Cold start engine shakes and sputters

[bearsbmw]

can everyone please post all the item's they replaced when trying to fix this problem

Me=

AFM
02 sensor
Coolant Temp Sensor
Spark plugs
Intake gaskets
Alternator
fuel filter
Relays
Fuses
battery

[roundel318]

Since I have a good running car, I decided to play around with it this morning during cold start (it was 35.F out this morning).

I disconnected the AFM, cranked once and turned over a few times sputtering trying to start. Cranked again and fired right up to 1200rpm ish hovering smooth.
Shut off car.

Disconnected ICV AND left AFM disconnected.
Started up and idled low ~500-600rpm, vibration is pretty bad, not sure if this is what you are seeing.

Reconnected everything, started back up, ran for 5 seconds around 2000rpm then dropped and almost stalled but my ICV IS dirty so it was a little slow to catch it. Engine returned to normal idle, 700rpm.

Is yours dirty? What if you disconnect the ICV when you start up?

I don't have this problem so I am just providing some perspective :confused:

[bearsbmw]

Im going to try and disconnect the ICV and note what happens .. good idea ! but yes I have had it out for cleaning a few times & I tested 12 volts on it and it opened fine

[roundel318]

I wish I was a little more familiar with how M1.7 runs, its also worth paying attention to any fuel delivery related issues. There is a prestart pump that primes the system before startup, then the main pump that runs when the engine starts up.
You can hear the prestart pump prime for about 1/2 second when you turn the key to on.
Do you hear this taking place?

Do you own a Bentley manual for this vehicle?
I found a used working ICV off ebay for $20 shipped.
If this goes on and on with so many people, I could even ship you my spare ECU (factory chip) and spare ICV for a week or something if finding good working used parts is out of the question for you.
Just thinking out loud......again

[B318M42W]

crazy ideas... we know that the problem is during the open loop mode of the ECU... and then the engine is cold. also, the vent from the crankcase goes back into the intake boot, loaded with oil vapor. maybe a vacuum line is obstructed by oil gunk??? and by the time it "warms up", the oil inside heated up and permits "normal" airflow.. (maybe jammed the FPR also???) and just out of curiosity, how many ppl with that problem changed the fuel pump (or strainer), fuel filter, injectors and FPR. and also checking if the return fuel line isn't clogged.

maybe it could be as stupid as a bad wire from a sensor?
just throwing it out there...

[roundel318]

I was thinking wiring too, but it seems to run correctly he says.
Of course with car wiring anything is possible:)
He says he hot plugged his AFM after it was running with it disconnected.
Hot plugging anything ECU related cannot be good.
Curious what happens when he starts it with no ICV connection.
Can someone explain more about the ECU open loop mode?
I am always down to learn something

[bearsbmw]

ICV disconnect finding are =

disconnected ICV = clean cold idle but holding at 1200rpm untill the coolant temp get's past the blue it will start bouncing the idle

Disconnected ICV & Afm = rough idle with bouncing idle

AFM only dissconect  yields a high idle hold at 2000rpm

[roundel318]

When it starts bouncing, what rpm range? how fast does it bounce?

[bearsbmw]

When it starts bouncing, what rpm range? how fast does it bounce?

1200 range and up and down fairly quickly but only a few hundred rpm

[roundel318]

go drive around with the ICV disconnected and after the engine has warmed up some more, does the idle behaviour change?

[bearsbmw]

ok I will try that ... Does anybody know if the stock ecu chip is maped for startup or does the ECU board have that built in? .

[bearsbmw]

go drive around with the ICV disconnected and after the engine has warmed up some more, does the idle behaviour change?

Did that and got normal driving conditions but when I come to stop the idle is holding at 1200 and jumping to 1500 up and down quickly and the fuel usage meter is going wacko!

[roundel318]

I did the same, driving around and had a 1200rpm idle, with no flux.
Something is going on outside of your AFM or ICV.
I am curious because I am not 100% if the fuel usage meter is vacuum based or if its based off the ECU. I think you need to find a spare ECU to try out.
How is fuel delivery at WOT?

[bearsbmw]

I should mention that sometimes I get a CEL when at idle for a while throwing 1222 and Airfuel mix is holding rich... I also get this when Im cruising and if I push the gas it go's as quickly as it came

[B318M42W]

The ECU will throw you a mixture code if the mixture is unchanged for 10 seconds. as soon as there's a variation, it'll go away but reappear.