MK7 Bad MPG, Power Loss, Fault Codes

[Bertie90]

So here we go.....

Tipper with a cage and tail lift 2007 RWD, speed limited to 70mph, 80 000 miles, always serviced on time. I had it since 70 000miles

symptoms:
- up hills (sometimes a slight incline) the power drops, even when I drop it down a gear even in 4th and it still slows down! it's like the turbo is not even there (it is there and works)
- really bad mpg. 15mpg at best on motorways, about 10mpg in town. 250 miles a tank.
- sporadic idle when hot. The whole cab shakes

What did I do so far?
- service it
- changed the intake manifold gasket as it was cracked
- MAF replaced
- intake manifold pressure sensor cleaned although I think it's dead, you'll see why
- all brakes have been replaced, tyres changed so no seized wheels
- unplugged the EGR (great torque at low rpm!)
- plugged a code reader and I get the following - P1103 - P1402 - P1409(that's me unplugging the EGR)
- i drove at 56mph a whole tank and still crap MPG and power.
- No smoke of any kind out of the exhaust
- a commercial vehicle garage had it plugged in and was driving around while someone else reading some figures and they said it was the MAF so that's why it was replaced. No difference at all

I have another transit, same engine but with 100k miles more! Completely different animal. Sounds different, drives different, and does double the miles. This van had its EGR deleted at some point in its life.

What can i do to make the MPG and power better?
I speculate:
- injector/s
- boost leak
- a bad map
- bad turbo

help...

Thanks

Bertie

[knobby1]

A couple of questions:

What ps engine does it have..??
Have you had the codes read..??
When was the fuel and air filter last changed..??

Lord Knobrot

[Bertie90]

140ps
codes are all egr related (unplugged)
fuel filter changed 1 month ago

also the range computer works the opposite way. When downhill the range drops significantly and when standstill or idle or when i trash it it goes up

[knobby1]

140ps
codes are all egr related (unplugged)
fuel filter changed 1 month ago

also the range computer works the opposite way. When downhill the range drops significantly and when standstill or idle or when i trash it it goes up

Is the DTC or engine COG light on..? With the EGR valve disconnected, it will throw a fault code and can sometimes go into limp mode.
You'll not pass your next MOT with the EGR valve not working. They check for fitment and function now.

Lord Knobrot

[Bertie90]

140ps
codes are all egr related (unplugged)
fuel filter changed 1 month ago

also the range computer works the opposite way. When downhill the range drops significantly and when standstill or idle or when i trash it it goes up

Is the DTC or engine COG light on..? With the EGR valve disconnected, it will throw a fault code and can sometimes go into limp mode.
You'll not pass your next MOT with the EGR valve not working. They check for fitment and function now.

Lord Knobrot

The only light on the dash is the EML. It doesn't go into limp mode at all. FYI it has passed MOT without EGR working, it's all subjective on the garage but that's another thread.

If i plug in the EGR then the EML disappears and it's even lazier than before

[Bertie90]

any suggestions anyone?

[daraioj]

I would start by looking at live data (while driving) of boost pressure, fuel rail pressure, MAF reading, etc and see if anything seems abnormal.

Also as knobby said, has the fuel filter been changed recently? Could be a clogged filter causing fuelling problems.

[Bertie90]

I would start by looking at live data (while driving) of boost pressure, fuel rail pressure, MAF reading, etc and see if anything seems abnormal.

Also as knobby said, has the fuel filter been changed recently? Could be a clogged filter causing fuelling problems.

Boost pressure runs between 16 and 21, and when I cruise at 70pmh it sits at 16psi

What's the pressure i need to look for on the fuel rail?

Yes filter was changed 1 month ago and also a brand new MAF and nothing changed

[knobby1]

What's the pressure i need to look for on the fuel rail?

~1600Bar maximum at full throttle & full load. ~230bar at idle.

Lord Knobrot

[daraioj]

I would start by looking at live data (while driving) of boost pressure, fuel rail pressure, MAF reading, etc and see if anything seems abnormal.

Also as knobby said, has the fuel filter been changed recently? Could be a clogged filter causing fuelling problems.

Boost pressure runs between 16 and 21, and when I cruise at 70pmh it sits at 16psi

What's the pressure i need to look for on the fuel rail?

Yes filter was changed 1 month ago and also a brand new MAF and nothing changed

Knobby should be able to confirm this as he knows the 140's better but that boost pressure seems low to me... My 100ps runs at 30psi (2bar)

140's have a VNT turbo right? I would check the actuator is working properly and also check for leaks, split pipes, etc

[knobby1]

Knobby should be able to confirm this as he knows the 140's better but that boost pressure seems low to me... My 100ps runs at 30psi (2bar)

140's have a VNT turbo right? I would check the actuator is working properly and also check for leaks, split pipes, etc

The standard 140 doesn't boost more than ~21-22 psi, my "mapped" 140 does about 25psi at full load....so I think his turbo and boost pipes etc are ok....can't hurt to check though.

Lord Knobrot

[daraioj]

Knobby should be able to confirm this as he knows the 140's better but that boost pressure seems low to me... My 100ps runs at 30psi (2bar)

140's have a VNT turbo right? I would check the actuator is working properly and also check for leaks, split pipes, etc

The standard 140 doesn't boost more than ~21-22 psi, my "mapped" 140 does about 25psi at full load....so I think his turbo and boost pipes etc are ok....can't hurt to check though.

Lord Knobrot

Sorry knobby, are we talking absolute pressure or actual boost? When I said 2 bar I meant absolute. It's boosting 1 bar.

[knobby1]

orry knobby, are we talking absolute pressure or actual boost? When I said 2 bar I meant absolute. It's boosting 1 bar.

No, absolute pressure is written as psia. I have a boost guage on my beast and it's in psig or guage pressure, not absolute.

If your readings are in psia, I'd suggest there may be an issue. 1 Bar boost absolute is well below what it should be.

Lord Knobrot

[daraioj]

orry knobby, are we talking absolute pressure or actual boost? When I said 2 bar I meant absolute. It's boosting 1 bar.

No, absolute pressure is written as psia. I have a boost guage on my beast and it's in psig or guage pressure, not absolute.

If your readings are in psia, I'd suggest there may be an issue. 1 Bar boost absolute is well below what it should be.

Lord Knobrot

Absolutely!

I use torque most of the time to monitor boost and it will sit at 14.5 psi (atmospheric) at idle (or even with engine off) and peak at about 30psi. So it's clearly displaying absolute.

So going back to the OP's issue, I guess it would be useful to know how he's measuring boost. If he's using torque for instance, 16-21psi would be quite low. Right?

[knobby1]

So going back to the OP's issue, I guess it would be useful to know how he's measuring boost. If he's using torque for instance, 16-21psi would be quite low. Right?

Not if it's guage pressure....16-21 psig is normal-ish. If he's measuring in absolute, yes, it's too low.

Lord Knobrot