Experts, Code 1221... weird symtoms, please read!

[Jon K]

Ok so I was running my supercharger and fuel was at "full rich" so to avoid lean conditions. You could smell unburnt fuel when i'd come to a light. Anyway... i resorted back to stock because i needed to get out to school reliably. Anyways...

I start the car, its fine, I let it it to warm up... couple mins and its got a Check Engine light. Read the code, 1221. Interesting. I shut it off, reset ecu w/ battery off. Start the car, no codes, so I drive it. It drives juts fine but idles a little high, like 1,000ish. So I drive and drive, maybe 5 minutes, I come to a stop sign or traffic light. Then it will throw the Check Engine Light and it will idle at like 550 600rpm and rough, not misfiring just chunky. It doesn't stall. I drive some more, maybe 50mph for 2 or 3 minutes, and the Check Engine light goes out... car feels strong when driving at speed, no issues really. I am unsure of whats going on. I have a crack in the intake boot (stock rubber intake elbow) and maybe thats it but also its throwing code 1221. I kind of blocked the intake boot crack and it didn't change the issue. The car has always had this crack though, although it may be a little bigger now. I am thinking maybe since I ran the car rich with the adjustable fuel pressure regulator, could I have fouled my O2 sensor? And, if that's the case, why is it only having issues @ idle? Like i said, if the CEL is off, the idle is high sometimes, othertimes normal. When the CEL comes on (which it does at idle) the RPMs fall a little bit and bounce a little like 550 - 650 rpm....


Any help guys is greatly appreciated!

[632 Regal]

SOmehow your fuel curves are all messed up, I wouldnt worry about frying the O2 sensor yet. Since the fuel map is in the engine chip what is the purpose of the adjustable FP reg? Why dont you pop the stock FP back on, reboot and see whats up. As long as your injectors are larger than stock at WOT you should be seeing enough fuel and at idle it should lean back to the stock settings. I'm also thinking you are having some issues because the charger is pumping additional air at idle that may be dropping vacumm, upping FP and causing the rich at idle condition.

Fix that cracked boot man.

[Jon K]

SOmehow your fuel curves are all messed up, I wouldnt worry about frying the O2 sensor yet. Since the fuel map is in the engine chip what is the purpose of the adjustable FP reg? Why dont you pop the stock FP back on, reboot and see whats up. As long as your injectors are larger than stock at WOT you should be seeing enough fuel and at idle it should lean back to the stock settings. I'm also thinking you are having some issues because the charger is pumping additional air at idle that may be dropping vacumm, upping FP and causing the rich at idle condition.

Fix that cracked boot man.


Jeff,


Supercharger is not hooked up presently. Injectors are stock, so is the FPR. The adjustable FPR is out. The Adjustable FPR increases fuel pressure with boost, so as to provide more fuel with the additional air. But, now everything is back to stock and I have the above mentioned issue.

[Brandon J]

First off how old is your O2 sensor. Running rich can foul an O2 sensor. Now add to that the sensor is old. If you changed everything back to stock, did you unhook the computer to reset its stored memory? You may want to do that too. Initially you may have gotten the code b/c of the rich condition. While setting up your supercharger system, you might just foul more O2 sensors b/c of running rich.

[bahnstormer]

Jeff,


Supercharger is not hooked up presently. Injectors are stock, so is the FPR. The adjustable FPR is out. The Adjustable FPR increases fuel pressure with boost, so as to provide more fuel with the additional air. But, now everything is back to stock and I have the above mentioned issue.



just so we all have out terminology correct

jon do u have a RRFPR? a rising rate fuel pressure regulator raises fuel pressure as boost rises....

whereas bav auto's Adjustable Fuel Pressure Regulator


Get more power and better throttle response from your BMW. This adjustable rising rate fuel pressure regulator enriches the fuel mixture as you accelerate to increase power and improve mid-range throttle response. Maintains stock fuel mixtures at idle.

that doesnt take into account boost


ps - i am 99% sure this is correct....

[Jon K]

just so we all have out terminology correct

jon do u have a RRFPR? a rising rate fuel pressure regulator raises fuel pressure as boost rises....

whereas bav auto's Adjustable Fuel Pressure Regulator


that doesnt take into account boost


ps - i am 99% sure this is correct....


