Bmw E38 99 750IL P0170 Problem

[Cubehacker]

Hi E38 friends,

I have since owning the e38 a unsolved problem with the engine that run too lean during idle it shakes and ifeel vibrations during idle in P or N in D Or R its less but still there
I have already changed:

Both osv with the boots
12 Spark Plugs
3 new fuel injectors and the rest have get new lower o-rings
2 Distributor caps+2 Rotors
2 valve cover gaskets
Reseal the intake manifold gaskets with high temp sealent
Fuel pressure regulator including the fuel filter
Throttel body gasket and maf boots.

Ihave already exchange the maf from bank to bank nothing changed the problem is still there P0170 bank 1 too lean sometimes it set cel during idle.

Have anyone maybe a idea what ican do to solve this incredible hard problem that even the bmw dealer here in germany dont find?

[MIKYZZ4]

Check and possibly replace all rubber, gasket and o-rings on bank1:http://www.realoem.com/bmw/enUS/show...diagId=11_1432

[Cubehacker]

Thx for the advice but i already done evry part in the link.

[asianvenom]

Sounds like you still have a leak

[Cubehacker]

Is it possible that the method with the intake manifold gasket sealant didnt worked?but than i wonder why just on bank 1 besides ihad this problem since iown this car and it was always bank 1
Is there a possibilty for broken throttel body at bank 1?

Thx for all help

[MIKYZZ4]

Possibly a crack manifold then?
There is a chance previous owner removed and dropped manifold body,
unknowingly causing a crack, that has been present ever since.

[atakordie]

You could try a smoke test on the intake to see if you are leaking air, then fix the leak if you have one.

Check ignition coils, MAFs, engine compression, crank sensors, fuel pressure, fuel tank breather valves, secondary air system components, brake booster hose, and air valve hoses. There's probably more to check like coolant system pressure testing and cylinder leakdown, but you'll need the tools to do them.

[MIKYZZ4]

My first thought was to recommend a smoke test,
But it seems a pro smoke machine is hard to come by in Europe.

[Cubehacker]

Possibly a crack manifold then?
There is a chance previous owner removed and dropped manifold body,
unknowingly causing a crack, that has been present ever since.

That could be possible because ican hear something like a hissing noise but icant locate it even with brake cleaner.
Ur right here in germany nobody have a smoke mashine not even the biggest bmw dealer in town.
i orderd now this thing from the us ihope it can help me.
http://www.ebay.de/itm/SMK-1-EVAP-Sm...wAAOSwmgJY6ezh

[Cubehacker]

You could try a smoke test on the intake to see if you are leaking air, then fix the leak if you have one.

Check ignition coils, MAFs, engine compression, crank sensors, fuel pressure, fuel tank breather valves, secondary air system components, brake booster hose, and air valve hoses. There's probably more to check like coolant system pressure testing and cylinder leakdown, but you'll need the tools to do them.

ihave buy this one ihope it can help to find all kind of leaks can u advice me where is the best place to pressurise the intake manifolds?
http://www.ebay.de/itm/SMK-1-EVAP-Sm...wAAOSwmgJY6ezh

ignition coils checked
BOTH MAF checked
Fuel tank breather valves checked with DIS no codes
Crank sensors checked with DIS no codes and car starts always without any problems
Coolant System is evrything fine all gaskets and o rings changed new radiator,water pump,thermostat,expansion tank no coolant leak or loss
secondary air system components also checked with DIS no error codes
Air valve hoses also new
brake booster hose is checked as much icould even the sucking jet pump at the driver side is new
engine had get new head gaskets and nearly evry kind of gaskets was replaced by new ones exept the intake manifold gaskets was reused by high temp sealant

fuel pressure not checked because ithink than the code would be on both banks
engine compression not checked idont know how it works.
cylinder leakdown, not checked idont know how it works.

engine run in cold start with vibration and than it become smoother as soon the temp gauge reached the normal temp but vibratons are still there
specialy on colder days stronger vibration.
engine run full speed here at the open highway 250 km/h
its just that during idle the engine become to lean and set than the code P0170
when icheck the complete car with DIS this is the only error code including a failing pdc sensor that ihave
even when igo in both DME and make the engine procedure check the only error is Bank 1 too lean limit reached cant rich anymore.



Thx guys for all ur support ihope my english is not so bad but this problem is realy cracking my head.....

[XAlt]

Check motor mounts as well if it's vibrating, I don't think the code is the entire story with the vibration.

They're the same mounts as the V8's, and those are usually toast after 200k miles.

