Irratic running - stable VE gives different lambda?!

[Sprockets]

Hi, just a few questions/ideas.

Does the engine actually feel like it's running that rich?  Stupid question I know, but just because a sensor is saying it is, doesn't mean it really is   At 0.65 you should be seeing black smoke/eyes stinging with fumes etc.

If it is, then the only way it can do that with the same injector pulse (approx. 2.4ms in your log) is if the fuel pressure has gone sky high for some reason or if the secondaries are activating when they shouldn't.  Possibly worth disconnecting them entirely for an experiment, and plumbing a pressure gauge in for a bit.

Only other way is a restriction of air aswell.  Airfilter being sucked in and wedged and on restart it relaxing and going to a 'normal' state?

I see a lot of faults that are more mechanical than ECU related.  We've all been there, scratching your head with a misfire, changing outputs when it's actually an injector failure etc!

Also make sure your ITB's are going back to the same state on idle.  Seen a fair few incorrectly assembled and the plates resting at different positions everytime the throttle is blipped.

Just trying to come at it from another angle

-Gavin

[se7ensport]

Great input, I've been right through the ITB's and filter set up even measuring and recording individual vacuum... 

When I pull the plugs they are always a tan colour - not as light as I would like, but they are very far from black and dripping in fuel.

Had a massive bit of luck on ebay earlier today and now have a rocker cover on its way for the weekend that is COP and cam position sensor compatible

I then found this video: https://www.youtube.com/watch?v=MRNYdMdp-MQ

It is incredible the difference it makes so I'm happy with the outlay and time to get cam sync done correctly, until seeing this I really struggled to believe that it could have such an impact as when I first got my Vems I don't believe cam sync was tunable.

[Sprockets]

Interestingly enough, the last car I tuned had a very high duration camshaft, and that indeed seemed happiest with the injector angle at around 520.  It does make a noticable difference.

Good news with the E-bay find.  Hope it puts you in the right direction.

-Gavin

[fphil]

https://www.youtube.com/watch?v=MRNYdMdp-MQ

Thanks for the link.

From another point of view, one sees that at 300° injector angle, the afr gets richer and that the idle controller cannot keep the idle stable.

I found this page interesting
http://forums.haltech.com/viewtopic.php?f=16&t=2724
The guys there like to tune the injector angle to have the mixture richer. Although this is not obvious.
I have also quoted:
"More raw fuel out of the exhaust IS NOT necessarily a result of incomplete combustion. After all, it could just be excess fuel that was supplied - all of the oxygen may have been burned. However, it is true that incomplete combustion may result in excess unburnt oxygen and this MAY read lean on the wideband"

Philippe

[gunni]

Since when is oxygen being burned?

In any case. If you have fuel coming out of the combustion chamber that means it´s incomplete combustion, the reasons can be bad atomization, missfire , lack of spark and so on.

It is logical to consider that the richer reading will mean you can lessen your pulsewidth and maintain same effective torque output on the crank but with less fuel, comes in handy during MOT´s and emissions testing.

[fphil]

Alright, but on another hand, if one tunes the injector angle to get the best possible combustion, then the aim is to get less CO and more C02 and leaner lambda.

After then if one wish to have the same previous lambda he/she has to increase the VE value from the map since the Volumetric Efficiency have been improved by the injector angle tuning.

[gunni]

Volumetric efficiency is related to air volume flow only, so most certainly that has not changed. But what can be said is

Lowest possible pulsewidth to give certain target lambda will give the most correct VE representation.

i.e. if you piss some fuel at the wrong injection angle and get lambda 1 and VE of 70, then adjust the injection angle and you then have a VE of 50, 50 is more correct then 70

[Sprocket]

I was always led to believe that raw fuel in the exhaust (hydrocarbons)  is as a result of cam overlap and scavenging, or in worst case a miss fire. The low end hydrocarbons are a result of the mechanical construction of the engine itself for example, trapped fuel between the top ring land and any other quench area in the cylinder which prevents the fuel from burning during normal combustion. Partialy burnt fuel (carbon monoxide) in the exhaust is a result of incomplete combustion (rich mixtures)

Granted at the extreme rich end of the scale you could see raw fuel pass directly through the cylinder as the 'quench' is so great, but in the 'normal' range of combustion, raw fuel in the exhaust, has not been 'combusted' and come from somewhere else other than the combustion stroke.

Always remember that the lambda sensor measures oxygen either as oxygen, or as a reaction of Carbon Monoxide. A rich miss fire results in a lean indication.

a four gas analyzer is your best friend.

[se7ensport]

Just added cam sync sensor and wired in. 

I had assumed that I would need to make the following changes for it to run:
1. within Secondary Tigger, enable camsync and set to rising edge
2. Adjust Injector Angle Curve to suit.

Having done the above and tried injector angles of 200, 300, 400, 500, 600 and 700 (at all rpms) I get a massive back fire at the lower settings and an attempt to start at the higher end but incredibly lumpy.  What else do I need to consider as I don't want to risk damaging anything???

10 second log showing running engine and the impact of turning on cam sync:

http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=5y2RkN

[se7ensport]

Doh!  Trigger reference tooth table needed to be updated.

its now running with cam sync. 

[se7ensport]

Initial problem STILL exists.

Summary:
I have made a load of changes to the config, moved to latest vemstune and firmware, spend a fair amount of cash on sensors, wiring, new uprated alternator, moved to fully sequential injection and yet the lambda and running behaviour seems to be a 50/50 gamble.

Initial start runs up to operating temp and it shows massively rich on lambda (if I pull the plugs at this time they are brown, not black and dripping in fuel as I would expect for the lambda figure shown), turn it off and restart immediately and lambda goes straight to target (.97ish).

Initial start:
http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=58lY6t

Restart:
http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=hWzeVk

My suspicion is that it is a VEMS or lambda sensor issue, where can I get these thoroughly tested?

[VEMS]

Hello Se7ensport,

The behavior you are seeing matches that of broken lambda sensor, replace LSU sensor (or perhaps you could borrow a lambda sensor from someone for a small test) and i suspect it will be sorted (don't forget todo a free-air calibration before inserting into exhaust).

Best regards, Dave