Cold start rough

[marioz4]

I am thinking of changing Lambda/Oxigen sensors, car gave me engine light and on cold start first 60 sec runs like Yugo ( for those not familiar with Yugo cars well..) i am also changing both Solenoid valve part number 11367585425 ( each for aprox £40)

Do you guys know how many 02 sensors are on 2010 35i model, shall i change all of them? car has 60k milles.

After i do above only then will consider that rough cold start may be due to injectors or coils...

 

[mcbutler]

A diagnostic session might save you a lot of wasted time, money and effort here.

 

[mcbutler]

A diagnostic session might save you a lot of wasted time, money and effort here.
I think I am correct that on cold start the lambdas are bypassed to allow the richer mixture for startup.
I had one fail, it gave no error at all from start up, but once warm (and in use) it would give an error on starting.

 

[marioz4]

A diagnostic session might save you a lot of wasted time, money and effort here.
I think I am correct that on cold start the lambdas are bypassed to allow the richer mixture for startup.
I had one fail, it gave no error at all from start up, but once warm (and in use) it would give an error on starting.

Thanks Mark, did think of doing this need to find a inpa cable that work for z4...there is porgramme on line from BMW so i can see all code error etc

 

[ph001]

Correct...o2 sensors are ignored on cold start.

 

[mcbutler]

A diagnostic session might save you a lot of wasted time, money and effort here.
I think I am correct that on cold start the lambdas are bypassed to allow the richer mixture for startup.
I had one fail, it gave no error at all from start up, but once warm (and in use) it would give an error on starting.

Thanks Mark, did think of doing this need to find a inpa cable that work for z4...there is porgramme on line from BMW so i can see all code error etc

Post your location, you may have a local member with the Carly diagnostic app who can pop round and read your codes for a coffee and a bun

 

[hdbiker1]

I started having the cold start heavy misfires. After changing plugs and coils, still had same issue. If I let it run a bit and shut it off and restart the check light would clear and ran alright, but eventually got worst. I found the fix was to replace the injectors on one bank. Luckily the injectors were covered by BMW's factory warranty. You might have the same issue, look at your injector numbers. See what the -# is. If they are -11 or -12 you might be out of luck for the warranty.
I have a 2011 Z4is with approx. 63000 miles at the time.
Btw Carly only showed misfires.

 

[marioz4]

I started having the cold start heavy misfires. After changing plugs and coils, still had same issue. If I let it run a bit and shut it off and restart the check light would clear and ran alright, but eventually got worst. I found the fix was to replace the injectors on one bank. Luckily the injectors were covered by BMW's factory warranty. You might have the same issue, look at your injector numbers. See what the -# is. If they are -11 or -12 you might be out of luck for the warranty.
I have a 2011 Z4is with approx. 63000 miles at the time.
Btw Carly only showed misfires.

Thanks - i am in Barcelona with UK car, i think that extended waraty only applies to US market...

I can hear low pressure fuel pump buzzing...i think that this may be part of the problem but i am very aware that injectors have issue... my car is 60.000 miles...

 

[Anonymous]

I'm not a 35i expert, but I understand that the behaviour is normally associated with the injectors failing and allowing fuel in when shut down..then running rough on next start..if so you can get away with one bank at a time..I'd do both..you need a diagnostic on that to exclude other issues.. :thumbsdown:

 

[marioz4]

I'm not a 35i expert, but I understand that the behaviour is normally associated with the injectors failing and allowing fuel in when shut down..then running rough on next start..if so you can get away with one bank at a time..I'd do both..you need a diagnostic on that to exclude other issues.. :thumbsdown:

Thanks - where to get new and whats the cost?

 

[sunnydays]

Very likely to be fuel injectors on the N54, pull your spark plugs and check for any signs of fuel on them or oil from the valve cover. Since your car is throwing a CEL light, plug a diagnostic tool in and see what code it is throwing.

Injectors can be obtained from BMW, make sure you get the latest revision 12 injectors. Make sure you get new and not refurbished, as the refurbished injectors will not have accurate calibration figures when programming these in via INPA.

Edit: it is generally advisable to change them in banks of 3 at a time.

