Help with my data log?
Thread Starter
Drifting
Joined: Apr 2014
Posts: 1,699
Likes: 231
From: Hawthorne CA
Help with my data log?
So yesterday I went to the dyno to get a read on my wheel power and get a tune. Good news is that the tuner was able to get my idle and mid range driveability WAY better, but was not able to tune the WOT.
We were seeing what appears to be a misfire in one cylinder on the divers side. You can hear a slight miss once the rpms started to climb above 3500 rpms so he basically side, "hey go figure out your misfire and comeback to get a real dyno tune/readout of your power at the wheel". As for the power it did make, it was making 350tq at the wheel at 3500 when the misfire condition would develop. The tuner felt pretty confident this was being caused by fouled plug or bad wire. He was confident the misfire was spark induced. Looking at the data logs since leaving the dyno I do see that at various rpms the bank 1 o2 sensor is reading much higher than the bank 2.
What in your opinion is causing this? Do you agree its spark?
I should add that this chart is sorted by time, then filtered for instances where there was an amount of difference in the o2 readings. This is that the totally unfiltered chronological log data looks:
We were seeing what appears to be a misfire in one cylinder on the divers side. You can hear a slight miss once the rpms started to climb above 3500 rpms so he basically side, "hey go figure out your misfire and comeback to get a real dyno tune/readout of your power at the wheel". As for the power it did make, it was making 350tq at the wheel at 3500 when the misfire condition would develop. The tuner felt pretty confident this was being caused by fouled plug or bad wire. He was confident the misfire was spark induced. Looking at the data logs since leaving the dyno I do see that at various rpms the bank 1 o2 sensor is reading much higher than the bank 2.
What in your opinion is causing this? Do you agree its spark?
I should add that this chart is sorted by time, then filtered for instances where there was an amount of difference in the o2 readings. This is that the totally unfiltered chronological log data looks:
Last edited by AgentEran; Jun 27, 2020 at 03:28 PM.
Safety Car
Joined: Jun 2010
Posts: 4,564
Likes: 1,676
Since Golen ran it on the dyno, I would say we can rule out a mechanical issue with the valvetrain.
I would like to see the full scan log to give a better opinion. Seeing info in bits and pieces doesn't really help. Since you have headers, go ahead and remove the plugs and inspect them and see how they look. Throw up some pictures as well. If you are really ambitious, you can pull the plug wires and inspect them for possible breaks and ohm test them as well.
I am surprised that the car did not trigger a misfire code, for either a specific cylinder or at least the general misfire code.
I would like to see the full scan log to give a better opinion. Seeing info in bits and pieces doesn't really help. Since you have headers, go ahead and remove the plugs and inspect them and see how they look. Throw up some pictures as well. If you are really ambitious, you can pull the plug wires and inspect them for possible breaks and ohm test them as well.
I am surprised that the car did not trigger a misfire code, for either a specific cylinder or at least the general misfire code.
Thread Starter
Drifting
Joined: Apr 2014
Posts: 1,699
Likes: 231
From: Hawthorne CA
Since Golen ran it on the dyno, I would say we can rule out a mechanical issue with the valvetrain.
I would like to see the full scan log to give a better opinion. Seeing info in bits and pieces doesn't really help. Since you have headers, go ahead and remove the plugs and inspect them and see how they look. Throw up some pictures as well. If you are really ambitious, you can pull the plug wires and inspect them for possible breaks and ohm test them as well.
I am surprised that the car did not trigger a misfire code, for either a specific cylinder or at least the general misfire code.
I would like to see the full scan log to give a better opinion. Seeing info in bits and pieces doesn't really help. Since you have headers, go ahead and remove the plugs and inspect them and see how they look. Throw up some pictures as well. If you are really ambitious, you can pull the plug wires and inspect them for possible breaks and ohm test them as well.
I am surprised that the car did not trigger a misfire code, for either a specific cylinder or at least the general misfire code.
Let me know what sensors to add to this data log I can select what I want.
Im going to pull the plugs and see what they look like as well. Ill post pics later.
I dont think I can have a misfire code because the crank position sensor has been removed and programmed out.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Oscilloscope would be helpful. I'm somewhat surprised dyno shop didn't have one.
I wouldn't have thought to bring a 2nd set of plugs and wires as a just in case. Now I know spare parts maybe required.
I wouldn't have thought to bring a 2nd set of plugs and wires as a just in case. Now I know spare parts maybe required.
