Hi, so my 2.2 HDi (4HX) has been giving me a headache lattley with this DTC (P1112 Low fuel pressure on high pressure side). The car with stock IQ, shuted down on 3rd gear and pulling hard but when i replaced the injetors it improved ( no limp mode)! I saw on logs that the fuel pressure is all over the place, it cant regulate accuratly. After a soft remap and many tryes to improve the performance, it shuts down when pulling a little hard on +3rd Gear always on the same revs and it sucks. I have checked everything like this diagram of the fuel system. I have tried to delete the P1112 DTC but it wasnt successfull. I want to cry :|


The car is a PUG 406 Manual
I have deleted:
- EGR,
- Swirls,
- Air doser,
- All FAP related stuff,
- Air Heater,
- Fuel Heater.
All this deletes have the DTC on EEPROM deleted btw.

Things i've tested:
-Fuel lines (almost 3 bar on the Low pressure side);
-Wiring: Apparently ok, checked with multimeter;
-Replaced the fuel pressure regulator;
-Replaced injectors;
-I tried the 2.0L Pump (R65) and i got limp either way (at diferent revs).
-Replaced fuel pressure sensor;
-Tested the low pressure fuel pump power supply and its ok;

My remap + mappack.


Any advice? :thumbup:

626A4 (16*1)rpm, 62710 (1) - permissible pressure deviation. delta below the specified.
I often encountered error 1112 with a large fuel supply, I think a weak pump.

Deman wrote:626A4 (16*1)rpm, 62710 (1) - permissible pressure deviation. delta below the specified.
I often encountered error 1112 with a large fuel supply, I think a weak pump.

Thanks alot man!! Should i restore the pump? with like a gasket rebuild kit?

im gonna look at your tune... relax bro... its all good.. i just sold my 1200hp hellcat with the fore innovation tripple fuel pump on E85.. trust me when i say " i feel your pain" .... its all good though.. just eliminate one thing at a time until you get it.. dont let it drive you nuts.. anyways i would replace the fuel pump if its malfunctioning.. i will look at your tune... If you were using the HP TUNERS PLATFORM id be able to fix it in no time.... everybodys setups are all different.. anyways im new to this site and ill try to help you... ive been tuning bikes for 10 years now and cars for 3 years so ive got some knowledge,,

what Software are you running???? ECU? has it been flashed by you? send me the stock map file so i can see it and i got the map you attached... what software your running is what i need to verify..

nicksi8 wrote:what Software are you running???? ECU? has it been flashed by you? send me the stock map file so i can see it and i got the map you attached... what software your running is what i need to verify..

Sry, i was reverse engineering (the software is IDA PRO) this ECU and i forgot to change the file format :D

The car came badly tunned but i remaped my "ori" to sock values, so my "ori" isnt really an ori.

Sounds like fuel starvation.
To state the obvious, checked the fuel filter?
Any air entering the system? ( Had many cars draw air from a dodgy hand priming pump and not leak a sniff of fuel).
Hoses ok?
Pump pressure v rev / load increase? And % variation?
Bypass / pressure relief valve ok?
If that plus what you have already done doesn't work then look for abnormalities in the data

Friied wrote:Sounds like fuel starvation.
To state the obvious, checked the fuel filter?
Any air entering the system? ( Had many cars draw air from a dodgy hand priming pump and not leak a sniff of fuel).
Hoses ok?
Pump pressure v rev / load increase? And % variation?
Bypass / pressure relief valve ok?
If that plus what you have already done doesn't work then look for abnormalities in the data

Thanks for the response!!
I have replaced the fuel filter 1 year ago, i'm going to do it again very soon, it has some dark tint but nothing to worry about i think.
Air in the system is unlike, with the fuel pressure it must leak somewhere.
Hoses in the engine are ok and the remaining are plastic. I have done alot of things on the car, right now i'm checking all the piping and blowing it with compressed air (debry).
Pressure valve was replaced and wiring checked. I have videos datalogging, it's really weird, pressure goes up by RPM and a sudden drop in pressure. It's like the pump cant keep up with the "recommended" pressure, the only thing that i see it works is tunning the pressure valve to open sooner.
I will give updates