M50 Idling issues.

[newman8r]

Okay I need help guys. M50tu (vanos)

Problem started when trying to fix small fluctuation of idle.

I've been on this for a week now. code 1222. Here is the scenario. I start my car up it idles fine. 1st stop light just fine. city cruising ( around 5 minutes of engine being on.) 3rd gear @2000 rpms starts to buck ever so slightly. When I go to hit next stoplight take out of gear to stop. Idle drops to 100 shoots up to 1000 bounces between for a length of stop and sometimes stalls out. If I turn off at gas station for a few minutes and drive away its fine for the about 2 minutes.

driving at highway speeds no problem, car cuts out at WOT can hear unburnt fuel popping in the exhaust.

Car will idle fine and get good gas milage and all of a sudden my mpg needle will go down between 25-20mpg and if I come to a stop the engine will surge and die.
After it dies I can start it and throttle it for a minute and it'll idle no problem.
If I step on it it'll go until around 5500 rpms and flatten out.
Stock tune. All plugs are black. I've installed;
New fuel pump,
Known working maf
New icv
Ohm my tps it is in spec.
new fpr,
new o2 sensor.
new coolant temp sensor,
new crank position sensor.
Only code is lambda control 1. I have done smoke test and have no leaks.

[BritishMike]

FWIW: I had similar symptoms with an M20 and it ended up being a Crank Position Sensor.

[Mwishlist]

Code 1222 through the stomp test? That's your o2 sensor. Does it only do it when warmed up? Not sure on the M50 engines but the M20 ECU runs off a map until warm, then it starts working off data from the o2 sensors. If you car runs fine cold but starts having issues when warm and you are getting 1222, you need to check / possibly replace your o2 sensor(s).

[newman8r]

Code 1222 through the stomp test? That's your o2 sensor. Does it only do it when warmed up? Not sure on the M50 engines but the M20 ECU runs off a map until warm, then it starts working off data from the o2 sensors. If you car runs fine cold but starts having issues when warm and you are getting 1222, you need to check / possibly replace your o2 sensor(s).

Yeah it is fine until it warms up. Isn't the stomp test code for o2 1221? Also I unplugged it today and drove it around and it did act better for about 10 minutes then it wouldn't even stay on unless I feathered the gas pedal

[Mwishlist]

Actually your right. That's a lamba code which I think means any lean running condition that the O2 sensor is getting? If the car was cold when you started with it unplugged, that makes sense. I don't think it takes into account the O2 sensor at all until it warms up.

[newman8r]

Okay so I was at the gas station the other day, got the car to idle fine just by driving. got the gas station, went in for coffee, turned it back on and it wouldn't hold an idle. so I took off and got to a light about a minute down the road and it was idling fine...
Swapped out o2 sensor. no change.

Also just pulled spark plugs, all of them are black. so I'm running rich.

[newman8r]

BUMP updated

[Daeldalus]

code 1222 is the lambda 1 code.
which means that the ecu is reading an afr out of range for an extended period of time.
could mean lean or rich but since you have black plugs that definitely means you are rich.

o2 has to be reading correctly to throw that code.

an intake side vacuum leak would cause you to be lean so probably not that.

what size(color) injectors do you have installed? are you 100% sure that your chip
is tuned for that size?

try cleaning your MAF. cheap and rules out a dirty MAF as the problem.

double check that your fpr is getting proper vacuum.

which engine coolant temperature sensor are you running? if not the stock m50 one
then try switching to it. also put a test light to the connector for it just to make sure
you have no wiring problem there.

long shot here but if you have big exhaust leak before your upstream o2 then it would
read much leaner than it actually is and try to dump more fuel to it once the car
warms up. oh, and double check the wiring from o2 to the ecu.

[newman8r]

code 1222 is the lambda 1 code.
which means that the ecu is reading an afr out of range for an extended period of time.
could mean lean or rich but since you have black plugs that definitely means you are rich.

o2 has to be reading correctly to throw that code.

an intake side vacuum leak would cause you to be lean so probably not that.

what size(color) injectors do you have installed? are you 100% sure that your chip
is tuned for that size?

try cleaning your MAF. cheap and rules out a dirty MAF as the problem.

double check that your fpr is getting proper vacuum.

which engine coolant temperature sensor are you running? if not the stock m50 one
then try switching to it. also put a test light to the connector for it just to make sure
you have no wiring problem there.

long shot here but if you have big exhaust leak before your upstream o2 then it would
read much leaner than it actually is and try to dump more fuel to it once the car
warms up. oh, and double check the wiring from o2 to the ecu.

I'm running green top injectors with stock chip. (Stock) I'm running an m50 cts so no problem there. I will check for an exhaust leak before my o2 sensor but I doubt I have one. Someone is suggesting my cat might be clogged but I don't think so. Would that cause the code? Also I don't have a canister filter but have all the lines plugged.

[M3PO]

I'm running green top injectors with stock chip. (Stock) I'm running an m50 cts so no problem there. I will check for an exhaust leak before my o2 sensor but I doubt I have one. Someone is suggesting my cat might be clogged but I don't think so. Would that cause the code? Also I don't have a canister filter but have all the lines plugged.

My cat was wedged sideways in the housing. No codes, idled fine. Just didn't have ANY power at all.

[newman8r]

I pulled off my exhaust after the o2 sensor (took off the cat) and it still ran terrible (went on a 25 minute drive) What is everyone's thoughts on camshaft position sensor or possibly a bad dme?

[newman8r]

Up

[berlow94]

Try pulling your vacuum line off of the throttle body that leads to the charcoal canister. Cap that port on the throttle body and try driving like that. You can leave that line uncapped and dangling in your engine bay for now.

If your charcoal canister or vapor tank is clogged or malfunctioning then the vacuum that your throttle body is pulling can either pull gas through the evap system or put a vacuum on your gas tank. Obviously gas sucking through your evap system is no good. Having a vacuum on the gas tank will starve the motor of fuel.

[Tommiie]

Not trying jack thread, but In my s52 without fail for last year, if I dont apply throttle for about 20 seconds on a cold start engine will die. When its warmed up it idles rough but fine, drives fine, will restart up fine.

Could this have anything to do with my throwing an exhaust on the car and just unplugging the rear o2 sensors lol.

[berlow94]

As mentioned before, your o2 sensors don't have any effect on the engine until the car is warmed up. And with that being said, with a factory dme, only have a marginal effect on anything. Sounds like you have something else going on.



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