Mk7 2.4TCDi RWD, Loss of Power, P0089 and P121C

[ndrt]

Hi Transit forum, posting here for sanity checking approach to solution, as it's a campervan I need to keep her running

I have a Mk7 with MIL on and the following codes and symptoms:

- Sometimes subtle loss of power when slowly getting to high load
- Loss of power sometimes limp mode when quickly getting to high load
- Hunting for idle sometimes
- Higher pitched whistling / whoosing noise on acceleration - might be unrelated / additional turbo issue?

Started from cold today for first time in a couple of weeks and there was a fair bit of white smoke from exhaust which then cleared.

Codes:
VIN: WF0DXXTTFD6P43662
============================
OBD-IIOBD-II
DTCs: 7
----------------------------
P0089(7A) [0x00897A]
Fuel pressure regulator 1 - performance problem
Status: Test failed, Test failed (current drive cycle), Pending, Confirmed, Test failed since last DTC clear
----------------------------
P121C(00) [0x121C00] Archive (inactive)
Status: Confirmed, Test failed since last DTC clear
----------------------------
P116E(00) [0x116E00] Archive (inactive)
Status: Confirmed, Test failed since last DTC clear
----------------------------
P1103(00) [0x110300] Archive (inactive)
MAF Sensor In Range But Higher Than Expected
MAF Sensor In Range But Higher Than Expected
Status: Confirmed, Test failed since last DTC clear, Test not completed during this operation cycle
----------------------------

The previous owner had the injectors and ECU replaced (he sourced the ECU himself) and the ECU programmed. The injectors he paid £50 each for so... It ran fine until MIL light came on and a few hours later it kept loosing power when changing gear as revs would go through floor and engine stalled. I got a load of error codes relating to the injectors which suggested an injector had failed but no symptoms of that. The mechanics agreed with that but said it wasn't the exact right ECU hence error codes that didn't make sense so got it replaced it, Ford technician came and re-programmed and signed off everything, mechanics drove it round 30 miles and all fine.

A few hours later MIL light comes back on but it runs fine and I can't take it to a mechanic for a fair few miles but it slowly develops the symptoms above. Now it more often than not goes into limp mode at high load. Saying that, it'll get up to 60/70mph if you go slowly and as far as I can tell there's no smoke pouring out the back and no intense vibration.

I'm now looking at doing repairs myself to save money, searching around I found that replacing the PRV and SCV is first port of call which I will do this week, think I can do this as I'm new to engine maintenance but I have the parts. I also have Forscan and a matching USB OBDII dongle so I can do "the learns".

Is this as sensible a next step as anything? I read that P121C is that the release valve is being triggered at pressures lower than expected - so it could just be a faulty PRV? Or is it likely the second hand injectors or something else? What am I looking for if it's the latter?

Also any tips on diagnosing rattly whooshing whistly noises?

[knobby1]

Hi Transit forum, posting here for sanity checking approach to solution, as it's a campervan I need to keep her running

I have a Mk7 with MIL on and the following codes and symptoms:

- Sometimes subtle loss of power when slowly getting to high load
- Loss of power sometimes limp mode when quickly getting to high load
- Hunting for idle sometimes
- Higher pitched whistling / whoosing noise on acceleration - might be unrelated / additional turbo issue?

Started from cold today for first time in a couple of weeks and there was a fair bit of white smoke from exhaust which then cleared.

Codes:
VIN: WF0DXXTTFD6P43662
============================
OBD-IIOBD-II
DTCs: 7
----------------------------
P0089(7A) [0x00897A]
Fuel pressure regulator 1 - performance problem
Status: Test failed, Test failed (current drive cycle), Pending, Confirmed, Test failed since last DTC clear
----------------------------
P121C(00) [0x121C00] Archive (inactive)
Status: Confirmed, Test failed since last DTC clear
----------------------------
P116E(00) [0x116E00] Archive (inactive)
Status: Confirmed, Test failed since last DTC clear
----------------------------
P1103(00) [0x110300] Archive (inactive)
MAF Sensor In Range But Higher Than Expected
MAF Sensor In Range But Higher Than Expected
Status: Confirmed, Test failed since last DTC clear, Test not completed during this operation cycle
----------------------------

The previous owner had the injectors and ECU replaced (he sourced the ECU himself) and the ECU programmed. The injectors he paid £50 each for so... It ran fine until MIL light came on and a few hours later it kept loosing power when changing gear as revs would go through floor and engine stalled. I got a load of error codes relating to the injectors which suggested an injector had failed but no symptoms of that. The mechanics agreed with that but said it wasn't the exact right ECU hence error codes that didn't make sense so got it replaced it, Ford technician came and re-programmed and signed off everything, mechanics drove it round 30 miles and all fine.