Edit 2: Also if your spark plugs are wet, replace the those too

 

[marioz4]

Very likely to be fuel injectors on the N54, pull your spark plugs and check for any signs of fuel on them or oil from the valve cover. Since your car is throwing a CEL light, plug a diagnostic tool in and see what code it is throwing.

Injectors can be obtained from BMW, make sure you get the latest revision 12 injectors. Make sure you get new and not refurbished, as the refurbished injectors will not have accurate calibration figures when programming these in via INPA.

Edit: it is generally advisable to change them in banks of 3 at a time.

Edit 2: Also if your spark plugs are wet, replace the those too

Thanks - today we conected the car and it gave reading that low presure fuel pump is spinning like mad, so i will chnage the LPFP first and while his work is beeing done will take this oprotunity to ask them to take spark plugs out and check them.

I forgot to ask them if they can see in car history when they did diagnostic what code car gave when CEL light came on ( it came on only once some 10 day sago and it vent away afer 1 min.)

Will keep you posted

 

[sunnydays]

Very likely to be fuel injectors on the N54, pull your spark plugs and check for any signs of fuel on them or oil from the valve cover. Since your car is throwing a CEL light, plug a diagnostic tool in and see what code it is throwing.

Injectors can be obtained from BMW, make sure you get the latest revision 12 injectors. Make sure you get new and not refurbished, as the refurbished injectors will not have accurate calibration figures when programming these in via INPA.

Edit: it is generally advisable to change them in banks of 3 at a time.

Edit 2: Also if your spark plugs are wet, replace the those too

Thanks - today we conected the car and it gave reading that low presure fuel pump is spinning like mad, so i will chnage the LPFP first and while his work is beeing done will take this oprotunity to ask them to take spark plugs out and check them.

I forgot to ask them if they can see in car history when they did diagnostic what code car gave when CEL light came on ( it came on only once some 10 day sago and it vent away afer 1 min.)

Will keep you posted

Huh what country is your 35i from? The E89 35i / 35is does not have a LPFP last time I checked....
What code was thrown by the ECU?

 

[marioz4]

Very likely to be fuel injectors on the N54, pull your spark plugs and check for any signs of fuel on them or oil from the valve cover. Since your car is throwing a CEL light, plug a diagnostic tool in and see what code it is throwing.

Injectors can be obtained from BMW, make sure you get the latest revision 12 injectors. Make sure you get new and not refurbished, as the refurbished injectors will not have accurate calibration figures when programming these in via INPA.

Edit: it is generally advisable to change them in banks of 3 at a time.

Edit 2: Also if your spark plugs are wet, replace the those too

Thanks - today we conected the car and it gave reading that low presure fuel pump is spinning like mad, so i will chnage the LPFP first and while his work is beeing done will take this oprotunity to ask them to take spark plugs out and check them.

I forgot to ask them if they can see in car history when they did diagnostic what code car gave when CEL light came on ( it came on only once some 10 day sago and it vent away afer 1 min.)

Will keep you posted

Just back from BMW

Injectors 13 53 8616079 300 euros each, you mention that revision 12 are the latest, so this one 13 i guess is totally new version?
Also they qouted me 420 euros for low pressure fuel pump...

 

[sunnydays]

Very likely to be fuel injectors on the N54, pull your spark plugs and check for any signs of fuel on them or oil from the valve cover. Since your car is throwing a CEL light, plug a diagnostic tool in and see what code it is throwing.

Injectors can be obtained from BMW, make sure you get the latest revision 12 injectors. Make sure you get new and not refurbished, as the refurbished injectors will not have accurate calibration figures when programming these in via INPA.

Edit: it is generally advisable to change them in banks of 3 at a time.

Edit 2: Also if your spark plugs are wet, replace the those too

Thanks - today we conected the car and it gave reading that low presure fuel pump is spinning like mad, so i will chnage the LPFP first and while his work is beeing done will take this oprotunity to ask them to take spark plugs out and check them.

I forgot to ask them if they can see in car history when they did diagnostic what code car gave when CEL light came on ( it came on only once some 10 day sago and it vent away afer 1 min.)

