Fiesta Diesel Warning Light When Going Uphill

[BrettSh]

Hi,

My wife's Fiesta gets warning light and limp mode when going uphill. We've taken it into the Ford dealership 3 times and still no fix. Any suggestions? Details as follows. 

When going up hills (or even relatively modest inclines), the warning light on my wife's 2010 Fiesta 1.6 diesel comes up (on a daily basis) and the car goes into limp mode. If she stops and restarts the car the fault will clear... until the next hill. I have connected a bluetooth ODB2 to her car and I see a P0299 (turbocharge underboost) error.

We took the car into the Ford dealership and they said the (suprisingly expensive) intercooler needed replacing. My wife asked if that would "definitely" fix the problem and the dealership said yes. However, got the car back and the problem was still occurring. 

Back to the dealship and they cleaned an air sensor they said was covered in oil. Got the car back and the problem was still occurring.

Back to the dealship and they replaced the air filter that they said was clogged up. Got the car back and the problem was still *!Removed!* occurring.

To be fair to the dealership, intermittent faults are harder to fix and they haven't charged us after the (suprisingly expensive) intercooler. But we are getting sick of the hassle.

Does anyone have any suggestions?

Thanks

Brett

[TDCiST]

Fuel issues can cause this.

Similar issue with a mondeo I know of, when accelerating hard or giving more to go up hill, would go into limp mode... 

Fuel filter replaced, and now using non supermarket diesel and the issue has gone away.

[Tdci-Peter]

2 hours ago, BrettSh said:

they cleaned an air sensor

The most likely sensor for this problem is the MAP (manifold pressure) sensor, as it measures the turbo boost. oil is unlikely to cause a problem with this sensor, it could be wiring or just a faulty sensor.

I hope they checked all the intercooler hoses for leaks, before replacing the intercooler.

Other suspects are the Throttle or Anti-Shudder valve on the air intake, and the turbo actuator, or the turbo itself. But leave that until last!

Does it happen on every hill, and does it do it when accelerating on the flat with similar throttle opening?

If it is only on hills, then a fuel problem like a split hose that is allowing air in, or blocked filter, could also be the cause. The turbo can not spool up & give correct boost if there is not enough fuel. However there is a pressure sensor on the fuel rail, and I would expect that to flag up an error if it was fuel starvation.

A decent diagnostics system like Forscan (or the IDS system that the garage should have), can monitor all these sensors, and help to isolate the problem. Changing bits on a random basis is never a good idea!

 

 

[DJ_Andy_M]

FYI wrong forum. This is the Focus  forum :) 

[Tdci-Peter]

14 hours ago, BrettSh said:

My wife's Fiesta

Don't worry too much about the wrong forum, hardly anyone else seems to! It is pretty much complete chaos

If you want, just PM (message) alexp999, one of the Staff mods, he can move it for you.

And he might have useful info too, you never know!

Peter.

[BrettSh]

Thanks for the replies guys.

It only happens on hills, not when accelerating on the flat.

The dealership told my wife that the intercooler was cracked and also, one of the hoses was split.

I loaded Forscan Lite onto my phone, but that didn't give me any further insights.

Sorry about posting on wrong forum.

Cheers

Brett

[Tdci-Peter]

3 hours ago, BrettSh said:

I loaded Forscan Lite onto my phone, but that didn't give me any further insights.

The PID I would look for first is FRP - Fuel Rail Pressure.

If that drops badly when climbing hills, then air getting into the fuel supply to the pump could be the problem. Or some other fuel blockage.

But I have been looking at the Forscan site, there are reports of difficulties reading this PID. There are lots of reports of problems with WiFi adapters in general.

The MAP (or intake pressure) sensor PID might also be informative, it should rise to about 2.4 Bar abs (240kPa) if the turbo is on full boost.

The preferred adapter type, for reliable connection, is USB (by quite a margin), then bluetooth.

If you are interested, see: http://forscan.org/forum/viewtopic.php?f=6&t=955

A small crack, or small hose leak will not give major power loss. But a small crack can grow (suddenly!), so as well to have replaced it.

It would be difficult and expensive for a garage to do this sort of full power testing. Forscan will run in logging mode, so can be used while driving, without distracting the driver.

[m1tch]

What is the service history like on the car? Could be something like stuck vanes in the turbo, it could also be something like the fuel filter being clogged meaning that when going up a hill the engine is starved of fuel. I would however check all connections and hoses as a first port of call, the 1.6 TDCi turbo is right at the front so its quite easy to get to - pretty much the only good thing about the DV6 engineering.

[DieselPig]

Did the dealer check the cam sensor?  My Mondeo had a similar problem, very hard acceleration or attempting to climb a hill and it would cut out.

£15 sensor fixed it.

[BrettSh]

Still having poblems.

We just got the Fiesta back after it's forth trip to the dealship. I printed out the comments posted here and gave to the Ford guys. They had the Fiesta for 6 days, replaced the MAF sensor and cleaned the MAP sensor again. It seems to have a bit more power, but now the engine warning light is occasionally coming on on flat roads.

Please, does anyone have  other recommendations for the dealership? This is driving me crazy.

Cheers

Brett

[Tdci-Peter]

1 hour ago, BrettSh said:

now the engine warning light is occasionally coming on on flat roads.

Have you got the codes for that?

What did the dealer say when you offered him the advice from here? He probably stuck pins in it, or did something even more unpleasant to it, once you had gone. Most dealers hate this internet advice, for two reasons: Sometimes it is wrong or misleading, and that makes life harder for them. But sometimes it is right, and makes them look foolish, and that makes life even harder still for them!