Having some idle and stalling issues

[Ntracing777]

Hello all,

 

I am running into some issues that are making life difficult for my daily driver and wanted to get some feedback and advice on the problems.

 

I have a 1999 C4 Coupe with ~122k miles on it.  I have owned and maintained the car for the last 60k give or take.  I have a K&N intake and gundo hacked 

 

Problems are as follows:

 

Idle surge from 700-1200 RPM's (each surge is accompanied by an audible air sipping noise that can be heard outside the car near the engine).

 

ABS/PSM lights come on randomly (always together).  I've noticed this happens more often when using partial throttle but decelerating.  Turning the car off and back on usually clears these lights but they come on nearly every day now.

 

Car will occasionally go into limp mode.  It doesn't completely die it just stops responding to throttle input.  Sometimes the car also dies.  This is most common at low speeds and restarting the car fixes the problem.

 

It is throwing a CEL.  I will detail the codes below that I obtained with the Durametric scanner.

 

P0140 - Oxygen Sensor after TWC, bank 1

 

P1118 - Factory Fault Code 4 - Oxygen sensor heating after TWC, bank 2

 

P0102 - Factory Fault Code 115 - Mass Air Flow Sensor

 

P1119 - Factory Fault Code 5 - Heating of oxygen sensor ahead of TWC, bank 2

 

P0159 - Factory Fault Code 23 - Ageing of oxygen sensor after TWC, bank 2

 

P1266 - Factory Fault Code 409 - Fuel Shutoff Function Monitor

 

P1505 - Factory Fault Code 404 - Throttle Jacking Unit, Control Range

 

P0139 - Factory Fault Code 17 - Ageing of oxygen sensor after TWC, bank 1

 

P1501 - Factory Fault Code 403 - Throttle Jacking Unit, Output Stage (signal implausible)

 

P0160 - Factory Fault Code 20 - Oxygen sensor after TWC, bank 2

 

Alarm Fault Codes - These relate to separate issues I am going to address later (unable to program key, alarm goes off randomly)

 

33 - No passenger compartment monitoring

 

60 - Central locking limit position locked not reached

 

48 - Airbag signal acknowledged

 

I have a few theories based on my research thus far but thought this would be a good place to discuss them and possibly get insight from people with more experience and wisdom on the topic than myself.  I think a large portion of the codes stem from a somewhat recent change to catalytic converters.  The placement of the O2 sensors were vastly different on the replacement units that they were on my original units.  I have attached pictures of the new cats and a stock photo that shows the old ones.  I installed all new O2 sensors at the same time I installed the new converters.  This was done at 106k.

 

At 112k I replaced the evap purge valve to fix a non starting issue.  At the same time I also replaced the MAF sensor with the most current revision in hope of clearing up the ABS/PSM lights coming on.  Clearly it didn't work haha.

 

The throttle jacking code makes me think it could be an issue with the throttle body which isn't terribly expensive or difficult to replace, so this is the one I am rooting for!

 

I've read some posts relating the P1266 to ECU failure which requires the ECU to be rebuilt or replaced.  While it isn't too hard to get to, it's not cheap either.

 

Any info or suggestions are appreciated!  Thanks everyone!

 

Brock

 

[Loren]

I would start by clearing all the codes and seeing what comes back.

 

Are the new cats the correct part number? Likewise with the new O2 sensors.

[Ntracing777]

I cleared the codes this morning a drove to work and back, about 10 miles.  The codes have not popped back up yet but they have after clearing them previously to run this type of check.  The ABS/PSM lights stay on regardless of the codes being cleared.  I haven't hooked it back up to the durametric but my hand held scanner doesn't show any pending codes yet.  I'll take the long way in or out tomorrow and see what turns up.

 

The catalytic converters are not OEM and I do not recall if any part numbers where stamped on them.  They are made by Davico Manufacturing and listed as part numbers 57124 for the right and 57123 for the left.  Their website confirms these to be the correct part numbers for a 1999 911 C4 Coupe.  O2 sensors were ordered from Rockauto and made by ULTRA-POWER, two upstream 2344182 and two downstream 2344184.  I know those aren't the OEM part numbers.  The difference in exhausts left me with a quandary when installing.  On my original cats, the upstream O2 sensor wire plugged into the opposite side from the downstream sensor because the bungs were at opposite ends of each pipe.  On the new cats there is a bung dead in the center of the cat.  I have considered using spacers on the downstream sensors to try and offset the issue.  I have also considered a cat delete with spacers as I have read several reports of people using those with no CEL's thrown.  Obviously just spacers would be more budget friendly than the cat delete x-pipe.  My car is also on the edge of being overly loud as it is with the 2" gundo hack haha.

