Error P0190 fuel pressure but only on idle...
Dear all, I am writing from Italy and I have a problem with my Pinin (Pajero IO) 2.0 GDI. The engine light is ON and the error I see reading ECU with an ELM327 device is P0190 that is wrong fuel pressure.
The engine works perfect when I requires power, no voids, good performances (this is also the reason why I am here to ask you and not in a Mitsubishi dealer…). The only problem is on idle: sometimes the rpm goes down and sometimes the engine stops. This is frustrating 
.
I premise that throttle body is clean and measuring the voltage of throttle position sensor as indicated in the manual, the result is ok; the same for the accelerator position sensor.
I disconnected battery to reset ECU: after this, the idle set up in few seconds (I know that idle regime need some time that ECU set it up) and I thought to have solved the problem. But when I left the engine on idle for some minutes (I was offroad and I was waiting for my friend with a Jimny 
) I heard idle goes down (near to zero) and the engine light switched ON . Some time ago I read with ELM327 the ECU during functioning and I remember that idle regime change (decrease a little bit) when ECU change from OPEN to CLOSE loop that, if I well understood, means that ECU regulate air/fuel also reading the Lambda value. I don’t know if this is correct but now it seems that it this decreasing that has become very high.
I checked fuel filters, low pressure fuel pump, fuel pipe from tank to high pressure and vice versa. The only strange thing is that on one return pipe (the one from pump to the left tank where there is low pressure pump) do not come back fuel (I disconnected it with engine ON). I did not check the other return pipe (the one that goes on the right tank). Is this right?
Thanks a lot for your help.
Regards
GDI is different
Thank you for your answer. I checked but GDI is a little different. It has two fuel return lines, both coming from high pressure pump. One goes into right tank like in your picture (REF 13-020 number 6 in next picture). The other (Z REF 13-020 number 7) goes into left tank.
I checked only 13-020 6 and nothing come back. I did not check 13-020 7 (Z). Both exit from high pressure pump and there isn't any device between pump and tank.
I had the same problem but
I had the same problem but went away by itslef, if you have recently opened the fuel circuit it is because air might have been trapped in the circuit... do u experience any other malfunction? if yes it's probably the high pressure fuel pump to the injectors. Is there any stalling in low RPM between 1.0000-2.000 ?
I hope it will go away by
I hope it will go away by itself. Stalling occurs only at idle and not always; mainly with cold engine. If i keep engine at around 1200/1500 giri/min (accelerating a bit just to test) no problems, engine light do not switch on. At idle, after some seconds (let's say 5-10 seconds) RPM decrease suddenly to about 500 giri/min for few seconds and light come on. With cold engine, with same situation, engine stall.
Today i put some additive in fuel; tomorrow I will have 100km offroad. Let's see...
Ciao
did You change this BIG fuel
did You change this BIG fuel filter whos located on the tank ?
DId You change the small filters on HIgh Pressure fuel pump ?
honestly - i had the same problem as You .. so i decide to make High Pressure fuel pump regeneration follow russian thread
http://mycarisma.ru/statya/toplivnaya-sistema/remont-tnvd-micubisi-karizma-gdi
that's my photos below
https://www.dropbox.com/sh/hxyyjf32wpvn4kn/AAB7Q1_fpC3J575TLsr7m5Psa?dl=0
try to download EVOSCAN, then on evoscan you are abble to add field "pressure on HIgh Pressure fuel pump" .. and you are abble to read data from Pressure Sensor on the fly.
Always check engine will be light ON when pressure is to high, or to low tfor more then 4 seconds ... botom value is 40 - normally should be 52 still ) no matter is on iddle or normal driving.
cause you didnt see when fuel is comming back to the tank - i suspect problems with low pressure... always on iddle some of gasoline MUST go back to the tank. ALWAYS.
alot of ppl buy the new low pressure fuel pump whos only right with dimension and pressure - they forgot about flow... flow is also important .. that is mean you are abble to buy low pressure fuel pump who give you the same pressure with lower flow ... that is frequent problem
what about fuel consumption on iddle ? on my issue was exteremally HIGH when the car was STOPT .. what's in your car ?
some photos from mounting process .. i also change EGR ( i buy second for 10 usd and clean it )
https://www.dropbox.com/sh/rmvhd1om1fwmqjp/AACUIY8qWv_Xl_2Zy7gyc7WCa?dl=0
soory for my English ;) ..
Thank you for the answer Yes,
Thank you for the answer
Yes, i changed filter in tank (few months ago) and microfilter two years ago.
I would like to change microfilters again but now I can't find easily in Italy or online.
I will study the russian guide and your photos (thank you very much) and then I'll decide if start this adventure.
Ciao
small thing, your welcome..
small thing, your welcome.. at 1'st you must be sure about Your low pressure system works right ..
my Pinin is from italy - from Alp mountains near Switzerland - i have to say about previous owner didnt take care about this car .. The fuel filler pipe was corroded, on the tank i found alot of sand and water.. do not use ANY cleaning liquid who should be pour into a tank, at 1st he will dissolve whole contaminants whos normally stopt by every filter on your fuel system - i did the same, then my pump was complettely destroyed, and i must buy another one ( used one ).. if you need to clean fuel hoses - try to ask your mechanics about Liquid Molly Jet Clean Tronic.. ( i did that to be sure about my fuel system is totally clean )..
Syndicate
left tsnk pipe
The left side of the tank has no pump, it stucks fuel over using the primary return line as a venturi. Only the right side of the tank will have an active return line.
We do not have the GDI motor here BUT we have an issue with the fuel pressure regulator on the MPI engines - it is metered by a vacuum hose and if it is clogged etc the fuel pressure will reduce.
Also download the manuals from this site and go through the GDI engine fault-find flow chart, several things can result in low fuel pressure or dropping idle.
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