, since you'll be cranking for a bit - want to keep the cranking speed up.

Are the EDIS components new or used?
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Fasteddie313]

If your pickup is 90 degrees advanced, and default is 10 degrees advance, wouldn’t you be firing at 100 degrees advance?

With EDIS on its original engine, where is the missing tooth in relation to TDC on that?
(Calculate this difference and put that into your MS base timing to counter it)

I don’t think sensor/TDC matters with MS because you can dial it back to basically anywhere you want, but the difference between your sensor/TDC and what EDIS is supposed to be sensor/TDC my logic would assume that it would fire at that difference in your limp mode..
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80 Turbo - Slightly Modified

[joewest]

Hi Team,

The EDIS components are pulled from a working converted 931 (Britian's 931 that now has an AAN motor in it, he is sometimes on this board) and I replaced the coil pack with a new unit:



All stock wiring is long gone and replaced. The ECU and all sensors are on a floating ground circuit isolated from the large gauge items that create ground and voltage spike issues, like the starter and alternator. The ECU is essentially independent.

I double checked the wiring and they are all correct in the EDIS system and its connection to the ECU. I checked spark plug connections and they are sparking well. New plugs and wires are on board.

Tonight I will try to strobe out the base timing. We cannot get much further until that is sorted.

With no SAW signal provided to the EDIS, it defaults to limp mode. There is no other calculation made other than the sensor/missing tooth vs. TDC. EDIS senses the teeth only and when the VR sensor picks up the 9th tooth after it sensed the missing one. It reads tooth 9 and considers that TDC. So the image I have of the trigger wheel is a diagram of that moment.

Here is more data on the EDIS and MS relationship. http://www.megamanual.com/ms2/EDIS.htm

Its tough to get the timing light to actually produce a strobe flash due to the nature of the wasted spark function of the coil pack, according to the MS forums anyway.

If I cannot get a solid strobe, I know that the MS ECU is reading the PIP signal from the EDIS system. I can alter the timing advance/retard during cranking using Tunerstudio and hunt for a moment when it will actually fire. Again, non interference in the motor so little risk there.

More to come.
_________________
'79 924 Supercharged / Track Prepared
'80 931 Daily Driver - Sold
"The number of posts in my profile may represent the number of times I have screwed something up...and admitted it here."

[joewest]

Base and ECU Controlled Timing SUCCESS!

1. This EDIS does not like the slightest degradation in battery voltage. Goes from solid spark to intermittent to none in almost a linear direction with battery voltage when cranking.
2. When I did get a strobe, it hit a piece of reflective tape I placed 90 degrees away from TDC on the crank pulley. The opposite coil bank was firing at TDC. Now with the plug wires reversed on the coil pack and the battery at full charge, I get a solid strobe at 10 degrees BTDC "limp-mode", and with the ECU installed I can alter and measure the timing in any direction.

Now I am off to sort out the fueling setup. Still no fire.
_________________
'79 924 Supercharged / Track Prepared
'80 931 Daily Driver - Sold
"The number of posts in my profile may represent the number of times I have screwed something up...and admitted it here."

[924RACR]

That's good progress. Maybe the same error with fuel injector wiring as with coil packs? Sounds like test mode on the injectors will be your friend...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[joewest]

Absolutely doing that next...

I repeated the injector test procedure and the correct injectors are "buzzing" when turned on. Tested individually, INJ1=cyl#1 & cyl#4 and INJ2=cyl#2 & cyl#3. Battery voltage at each injector. Replaced the FP fuse and tried cranking again.

There is a lot of fuel on the plugs when pulled. I tried to lower the required fuel settings, clearing the cylinders of fuel and turning it over again but no change. Tried to alter the cranking timing advance 10-50 degrees with no fire. Tried to change the fuel injector firing from 2 to 4 squirts per event. The base and ECU timing is still working well.

Nothing. Not one fired cylinder.

I will clear the cylinders of fuel again, pull the fuel pump fuse and try to get it to fire with starter fluid tomorrow. Maybe it is over-fueled? I need to read more about this on the MS forums, but I really need to educate myself on what a realistic fuel and ignition table should look like. Right now its Greek too me.

