sources of vacuum leaks 535i

[skidmark]

I have been chasing a 1222 code and have searched and read most of what's on this site for causes of a 1222 code.
I have replaced O2,plugs,wires,cap,rotor various vacuum hoses. I most likely have a vacuum leak. If I was reading right, a bad oil dipstick O-ring can cause a vacuum leak.

To take that source of vacuum leak furthur, I know I have a bad pan gasket. It leaks and I found a hunk of it hanging out of the side of the pan when I looked at it on the ramps.

My question - Can a bad pan gasket cause a 1222 code?

[Jeff N.]

Does your car idle smooth? If you have a large vac leak, it will idle like crap. A small vac leak will cause a slightly rough idle. Small vac leak should not be enough to trip a 1222 code.

Assuming it idles fine, check the fuse to the O2 sensor power circuit to make sure the fuse is not blown. Do a code clear and see if you still get the same error.

Jeff

[BIGRED]

I have been chasing a 1222 code and have searched and read most of what's on this site for causes of a 1222 code.
I have replaced O2,plugs,wires,cap,rotor various vacuum hoses. I most likely have a vacuum leak. If I was reading right, a bad oil dipstick O-ring can cause a vacuum leak.

To take that source of vacuum leak furthur, I know I have a bad pan gasket. It leaks and I found a hunk of it hanging out of the side of the pan when I looked at it on the ramps.

My question - Can a bad pan gasket cause a 1222 code?

A 1221 or 1222 code can represent a symptom rather than a problem.

In my case I had both those codes and the problem was fuel related which caused the mixture to go off and trigger the codes.

Other than the code, how does it start, run etc.

Good Luck
Don

[whiskychaser]

From what I remember this code can be generated by anything that causes the mixture to be too rich or too lean. A quick look at a plug will tell you which. I read somewhere a quick way to test if your inlet vacuum is OK is to place a plastic bag over the oil filler cap hole and see if it gets sucked inwards.

[skidmark]

Thank you for the replys. The car does idle like crap. It does not die but sounds like it wants to. It sounds/feels like it's missing. It takes about 15 seconds after starting the car until the check engine light comes on. If I blip the throttle the light goes out(again taking about 15 seconds to come back on) If I slowly increase revs the light will stay lit (tried it to about 3k rpm and it stayed lit) when I let off the throttle the light goes out. Once under way the light stays out until I settle at a certain rev (say on the highway) then comes back on.

I tried re-setting codes by reseating both ecu harness. The code comes back. The code did change from a 1221 to 1222 after replacing many things plugs, wires, o2, fuel filter, any vacuum hose brittle or cracked, valve cover gasket.

I cleaned the ICV and camshaft sensor (oil leak had it a mess).

The old plugs that came out where sorty white colored. (lean I think)

Car seems to run OK when I get on it, and gets decent MPG 16 in town 22 on highway.

[whiskychaser]

Plugs should be a sort of yellow colour. White sounds like its running too lean. If your vacuum hoses are sound I'd be thinking fuel pressure - maybe the regulator? A pressure check would soon tell

[BIGRED]

Thank you for the replys. The car does idle like crap. It does not die but sounds like it wants to. It sounds/feels like it's missing. It takes about 15 seconds after starting the car until the check engine light comes on. If I blip the throttle the light goes out(again taking about 15 seconds to come back on) If I slowly increase revs the light will stay lit (tried it to about 3k rpm and it stayed lit) when I let off the throttle the light goes out. Once under way the light stays out until I settle at a certain rev (say on the highway) then comes back on.

I tried re-setting codes by reseating both ecu harness. The code comes back. The code did change from a 1221 to 1222 after replacing many things plugs, wires, o2, fuel filter, any vacuum hose brittle or cracked, valve cover gasket.

I cleaned the ICV and camshaft sensor (oil leak had it a mess).

The old plugs that came out where sorty white colored. (lean I think)

Car seems to run OK when I get on it, and gets decent MPG 16 in town 22 on highway.

Did you replace those items by diagnosing each and found them to be out of spec or did you replace them in an attempt to cover all the bases? I ask because...

If you have a manual, you can follow the various procedures to determine what the condition is of parts, rather than replace them....going forward.
There are a lot of possibilities.

Bentley's says your symptoms can be caused by...