The one I am using is made by Billet Engineering, it is an adjust RISING RATE fuel pressure regulator. I am thinking and hoping I just fouled the O2 sensor by running so rich. The O2 sensor is probably 9 months old or so.

[bahnstormer]

can u pull it out and wash it with alcohol?

[Jon K]

can u pull it out and wash it with alcohol?


I am not sure. I can pull it out, yes. Can I wash it with alcohol? Not sure.

Also, is there a way I can test its reading with an Ohm meter?

[Shaun]

Ok so I was running my supercharger and fuel was at "full rich" so to avoid lean conditions. You could smell unburnt fuel when i'd come to a light. Anyway... i resorted back to stock because i needed to get out to school reliably. Anyways...

I start the car, its fine, I let it it to warm up... couple mins and its got a Check Engine light. Read the code, 1221. Interesting. I shut it off, reset ecu w/ battery off. Start the car, no codes, so I drive it. It drives juts fine but idles a little high, like 1,000ish. So I drive and drive, maybe 5 minutes, I come to a stop sign or traffic light. Then it will throw the Check Engine Light and it will idle at like 550 600rpm and rough, not misfiring just chunky. It doesn't stall. I drive some more, maybe 50mph for 2 or 3 minutes, and the Check Engine light goes out... car feels strong when driving at speed, no issues really. I am unsure of whats going on. I have a crack in the intake boot (stock rubber intake elbow) and maybe thats it but also its throwing code 1221. I kind of blocked the intake boot crack and it didn't change the issue. The car has always had this crack though, although it may be a little bigger now. I am thinking maybe since I ran the car rich with the adjustable fuel pressure regulator, could I have fouled my O2 sensor? And, if that's the case, why is it only having issues @ idle? Like i said, if the CEL is off, the idle is high sometimes, othertimes normal. When the CEL comes on (which it does at idle) the RPMs fall a little bit and bounce a little like 550 - 650 rpm....


Any help guys is greatly appreciated!


I just went through this same scenario almost to a 'T'. I replaced my O2 sensors and my MAF, and still had the CEL and code 1221 popping up. It turned out to be my cracked intake elbow. Replaced it and the problems stopped immediately. My elbow was always slight cracked as well (since I got the car at least), and it just decided to take a **** one day. It's a cheap part and worth replacing either way.. I would start there if I had to do it again.

[Jon K]

just bumping to get this to the top, any more ideas? I am giong to replace intake boot, intake manifold gaskets, and perhaps O2 sensor.

[Interceptor]

just bumping to get this to the top, any more ideas? I am giong to replace intake boot, intake manifold gaskets, and perhaps O2 sensor.
That should be it. I just got back my power and acceleration, and no more stalling on low rpms by simply fixing the rubber intake boot today! Maybe you should delay the O2 sensor until you've tried replacing the boot first.

[ryan roopnarine]

your pm box is full, damnit

cut and paste

for the most part, (my experience) with the ICV, restrictions going to it cause lowered idle, with the car bouncing up and down as the idle gets precipitously low (<600) and the engine struggles to maintain a steady idle. the dme will eventually increase the idle to 800 rpm or so. slight air leaks WRT the ICV cause maybe a 800 rpm idle with load (in drive, stopped). gross air leaks at the icv will cause your idle to go in the toilet (500 or lower) the hose coming off the icv will cause the car to struggle to try stay started, but the car won't stay started for more than 5 seconds.

what you describe, a "chunky" idle.....that sounds like a leaky air boot, old spark plugs or coils or coil boots going bad or covered in oil. you need to get the hole in your boot fixed first before you replace anything else.

about the "up and down idle". i had a similar situation where when rolling to a stop (ie on a highway offramp and decelerating to a stop), the idle would go up and down about 300-400 rpm as i was rolling, and would be high (like 800+) in drive at idle when i finally came to a stop. i originally thought that there was a problem with the icv, when really it was external. if the idle is doing this it generally means that the ICV is good because it is working hard to try to fix a problem elsewhere in the air intake/ignition system. in my case, the problem was that the throttle body was not coming to a full close when the gas was let off, so the icv was constantly trying to adjust. it would also cause a very high parked idle (900+ rpm). when i fixed it by lubricating the throttle body linkages, the problem disappeared. it might apply in your case because you are pulling in air from elsewhere, which confuses the ICV, causing the idle to undulate.

what did you do with the hose coming off the ICV, you say it isn't connected? that will cause in increase in idle if it isn't plugged or taken care of.


if i were you, i'd hit these (i see the list of things you wanna try on the board)

-if you think the blower popped the intake manifold gaskets, then deal with them. otherwise, i wouldn't. i'd soak the intake manifold gasket area with carb cleaner at idle to see if there are any air leaks first.