Below are links to the Tune and Datalog for experienced eyes to examine (which I greatly appreciate!)

Current Tune:

https://app.box.com/s/a5dt3yfvlh35gw3l1mrujh6gszj338zk

Datalog:

https://app.box.com/s/xshd7lmhf1qre56w9wdzpke0nx9m8iar
_________________
'79 924 Supercharged / Track Prepared
'80 931 Daily Driver - Sold
"The number of posts in my profile may represent the number of times I have screwed something up...and admitted it here."

[joewest]

Hi Everyone,

Here is a good one. I am baffled at this.

With the flywheel -----[] mark lined up with the bellhousing cast edge, and the "dot" on the BACK of the factory camshaft pulley aligned with the cast arrow on the cam cover, I run a compression test and get ~30lbs in each cylinder. If I turn the camshaft one tooth CW (leaving the crank in place), I get ~62lbs in each cylinder. If I continue to one more tooth CW, I get ~156lbs each, which is what the Haynes calls for as within specs. It also will hold 80psi of air for a long time in that +2 tooth position. None in the others.

I have a non-standard crankshaft pulley so there is no mark to verify other that the one I made when the cylinders were exposed. I used a micrometer to find TDC#1 and verify the flywheel marks prior to putting the cylinder head back on.

WTF?
_________________
'79 924 Supercharged / Track Prepared
'80 931 Daily Driver - Sold
"The number of posts in my profile may represent the number of times I have screwed something up...and admitted it here."

[safe]

[joewest]

I installed the damn flywheel 60-degrees off.

Now I have a good reason to swap the trans out with the LSD one in the corner of the garage....

Until then, I have the front marks lined up with #1 TDC and ~167psi compression in all the holes! Moving forward with setting the base timing with the ECU and trying to start it this weekend.
_________________
'79 924 Supercharged / Track Prepared
'80 931 Daily Driver - Sold
"The number of posts in my profile may represent the number of times I have screwed something up...and admitted it here."

[safe]

Isn't the flywheel keyed, or is it just a dowel pin (that you can forget)?
I don't remember...
_________________
/Magnus, Stockholm Sweden
=======================
Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe

[924RACR]

Good work!

The flywheel has reference lines scribed on it, but nothing to keep it from being installed one or more bolt off... 6 bolts... yeah.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[joewest]

SHE LIVES!!

It's been 5 years of slow steps, but she fired right up! The supercharger sucked the elbow down so I unhooked the plumbing to it for now and disengaged the clutch on it.

Idles really high at about 2200 rpm but I can at least get to tuning now!!!

WOOHOO!!
_________________
'79 924 Supercharged / Track Prepared
'80 931 Daily Driver - Sold
"The number of posts in my profile may represent the number of times I have screwed something up...and admitted it here."

[joewest]

Here is a down and dirty video of the first start.

https://www.youtube.com/embed/sPtFSgHl9O0

Lots of "button-up" little projects to get done then off to the dyno shop.
_________________
'79 924 Supercharged / Track Prepared
'80 931 Daily Driver - Sold
"The number of posts in my profile may represent the number of times I have screwed something up...and admitted it here."

[924RACR]

Awesome! That's why I love modern fuel injection - had the same result with mine after the first install, and again after reinstalling the rebuilt motor a couple weeks back... and now every morning, even though it's averaging 30F when I go to work! Just love that predictability and reliability.

I see your throttle response isn't great... obviously will improve just with general tuning, but wanted to mention I found the MAP-based accel enrichment more useful than TPS dot - though I think I'm in fact using a little of both, has pretty good tip-in response these days.

Also, for good idle quality... not sure your setup, I'm using still the stock aux air valve plus ignition timing to manage idle speed, just like original... using 6 degrees of advance for the ignition table at 1000rpm and the highest two vacuum points (30-45kPa)... then at 600rpm I have 27 degrees of advance, which will keep it from dropping off and stalling... 1500 rpm gets 8 degrees of advance, and then we ramp into the driving cals above that. Gives a nice sweet spot in the table for the engine to rest at idle.

Hope that helps...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype