sources of vacuum leaks 535i

[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