P1093 SEARCH FOR A FIX CONTINUES...
 

Not sure the proper way to bump this issue back up but here's a follow up to my previous string of posts " catalytic converter diagnosis help ".

I've been chasing down this pre cat fuel trim too rich bank 2 code for a while now to no avail.

So far I've done:
MAF
Secondary MAF
DISA valve removal, clean, inspect checks out ok
ICV clean, checks ok
Vacuum lines, all ok. ( no smoke test but vacuum leak would show a lean condition vs my rich condition as discussed in prior posts)
New plugs
Swapped coils from bank 1 to 2. No change...
New valve covert gasket ( not related but could introduce unmetered air)
Fuel pressure test at the rail ( shows ok, 50 psi, and holds pressure)
New pre cat bank 2 O2 sensor
All O2 sensors voltages show normal at idle and at speed.
Cat temps show normal pre and post cat ( testing with a laser temp gun)
Previous owner says ALL 02's replaced at 100k, ( car has 118k now)
Previous owner says 1 or 2 cats replaced at bmw dealer at 100k
Live data fuel trims both short and long term show normal.
In fact EVERYTHING shows normal on my Lemur code scanner from BAV Auto. It supports most of the pertinent data live. As I watch the live data via Bluetooth on my iPad both cold, warm, idle, hwy speed, etc. with a seasoned mechanic sitting next to me he says all looks like it should.

The interesting part is that I tracked down the previous owner, and he was hugely helpful in explaining that the check engine light that's been on for YEARS! Holy! He said the car drove fine, showed no issues, same as I'm experiencing. He's a car guy and explained that he didn't want to continue to have the dealer throw parts at it at when the car seemed fine, sans the light. Said the dealer and indi's couldn't figure out the exact issue, and they too concurred the cars "fine"..

Only thing I haven't checked is fuel injectors. I am going to swap bank 1 to 2, and install new O rings. Any other injector tips short of throwing new ones in?

I'm thinking this thing might need a reflash of the DME? Given the previous owners comments, my findings, and with all these dealers and indi's scratching there heads as well. Any suggestions? Cost to re flash? I figured that's a dealer job vs all the threads I read on diy software?

I skimmed your list and didn't see injectors. That was the first thing I thought after I saw what you had done.

I would get one known good injector and swap it in one at a time for existing. Reset codes. Drive, see what happens.

Also keep in mind BMWs are very finicky about oxygen sensors. Are they OEM? Even supposedly good quality non-OEM sensors can throw a code intermittently. Try swapping your o2 sensors from bank to bank and see if the code moves banks.

How did you check the ICV?
Did you do an Ohm test on the terminals? What were the ohm readings?
Did you just shake the ICV and because you heard it rattle you determine that it was O.K.?

When I had the PO1093 error code I replaced the IVC, I didn't bother to clean it.

ICV should make a buzzing sound when you turn the keys to the run position, but do not start the engine. Does your ICV buzz?

I used a mechanics stethoscope on each injector and they are alol making a tapping sound as they should but I haven't actually taken them out as yet. I read that I can test they with a multi meter as well?

On the ICV I did clean it, see it shake properly, and do hear w a scope that buzzing prior to starting the car.

The previous owner said he checked everything as well, as did the dealer and no dice.

I'm wondering if a DME re flash would do it if everything else is ok? Im tempted given my frustration to bring it to a dealer where I live in Maine and have them have a look at it. Given the area they see a lot of X5's...

I do however feel like injectors would be the last unknown... Any thoughts on further testing them? Trying to figure if I multi meter test them, or my scope sound test is good enough, etc. don't want to check something and cross off the list with being 100%.

Going to try swapping 02 wires rear left to right now... They are Bosch I believe...

I have had random intermittent lean codes from Bosch 02s for years. Could just be me.

By using a multimeter across an injector, you are only determining that it is getting the open/close signals via the harness. It will not tell you if there is some mechanical issue with the injector (eg it's "dribbling"), or over/under flowing.

