R520 Cold start smoke and stutter - Page 2

jsrmonster · October 24th, 2011, 17:24

There are a few important mappings that need modified to eliminate the burning eye white smoke, and shudder on cold start.

Jeff

http://www.youtube.com/watch?v=hIe3hvcu_ms

brum · October 25th, 2011, 01:35

Can you be more specific

?

I also had some problems with cold start (11mm complete pump, .240mm Firad nozzles). I've modified the preheating, the starting IQ and still got some issues.

What I will modify is the pump position (will push it to a little bit more advanced position). SOI I guess is fine, because after start there is no sign of any smoke (except little black smoke if I push it harder first few minutes).

Maybe SOI maps will provide some additional benefit, but I'm waiting for colder times (it is now around 50F). I guess 20-30F will be good time to find what is the correct solution for large nozzles and cold startup

.

ArturCosta · October 25th, 2011, 14:25

Quote:

Originally Posted by jsrmonster

There are a few important mappings that need modified to eliminate the burning eye white smoke, and shudder on cold start.

Jeff

http://www.youtube.com/watch?v=hIe3hvcu_ms

Thats a rough start

I have tested at -2ºC at sea level in my car and starts nearly smoke less.

I have to find a 12mm pump R520 to do this testing.

Keebler145 · October 25th, 2011, 14:43

-2 celsius isn't quite as cold as 9 farenheit, and I'm pretty sure where jeff lives isn't sea level

Bdpprocessors · January 1st, 2012, 13:55

i have shudder for maybe 3 seconds on my car with the r520's but it has many mods and 16.1-1 compression it also smokes white for maybe 30 seconds on first start up of the day if its around freezing outside . the smoke is just a slight haze and clears up quickly

(cylinder temps are too cold and all the fuel isnt properly burning)

bhodgkiss · January 14th, 2013, 01:44

Just installed calibrated 220/350bar R520's and mine hesitates and take a while to start.... Some white smoke in idle too.
Stock compression. Cold here (below freezing)
Glow plugs I think are working.

Pump is just below mid timing line.
Idle IQ is 5.2mg/str at 32768

Not adjusted any thing other than my remap which affects the numbers higher up the rev range and runs beautifully otherwise.

What shall I do please?

TDIJetta99 · January 14th, 2013, 05:25

Get the timing up to the green line, maybe a touch over, and see if it starts any better..

bhodgkiss · January 14th, 2013, 15:25

Can I do that with group 4 timing adaptation? This will change it across the rev range of course, but can i then get it back to what it was previously with reduced advance at upper revs?

TDIJetta99 · January 14th, 2013, 16:20

No.. the timing graph represents the physical pump timing..

bhodgkiss · January 15th, 2013, 01:28

Which is fine, but within the timing range of the pump can't I adjust the entire range (advanced or retarded) by a certain amount by adjusting the 32768 value in group 4? I thought adjusting this by a value of +/- 100 changed the pump timing by a degree?

Then to restore the timing in the rest of the map I'd back it off by a degree in the soi map to suit?

Aside, why am I not able to adjust idle timing in the soi map? I think the map has a value at 800rpm and 3-5mg fuel?

Thanks

TDIJetta99 · January 15th, 2013, 06:26

the adaptation and static timing are 2 different things.. You can put the adaptation wherever you want and the timing on the graph won't move because that's not what you are measuring with the graph.. To move the plot on the graph, the pump itself needs to be adjusted.. I'm not sure how the AFN is set up, but you'll either have to rotate the pump, or adjust the pulley on it..

bhodgkiss · January 15th, 2013, 12:07

Yes and I agree with that too, but what I mean is:

- the pump mechanical timing sets the vcds graph.
- the adaptation can then change the timing across the rev range and effectively give an offset to this. So in reality this is equivalent of mechanical timing being different to begin with. There is only so much scope to advance/retard the ignition but maybe a degree or two with adaptation.
- this then offsets the timing across the rev range so in the Soi map you could potentially pull it back for the rest of the rev range.

So just say my mechanical timing is showing as 1 deg retarded from the mid line in vcds at idle. I tweak the 32768 value in group 4 to change this to 1 deg advanced instead, so move it two degrees. But then my entire map is 2 deg too advanced so at top end it's now giving 17 deg advanced, not 15 deg. So in the soi map I change the advance from 15 deg to 13 deg at top end and I'm back where I started and smooth out inbetween, but what i have done is advanced the idle timing?

Does this work?

Can I change the soi map at idle revs or does it ignore this please?

m1ketdi · January 15th, 2013, 12:30

The problem is ben that the control system cannot adapt the timing during starting the engine. So you need the mechanical advance to make it start well...

bhodgkiss · January 15th, 2013, 12:32

Ah I see! Thanks! Not easy on mine, well not as easy as it could be, bumper needs removing, front carrier tipping forward to get onto pulley bolts..... If I'm doing that might as well install the 11mm pump!!!

It's only just below the mid line so not excessively retarded..... I assume the higher pop pressures have caused this? What else should I try first please?

TDIJetta99 · January 15th, 2013, 15:23

Just advance the pump.. It takes 15 minutes..

You're asking for advice and we're giving it to you, but you're somehow insisting on trying other things.. JUST ADVANCE THE PUMP AND GET THE GRAPH UP TO THE GREEN LINE...