[Cubehacker]

Ihave already replaced engine mounts,transmission mounts driveshaft center support bearing guibo disc and all exhaust mounts.Including transmission and diff fluid change with original BMW Filter and gasket kit.

[atakordie]

That could be possible because ican hear something like a hissing noise but icant locate it even with brake cleaner.
Ur right here in germany nobody have a smoke mashine not even the biggest bmw dealer in town.
i orderd now this thing from the us ihope it can help me.
http://www.ebay.de/itm/SMK-1-EVAP-Sm...wAAOSwmgJY6ezh

Make sure the hissing noise isn't coming from the cabin air intake flaps, which are closed when the hood is open. If the fan is on with the flaps closed, they make noise as the air tries to get into the cabin. Turn off the cabin fan to eliminate that possibility. I had that happen to me and thought I found an air leak when there wasn't one.

ihave buy this one ihope it can help to find all kind of leaks can u advice me where is the best place to pressurise the intake manifolds?
http://www.ebay.de/itm/SMK-1-EVAP-Sm...wAAOSwmgJY6ezh

ignition coils checked
BOTH MAF checked
.....

You've done a lot of good work. Assuming your oxygen sensors are working correctly, chances are you have unmetered air getting in the intake somewhere. The kit you ordered should really help find those leaks. I bought a similar smoke machine and found 3 leaks, one after another (fixed one, tested again, found more leaks). Best way I have found is by connecting a hose from the smoke machine to the engine at one of the throttle bodies. There should be a rubber cap there that you can remove to gain easy access to the intake manifold. You only have to blow smoke into one throttle body; the entire intake will fill with smoke from one side to the other. Also, the easiest way to isolate the manifold from the atmosphere (in order to maintain smoke pressure) is to disconnect the MAF boots from the air filters, slip in a plastic sheet or bag over the MAF boot inlet, then reattach the boot to the air filter housing. This will seal off the intake manifold to run the test.

Another tool you could try is a vacuum gauge to see if there is a proper manifold vacuum. I get around 19-20 inches of mercury vacuum with engine warm at idle. An air leak somewhere will give a lower vacuum reading. The vacuum gauge can also tell you other things about the engine's health. Look up charts or videos for more on that.

Both INPA and DIS have an engine smoothness, or "laufunruhe," status page under the EML module. You probably have already looked at it. Maybe you could see there is a particular cylinder or cylinders that are causing trouble.

Also, less likely is the possibility of a bad spark plug or wire that intermittently shorts the power to ground. Sometimes I have found that even though a part is new doesn't mean it is good. A spark plug could have a cracked porcelain sheath - which can happen during installation - that may let the spark short to ground before it gets to the spark plug electrode. Similarly, a bad spark plug wire insulation can let the electricity short out before getting to the spark plug. You can look for this by misting the engine spark plug and coil wires with water at night time to look for sparks jumping around...you can also check for this particular problem with a test light hooked to the car body.

[Cubehacker]

Make sure the hissing noise isn't coming from the cabin air intake flaps, which are closed when the hood is open. If the fan is on with the flaps closed, they make noise as the air tries to get into the cabin. Turn off the cabin fan to eliminate that possibility. I had that happen to me and thought I found an air leak when there wasn't one.



You've done a lot of good work. Assuming your oxygen sensors are working correctly, chances are you have unmetered air getting in the intake somewhere. The kit you ordered should really help find those leaks. I bought a similar smoke machine and found 3 leaks, one after another (fixed one, tested again, found more leaks). Best way I have found is by connecting a hose from the smoke machine to the engine at one of the throttle bodies. There should be a rubber cap there that you can remove to gain easy access to the intake manifold. You only have to blow smoke into one throttle body; the entire intake will fill with smoke from one side to the other. Also, the easiest way to isolate the manifold from the atmosphere (in order to maintain smoke pressure) is to disconnect the MAF boots from the air filters, slip in a plastic sheet or bag over the MAF boot inlet, then reattach the boot to the air filter housing. This will seal off the intake manifold to run the test.

Another tool you could try is a vacuum gauge to see if there is a proper manifold vacuum. I get around 19-20 inches of mercury vacuum with engine warm at idle. An air leak somewhere will give a lower vacuum reading. The vacuum gauge can also tell you other things about the engine's health. Look up charts or videos for more on that.

Both INPA and DIS have an engine smoothness, or "laufunruhe," status page under the EML module. You probably have already looked at it. Maybe you could see there is a particular cylinder or cylinders that are causing trouble.

