Durametric Actual Values Look-up? or Data Tutorial?

[innov8]

Hello. Great site. I recently purchased a 04 996 AE with 113K. My OBD showed random misfires. I checked the plugs and coils. Coils were cracked so I replaced all plugs and coils. The plug condition was consistent across all cylinders... ash gray color and no pitting or carbon or oily plugs. The misfire codes returned and I noticed the idle is rough but the engine pulls and is smooth off idle and through the rev range.  I purchase the Durametric and I ran actual values (codes showed random misfires across most cylinders) the check engine light came on at one point but had gone away on it's one while waiting for my cable to arrive.

My problem is I have lots of data to look at but no way to understand or to translate it into actionable information. I am not even sure that I captured the right parameters for my misfire error codes. Is there a good place to look at what the actual values should be for a 996? or a link to any tutorials on how to read the data and translate that into a what to check or troubleshoot?

Any advice would be greatly appreciated and thoroughly utilized. 

[Ahsai]

I would suggest the following values with the engine fully warmed up and the car stationary:

 

- a/c and headlights off. All other accessories off

- Cam deviation on both banks (the values should be rock solid at idle and when you give the gas a short blip)

- rpm

- MAF reading (kg/hr) at idle and @3k rpm

- RKAT on both banks

- FRA on both banks

[innov8]

@Ahsai  Attached the work log and the actual data file here. Sorry it took me some time to get back to doing the test. Let me know how I should respond to the data... more criteria or try something else? Thanks in advance of any insight you (or anyone else) can add.

new test actual_n04.xls

[innov8]

this is the PDF showing the error codes. Thx

996 Test log 062117.pdf

Edited June 23, 2017 by innov8

[Ahsai]

All the numbers look great on the spreadsheet. Cam deviation, FRA and RKAT, MAF all are perfect. Was the engine running rough when you took these measurements?

 

I suggest you log the misfire counters (6 of them, one for each cylinder) and rough running values (also 6) when the engine feels rough and when it's at idle.

 

Have you checked all your coil plugs are engaged properly? When you plugged in the coil connectors, did you hear a faint click?

[innov8]

Thx Ahsai. Appreciate the quick reply! 

I did check the 'seating' of the coils when I was installing them... gently pulling the backward until I felt resistance to confirm that they grabbed the plug. Then I screwed the coils down to spec.

The rough idle is mostly at cold start but even at op temp, when pulling off from a start I notice the RPMs drop and the jump back as I'm feathering the throttle up. I'm attaching here a test report that I did originally... it might seem like a random list b/c I was using my own intuition to choose the data points. I did include the Mis-fire counters and the rough idle values... and it was at cold start.

You can see in the data that I am turning on the different data points during the start of the recording. The really strange thing that I see and I don't see why or how this would happen is in the misfire counters... you'll see the counts start very low then jump up and then go to zero... at the point that the count goes to zero, the next cylinder jumps (assuming they are listed in firing order) from a low number to a spike at a slightly high rate then the previous cylinder. (see cylinder 1 misfire counter row 16 and then 144 to see what I mean). When I saw this, I just assumed I did the test wrong b/c it was my very first time with the software. That data set is attached to this post.

This is a huge help. I am new to the 996 and excited to own it and learn how to fix it when possible. Couldn't do it with the support of this community.

 

2017_06_16_08_07_29 996 AE first test actuals.xlsx

[innov8]

@Ahsai one additional note... I recorded the SPEC RPM (?) and not the RPM during that first test and the AC was probably on during the test (if that is a contributing factor). If you think this data is junk, I can re-run the test in about 7-8 hrs when I am out of work. Thx again.

 

[Ahsai]

Some formatting issues with your second spreadsheet. The rows are all very tall and I can't see the numbers.

 

the misfire counter counts the number of misfire per k crankshaft resolution, then it resets to 0 and start again so what you observed was normal. Forgot the value of k, could be 100 or something like that.

[Ahsai]

BTW, my previous comment was about the electrical connector on each coil. You need to hear a click when you plug each one in. No click = not engaged fully.

[innov8]

Hi again. Confirming that I did hear a click when pushing the coils on the plugs. Also, while I did not have the Durametric testing equipment prior to changing the plugs and coils, I was getting the same CEL and random misfire error codes across many of not all cylinders with my cheapo ODB-II reader. Those error codes were what prompted me changing the plugs and coils to begin this odyssey.

