another Alfa Romeo conversion

[festy]

I tried to start the engine, but no luck yet
The plugs are getting wet, and getting very lazy rich flames out of the headers.
The logs show that occasionally my spark sensor is still passing a bad rpm signal now and then, and I'm guessing that the injectors are going to 100% at that point and it's instantly flooding. Sometimes the spark signal is very clean, but often seeing one or two very high rpm pulses while cranking.
How is the fueling calculated once it thinks it's past 9600rpm? Is there a factor applied, or does it use the 9600rpm table cells?
I imagine it's going to add a whole lot of fuel at 60,000rpm

cranking.JPG (26.45 KiB) Viewed 4589 times

An example of the spike:

Code: Select all

Sample #,Time -Seconds,Engine Revolution Flag,Engine RPM,Fueling Mode,Injector Duty Cycle %,
1515,163.139,Clear,635.0,Open Loop,32.5,
1516,163.223,Set,635.0,Open Loop,31.1,
1517,163.358,Set,633.0,Open Loop,32.4,
1518,163.442,Clear,187.0,Open Loop,9.2,
1519,163.576,Clear,187.0,Open Loop,9.2,
1520,163.660,Clear,61440.0,Open Loop,3226.4,   <---
1521,163.795,Clear,694.0,Open Loop,36.4,
1522,163.914,Set,189.0,Open Loop,9.7,
1523,164.045,Set,649.0,Open Loop,33.4,

[Holden202T]

once it gets to the top of the table it uses the last value from then on.

something doesn't seem right with your injector DC % .... its like 20-30% at 1000rpm or less .... i wouldn't think it would be higher than the RPM ....

i'd also be changing the scale of the injector DC % so it only shows up to maybe 110 .... in theory you really don't need anything over 100% though.

[festy]

Yes, I was suspicious about the DC% - if it's 25% during cranking, it'd max out just off idle
I tried it again this morning with a different bin and saw 11% DC while cranking at 600rpm.
How do you adjust the scales in TP?

That's as far as I got because it then backfired and blew the plenum off the engine, I'd advanced the distributor a bit too much I think
I'll have DIS set up done in a day or two so will try again at that point.

[festy]

My brother kindly donated a Saab 9000 ABS sensor, this afternoon I started on a mount for it. It still needs a bit of shaping/tidying up, but should do the trick.
It also doubles as a block off plate for the mechanical fuel pump, 2 birds with one stone

CAS_mount.jpg (36.4 KiB) Viewed 4525 times

[antus]

That looks the goods, nice and solid. Double function is a nice bonus hehe.

[festy]

Now I'm starting to feel like I'm making progress again.

triggerwheel.jpg (37.93 KiB) Viewed 4491 times

Almost 6 months since I started this conversion, and I haven't got sidetracked with another 'project' yet - that's a new record for me!

[Holden202T]

Almost 6 months since I started this conversion, and I haven't got sidetracked with another 'project' yet - that's a new record for me!

hehehe i think we can just about all understand what you mean there!

[festy]

Hmmm...
All set up for DFI, cranking RPM reading looks good.
There's obviously a good spark, because it just blew the plenum off again - much bigger bang this time
I *think* I've got the spark plug leads around the right way, better go check cam timing etc

[delcowizzid]

what are your plug gaps ,with shared coils like the v6 coils you need a big gap so only the plug in the firing cylinder fires not both. the cylinder on the exhaust stroke that shares the coil shouldnt fire.if both fire and you have a big overlap cam setup it could blow the plenum off.but so would wrong firing order or wrong timing.maybe unplug injectors and crank the engine with timing light connected and verify 10 degree cranking timing

[festy]

Yeah, I'll check the cam timing tomorrow - maybe the inlet cam is off by a tooth or something.
I cranked it over with the plenum off, and there's more flames out the inlet than the exhaust and it's backfiring on at least 3 of the 4 cylinders, so not a stuck valve.
I've got cylinders 1/4 on the left coil, and 2/3 on the right. Gaps might be a bit tight, but that shouldn't cause a cylinder to fire while the inlet valve is open?

If the cranks sensor was wired backwards, that'd have the same effect as retarding the spark wouldn't it? The zero crossing point would be the trailing edge of the crank notch?