Idle stabilizer valve
Throttle position switch
Large intake system leak
Fuel pressure being too low or too high
Faulty coolant temp sensor
Faulty oxygen sensor
Leaking fuel injectors
Broken or corroded electrical connections
Broken or corroded ground connections
CO content too low or too high
Input signals to DME Motronic ECM missing, ECM in limp mode
Faulty DME Motronic ECM

If you have a fuel pressure gauge, run those tests first. If you don't have one, you can get one good enough to diagnose the fuel system at Harbor Freight for about $15.00


Don

[skidmark]

Yes I do have the bentleys. The items I replaced were all original equipment. (car has 60k) I do have a pressure gauge. Where is the best place to tap into the fuel line?

[BIGRED]

I would follow Bentley's... that way you have a source to walk you through each diagnostic test having said that..... I did not follow Bentley's (lol) on the fuel pressure test.

First find your fuse for the fuel pump, pull it and start the engine to bring the pressure down....

I disconnected the fuel line (supply side) at the rail (I have a 3.0 V8) and connected the gauge there.

Your going to need several readings...

Running (put the fuse back)
After shut down... check it in 30 mins or longer and note FP drop (should hold close to original psi (listed in Bentley's).
With the FPR vacuum line disconnected (it should rise)
Slight crimping of the rubber fuel return (off the rail) should increase.
Finally you probably should do a fuel output test. XX amount in 30 seconds (I think) In Bentley's.

With that info, you will know what the condition of the fuel system is....if it isn't right, another level of diagnostics will be necessary to narrow down the problem.

Don

[skidmark]

Don, I notice you have a wagon. I've got an 03 325xiT. I will do the fuel pressure test this weekend. Thanks for all of your advice. I need to follow thru on the various things Bentleys suggest for this 1222 code. I was hoping some of the things I already did was going to fix it, but at least this is a good way to go thru and get familar with the operating system on this car.

[BIGRED]

Don, I notice you have a wagon. I've got an 03 325xiT. I will do the fuel pressure test this weekend. Thanks for all of your advice. I need to follow thru on the various things Bentleys suggest for this 1222 code. I was hoping some of the things I already did was going to fix it, but at least this is a good way to go thru and get familar with the operating system on this car.

Your Welcome....

Good luck

[Jeff N.]

I'd be surprised if it's fuel pressure. Typically, low FP problems will not be at idle but at upper RPMs when fuel flow is high. It's possible you do have a bad FPR which would lead to high FP and a rich condition but that would tend to occur at all RPMs, not just idle.

Has it always idled like crap or just recently? How does it run when cold? Better or worse?

A FP test like BigRed suggested is a good thing, you may want to check these first:

Throttle position sensor - make sure you are tripping the idle circuit switch.

All your intake boots - a split in one of them will cause a big air leak

All ICV hoses - it's hard to inspect the one from the manifold to the ICV but a hidden split will cause a big leak.

Do you have a manifold vacuum gauge? Connect that and see what your intake vacuum is. Should be around 18 inches or so. Anything much less than that you and have a leak.

Try setting your idle circuit adjustment on the AFM. The bleed screw could be way in or way out hosing up the mixture.

Cheers,

Jeff

[BIGRED]

I'd be surprised if it's fuel pressure. Typically, low FP problems will not be at idle but at upper RPMs when fuel flow is high. It's possible you do have a bad FPR which would lead to high FP and a rich condition but that would tend to occur at all RPMs, not just idle.

Jeff... Just went through this... at times I could barley get the engine to run once started and the rpm higher it would be fair to good. If it got down to idle it died, I replaced both the FP and FPR and the problems are gone. My guess was it was running way rich and couldn't handle the amount of fuel at idle but as the RPM increased it was able too.

Have a good weekend

[skidmark]

I found a major vacuum leak this weekend. One of the intake manifold gaskets is leaking. I saw a large piece of the gasket hanging out and sprayed carb cleaner at the intake. Idle picked up bigtime.

That repair, along with a planned oil pan gasket replacement should give me plenty to do.

I have no idea how long it's had this intake vacuum leak. Is there a worry about engine/cat damage from running lean for a lengthy amount of time?

[Jeff N.]

When you remove your intake manifold, here are some other things you should consider replacing:

- both the water hoses that run under the manifold, also order the two special clip holders for the hoses. They are almost always broken. Doing these hoses any other time is PITA.
- New manifold to ICV hose; simple to do now.
- Not a bad time to put in new injector o-rings
- If you want to take an extra day or so, consider having your manifold hot tanked to get out the typical blow by crap that builds up. Shop usually needs it overnight
- Be sure to use new manifold nuts

The lower nuts can be PITA to remove. Simplest if you use 1/4" socket gear and some extensions and flex drives.

I wouldn't worry too much about any damage.

Let us know how it turns out.

Jeff