As you've already listened to each of them with a stethoscope, the chances are better than average that they are actually opening and closing. Whether they are flowing and sealing correctly is another matter entirely.

Changed my ccv valve last week at the suggestion of my bmw dealer... Still no fix for my p1093 code... I did smell a slight rotten egg smell a couple times on the hwy last week... Wonder if this could be the rear cat that wasn't replaced like the front? I haven't replaced the fuel injectors or tested them other than my stethoscope test... dealer says they would need a few hours or more to figure all of this out... Gas mileage combined is 18... Also, I get a p3013 misfire code with low fuel and or when it's super cold 10 degrees... Not every time but has happens a few times...

Trying to think logically here and let all of these symptoms point me in the right direction...

Any ideas? Have a look at my previous list of things I've fixed... In other news I've got a coolant leak at the coolant temp sensor... Radiator was replaced 25k miles ago... I assume the hoses too?!

I would connect a fuel pressure gauge to the fuel rail and see what type of fuel pressure you have at the fuel rail. The pressure regulator could be bad or the vacuum line to the regulator could be bad so there is little vacuum at the regulator which will signal a wot situation which will increase the amount of gas to the injectors.

Tried that already. Pressure at the rail was fine...

Trying to think of other stuff it could be...

Bump

are the o2 sensors hooked up backwards? In other words, are the connectors swapped between the pre and post cat sensors?

Ever figure this out? I am getting this code now as well and the Indy has no clue what the issue is. They replaced the gas cap and light went away for a few weeks and now it is back. I cleared it this am and came back about 20 miles later.

You need to find a better INDY. A bad gas cap will produce an evap code/problem.

Check this guy post on the P1093.

http://www.xoutpost.com/bmw-sav-foru...xed-p1093.html

well to start of to much air=lean not enough air =rich
i had it were on bank to was giving me both codes even though the o2 were new NGK
so after some more reading these vehicle are pickie i bought 2 new BOSH o2 reset ses
after 10 miles no more codes but now i would get po430 for the same bank 2 WTF
with NGK only 2 same codes with BOSH only 430 code also the mass airflow controls the air to fuel mixture for both banks guys were using the k&n filter and the oil would get on the element and give the lean or rich code also if the upstream o2 is loose same
thing and at time even though the ICV sounds good when shaken it doesn't really mean it is good meaning it might not be opening or closing like it should on mine with out AC on i get a certain fuel trim reading then when ac is on they go down
but the rule of thumb is lean=more air than fuel rich=less air more fuel
a friend of mine with same problem did a adaptain reset with inpa and it went away

in inpa you can turn off individual injector. a leaky injector would also give rich code

P1093 since 10/2015
 

Just in case somebody is having the same problem, to make a long story short ,what fixed this code for me was replacing the post cat oxygen sensor Bank 2 Sensor 2 and I haven't even replaced the other post cat O2 sensor yet ,x5 is due anyway. Vehicle is 2005 X5 3.0 120,818. Original MAF,IACV,intact intake ,new fuel filter after reset and 200 miles mixed drive.
Hope this helps.

I've just started looking into these codes on my 2005 X5 3.0 as well and posted a video today:

https://www.youtube.com/watch?v=fykuAkjVI4g

loose oxygen sensor was all it was for me
 

to this day, P1093 has not been back, by this time ALL of my oxygen sensors have been replaced. The one replacement that cured it all was when i found that one of my oxygen sensors underneath was in fact off not just loose. replaced that and code was gone,even took my time replacing the other 3 finally the last of which I did last week.

Thanks for coming back to comment. Thinking it may be worth throwing in those post-cat sensors as well!

Just wanted to post an update here. P1093 code on our 2005 3.0i, replaced both pre-cat oxygen sensors since they were original with 140k!

Replaced the post-cat bank 2 sensor after reading 5-6 threads across xoutpost/bimmerfest that it was a confirmed fix. Cleared the code with scan tool.

The light came right back on after about 25 miles!

sorry it did not work for you R.
 