 

Love the avatar pic btw, looks just like mine from what I can see!

[Ntracing777]

OK, CEL returned on my way to work today.  None of the more sinister codes are showing back up yet, but I also haven't experienced limp mode recently either.  Here is what I have so far:

 

P0102 - Factory Fault Code 115 - Mass Air Flow Sensor

Below Limit

 

P0140 - Oxygen Sensor after TWC, bank 1

 

P1119 - Factory Fault Code 5 - Heating of oxygen sensor ahead of TWC, bank 2

 

P1118 - Factory Fault Code 4 - Oxygen sensor heating after TWC, bank 2

 

P0154 - Factory Fault Code 18 - Oxygen sensor ahead of TWC, bank 2

 

P1117 - Factory Fault Code 14 - Oxygen sensor heating after TWC, bank 1

[Ntracing777]

More codes today.  The car died out as I was approaching a stoplight.

 

P0102 - Factory Fault Code 115 - Mass Air Flow Sensor

 

P0140 - Oxygen Sensor after TWC, bank 1

 

P1119 - Factory Fault Code 5 - Heating of oxygen sensor ahead of TWC, bank 2

 

P1118 - Factory Fault Code 4 - Oxygen sensor heating after TWC, bank 2

 

P0154 - Factory Fault Code 18 - Oxygen sensor ahead of TWC, bank 2

 

P1117 - Factory Fault Code 14 - Oxygen sensor heating after TWC, bank 1

 

P1266 - Factory Fault Code 409 - Fuel Shutoff Function Monitor

 

P1505 - Factory Fault Code 404 - Throttle Jacking Unit, Control Range - open cicuit

 

Any thoughts or suggestions on these?  I can try to upload a video to youtube with the idle surge associated sipping noise if that would be of benefit.

 

Thanks again!

 

Brock

[Ahsai]

A couple of thoughts:

- Too many variables with aftermarket cats, O2 sensors, and MAF (what brand is the MAF btw? If it's not Bosch, it's a suspect as well)

- The $20 O2 sensors are highly suspicious. I suggest using the Bosch sensors (~$65 each)

- Do you still have problems if you drive the car but keep the MAF disconnected?

- You can generate a cold start plot (~3 minutes worth of initial start up) and log the O2 sensor voltage for all 4 O2 sensors. That should give us some idea of how the cats and O2 sensors work. Repeat the log but with the engine fully warmed up and at idle ( log for ~1 minute)

- Your new cats are of the stock 996.2 style where the post-cat O2 sensor sticks to the middle of the cat, right between the two elements inside the cat. They may not work well for your car, which expects the post-cat O2 sensor way after the cat with the exhaust air better processed by potentially the same two elements or a larger single element (I have not taken one from a 996.1 apart so I'm not sure).

- Check your engine oil cap. Do you feel some vacuum when you remove it when the engine is running? If not, you may have a gross intake air leak (check the oil filler tube for cracks)

[Ahsai]

Btw, do you still have your old O2 sensors and the cats?

[White987S]

Why did you replace cats? Surprised the original cats failed. We don't hear too many cases of failed cats.

[Ntracing777]

MAF is Bosch, part #0280218055.  I generally buy OEM but O2 sensors are such a common part it seems like it would be hard to have them be an issue.  The cats I replaced due to some damage to the rear that caused them to buckle.  I did not go OEM on the cats because they were somewhere in the range of $900 - $1600 each (at that price I would be giving fabspeed a call for some cat deletes).  They have long since been sent to the scrap yard along with the O2 sensors.

 

- I have not tried driving with the MAF disconnected, I honestly didn't know that was feasible but I will give it a go.  Are we talking just around the neighborhood or freeway speeds?

- I recall trying the oil cap off while running and checking for too much suction when I wasted to make sure the AOS was good.  I will try that this evening and see if there is a lack of suction.

- I have not logged data on the car before but I am assuming that is a durametric function.  I will do some digging tonight and figure that out.  I can't imagine it will be terribly difficult.  I have seen the section to monitor actual values and would guess that is the place to start.