-spark plugs, if there is even the slightest chance that they're tired.

-complete vacuum hose set, including the elbow. it costs less than $50 from bma for all of it.

SOAK every possible air leak site (junction, gasketed joints) with carb cleaner, including the icv nipple to check for air leaks

if you need new coil boots, now would be the time to change them. if you need new coils, same.

do you use a different FPR than the stock? does that require vacuum at all?

[Jon K]

your pm box is full, damnit

cut and paste

for the most part, (my experience) with the ICV, restrictions going to it cause lowered idle, with the car bouncing up and down as the idle gets precipitously low (<600) and the engine struggles to maintain a steady idle. the dme will eventually increase the idle to 800 rpm or so. slight air leaks WRT the ICV cause maybe a 800 rpm idle with load (in drive, stopped). gross air leaks at the icv will cause your idle to go in the toilet (500 or lower) the hose coming off the icv will cause the car to struggle to try stay started, but the car won't stay started for more than 5 seconds.

what you describe, a "chunky" idle.....that sounds like a leaky air boot, old spark plugs or coils or coil boots going bad or covered in oil. you need to get the hole in your boot fixed first before you replace anything else.

about the "up and down idle". i had a similar situation where when rolling to a stop (ie on a highway offramp and decelerating to a stop), the idle would go up and down about 300-400 rpm as i was rolling, and would be high (like 800+) in drive at idle when i finally came to a stop. i originally thought that there was a problem with the icv, when really it was external. if the idle is doing this it generally means that the ICV is good because it is working hard to try to fix a problem elsewhere in the air intake/ignition system. in my case, the problem was that the throttle body was not coming to a full close when the gas was let off, so the icv was constantly trying to adjust. it would also cause a very high parked idle (900+ rpm). when i fixed it by lubricating the throttle body linkages, the problem disappeared. it might apply in your case because you are pulling in air from elsewhere, which confuses the ICV, causing the idle to undulate.

what did you do with the hose coming off the ICV, you say it isn't connected? that will cause in increase in idle if it isn't plugged or taken care of.


if i were you, i'd hit these (i see the list of things you wanna try on the board)

-if you think the blower popped the intake manifold gaskets, then deal with them. otherwise, i wouldn't. i'd soak the intake manifold gasket area with carb cleaner at idle to see if there are any air leaks first.

-spark plugs, if there is even the slightest chance that they're tired.

-complete vacuum hose set, including the elbow. it costs less than $50 from bma for all of it.

SOAK every possible air leak site (junction, gasketed joints) with carb cleaner, including the icv nipple to check for air leaks

if you need new coil boots, now would be the time to change them. if you need new coils, same.

do you use a different FPR than the stock? does that require vacuum at all?


thanks ryan, i plan to do basically what you suggest.

the rising rate fpr goes in-line with stock fpr, after it.... it requires vacuum, i t-tapped for that, but everything, and i mean everything, is stock now.

[Interceptor]

Any help guys is greatly appreciated!
From the Bosch Motronic error code list:

1221 - Lambda (O2) Sensor 1

This code is stored when the engine temperature is >70C and the Oxygen Sensor value is out of range or not present. Check the Oxygen Sensor wiring and the operation of the sensor. The value should fluctuate between 0.02 and 0.85V. Slow fluctuation indicates a polluted Oxygen sensor and negative values indicate a damaged sensor.

Note: Cars without Catalytic Convertors will incorrectly store this code.

[Jon K]

From the Bosch Motronic error code list:

1221 - Lambda (O2) Sensor 1

This code is stored when the engine temperature is >70C and the Oxygen Sensor value is out of range or not present. Check the Oxygen Sensor wiring and the operation of the sensor. The value should fluctuate between 0.02 and 0.85V. Slow fluctuation indicates a polluted Oxygen sensor and negative values indicate a damaged sensor.

Note: Cars without Catalytic Convertors will incorrectly store this code.


Thanks so much! But I have seen other things trip the 1221 code also... however... you say I can check the voltage. Where would one check the voltage? I have an Air/Fuel Ratio gauge installed... comes from the ECU O2 sensor connector... can I use a multimeter on that line and if so how?