Sorry to hear that ,I cant think of anything else as I had stopped when I changed the O2 sensors. Mind you I was chasing this starting 10/15 started with cleaning IACV,DISA, MAF and inspecting the intake boots,whatever was in the area,didnt touch the fuel injectors but treated 2 full tanks of gas with cleaners,didnt work,still getting intermittent P1093 code,lived with it and reset as needed, only thing i changed was the fuel filter since it was original at 120k,up until 3/16 when it was warmer when I was able to check the O2 sensors....hope somebody on here with more expertise can help you out, try our brothers at e46fanatics, see if they can help you out...X5 3.0 now has 125K miles, nothing new added since the last oxygen sensor was changed,no P1093.

Any solution for P1093 ?

UPDATE NO P1093
 

Dear Sir,
to this day i am happy to report that i have not had any SES problems since i changed the 2 lower and 2 upstream o2 sensors.
2005 BMW X5 3.0 other than the O2 pilot mod car is bone stock, auto 135800 miles.
cheers
Rudy T

Previously, cleaning the idle control valve resolved this issue for us in 2016. Well, 42,XXX miles later and the P1093 code is back on.

M54 ICV cleaning video: https://youtu.be/lVPV-XnmJyk

Just replaced both pre-cat sensors again, no luck there.

Cleaned my MAF with MAF specific cleaner, put a big bottle of Lucas complete fuel injection system cleaner in the tank. Drove 130 miles this week, the light came right back on.

At 132 miles, the service engine soon light turned off on its own! The code was gone for about a day, several drive cycles. Then it returned. I thought this was quite unusual. Anyone have some insight?

Update on this issue: I used a $75 smoke tester kit (found on eBay and Amazon) to smoke the intake on our X5. Through a glove on the air intake, in front of the MAF. Removed the MAF to avoid any potential damage from the smoke fluid vapor.

Here's a video of the smoke test kit/process I used on my E32: https://youtu.be/QIGQGai5ngs

After about 10 minutes of smoke building up, it began to pour from a vacuum hose attached to the lower intake boot. For some reason the vacuum line was barely on the fitting, and smoke began to billow out. Definitely a leaking spot. Pushed the hose back on, and done. Erased the code, will report back when or if the codes return.

If the code does return, I've purchased a new Bosch Idle Control Valve for around $175 at FCP Euro to install. Several people have reported a faulty ICV causing this code and issue.

The SES light came back on within 37 miles of erasing the code and fixing the leaking vacuum line. New idle control valve will go in this weekend... sigh...

That's dissapointing.

I was excited for you when the smoke tester "worked" so I built myself a little tester and was hoping that would point me in the right direction chasing down my misfire.

Hopefully the ICV is the answer for you (fingers crossed)

Hey everyone, bad news. Installed new ICV Sunday and erased the code.

24 miles after the installation of the new idle control valve the service engine soon light returned.

Not sure what is next.

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.

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.

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.

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.

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

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

:thumbup:

196K, I'm in the same boat P1093 bank 2 ... I'm going to try a clear adaptions with ISTA. I did it with my autel but didn't work. Replace both O2 sensors on bank 2, but no reason to believe they are bad as they respond fine. Output voltage on downstream o2 is low at times, and bank 2 fuel trim is slightly high at 7 to 9% (again at times), both long term fuel trims are below 1%. 3 months until inspection expires.. the clock is ticking.

not in the same boat, but sailing in the same waters
 

Never read this thread before, so here's my 2 cents input.

I've never had a P1093, but initially, before I started doing MAF resets, I was having repeated problems with P0171 and P0174 (lean codes) going so far above normal range that the SES (CEL,MIL) would trip. This started just following inspection in late Oct '21. For the last four years I've been trying to find what's wrong, and though the fuel trims have sttled down a bit, I'm still looking.

Many smoke tests, fuel pressure tests, MAF sensor resets and/or replacements, DISA rebuild, ICV tests and cleaning, etc. (plus some experiments that could've fried my DME, but didn't) later, like mendes9, i'm going to do more testing, as is my habit, this time of year.

