carlossus
Sr. Member
Karma: +38/-0
 Offline
Posts: 394
Leon Curpa Stg1+
|
 |
« on: November 12, 2011, 01:09:02 PM »
|
|
|
Since changing to a decat and big bore downpipe my car smells seriously rich. I changed the oil yesterday and the oil smelled of fuel.
The logged AFR seems OK apart from sporadic lean spikes which my be a failing wideband or maybe it's normal.
I need some experienced eyes please.
during WOT runs everything is normal so attached are normal commute logs. One short and one looong.
|
|
|
|
« Last Edit: November 12, 2011, 01:11:09 PM by carlossus »
|
Logged
|
|
|
|
New2Tune
Full Member
Karma: +3/-1
Offline
Posts: 55
|
|
« Reply #1 on: November 12, 2011, 02:50:33 PM »
|
|
|
So in the shorter log. Row 226 on is that correct that it is taking nearly 4 seconds to get back to target Lambda after a decel event or being put into neutral?
Then it gets to the desired lambda about row 300, and passes well below target and runs rich for about 5 seconds till row 400ish when it finally climbs back up to target. I'd imagine that's the really rich smell you're getting when you put the car in neutral and get out for several seconds of it settling from .750 (which is about 11:1 at idle) back to 1.0 over the course of 5 seconds.
I'd look into decel fueling or injector correction in this area. Also I thought the MAF numbers looked a bit curious, anything going on there with MAF scaling or non stock MAF?
|
|
|
|
|
Logged
|
|
|
|
carlossus
Sr. Member
Karma: +38/-0
Offline
Posts: 394
Leon Curpa Stg1+
|
|
« Reply #2 on: November 12, 2011, 03:10:10 PM »
|
|
|
Thanks for taking the time to look.
I should have given more info. It's a Leon cupra 1.8T with a stage 1 tune which I have tweaked a little bit to suit my requirements. The car is essentially stock until the decat / downpipe this month. I've been driving this tune for 14 months before this rich small started.
If you look at the AFR current, it seems to saturate to 4.0 then take an age to return to requested, then overshoot and stay rich for another few seconds. Weird thing is, the fuel trims are ok.
I've been driving this tune for 14 months before this obvious rich smell. Could a dying wideband cause this?
|
|
|
|
« Last Edit: November 12, 2011, 03:14:08 PM by carlossus »
|
Logged
|
|
|
|
carlossus
Sr. Member
Karma: +38/-0
Offline
Posts: 394
Leon Curpa Stg1+
|
|
« Reply #3 on: November 13, 2011, 05:32:33 AM »
|
|
|
Quick log of 3rd gear pull and off-throttle. Seems to track requested pretty during these runs then goes off the scale when requested is >1. I'll change the probe. In the meantime, does anyone have a set of good AFR logs so I can educate myself?  |
|
|
|
« Last Edit: November 13, 2011, 05:35:49 AM by carlossus »
|
Logged
|
|
|
|
carlossus
Sr. Member
Karma: +38/-0
Offline
Posts: 394
Leon Curpa Stg1+
|
|
« Reply #4 on: November 15, 2011, 01:30:47 AM »
|
|
|
So, New pre-cat lambda fitted, resultant WOT then coast, AFR log...  |
|
|
|
« Last Edit: November 15, 2011, 01:36:41 AM by carlossus »
|
Logged
|
|
|
|
|
masterj
|
|
« Reply #5 on: November 15, 2011, 02:46:56 AM »
|
|
|
I have 1.8T PASSAT AWT and for about one year I'm fighting similar thing - fuel trims are OK but my fuel usage is very high atleast 20l / 100 km... Lools like o2 sensor is working OK. Don't know how to fix this problem... literally everything in vcds looks great...
Also I'm decat, no post cat o2 and no SAI - everything coded out from bin
|
|
|
|
|
Logged
|
|
|
|
carlossus
Sr. Member
Karma: +38/-0
Offline
Posts: 394
Leon Curpa Stg1+
|
|
« Reply #6 on: November 17, 2011, 02:08:51 AM »
|
|
|
I would really appreciate it if someone could point me towards some normal 1.8T AFR logs.
|
|
|
|
|
Logged
|
|
|
|
|
littco
|
|
« Reply #7 on: November 17, 2011, 03:20:44 AM »
|
|
|
Is your fpr faulty? A leak would cause it to go lean but a weak diaphram in the fpr would cause the fuel pressure it increase when on boost. I know you said its only happened since the changes but worth a look at.
|
|
|
|
|
Logged
|
|
|
|
carlossus
Sr. Member
Karma: +38/-0
Offline
Posts: 394
Leon Curpa Stg1+
|
|
« Reply #8 on: November 17, 2011, 06:12:57 AM »
|
|
|
I have a spare 3bar fpr. I'll swap it out (have to correct KRKTE). It's an easy thing to try.
Thanks for the suggestion.
|
|
|
|
|
Logged
|
|
|
|
|
julex
|
|
« Reply #9 on: November 18, 2011, 08:10:32 AM »
|
|
|
I don't see any problem.
You are coasting down IN GEAR essentially turning your motor with your wheels. In such a case, the Lambda always go off the charts since ECU shuts the throttle plate almost completely down to the idle angle.
If you had pressure gauge, you'd see very deep vacuum in manifold. Combined with proper AFR gauge, you'd see AFRs off the scale (20+) or Lambda well above normal 1.
Just look at your MAF readings on the coast down and you will immediately see what's happening. You log about 3-4g/s which is essentially idle amount while your RPMs are in thousands there. Pistons are trying to suck all the air in but there is close none to spare.
Anyway, your logs are very incomplete, you need to log more stuff. Like actual engine load and injector time to see clearer what's up. Just log a typical set plus any extras you might want instead of that subset your current config is set to. With Ecux/Me7 logger, there is really no reason to limit variables since these loggers are sooooo fast regardless of how many things you're logging at once.
|
|
|
|
|
Logged
|
|
|
|
carlossus
Sr. Member
Karma: +38/-0
Offline
Posts: 394
Leon Curpa Stg1+
|
|
« Reply #10 on: November 18, 2011, 11:49:48 AM »
|
|
|
Thanks Julex,
In my case I *do* have a limit yo variables because of persistant timeout errors if I log more than about 32 bytes. I have been tweaking the variable set and I think I have a far better set for this problem. I'll run some more logs when I get a minute.
Incidentally, it's not the super lean spike that is annoying me it is how log it stays rich after the recovery.
I really appreciate your feedback on this, so thanks again.
|
|
|
|
|
Logged
|
|
|
|
carlossus
Sr. Member
Karma: +38/-0
Offline
Posts: 394
Leon Curpa Stg1+
|
|
« Reply #11 on: November 24, 2011, 02:36:45 PM »
|
|
|
Just to close this thread off... The AFR issue (I have yet to confirm really was an issue as I can't find a nominal log) seems to have become less of an issue. I replaced the N75 for another issue and re-clamped a load of hoses. Maybe a leak was to blame. I have typed the work issue too many times and it has become an issue.
|
|
|
|
|
Logged
|
|
|
|
|
