Drivers door not priming fuel pump, hard to start when cold

[Connor H]

Hey guys,

Ive recently had trouble starting from cold, super lumpy and dies. Fuel pump primes on ignition but not on drivers door which it definitely used to, I assume its a relay or a fuse thats died? If anyone knows where to look be much appreciated

cheers

 

[mty12345]

Hey guys,

Ive recently had trouble starting from cold, super lumpy and dies. Fuel pump primes on ignition but not on drivers door which it definitely used to, I assume its a relay or a fuse thats died? If anyone knows where to look be much appreciated

cheers

It's probably the drivers door lock module, mine did it when it started to fail. Is the headlight warning bleeper not working when you open the drivers door too?

 

[Connor H]

It's probably the drivers door lock module, mine did it when it started to fail. Is the headlight warning bleeper not working when you open the drivers door too?

Its the lock module is it? I figured it might be a relay. Thats cool i have the OEM one here that still works.

Ill give the headlight warning beep a check today

 

[Connor H]

It's probably the drivers door lock module, mine did it when it started to fail. Is the headlight warning bleeper not working when you open the drivers door too?

It would appear i am mistaken, the door is priming the pump. (bleep warning still works too)

Not quite sure what is causing the cold start issue then, havnt got any codes yet. Maybe the FPR on its way out?

 

[mty12345]

Is it only when the Secondary air injection runs for the first min or so? Mine runs like crap on some cold mornings when the SAI runs, but fine as soon as it turns off Having the aircon switch turned off until after that thing finishes running helps a lot. I think the extra load of the aircon causes misfires.

 

[Connor H]

Is it only when the Secondary air injection runs for the first min or so? Mine runs like crap on some cold mornings when the SAI runs, but fine as soon as it turns off Having the aircon switch turned off until after that thing finishes running helps a lot. I think the extra load of the aircon causes misfires.

no ive had all that long time ago, SAI is gone and mapped out

Ive had similar symptoms before , its like its got not enough fuel pressure , it coughs and dies unless i step on the gas. I checked fuel was coming to the rail on prime which is it. Sods law i dug my pressure gauge out and its leaked and effed.

Wonder if theres anything i can monitor on VCDS with it?

 

[mty12345]

no ive had all that long time ago, SAI is gone and mapped out

Ive had similar symptoms before , its like its got not enough fuel pressure , it coughs and dies unless i step on the gas. I checked fuel was coming to the rail on prime which is it. Sods law i dug my pressure gauge out and its leaked and effed.

Wonder if theres anything i can monitor on VCDS with it?

Don't think the fuel pressure is monitored on the 1.8t, I think the ECU just assumes it's 3bar, so you would need a gauge.

Woud definietly check the Coolant temp sensor on VCDS and make sure that is correct.

Also worth looking for any PCV or intake leaks as well, as they can have a huge effect on idle mixture as the O2 sensors are disabled until they warm up and the ECU switches from open loop to closed loop.

 

[Connor H]

Don't think the fuel pressure is monitored on the 1.8t, I think the ECU just assumes it's 3bar, so you would need a gauge.

Woud definietly check the Coolant temp sensor on VCDS and make sure that is correct.

Also worth looking for any PCV or intake leaks as well, as they can have a huge effect on idle mixture as the O2 sensors are disabled until they warm up and the ECU switches from open loop to closed loop.

I did replace the coolant sensor a month ago as it goes, ill check the temp when cars cold see if its accurate.

ill have a look around for air leaks, but the gauge is showing good vac n boost, and car runs as normal.