Car stumbling, Logs/Maps inside..
Aug 8, 2006, 04:38 AM
#32
Evolved Member
Thread Starter
iTrader: (11)
Join Date: Sep 2005
Location: CT
Posts: 834
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by MalibuJack
If your using Evoscan those codes are probably "phantoms"
Aug 8, 2006, 05:05 AM
#34
Evolved Member
Thread Starter
iTrader: (11)
Join Date: Sep 2005
Location: CT
Posts: 834
Likes: 0
Received 0 Likes
on
0 Posts
Yea, that's a PITA.
Anyway, charted some of the data from last night's logs.. More charts can be easily produced upon request.
Third Gear
Fourth Gear
Anyway, charted some of the data from last night's logs.. More charts can be easily produced upon request.
Third Gear
Fourth Gear
Aug 8, 2006, 05:16 AM
#35
I have never seen knock counts that high before.. Your car must be running pretty lean.. The timing doesnt appear to be unusually aggressive, but its hard to tell...
Was boost raised after the tune was done?
I would strongly suggest turning the boost way down until you can get a wideband on the car and see if there is something else wrong, perhaps your getting unmetered air bypassing the MAF causing it to run real lean.
Was boost raised after the tune was done?
I would strongly suggest turning the boost way down until you can get a wideband on the car and see if there is something else wrong, perhaps your getting unmetered air bypassing the MAF causing it to run real lean.
Aug 8, 2006, 05:32 AM
#36
Evolved Member
Thread Starter
iTrader: (11)
Join Date: Sep 2005
Location: CT
Posts: 834
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by MalibuJack
I have never seen knock counts that high before.. Your car must be running pretty lean.. The timing doesnt appear to be unusually aggressive, but its hard to tell...
Was boost raised after the tune was done?
I would strongly suggest turning the boost way down until you can get a wideband on the car and see if there is something else wrong, perhaps your getting unmetered air bypassing the MAF causing it to run real lean.
Was boost raised after the tune was done?
I would strongly suggest turning the boost way down until you can get a wideband on the car and see if there is something else wrong, perhaps your getting unmetered air bypassing the MAF causing it to run real lean.
Per request yesterday, Octane number starts off at 255 around 3000 RPM and slowly (and very linear) makes its way down to 248 by 7000 RPM.
O2 feedback trim is at 100 for the length of the WOT run, and readings from the O2 sensor flutter between .8775 and .9165 throughout the run, with one random dip to .4485 at 3906 RPM.
Air flow starts at 377 Hz at 3200 RPM and is max out from 5375 RPM through the end (7125 RPM).
Fuel trims stay constant with the High being at 100, the Low being at 138.28 and the Middle being at 95.31.
Get this, one of the stumbles was strong enough so our sequential RPM readings are: 3750, 3875, 3906, 3812, 4375. It actually drops once it hits 3906. Almost like the car falls FLAT on its face for 1/10 of a second, then it's back on like an animal again. hm.
Aug 8, 2006, 06:32 AM
#37
Evolved Member
Thread Starter
iTrader: (11)
Join Date: Sep 2005
Location: CT
Posts: 834
Likes: 0
Received 0 Likes
on
0 Posts
Just messed around with the simple load calculation as well (Airflow/RPM * 852) and according to that equation we are at 296% load around 3812 RPM, which is just after the RPM's DROP at WOT from 3906, and the next timing cell after this one (4) drops to 3, which is not on either of the timing maps in the ECU. Here's a graph of Load & Airflow, and I'm going to use the simple calculated load to map on the timing charts in other locations and see if it looks to be accurate for this car.
Aug 8, 2006, 07:02 AM
#38
Originally Posted by Stew
...and readings from the O2 sensor flutter between .8775 and .9165 throughout the run, with one random dip to .4485 at 3906 RPM.
Originally Posted by Stew
Almost like the car falls FLAT on its face for 1/10 of a second, then it's back on like an animal again. hm.
Graph your front O2 readings against RPM and if you see any downward spikes, that is misfire. It will feel like you momentarily hit fuel cut or a rev limiter.
Eric
Last edited by l2r99gst; Aug 8, 2006 at 07:06 AM.
Aug 8, 2006, 07:29 AM
#39
Evolved Member
Thread Starter
iTrader: (11)
Join Date: Sep 2005
Location: CT
Posts: 834
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by l2r99gst
That is misfire.
Graph your front O2 readings against RPM and if you see any downward spikes, that is misfire. It will feel like you momentarily hit fuel cut or a rev limiter.
Graph your front O2 readings against RPM and if you see any downward spikes, that is misfire. It will feel like you momentarily hit fuel cut or a rev limiter.
Aug 8, 2006, 07:56 AM
#40
Newbie
Join Date: Aug 2006
Location: Naples, Italy
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
misfire is often caused by vacuum leaks or an EGR valve that's stuck open right? now, could this be the result of the barometric pressure indicator failure that shows up on EvoScan?
Aug 8, 2006, 07:59 AM
#41
Stew,
What plugs are you using and what are they gapped at?
If you want to see if this is really a misfire, just change to a new set of plugs gapped a little bit smaller. If the smaller gap lessens or eliminates the stumble, it was a misfire.
Eric
What plugs are you using and what are they gapped at?
If you want to see if this is really a misfire, just change to a new set of plugs gapped a little bit smaller. If the smaller gap lessens or eliminates the stumble, it was a misfire.
Eric
Aug 8, 2006, 08:37 AM
#44
Also, just so I don't have to go back and reread all of the threads, you have eliminated fuel cut, correct?
Your graph of O2 definitely takes the shape of a misfire, but even bigger than expected. It's either a big, nasty misfire or possibly fuel-cut. So, I wanted to make sure that you eliminated fuel-cut with your flash.
Eric
Your graph of O2 definitely takes the shape of a misfire, but even bigger than expected. It's either a big, nasty misfire or possibly fuel-cut. So, I wanted to make sure that you eliminated fuel-cut with your flash.
Eric