[Interceptor]

Thanks so much! But I have seen other things trip the 1221 code also... however... you say I can check the voltage. Where would one check the voltage? I have an Air/Fuel Ratio gauge installed... comes from the ECU O2 sensor connector... can I use a multimeter on that line and if so how?
I suppose you have the 4-pin O2 sensor - you can test it by disconnecting the connector and applying 12V from the battery directly to the pins 3 and 4 (that's the heater) and measuring the voltage between pins 1 and 2 (the sensor itself). The voltage should be somewhere around 0.4V/0.5V - less is lean, more is rich. Take note that it's very difficult to measure it with a digital voltmeter because the voltage fluctuates constantly.

Also, take into consideration that when you disconnect the O2 sensor your DME will switch to preprogrammed fuel maps and the readings might be off a bit. It would be ideal to measure the voltage WHILE it's connected. Might be difficult without splicing wires or making a custom pass-thru connector.

[Jon K]

I suppose you have the 4-pin O2 sensor - you can test it by disconnecting the connector and applying 12V from the battery directly to the pins 3 and 4 (that's the heater) and measuring the voltage between pins 1 and 2 (the sensor itself). The voltage should be somewhere around 0.4V/0.5V - less is lean, more is rich. Take note that it's very difficult to measure it with a digital voltmeter because the voltage fluctuates constantly.

Also, take into consideration that when you disconnect the O2 sensor your DME will switch to preprogrammed fuel maps and the readings might be off a bit. It would be ideal to measure the voltage WHILE it's connected. Might be difficult without splicing wires or making a custom pass-thru connector.


Well like i said, i have an Air/Fuel gauge that taps into the ECU, which is fed the signal from the O2 gauge... I basically have a "O2 signal wire" running into my car. Its a signal wire though, I am not sure how I could read it... would I just put the Multimeter in V mode, earth the black wire and touch the O2 signal wire with red pin?

[Interceptor]

I basically have a "O2 signal wire" running into my car. Its a signal wire though, I am not sure how I could read it... would I just put the Multimeter in V mode, earth the black wire and touch the O2 signal wire with red pin?
O2 sensor creates a difference in potential between the signal contact and the ground - so, yes, you CAN measure it's voltage by selecting Volts in a range of 2V. The rest you figured out on your own :)

[Robin-535im]

thanks ryan, i plan to do basically what you suggest.

the rising rate fpr goes in-line with stock fpr, after it.... it requires vacuum, i t-tapped for that, but everything, and i mean everything, is stock now.
If the stock one is still there, won't it cap the flow at 3 bar?

[Jon K]

If the stock one is still there, won't it cap the flow at 3 bar?


No. 3 bar is the min pressure the stock one will allow... the aftermarket fuel pressure regulator goes after that...

fuel rail stock fpr rrfpr return line
=*=*=*=*=*=*=[]--------[]--------


The 3 Bar refers to the baseline of the FPR (I think). 3 bar is ~45 psi, 3.5 bar is 51 psi. The 3 bar will flow higher than 3 bar... think about it, if you straight up blocked the fuel return line, the fuel pump will force fuel thru the 3 bar FPR and if theres no where for the fuel to go that is not used, it will just build pressure and raise the fuel pressure. The FPR sits on the BACK (return) of the fuel rail, so it's like a "dam" in Scott H's words.

Think of it as the stock one being the MINIMUM pressure it will ever flow. 3 Bar will never be a 2.5 bar. But, let's say the fuel pump is 6 bar, and you cap the fuel return line, your 3 Bar will run 6 bar... do you get it?

[Bellicose Right Winger]

No, the downstream RRFPR will control provided it's set higher then the factory FPR. Remember that fuel pressure regulators are "back-pressure" regulating devices, they control their inlet pressure. This is different from the pressure regulator on a shop air compressor that controls the outlet pressure.

Paul Shovestul


If the stock one is still there, won't it cap the flow at 3 bar?

[Jon K]

No, the downstream RRFPR will control provided it's set higher then the factory FPR. Remember that fuel pressure regulators are "back-pressure" regulating devices, they control their inlet pressure. This is different from the pressure regulator on a shop air compressor that controls the outlet pressure.

Paul Shovestul


hehe confirmed my point :)

[Jon K]

Looking for info from Bill R/Winfred as to what they'd do....