P1093 SEARCH FOR A FIX CONTINUES...

[richardb]

Originally Posted by upallnight

Is it still the same code? What are some of your data when the light comes on? STFT, LTFT, MAF air flow g/s?

Using my generic scan tool we keep in the X5, it came back with P1093. Perhaps this is the issue... I grabbed my C310 BMW tool from my car and used that for the live data and codes. It showed more codes...

EC Trimming, oxygen sensor before cat converter bank 2
E4 Fuel trim bank 2, permissible range exceeded
E3 Fuel trim bank 1, permissible range exceeded
F2 misfire cylinder 5
F0 misfire cylinder 3
EE misfire cylinder 1

The coil packs are original, except for one we replaced over the summer due to a single cyl midfire code. I wonder if the other 5 need replacement. 185k and 2005 on the originals! Spark plugs only have a few thousand miles on them.

Started the car this morning, ice cold engine (below freezing ambient temps here this morning) and at idle the air mass flow is 21 kg/h. I revved it a bit to 2,000 RPM and it went up around 60ish kg/h. Should verify the readings at different RPM later, it was early, had to check before my wife took the car to work.

[upallnight]

Normally when you have a bad coil, you will get misfires but eventually, the DME will shut down the injectors. With no gas coming from the injector(s) you can feel the misfire. A misfire to the computer is when a cylinder(s) don't provide the same power when the spark plug is ignited. The computer can determine this by the crank rotation speed (RPM) if the cylinder is as strong as the other cylinders. Most people think of a misfire as a bad coil or bad plug, but a bad injector can also cause a misfire or a cylinder with low compression can also attribute to a misfire.

E4 Fuel trim bank 2, permissible range exceeded
E3 Fuel trim bank 1, permissible range exceeded

It will be helpful if we knew which range the sensor was reporting, either too lean or too rich.

As for the MAF of 21kg/hour which means dilly to me since I'm more used to g/s that converts to 5.8333 g/s which kind of high for an airflow at idle. Airflow through a MAF is used to cool a hot wire or hot film and the DME can determine this base on the current required to heat up the hot wire or hot film.

[richardb]

Originally Posted by upallnight

Normally when you have a bad coil, you will get misfires but eventually, the DME will shut down the injectors. With no gas coming from the injector(s) you can feel the misfire. A misfire to the computer is when a cylinder(s) don't provide the same power when the spark plug is ignited. The computer can determine this by the crank rotation speed (RPM) if the cylinder is as strong as the other cylinders. Most people think of a misfire as a bad coil or bad plug, but a bad injector can also cause a misfire or a cylinder with low compression can also attribute to a misfire.

E4 Fuel trim bank 2, permissible range exceeded
E3 Fuel trim bank 1, permissible range exceeded

It will be helpful if we knew which range the sensor was reporting, either too lean or too rich.

Adaptation mixture, bank 1, multiplicative 6.1%
Adaptation mixture, bank 2, multiplicative 6.1%

This sounds consistent with a rich condition generic code (P1093)

How does that MAF value look?

[upallnight]

Originally Posted by richardb

Adaptation mixture, bank 1, multiplicative 6.1%
Adaptation mixture, bank 2, multiplicative 6.1%

This sounds consistent with a rich condition generic code (P1093)

How does that MAF value look?

As for the MAF of 21kg/hour which means dilly to me since I'm more used to g/s that converts to 5.8333 g/s which kind of high for an airflow at idle.

Airflow through a MAF is used to cool a hot wire or hot film and the DME can determine this base on the current required to heat up the hot wire or hot film.

So when the weather outside is cold, it will take less air flow to cool down the wire or film to a specific temperature.

[richardb]

Erased code and cleared adaptations with the BMW scan tool this time, code has not returned in 38 miles. Exhaust gaskets getting repaired at shop today, will see how long the light takes to return... any other thoughts on where to diagnose?

Drivability is fine, other than a low 16.5 mpg average. It should be closer to 18.5 in a healthy car I think. Other notes, when I removed the ICV the intake smelled strongly of gasoline, definitely rich.

[upallnight]

Originally Posted by richardb

Erased code and cleared adaptations with the BMW scan tool this time, code has not returned in 38 miles. Exhaust gaskets getting repaired at shop today, will see how long the light takes to return... any other thoughts on where to diagnose?

Drivability is fine, other than a low 16.5 mpg average. It should be closer to 18.5 in a healthy car I think. Other notes, when I removed the ICV the intake smelled strongly of gasoline, definitely rich.

Since the MAF seems to be reporting inaccurate data I would start with the MAF. Either purchase or borrow a Genuine Siemens MAF or buy a good used Genuine Siemens MAF. Stay away from those cheap MAF on eBay or Amazon.

Another item worth checking out is the DISA valve. It could be sticking so the amount of air going through the intake could be off.

[richardb]

Update. 72 miles and engine light has not returned.

What is strange though is if it was the ICV, MAF, or DISA - all of those items affect both banks, not just one. So rich on one bank doesn't make sense.

The VDO MAF is $203 at FCP Euro right now, also made in Germany.
Genuine BMW MAF is $347 at FCP, not sure who makes it, Siemens?

[c-bass]

Originally Posted by richardb

Update. 72 miles and engine light has not returned.

What is strange though is if it was the ICV, MAF, or DISA - all of those items affect both banks, not just one. So rich on one bank doesn't make sense.

The VDO MAF is $203 at FCP Euro right now, also made in Germany.
Genuine BMW MAF is $347 at FCP, not sure who makes it, Siemens?

I'm pretty sure I have a VDO with the BMW logo stamped on it.

I believe both were OE suppliers

[richardb]

Hit 100 miles, no code return. Took it through emissions, good for another 2 years. Will report back after more mileage.

[docnabimmer]

Originally Posted by richardb

Hit 100 miles, no code return. Took it through emissions, good for another 2 years. Will report back after more mileage.

Hey R

you still battling this code,hoping that exhaust repair fixes it.
154790 miles and no P1093 code since.
Another Engine failsafe problem for the past year though but a new MAF VDO Siemens has so far kept that light off.
R