Thread Starter
Drifting
Joined: Apr 2014
Posts: 1,699
Likes: 231
From: Hawthorne CA
Thread Starter
Drifting
Joined: Apr 2014
Posts: 1,699
Likes: 231
From: Hawthorne CA
I am data logging with Torque app so I dont have access to all the data the ECU has. What data elements were available I added to the log. In this log the car drove fine until about 5:43pm. I then pulled over and sat until 5:57pm. This is when the condition is experienced and it lasted for at least 3 or 4 min, then the car went back to driving decent again.
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Burning Brakes
Joined: Mar 2005
Posts: 1,082
Likes: 115
From: Richmond Hill Ontario
From the limited data that Torque App provided I can see that the " O2 Volts Bank 2 sensor 1" is reading 0.35 volts and under for over 40% of the entire datalog that you provided. To me that represent significant Lean event on that side. I would concentrate your efforts on that side of the engine (whatever side O2 Volts Bank 2 sensor 1 represents)
Thread Starter
Drifting
Joined: Apr 2014
Posts: 1,699
Likes: 231
From: Hawthorne CA
From the limited data that Torque App provided I can see that the " O2 Volts Bank 2 sensor 1" is reading 0.35 volts and under for over 40% of the entire datalog that you provided. To me that represent significant Lean event on that side. I would concentrate your efforts on that side of the engine (whatever side O2 Volts Bank 2 sensor 1 represents)
Your comment helped me find the issue. Lean as we all know is generally caused by vacuum leak or more specifically unmetered air! This got me looking around and I found that the stock intake tube was a bit too small for the 58mm TB that's on the motor. This caused a tear on the underside of the tube just under the throttle body. This of course is after the MAF and would be unmetered air. The condition is exacerbated when rpms increase along with the amount of air leaking through the hole.
So I went to Lowe's and picked up a 4 x 3 inch rubber plumbing coupler and slapped it on there. Now both O2 sensors are within normal range and the car now runs like a scalded dog. Headed back to the Dyno next week.
It's running better than I ever anticipated. I was driving down the street in 3rd at about 3500 rpm and decided to rip it, well the car went into a full burnout.. at 65mph. Not wheel spin, burnout. There was so much smoke I thought I broke it. There was so much smoke that there was smoke coming out the gear shifter boot.
Burning Brakes
Joined: Mar 2005
Posts: 1,082
Likes: 115
From: Richmond Hill Ontario
With unmetered air I would suspect the entire previous tune will need some correction as well.( Make sure you ask your tuner to go over it) Looking forward to your final results.
Pro
Joined: Mar 2020
Posts: 500
Likes: 27
Frankie D gets the cigar.
Your comment helped me find the issue. Lean as we all know is generally caused by vacuum leak or more specifically unmetered air! This got me looking around and I found that the stock intake tube was a bit too small for the 58mm TB that's on the motor. This caused a tear on the underside of the tube just under the throttle body. This of course is after the MAF and would be unmetered air. The condition is exacerbated when rpms increase along with the amount of air leaking through the hole.
So I went to Lowe's and picked up a 4 x 3 inch rubber plumbing coupler and slapped it on there. Now both O2 sensors are within normal range and the car now runs like a scalded dog. Headed back to the Dyno next week.
It's running better than I ever anticipated. I was driving down the street in 3rd at about 3500 rpm and decided to rip it, well the car went into a full burnout.. at 65mph. Not wheel spin, burnout. There was so much smoke I thought I broke it. There was so much smoke that there was smoke coming out the gear shifter boot.
Your comment helped me find the issue. Lean as we all know is generally caused by vacuum leak or more specifically unmetered air! This got me looking around and I found that the stock intake tube was a bit too small for the 58mm TB that's on the motor. This caused a tear on the underside of the tube just under the throttle body. This of course is after the MAF and would be unmetered air. The condition is exacerbated when rpms increase along with the amount of air leaking through the hole.
So I went to Lowe's and picked up a 4 x 3 inch rubber plumbing coupler and slapped it on there. Now both O2 sensors are within normal range and the car now runs like a scalded dog. Headed back to the Dyno next week.
It's running better than I ever anticipated. I was driving down the street in 3rd at about 3500 rpm and decided to rip it, well the car went into a full burnout.. at 65mph. Not wheel spin, burnout. There was so much smoke I thought I broke it. There was so much smoke that there was smoke coming out the gear shifter boot.