Will keep you posted

Just back from BMW

Injectors 13 53 8616079 300 euros each, you mention that revision 12 are the latest, so this one 13 i guess is totally new version?
Also they qouted me 420 euros for low pressure fuel pump...

13 is fine aswell, I am confused as to how they are quoting you for a low pressure fuel pump when the Z4 doesnt have one?

 

[marioz4]

Thanks - today we conected the car and it gave reading that low presure fuel pump is spinning like mad, so i will chnage the LPFP first and while his work is beeing done will take this oprotunity to ask them to take spark plugs out and check them.

I forgot to ask them if they can see in car history when they did diagnostic what code car gave when CEL light came on ( it came on only once some 10 day sago and it vent away afer 1 min.)

Will keep you posted

Just back from BMW

Injectors 13 53 8616079 300 euros each, you mention that revision 12 are the latest, so this one 13 i guess is totally new version?
Also they qouted me 420 euros for low pressure fuel pump...

13 is fine aswell, I am confused as to how they are quoting you for a low pressure fuel pump when the Z4 doesnt have one?

Model 35i - yes it has low presure pump, item number: 16 14 7363076 - i just found one on internet for half price.. not original bmw but i am sure it will be just fine

 

[ph001]

Yes, the N54 certainly does have both a low pressure and a high pressure pump. The LPFP sits in the tank and is electrically powered - it is used to 'prime' the fuel rail to around 70psi (so not that low pressure)! The HPFP is mechanically driven from the engine and boosts the fuel rail to over 2000psi (around 700psi at idle).

It is rare indeed for the LPFP to fail but it is not unheard of for the LPFP pressure regulator to fail. You need to look at log of fuel pressure to confirm, but basically the correct operation is for the LPFP to come on with ignition and prime the fuel rail to around 70psi, then turn ignition off again and check fuel rail stays at around 70psi. Even the next day it should be above 50psi. If fuel pressure regulator is bad then the 70psi drops off very quickly when ignition is switched off.

Normally, a bad LPFP pressure regulator causes long delay in starting - maybe 5-10 cranks of engine, but when it does start it usually runs OK. Bad / rough running from cold is nearly always an injector problem.

 

[marioz4]

Yes, the N54 certainly does have both a low pressure and a high pressure pump. The LPFP sits in the tank and is electrically powered - it is used to 'prime' the fuel rail to around 70psi (so not that low pressure)! The HPFP is mechanically driven from the engine and boosts the fuel rail to over 2000psi (around 700psi at idle).

It is rare indeed for the LPFP to fail but it is not unheard of for the LPFP pressure regulator to fail. You need to look at log of fuel pressure to confirm, but basically the correct operation is for the LPFP to come on with ignition and prime the fuel rail to around 70psi, then turn ignition off again and check fuel rail stays at around 70psi. Even the next day it should be above 50psi. If fuel pressure regulator is bad then the 70psi drops off very quickly when ignition is switched off.

Normally, a bad LPFP pressure regulator causes long delay in starting - maybe 5-10 cranks of engine, but when it does start it usually runs OK. Bad / rough running from cold is nearly always an injector problem.

Thanks - bit late now but hey... when they conected the car to PC it gave off scale reading for low presure pump, i can also hear it buzzing like crazy, as fuel filter is attched to the pump i decided ( as there is no extra labor cost) to change the fiter as well ( 60k miles).

I found injectors for 1/3 of the price from bmw thanks to another member here who advised alternative BMW original injectors.. so if changing the pump dos not solve the issue...next thing would be injectors...my feeling is that its the pump as issue with rough start ( even when car is hot revs are very low ) is that its the low presure fuel pump...( or leaking injector) as i am off for holidays most likely all of this will be done in January.

 

[ph001]

Is the fuel pressure regulator attached to the pump? If the pressure was off the scale then the regulator must be duff. You can’t have a bad pump and a good regulator giving you those symptoms if you know what I mean.

The other member specifying the alternative injector part numbers was me!

 

[R.E92]

There's no pressure sensor for the low pressure line on the Z4 so it's hard to diagnose the low pressure pump.

My advice would be to get the genuine parts. Go with either index 12 or 13 injectors, everything else will cause you headaches.