A few hours later MIL light comes back on but it runs fine and I can't take it to a mechanic for a fair few miles but it slowly develops the symptoms above. Now it more often than not goes into limp mode at high load. Saying that, it'll get up to 60/70mph if you go slowly and as far as I can tell there's no smoke pouring out the back and no intense vibration.

I'm now looking at doing repairs myself to save money, searching around I found that replacing the PRV and SCV is first port of call which I will do this week, think I can do this as I'm new to engine maintenance but I have the parts. I also have Forscan and a matching USB OBDII dongle so I can do "the learns".

Is this as sensible a next step as anything? I read that P121C is that the release valve is being triggered at pressures lower than expected - so it could just be a faulty PRV? Or is it likely the second hand injectors or something else? What am I looking for if it's the latter?

Also any tips on diagnosing rattly whooshing whistly noises?

The "P0089" code is the one you should be sorting...As you mention, The SCV & PRV are the main culprits.... basically the P0089 code means the fuel system learns have been attempted and have failed to complete successfully at some point.

Be sure to get "genuine" SCV and PRV if you're changing them out...or you'll be doing it again in no time.

An injector leak-off test is also a good idea and will give a good indication of injector health.

Rattly noises..?? Check the turbo impeller for radial movement...anything more than ~0.5mm in any direction may point to failing turbo bearings/bushes. Whistly noises can be split boost pipes and or intercooler, check them all thoroughly.

Lord Knobrot

[ndrt]

Thanks! I've replaced the PRV and SCV after having a lot of fun getting the intake manifold out and back in. I've done a Pump learn and cleared the PRV count using forscan. I still immediately get a P0089 code but no other errors. I noticed on another thread that other learns are mentioned, but I don't have the codes from the injectors written down so didn't want to re-do injector learns but my local mechanic has been helpful with a couple pointers so taking it to him to see if he can get to the bottom of it.

I couldn't see any holes in the turbo pipes, I didn't dare take the turbo off to check the impeller or is that accessible somehow?

Will buy a leak-off test also, appreciate the help!

[knobby1]

Thanks! I've replaced the PRV and SCV after having a lot of fun getting the intake manifold out and back in. I've done a Pump learn and cleared the PRV count using forscan. I still immediately get a P0089 code but no other errors. I noticed on another thread that other learns are mentioned, but I don't have the codes from the injectors written down so didn't want to re-do injector learns but my local mechanic has been helpful with a couple pointers so taking it to him to see if he can get to the bottom of it.

I couldn't see any holes in the turbo pipes, I didn't dare take the turbo off to check the impeller or is that accessible somehow?

Will buy a leak-off test also, appreciate the help!

You don't need to remove the manifold to change the SCV...it's difficult but can be done if you have little girly hands and three wrists.

You don't need to remove the turbo to check for excess movement, just pop the black plastic inlet pipe off, (two bolts), and have a fiddle with the impeller...any excess movement will be cause for concern.

Generally we do the PRV counter/timer reset first...then the pump learn...then the pilot/injector learns.

The injectors ideally need to be properly coded to the PCM before doing all the above....they have a 16 digit "correction factor code" stamped on the electrical connector....usually starts with an "F".

20210626_094446.jpg

Lord Knobrot

[ndrt]

hahaha yeah these bear paws aren't getting down in there I have ordered an extra wrist though arrives Monday

So the local garage did the learns in the correct order and that all goes through fine, it then drives OK but he took it round the block and the error comes back and it goes into limp mode. Mechanic did a leak off test all the injectors are fine he said. He's out of ideas / expertise, suggested maybe something with the electronics? I'm OK with a multimeter, would like an excuse to buy an oscilloscope but no idea really what I'd be doing with it, unless it is something else mechanical, any ideas??

[ndrt]

To clarify, it's a P121C code when the fuel pressure gets high and it goes into limp mode. The mechanic did a smoke test and he said all good, so he's totally stumped by this code as there's seemingly no leak, he's decent so I trust him. I'll keep on searching, I've now seen other threads with this code.

It is a PF Jones PRV and SCV, I'd bought them before I saw about using bank-breaking ford official parts, but the learns all pass no problem.

[knobby1]

To clarify, it's a P121C code when the fuel pressure gets high and it goes into limp mode. The mechanic did a smoke test and he said all good, so he's totally stumped by this code as there's seemingly no leak, he's decent so I trust him. I'll keep on searching, I've now seen other threads with this code.

It is a PF Jones PRV and SCV, I'd bought them before I saw about using bank-breaking ford official parts, but the learns all pass no problem.

If the SCV isn't "genuine" you'll likely be doing it again....they rarely pass the learns...but if by some mirable they do pass, they usually fail soon after.

Lord Knobrot