 

Thanks for the input thus far.

[Ahsai]

- It's ok to drive the car just like mormal even with the MAF disconnected

- the DME is monitoring the heater resistance of the O2 sensor so deviation in aftermarket part may trip the error codes

- yes, logging using the actual values. More details here http://www.renntech.org/forums/topic/49414-secondary-air-test-readiness-monitor-incomplete-with-o2-voltage-graph/

[Ahsai]

You may also want to do an e-gas throttle recalibration first before anything. Just turn the key to the last position before crank, foot off the gas pedal and wait for 1min. Then remove key and it's done.

Also, per Bosch site, your MAF should be this one http://www.boschautoparts.com/en/auto/air-management-sensors/mass-airflow-sensors?partId=0280218009

If you punch in your current Bosch p/n, it will say the part is not compatible with your 1999 C4.

[Ntracing777]

Sweet jesus that's frustrating haha.  I ordered the part after what I felt was a fair bit of research based upon the Porsche part number 996.606.124.00 listed for cars with e-accelerator.  I wanted to be extra careful so I didn't waste over $200.  I had no idea there was a further subset of Bosch part numbers that somehow superseded the numbers.  I assumed Pelican Parts wouldn't lead me astray.  Oh well, /rant off.  I suppose if it ends up just being the MAF it'll be cheaper than a new DME.

 

As a side note I looked that the MAF i removed from the car and it was Bosch #0280218009 and was exhibiting the same issues with the idle surge and the ABS/PSM warning lights prior to replacing it.  In fact the replacement was an attempt to remedy the issue.

 

I didn't have a chance to log yet tonight so that will likely be later this weekend, I spent the evening chasing down a brake issue on the wife's Audi (it's been a busy week haha).  Same goes for driving without the MAF.  Per my notes I never had the P0102 with the old MAF but I did get a P0103 at one point.  I believe I used electrical cleaner on the MAF to clear that one though.  I could always try popping the old MAF back in and see if the P0102 comes back.  I will also try the e-gas throttle re-calibration.  I think I may have done that by accident several times over though as I will sometimes just pop into the car and listen to the radio on my lunch.

 

I did pull the oil cap off, there is some suction there, although nothing excessive.  The idle surge becomes much more pronounced with the oil cap off though.  Not sure if that means anything.

[Ahsai]

The slight vacuum and idle struggling are normal when the oil cap is removed.

Dis you use the MAF specific cleaner and not the regular contact cleaner? Do the K&N filter have too much filter oil that could foul the MAF?

More info on how the car got into this state would also be helpful. You mentioned you have had it for some time so at which point you started having idle issues and CEL?

[Ntracing777]

I used MAF specific cleaner, went out to the garage to double check.  I am always careful not to over oil the K&N filter when I do a cleaning.

 

The first time the car went into limp mode was while getting onto the freeway a little over two years ago.  Turned the car off then back on and I had no more issues for a long while.  The car didn't throw any codes then either.  I do not know exactly when the idle surge started but it was at least 7-8 months ago.  I think it was a gradual increase or I would've noticed it right off.

 

I am currently having some issues exporting the durametric logs on my windows tablet I use.  I will be playing with that today to get those uploaded.  I have only done the cold start log thus far.

 

I did an e-gas throttle calibration per the instructions above.  Moved the key to the position just before crank, touched no pedals, and removed the key after a little over a minute.

 

I unplugged the MAF and the car would start then immediately die unless I kept my foot on the gas.

[Ahsai]

So when were the old cats replaced? I'm trying to understand the sequence of events hoping that could give us more clues. E.g., do the new cats ever work without problems?

[Ahsai]

Btw, can you also log the following for 2 minutes during engine idle after fully warmed up?

- MAF

- rpm

- coolant temp

- Resistance of all 4 O2 sensors

- O2 voltage of all 4 O2 sensors

- FRA, RKAT on both banks

- cam deviations

[Ntracing777]

Cats were replaced 3/19/14 at 106325 miles, car is at roughly 122k now.  The O2 codes started popping up not long after the change with an increasing frequency.  I cannot remember with certainty if the idle surge was present at this point, but I am sure the PSM/ABS issue was already going on.  

 

Apologies for a lack of a more accurate timeline, I know it's frustrating not having the full picture.

[Ntracing777]

I will log those parameters as well, yes.  Is it easier to put them on separate logs or all lumped into one?