Also, less likely is the possibility of a bad spark plug or wire that intermittently shorts the power to ground. Sometimes I have found that even though a part is new doesn't mean it is good. A spark plug could have a cracked porcelain sheath - which can happen during installation - that may let the spark short to ground before it gets to the spark plug electrode. Similarly, a bad spark plug wire insulation can let the electricity short out before getting to the spark plug. You can look for this by misting the engine spark plug and coil wires with water at night time to look for sparks jumping around...you can also check for this particular problem with a test light hooked to the car body.

Hi Atakordie thank u very much for ur help iwill try it asap iget the smoke machine.
here are few pics of the error codes and the Laufunruhe from inpa sorry but my inpa and dis are a german version.
18762389_10213505074530720_561566690_n.jpg

The Fuel Trim values from Bank 1
18741938_10213505074730725_1414396476_n.jpg

And The only Error code ihave in Bank 1
18741874_10213505075170736_1761898194_n.jpg

Maybe it can give more information to find this problem out.

[Cubehacker]

Today iget my ebay smoke machine and finaly ididnt find any vacuum leak the only way where the smoke exit the engine is at the distributor housing on both banks.
Now idont know what to do next maybe changing the o2 pre cat sensor on bank 1 or the throttle body or even the extremely expensive intake manifold gaskets? Iam at the end with my know how with this error code could a leak anywhere else maybe in the exhaust set the same error code?
The only thing why i still think there is maybe a leak is that when the engine starts cold its more rough asap temperature gauge reach normal operation temperature it become much better but on idle still not perfect.

Thanks already for all ur help and advises.

[MIKYZZ4]

Swap precat sensors(bank 1>bank 2).
Swap MAF sensors if you can,
clear codes after each swap, take note of any changes.

[Cubehacker]

MAF sensores already swaped deleted codes no change.
o2 Sensors will be the next thing iwill try.
Iwill keep u informed asap idone it.

[MKIVJZA80]

my p0170 p0173 was fixed with the vacuum hose that attach to intake manifold from brake booster and from evap system. intake gaskets sealed, new caps on throttle bodies, new throttle body boots, etc.

[MIKYZZ4]

Check bank 1 throttle body vacuum caps(#5):http://www.realoem.com/bmw/enUS/show...diagId=13_0180
remove and check for cracks!
I feel these overlooked items will solve the mystery !!

[Cubehacker]

Hi MIKYZZ4 ihave already changed both caps same result its so incredible hard to fix this problem!

[Cubehacker]

Ihave a new information when i spray brake cleaner on the cold engine start beetween and under the intake manifold
The engine starts to become very rough and vibrations are stronger are they vacum leaks?

[MIKYZZ4]

Is it possible that the method with the intake manifold gasket sealant didnt worked?but than i wonder why just on bank 1 besides ihad this problem since iown this car and it was always bank 1
Is there a possibilty for broken throttel body at bank 1?

Thx for all help

Possibly a crack manifold then?
There is a chance previous owner removed and dropped manifold body,
unknowingly causing a crack, that has been present ever since.

Ihave a new information when i spray brake cleaner on the cold engine start beetween and under the intake manifold
The engine starts to become very rough and vibrations are stronger are they vacum leaks?

I suggest removing intake manifolds and removing/replacing with new manifold gaskets.
Once removed, carefully inspect manifold for any cracks or locations where a leak is possible.
Sorry, but we have to focus on repairs where human error can be involved.

[XAlt]

Reseal. Apply more than last time.

New gaskets should be the last-ditch effort.

[atakordie]

If you do replace the intake manifold gaskets, check to make sure all the lower o-rings on the fuel injectors are sealing correctly. I once had one that was pinched at the manifold, which was causing a leak. Use P-80 emulsion (temporary lubricant for rubber parts) or maybe oil to help ensure a smooth install of those o-rings. Also, definitely replace those distributor seals if they are leaking smoke. I am assuming the smoke machine you are using isn't putting too much pressure into the intake (maybe 3 psi or less). Does the smoke machine have a gauge that shows how big of a leak you have? That can help if you can't see any smoke, to know there is a small leak by reading the gauge. Put the car in a garage (no wind) and test with smoke. Sometimes you can smell it before you see the leak. If you still can't find a leak with the smoke machine (but you know you have one), there is a UV dye additive available that you can put in the machine along with the regular smoke juice. The dye should fluoresce when you shine a UV flashlight (~400-450 nanometer wavelength light) on the smoke with the garage lights turned off. This way, you can more easily detect a smaller vacuum leak.

[tsmvp]

Had very similar issues with my 750iL. Yes, the expensive intake gaskets fixed everything.

CR