Hi there

I would expect there will be no code if yours fuel pressure drops and car starts to misfire/splutter,this can cause like fuel pump/fuel controller or fuel pressure regulator

Yes I would always use stock sock as most of supplied socks doesn't fit the supplied pumps

Hard to diagnose without the knowing what fuel pressure is or if its dropping down when you start to push the car,but still I would get fuel pressure gauge and check if fuel pressure is dropping

I know from personal experience when we have similar issue on our EP3,too no CEL or errors,only started to splutter and misfire when car started to come on boost and at the end our sock has been in very bad state,due this we are running in car fuel pressure gauge with which we know for sure if fuel pressure is OK or not

But really hard to say if this can cause and why is this causing when car is cold etc.,but if you can borrow Fuel pressure gauge and try to monitor fuel pressure if its dropping when car starts to splutter/misfire,if yes then as above Fuel pump/controller or FPR is on way out

Fuel pressure gauge in car cost over on ebay £30-£50 and is well worth the money,yes off course you can buy DeFi,but really depends on you

Hope this helps and good luck there

Thanks,Jura

Hi there

As above I would suspect there will be no error code(active or historic) if fuel pressure starts to drop and when car starts to splutter/misfire which can cause fuel pump/sock/controller or FPR,usually when you applying light throttle fuel pressure doesn't rise so quickly or there is no big demand for more fuel.Usually when you drive normally or when you just apply throttle lightly,everything will be fine,same like on ours when we have similar issue,I know is not on Subaru,but usually is the same

As above if you could or he could source in car fuel pressure gauge and check fuel pressure during the driving or when car starts to splutter/misfire and then you can rule out fuel pressure or fuel pump/sock/controller

Hope this helps there and good luck with finding the fault

Thanks,Jura

 

Hi Jura

Is there second page to the fuel pump controller for testing it

 

Hi there

I don't have second page of this manual,I've found this over on Nasioc I think,but will check my PDF if don't have them

Thanks,Jura

 

Still have this issue but the last couple of days when i start car from cold idle starts 1500rpm but quickly goes to 1000rpm then up and down could iacv cause my problem

 

If you check spark plugs it may give you an idea of whether its over fueling or under fueling i.e if they are wet or dry!
I've always understood if the heater goes faulty in 02 sensor,then car will over fuel run rich not lean.

 

If you've changed cts and maf and don't mind spending to find out,then try a new iacv and possibly a tps but funny how its temperature related so doubt tps would be cause but its something else on the inlet manifold to try lol.
On another note,when was the last time you done an engine coolant flush/change?
My car was playing up a bit from cold sometimes and i removed the radiator cap,out of curiosity really and i was amazed how gunked up it was! I done a thorough flush and car runs like new!

 

Coolant was changed about 3 months ago as i had a thermostat chuck it spark plugs changed 6wks ago

 

Maybe just check coolant again to be sure its ok.
Does car run fine when up to operating temperature and only bad from cold? If so wouldn't a faulty fpr make it bad all the time?
Take your fuel hoses off from the fuel filter under the bonnet and turn ignition on and see how powerful the the fuel shoots out. I put my fuel hose in a bottle to catch the fuel,which shot off about 6ft so i know i had good pressure! Lol

 

Yes fine when upto 65degrees had a failed pump in december changed for new one

 

Did the icav move freely when you took it apart the last time .When I did mine just to make sure it was alright you move the flap open and it pings back shut .Yours could be sticking .There was a right up in one of the performance mags can't think which one .Were they stripped a newage icav of electrical parts and stuck the round bar that control the flap in a drill and spun it freeing it up

 

I just took the top off mine and sprayed it mate didnt think to take electric bit off

 

https://www.scoobynet.com/general-te...ode-p0507.html .Here something to read and it was scoobyclinic who did the icav clean up as mentioned in link

 

Its definitely temperature related by the seems of it then,although my friend had an astra with the c20let (vauxhalls turbo engine) and for some reason it used to get through spark plugs pretty quick and it would start running bad from cold,you couldn't floor it and when he fitted new ones, they had to be set correctly otherwise it would still run really bad cold

 

Yes temp related i dont blast it from cold i am talking 3rd 4th gear say 1300rpm quarter to half throttle cough choke bang like misfire it could still be 02 sensor or maf as i got those parts secondhand

 

Mafs are very sensitive,could be a faulty one still. I think you can test a maf by unplugging it when engines running and if car cuts out,the maf was working ok. you will have to reset engine light after unplugging it though. A maf also works by using a heater element

 

The maf trick is a old wifes tale mate

 

I run a rcm trumpet with large k&n so could be maf

 

Yea its not gospel but i think it will tell you if its completely dud. it should make it idle different when unplugged,if it doesn't then it probably is faulty

 

Ok cleaned iacv started it today idle sat fine but still cough choke misfire i read if you turn a/c on idle should rise mine doesnt and engine noise stays the same

 

what does the maf read Voltage wise when the ignition is on and engine not running

 

Hi sorry dont have meter to check will ask garage to check on monday

 

I've had a read over thread and you dont say you've changed ht leads or coil packs. A bad ht lead will cause problems

 

Sorry Parts changed
Cts
Plugs
Coil packs
Maf(second hand)
02 sensor(second hand)
Cleaned iacv

 

I knew of a vw golf that would flood itself,soaking the plugs and wouldn't start,which was due to a bad crank sensor. I'm not sure if a bad crank or cam sensor could cause your problem?

 

Has mapper looked at it since?

 

No as dont think its mapping issue car ran fine for 3months after mapping date Goes in to some one on monday he want to check fuel pressure

 

Mapper could probably put his computer on it and see what it is

 

Andy f offered me to drop it off for a couple of days but dont want to bother him hes booked upto august Guy on monday will be hooking his laptop up he does opensource but wont be touching map

 

Cool,let us know what he says 👍

 

Will do