It's because I'm three months away from another yearly inspection/emissions check (fortunately, the final one required for my '01 X5, which will be 25 next year, not subject to testing), and I always fear that the SES light will appear while at the inspection station. I have been resetting the MAF, then completing the "drive cycle" and immediately driving to the station, for the last few years.

Maybe not so, this year. X5chemist magnanimously sent me his used "Siemens/VDO" MAF sensor for me to use while testing start with post#43 https://xoutpost.com/bmw-sav-forums/...ml#post1245039, and though I've not driven many miles since (probably under 300), and had to reset the DME twice during that time (Trifecta once, battery disconnect once), no more lean codes have appeared.

I tried using my original Siemens MAF until it went completely off the rails, and two other cheap $20 MAF's that would be good for awhile before I had to reset the MAF/fuel trims (I cleaned them and carry them in my trunk as spares, just in case), but it seems that my M54 really prefers a Siemens MAF. Your engine probably does too.

If X5chemist wants/needs the MAF back, I'll probably try an alternative (German-made brand) from FCP Euro, ECS Tuning, or even Rock Auto, since my non-existent budget keep me from buying a genuine new Siemens or BMW-OEM MAF. The $20 cheao units from Amazon were useful, but not quite good enough for the tastes of my X5. I'm still hoping (but not expecting) to find the root cause of my elevated fuel trims...LongTerm from +3 to +8%, usually, lately, at any speed, with ShortTerm trims trying to balance those numbers. I'd like to see LTFT's stay around zero, like my '04 Chevy 2500HD 6.0L engine has, always.

I've don fuel pressure tests perfect at 50PSI, i've swapped downstream sensors (replaced both on bank 2). I've smoked tested from intake, and from tail pipe no leaks (smoke test from tail pipe does have small leak but it's after downstream O2 sensor. MAF doesn't make sense why wouldn't it effect both? Have to keep testing. Question, when you say reset the MAF, what do you mean exactly?

reset fuel trims by unplugging the MAF sensor, while running
 

As stated above, I've unplugged the MAF sensor many times in the past, when the cumulative values (LTFT + STFT, for each bank) would go past 20 (maybe 25, it's been awhile, so I forget which), and prevent the SES/CEL from happening. I didn't want to go into limp mode, especially if I was far out of town.

That's also the reason I had 3 MAF sensors with me for 3.5 years, and would swap in a fresh, clean one after reset. That worked OK, if not perfect, until my oreiginal OEM Siemens MAF went nuts and instantly set codes, & SES, and caused driveability problems once, out of town, and I had to quickly exit the highway to insatll a backup.

That was just prior to X5chemist sending me his spare Siemens MAF, which I'm testing (if ever so slowly). So far, the X is seeming to relearn, keeping the fuel trim number reasonable, but still on the lean side.

I have not read through the post in a long time. Was compression checked on all cylinders? I've never seen that code on any vehicle I've worked on. I'm curious to see a resolution.

Ok, so what you meant by a "MAF reset", is simply you unplugged the MAF sensor.

So yesterday I reset adaptations using ISTA, you get 3 options 1, 2 or number 3. I choose number 1 which should reset all adaptions. I know it worked because after I restarted the car, the car did the crank sensor re-learn procedure (car cranks for a little before it starts). When I checked the fuel trims long term were now at zero also. I restarted the car maybe a couple times since the adaptations clear yesterday, and today when I started the car, the P1093 was gone and the SES light was out by itself I didn't clear it. Now, I expect it will probably come back, but as is using this trick I should be able to get by inspection. In my state you can go 3 months early before it's due, so in September i will use this again unless I actually find the root cause of this. Note, I cleared adaptations already using my Autel MK808 maybe a month ago, but now doing it with ISTA I know it didn't work, because after restarting the car it didn't do the crank sensor relearn. I may try it again, the only differnce was with ISTA the car was running, and when I used the MK808 it wasn't running, not sure if that makes any difference. Anyway, this may be a good work around for anyone else facing this issue and needs to get through emissions inspection.

Adaptations should be reset with engine not running AFAIK.