(VIDEO) 327i hunting and running rich at idle

[rcfanatic]

I have a 327i with 885 head, decked .020". The head's only been on for about 2-3 weeks. Cam is new, 3 angle valve job, pressure tested fine, new cap/rotor, spark plugs, injectors were professionally cleaned about a year ago, new CTS, FPR, and wideband+narrowband o2 sensor

It's running very rich...I can remove both the oil filler cap and the dipstick and the engine won't stall. Every now and then the idle will smooth out for some unexplained reason. This can be seen at the very beginning of the video. However once the throttle is blipped it'll start hunting again. The mixture leans out at higher rpm under no load. At WOT under load it is about 12.5.

After driving the car for awhile at temperature it will begin to stall when you depress the clutch (at higher rpm), unless you baby the throttle back to a hunting state.

This morning I had a smoke test done to reveal a couple of minor leaks, but if anything those would contribute to helping it run leaner.

My mechanic told me that it sounds like a couple of valves are adjusted too loose. I set the lash to .010" before installing the head, but maybe some of them may have loosened up. Would this cause such a rough/rich idle? Any other ideas about what could be causing this?

[rcfanatic]

Also, my fuel pressure tested fine about 4 months ago before I did the head swap, and that was with the old FPR

[rcfanatic]

Aside from the valves, and possibly the DME, what else is there?

[mikegar]

i think im having the same problem. what happens when you unplug the afm?

[rcfanatic]

I'll let you know tomorrow

[call me jack]

test your fuel pressure, check out the vacuum line going to the fpr, check for vacuum leaks in general. you also might want to try running it with a known working fpr.

your car cant run with out the afm plugged in.

[rcfanatic]

As I said, I had a smoke test done yesterday, and it only revealed a couple of very small leaks. Even so, a leak would make it run lean and not rich. In fact it's running so rich that the engine is loving any leaks that are introduced. That is why I can remove the oil cap and dipstick without stalling the engine.

The FPR I have on there now is 2 weeks NEW, and it did not change anything when I installed it.

I'll check the fuel pressure again just for kicks and grins, but like I said I tested it a few months ago and it was fine. The problem is finding the time to do it since it gets dark now at 6pm. I hate daylight "savings" time

[mikegar]

It can run with the afm unplugged. My car runs with it unplugged

[call me jack]

It can run with the afm unplugged. My car runs with it unplugged

mine never does.....

any way, op, get us the fuel pressure reading if you if you can...

Also had you been working on the car right before it started running lean?

tps could be out of calibration (though unlikely)
icv?
afm could be having some issues... have you looked at your air box at all?
Also, are your running motronic 1.3? do a diagnostic test (either with the scan tool, or stomp test)

[call me jack]

wait. check your o2 sensor, as out lined in the bently manuel. if thats broken it will give your dme a voltage reading of 0, which tells the dme your running lean.

[nando]

Bad AFM, bad O2 sensor seem likely.

and yes, it will run without the AFM. Not well, but it has a substitute value it uses if there's no AFM, same for any other sensor (except the crank).

[call me jack]

huh, well i've tried running my car several time when i've forgotten to reattach the afm, and it would start and then die...

[nando]

"run" is a relative term. The motor should be able to turn over and hold some sort of idle, but it won't be very driveable. it probably has to be at least warm, or you have to keep your foot on the gas, etc. I've done it, I know it "works". Like I said though, it won't run very well.

[Mike]

retarded timing?

[rcfanatic]

Car won't run at all with AFM unplugged.

Checked the fuel pressure yesterday, looks like it is lower than spec. Should be about 5 psi higher



This the new fuel pressure regulator, it is supposed to be 3 bar

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Fuel-Pressure-Regulator-BWD-Intermotor_3036839-P_484_R|GRPFUELAMS_1571122266___

Still haven't had a chance to adjust the valves. I don't think the timing is retarded because I checked it multiple times when installing the head, and the valves would be hitting the pistons if it was off by a tooth (head is milled .020")