[Engine] Limp Mode no error codes or warnings Please help.

[ampy1]

Hi,
I'm getting desperate with my van. It is an Expert not a Berlingo but has the 1.6HDi engine.
The brief history: It was working fine but got left unused and a bit neglected during lockdown and only rarely started up. The battery died altogether and wouldn't even take a charge.
As lockdown came to an end I gave it a thorough clean up and new battery. It fired up within five revolutions. I a slight splutter for a second or two but then evened out. It has always been a harsh sounding engine leaving you no doubt it is a diesel but after a few seconds it was smoother and less harsh sounding. I took no notice at the time. When I went to move it, it would only rev to 2400rpm with a huge lack of power. Turned off and restarted but the same.
I wondered if the ECU needed to relearn due to flat battery for so long so left it running for a long while. No difference.
Plugged in my generic code reader and it came up with P1351 Glow plug and or relay fault. I checked and the all the heater plugs were dead.
I was intrigued that this would cause limp mode though. I did some googling and some people were saying yes it would because the heaters are needed to regen the DPF/FAP on vehicles that only did shorter journeys. OK, I can see the logic.
Fitted 4 new heaters and new relay, cleared the codes and checked a couple of times and they stayed clear. 
IT IS STILL IN LIMP MODE Argh!
No error codes, no dash lights, and it has not been anywhere or done anything so it can't be the turbo failed. (The vanes are free I checked)

Does anyone have any suggestions please?
I did some live checks as much as my cheap unit would do but the numbers do not mean much to me.

This were taken at idle.
Load PTC 49  (Air volume entering engine?)
MAP inHg 29.7  (Manifold Absolute Pressure?)
RPM 815
IAT 80F   (Something Air Temp?)
MAF Ib/Min 1.0    (Airflow?)
FRP (psi) 5557.5       (I take it this is fuel rail pressure)

[brodfather11]

Try unplugging the air sensor , they are quite delicate and easy upset.

Or the EGR with lying idle for a time it may have clogged up. Just unplug and see

[ampy1]

I'll give it that a try tomorrow. What can I expect to happen? I did read someone somewhere (spent a lot of time googling) saying that unplugging the air sensor makes the ecu use a default setting which can make it run better if the air flow sensor is faulty. Is this the same sort of idea? Thanks for you help.

[saskak]

I'll give it that a try tomorrow. What can I expect to happen? I did read someone somewhere (spent a lot of time googling) saying that unplugging the air sensor makes the ecu use a default setting which can make it run better if the air flow sensor is faulty. Is this the same sort of idea? Thanks for you help.

Exactly that, it reverts to a default ECU map. I would agree with broadfather that you may want to look into the EGR valve, potentially cleaning it, with standing for long it may have clogged up and would not budge. Potentially the EGR buttefly as well or maybe look into the turbo wastegate, it could have seized up and you would get limp mode. Easiest is to check the turbo wastegate for movement on startup (https://www.youtube.com/watch?v=WLsMzdKgI1o).

[ampy1]

I'll give it that a try tomorrow. What can I expect to happen? I did read someone somewhere (spent a lot of time googling) saying that unplugging the air sensor makes the ecu use a default setting which can make it run better if the air flow sensor is faulty. Is this the same sort of idea? Thanks for you help.

I've now had chance to spend some more time on this problem.
Unplugging MAF and EGR made very little difference.  The one thing I noticed though that the engine was very slightly surging when it reached it 2400rpm upper limit.
Plugged them back in and was back to smooth 2400rpm. Just like holding it at part throttle but the engine sounds more like a petrol than diesel.

If I blip the throttle it sounds like a diesel with power and responds but it is like that for 0.5 - 1 second when it reverts to being quiet and stops responding.
The ECU is sensing something it doesn't like and seems to be retarding the engine timing significantly.

[ampy1]

Just to add, I also unplugged the two on the other side of the engine. One is turbo boost pressure not sure about the other temp maybe? But I had the same pulsing results as I did with the EGR and MAF disconnect but slightly more so.

[saskak]

Just to add, I also unplugged the two on the other side of the engine. One is turbo boost pressure not sure about the other temp maybe? But I had the same pulsing results as I did with the EGR and MAF disconnect but slightly more so.

What did you unplug for the turbo boost pressure? Do you mean the vacuum pipe for the turbo wastegate or something else like the MAP sensor?
If it was the turbo vacuum wastegate connection and there was no difference it should mean that either the turbo wastegate is not working or the turbo solenoid at the back of the engine or the turbo itself.

[GraemeT]

Just to add, I also unplugged the two on the other side of the engine. One is turbo boost pressure not sure about the other temp maybe? But I had the same pulsing results as I did with the EGR and MAF disconnect but slightly more so.

What did you unplug for the turbo boost pressure? Do you mean the vacuum pipe for the turbo wastegate or something else like the MAP sensor?
If it was the turbo vacuum wastegate connection and there was no difference it should mean that either the turbo wastegate is not working or the turbo solenoid at the back of the engine or the turbo itself.

I'd go for the vacuum not working or the turbo actuator sticking - mityvac if you have one to test the turbo parts move, if you want to test the solenoid I have an old one lying around someplace I can post out to you (unless you're near Aberytsytwyth??) and you can swap it in for yours

[ampy1]

Just to add, I also unplugged the two on the other side of the engine. One is turbo boost pressure not sure about the other temp maybe? But I had the same pulsing results as I did with the EGR and MAF disconnect but slightly more so.

What did you unplug for the turbo boost pressure? Do you mean the vacuum pipe for the turbo wastegate or something else like the MAP sensor?
If it was the turbo vacuum wastegate connection and there was no difference it should mean that either the turbo wastegate is not working or the turbo solenoid at the back of the engine or the turbo itself.

Thanks for the reply. There are two sensors on the drivers side after the intercooler and what looks like a throttle housing. (Tried Unplugged that too)
I checked the turbo. It is spinning freely and has no free play that can be detected. I checked the vacuum lines and they hold vacuum. I also checked the actuator and that also work fine. I also marked the shaft with tippex and started the engine and the actuator operates.

[ampy1]

Just to add, I also unplugged the two on the other side of the engine. One is turbo boost pressure not sure about the other temp maybe? But I had the same pulsing results as I did with the EGR and MAF disconnect but slightly more so.

What did you unplug for the turbo boost pressure? Do you mean the vacuum pipe for the turbo wastegate or something else like the MAP sensor?
If it was the turbo vacuum wastegate connection and there was no difference it should mean that either the turbo wastegate is not working or the turbo solenoid at the back of the engine or the turbo itself.

I'd go for the vacuum not working or the turbo actuator sticking - mityvac if you have one to test the turbo parts move, if you want to test the solenoid I have an old one lying around someplace I can post out to you (unless you're near Aberytsytwyth??) and you can swap it in for yours

Thanks for the reply, (and your kind offer). 

I checked the turbo. It is spinning freely and has no free play that can be detected. I checked the vacuum lines and they hold vacuum. I also checked the turbo actuator and that also work fine. I also marked the actuator shaft with tippex and started the engine and the actuator operates which seems to suggest the solenoid is also working.
It's a real mystery at the moment.