[Ahsai]

I will log those parameters as well, yes. Is it easier to put them on separate logs or all lumped into one?

All in one log will be fine.

Excel file with raw values would be good but graphical plots are ok too as long as one can see the values clearly.

Edited January 31, 2016 by Ahsai

[Ntracing777]

I'll do multiple excel files since it only allows 8 values to be monitored at once.

[Ahsai]

Let me tell you what to expect so you have some feel too:

- MAF ~15-17kg/hr at idle. 50-80kg/hr at 3,000rpm

- MAF voltage ~1.3v at idle

- rpm ~700 +/- 40

- coolant ~90C

- resistance of O2 sensor ~100ohms, will fluctuate between 64 and 128 ohms

- precat O2 should swing between 0.1v to 0.7v about once a second. Postcat should stay at about 0.7v flat

- FRA ~1.0 +/-0.15 and RKAT ~0% +/- 15%

- cam deviations 0 degree +/- 7 degrees (measuesd at crank). Should be rock steady at all revs

Note MAF and rpm should be in the same log. So do the 4 O2 voltage. I'm not aware of the 8 sensors logging limitation. Are you using the latest version of Durametric?

Edited January 31, 2016 by Ahsai

[Ahsai]

Cats were replaced 3/19/14 at 106325 miles, car is at roughly 122k now.  The O2 codes started popping up not long after the change with an increasing frequency.  I cannot remember with certainty if the idle surge was present at this point, but I am sure the PSM/ABS issue was already going on.  

 

Apologies for a lack of a more accurate timeline, I know it's frustrating not having the full picture.

Np. So it seems PSM/ABS occured first, then after cats and O2 sensors replacement, you started to get O2 codes.

Seems to me the O2 sensors are very suspicious and hopefully durametric logs will confirm that. Once those are corrected, you can then see if the cats are good since O2 codes can supress cat codes. PSM/ABS sounds MAF related. Btw, have you cleaned the throttle body and rotate the butterfly carefully to check for smoothness and full range operation? The spring is quit strong so it takes some force to rotate the butterfly.

[Ntracing777]

Ok, I've been struggling to get logs to export on my Windows tablet and I am still not successful.  I wrote down the values I was seeing pop up during the logging sessions.

 

RPM - fluctuated from around 500 - 780

Mass air flow: 8-46

Engine Temp - 93 degrees

Cam Position 1 deviation: -10.23

Cam Position 2 deviation: was changing slowly from -1.14 to -1.15 and back

FRA 1: 1.05

FRA 2: 1.40

Rkat 1: 2.53

Rkat 2: 2.20

o2 voltage ahead of cat, bank 1: 0.72

o2 voltage behind cat, bank 1: 0.45

o2 voltage ahead of cat, bank 2: 0.45

o2 voltage behind cat, bank 2: 0.65

o2 resistance ahead of cat, bank 1: 384

o2 resistance behind cat, bank 1: 0

o2 resistance ahead of cat, bank 2: 16320

o2 resistance behind cat, bank 2: 1984

 

I have not tried cleaning the throttle body but I will give that a shot this weekend.  Should I be able to move the butterfly to a flat position with no resistance other than the spring?

[Ahsai]

I would really need to see the O2 plots in time to see if they are working. Just a single voltage value snapshot won't tell us anything.

Regarding your other numbers, I saw:

- bank 1 timing is out of spec, which is between -7 degree to +7 degree. Suggest check timing of bank 1. Could be due to excessive chain pad wear.

- your bank 2 is runnng way lean (FRA ar 1.4), could be due to bank 2 O2 sensors.

- your O2 sensor resistance values are all wrong. Suggest replace all O2 sensors with the correct Bosch sensors

Yes, you can rotate the butterfly with some force, just be careful not to pinch your fingers.

Edited February 6, 2016 by Ahsai

[DBJoe996]

I think Ahsai is pointing you in the right direction.  I know throwing money at a problem is difficult but more than likely what you will need to do.  Get the correct 02 sensors.  I cleaned my MAF sensor multiple times to no avail - so I replaced it with a new one and my problem was solved.  Remove the throttle body, then disassemble it.  Clean it completely with TB cleaner.  Clean out the Idle Control Valve because it really gets gummed up.  Make sure it is working smoothly.  I have found removing the TB and cleaning it is really the best way to ensure it is totally cleaned out.