 

So to summarize, I am getting the same fault codes and engine behavior (rough idle and slight hesitatione off the line) before and after changing the plugs and coils.

I did a quick reformat of the data to eliminate empty cells from the start-up of the app, other data point columns and I've narrowed the columns to make viewing the relevant data much easier. Let me know if this is better.

996 AE first test actuals_revised.xlsx

Edited June 23, 2017 by innov8
fixing typos

[innov8]

In this screenshot, you can see the specific moment where the 'cylinder 1 misfire counter' (Col H) goes from "2585" to "0" and in the next row and 'cylinder 6 misfire counter' (Col I) jumps from ".5" to "2610" and then shortly after, it goes to "0" and then 'cylinder 2 misfire counter' (Col J) to the right goes from "1.6" to "2726" misfires. This cascade of increased misfires, that then go down to "0" show throughout the data from one misfire counter to the next until all 6 cylinders show have the pattern followed by all cylinders showing "0" the misfires and each counter eventually reporting a count in single digits.

Is this strange or simply normal due to the engine adjusting fuel or ignition to stop the misfires? This data includes the "injector time" if that is any indication of fuel flow—but I'm just guessing. I'm just not knowledgeable enough to break this down. I own the Bently manual, I'll look to see if it include any troubleshooting protocols for specific ECU codes. Like the car, the WorkShop Manual is rather new to me but I am becoming more and more familiar with both with each passing mile.

Let me know your thoughts. Thank you very much for all your help. I hope I can do the same and pass this forward. Patrick

 

Edited June 23, 2017 by innov8

[Ahsai]

I can see the spreadsheet now. Some of the rows at the beginning are missing some columns. The 2000 something numbers should be under "ignition count". i.e., in your capture above, the first 5 rows should be shifted to the right one column!

 

For each row, the actual misfire counters start at the left of the "ignition count" column.

 

Anyways, looks like multiple misfires occurring right off idle, i.e., around 1k+ rpm.  Not at idle (680rpm). It would be useful if you can log these again but log the actual rpm (not the spec one) and make sure you don't have missing columns in some of the rows and things get shifted like above.

[Ahsai]

Your RAKT values look great so it doesn't indicate intake air leak. However, have you checked for any intake leak such as: where the intake tube mounts on the throttle body and any cracks on the oil filler tube?

[innov8]

OK. Got it. I will re-do the test and send you the file... most likely by tomorrow morning.

Thank you for your generosity of time and know-how.

[innov8]

@Ahsai I must thank you for your time and expertise here. I had some trouble getting good data on a cold engine (getting used to the software and Windows OS as a lifelong Mac User) but attached is a test that I think gets you what you were looking for... it is a cold start and that includes some drive time. The data reports always max out at 1000 rows so that seems to be a hard stop I don't know how to get more data. 

I also did a visual inspection of the intake boots and the oil filler tube and I do not see any issues with them... When I remove the oil fill cap there is a change in the engine idle but not so much suction that the cap is difficult to remove. I understand this can be related to the Air/Oil separator but I don't get the white smoke or any type of fuel small from the exhaust.

The only other item that I noted should be updated (from my visual inspection and limited knowledge is the radiator cap is not the most recent part number ending in 04 that I think is the one that properly vents the cooling system w/o seepage (which I occasionally) show but I suspect this has no connection the the misfire codes.

In addition to the data log of actuals, I am including the report from the quick test so you can see all the error codes. In addition to the Misfire codes, I have a re-occuring fault in the the alarm and the AC with a flapper motor. Again, these seem like they would not have any connection to the misfires.

Last question for this post: The CEL came on yesterday... I get the idea that it comes on when there is a certain total number of misfires. The last time this happened, the CEL went away on it's own... the car sat for 3-4 days while I was traveling.  This is my daily driver and am I running any risk of doing damage to the car by driving it while I try to trace down the cause of the misfires? Appreciate your advice. Thank you, 

 

996 62417 quick test results.pdf

Innov8_996AE_test 4 Misfires.xlsx

[Ahsai]

If the CEL is not blinking, it should still be OK to have short drives. However, in the long run, the misfires will need to be fixed.

