2007 crafter not revving past 2000 rpm

[Mars4407]

Good evening everyone, my name is Karl, I have a 2007 LWB crafter. I had a glow plug 2 fault. I changed the glow plug and now the engine will not run above 2000 rpm and judders. I have an open circuit fault showing on VDCS on glow plug 2,3,4,and 5. There seems to be no boost but I'm getting the correct readings at the turbo. Any help would be appreciated and a point in the right direction to getting this solved

 

[Seatman]

Only thing I've seen so far that have caused this was a broken turbo shaft blocking the air intake, that was on a T5 bus if I remember right. You could see the intake pipe squishing a bit as it was revved.

 

[Mars4407]

Morning Seatman, I have a new turbo fitted. I've just checked that the actuator vacuum pipe is connected. It's definately pointing to boost not being present. I'll have to do some more research and testing today.

 

[Mars4407]

I have checked the boost today and all is good. All glow plugs now are showing open circuit P161A,B,C,D,E. I have also lost the key symbol on the instrument cluster when I insert the key. I will test the resistance of the glow plugs tomorrow, but will the glow plugs showing open circuit cause the engine speed to not go over 2000 rpm and limp home mode?

 

[Seatman]

I don't know the answer to that one I'm afraid, was it all running fine before the glow plug change?

From a quick google I'm finding low voltage from the alternator or bad connection at the connector for the harness causing that fault code but nothing about stopping the engine revving.

Are you revving it in neutral or under load? If under load that could be a bad maf or that

 

[Mars4407]

Yes was running fine. I will do some electrical checks today. It’s being done in neutral. It has to be something ridiculously simple. It’s find it that’s the problem

 

[Mars4407]

Good morning. After doing some research last night I went out this morning and used a test light on the wiring harness from the glow plug relay which is situated behind the nearside headlight. I tested the wires sw/ws, sw/gn, sw/or, sw/vi, and sw/bl. The test light near lit up pointing to wiring loom issue. Traced the loom from the relay to the glow plugs and found a connection just behind the induction pipe at the top of the engine was on but no connection was being made. clipped the connection back on tightly and started the engine and now have full power and full rev range. Conclusion, glow plugs do effect the revs of the engine

 

[oilhammer]

No, they don't. But the other wires to the HPFP control in the same harness as the glow plugs would.

 

[Mars4407]

I’m confused. The harness was not connected, engine wouldn’t run over 2000. Connected it back up and all is well. What is the HPFP control?

 

[oilhammer]

High Pressure Fuel Pump. They do not sell those here, so I am just going off of an ETKA picture, but the engine sub-harness that goes to the glow plugs on the 2.5L engine also shows it has another circuit in it and it just says "high pressure pump". I suspect the ECU went to a default fixed value for that, hence the limited RPM. So when you left the connector loose that went to the plugs, you also left that one loose since it is in the same harness. Go take a look (I'm just curious) and see.

Google image search this: 076-971-277 That should be the sub-harness. See the extra connector on the end?

 

[Mars4407]

Yeah that makes sense as it was showing a fuel pump relay on the same diagram. The glow plug harness was reconnected and everything is working as it should. Getting full Rev range