 

I looked at the files and didn't see any clear pattern of the misfires. The numbers all look fine to me (other than a few multi-cylinder misfires @~2k rpm). How old is the gas and what's the part number of the spark plugs you used? Any mods to the intake? I suggest you use a bottle of techron or seafoam in the fuel tank and drive the car till the tank is empty. Then change the oil afterwards and see if there's any improvement.

 

[Ahsai]

It's less likely since you got misfires on both banks but I think it's still a good idea to check the variocam timing and lift solenoids on the cam covers (they are like spark plugs) and see if there's any oil/air leak.

[innov8]

That is good news. I'll look for the Variocam timing areas and lift solenoids for any leakage. The gas is less than a week old. The car has been throwing these random misfire codes since I purchased it I think. The coils were so old and cracked that I was confident that they were the source so the continued misfires are a frustration.

The plugs/coils I purchased from ECS...
the coils:

BERU, Mfg Part #

99760210402KT1KT

ECS Part #

ES#3083524
https://www.ecstuning.com/b-beru-parts/ignition-coil-update-kit/99760210402kt1kt/

the plugs:

BOSCH, Mfg Part # 99917022390KT1 ECS Part # ES#2718140
https://www.ecstuning.com/b-bosch-parts/spark-plugs-set-of-6/99917022390kt1/

This spring I also replaced the stock air filter with HENGST brand from GermanAutoParts.com but the order doesn't show a part number.
Some people have recommended cleaning the MAF but from that data, nothing indicates it needs that, right? I don't want to do anything to the sensitive (and costly) MAF element unless there is some indication it needs attention.

Seafoam and run through a tank of gas will also start tonight... the neighbors will love me for the smoke-screen. haha.

Will report back ASAP on results. Thx again.

 

 

 

Edited June 28, 2017 by innov8

[Ahsai]

Those parts are correct. It's ok to clean the MAF as long as you use the MAF-specific cleaner (available in any auto parts store) and do not wipe the sensor with anything. Can you remove the MAF and check if it's a Bosch unit and is it 98660612501?

 

Seafoam in the gas tank does not create any smoke so no worries. Seafoam introduced in intake would.

[Ahsai]

Actually I saw a pattern in the misfires but I'm not sure if the info helps. I'll post it here anyway.

 

The misfires seem to occur at ~2,000 rpm, ~40 ignition timing advance and ~5 degree throttle valve position (idle is 2~3 degrees). Basically just off idle.

[innov8]

Hi Ahsai. I just put in the seaform. I will take a look at the MAF a bit later and confirm the part number as well as clean it... should be late tonight.

I will also clean the throttle body and then report back as soon as I have burned through the tank of gas. Thank you.

[innov8]

I'm back... cleaned the MAF (appeared clean) and Throttle Body (only slightly dirty)... and checked the intake boots as best I could,,, no apparent cracks or loose fittings.
The part number on the BOSCH MAF is 986 606 125 01
Ran through 1.5 tanks of gas with 3 cans of Seafoam. Running clean gas now... CEL came back within a couple of days... 
Attached the codes report here along with a set of actuals with a hot-start. I will post a cold start based on this text in a few hours.
Not sure what to do next besides give-up and bring it to my local independent shop. Was hoping I could trace this and correct it without paying out.

Let me know if you have any other suggestions. Thank you!

2017_07_14_996AE 114K Misfire test hot start.xls

[innov8]

Attached here are two Fault Code tests that I ran 1 week ago and this morning before I ran the test above.

Note that the misfires are spread across the cylinders and are not always consistent in my codes but I have been throwing these misfire codes for months now and while the car drives strong and pulls hard, I am concerned that I am damaging the motor.

Thanks for your shared wisdom and experiences in advance. 

fault codes071417.pdf

Short test 996 070717.pdf

[innov8]

On 6/28/2017 at 4:33 PM, Ahsai said:

Those parts are correct. It's ok to clean the MAF as long as you use the MAF-specific cleaner (available in any auto parts store) and do not wipe the sensor with anything. Can you remove the MAF and check if it's a Bosch unit and is it 98660612501?

 

Seafoam in the gas tank does not create any smoke so no worries. Seafoam introduced in intake would.

Yes, the MAF part is Bosch 98660612501

[Ahsai]

Nothing stands out in the excel spreadsheet to me. I saw some mifires and timing got pulled but the MAF readings (kg/hr and voltage) look fine.

For further diagnostic, I can only think of intake air leak test, fuel pressure test, and unplug MAF and see if there's any difference.