Hi all,

There are loads of posts scattered around the depths of forums with this issue on the 1.4 tdci/tdi/hdi engines, but no-one ever comes to a definitive solution. My car has the same issue, and I want to get to the bottom of it once and for all.

2008 Mk 6.5 Fiesta with the 1.4 TDCI engine, starts fine, runs fine, no CEL, no codes.

How to reproduce: Get to an incline on an A-Road, drop to 55-60ish in 5th and put your foot to the floor loading the engine and demanding high fuel flow.

What happens: Engine picks up and begins to accelerate, if held under high load for long enough, SOMETIMES the engine stutters for one 'beat', electrics don't shut off, car doesn't stall, after a fraction of a second all is back to normal, passengers slightly concerned.

What has helped so far:

• Replacing the fuel filter dropped the frequency of this happening
• Driving the car more regularly seems to reduce how often this happens
• Using premium diesel reduced the frequency of this happening
• Having the tank over 1/2 full reduces the frequency of this happening

When I replaced the fuel filter, the engine had the same behaviour at idle while the air was cleared from the fuel lines, you'd see a bubble go through the primer bulb, and then a fraction of a second later that same engine stutter.

So this has me thinking either:

• There's somewhere in the system that pockets of air can get trapped, then on an uphill incline, the change in angle and friction under high fuel flow is enough to dislodge some of this trapped air, and it gets sent into the engine.
• High fuel flow draws more of a vacuum putting more stress on the system, promoting more instantaneous air ingress in high load conditions, same end result.

Has anyone ever managed to actually solve this gremlin, and does anyone have recommendations on how to test what might be leaking, I can't see or smell diesel anywhere south of the fuel filter in the system, so it all looks 'ok'

Very unlikely there’s a leak, if there was then air would get sucked in and the fuel would all just run back down the pipe to the tank and the engine wouldn’t start. These cars don’t have an electric pump they only have the high pressure pump driven by timing belt, this has to suck fuel from the tank. It can’t do that if there is air in there, hence the primer. 

But I don’t have the answer

Ted

apologies for getting to this quite late.

Ours does the same - relatively infrequently, high load situations (typically steeper hills, under acceleration), engine stutters.

I've previously assumed that this was the turbo boost limit being reached and was hitting a momentary "cut" when this happens.

What makes me think it's this is that we had reason to look at the turbo (oil getting into the intake pipe) and we adjusted the wastegate diaphram to dump boost earlier. This stopped the hesitation at the expense of a little less turbo boost.

We decided we'd adjust it back (work around the hesitation) to give the best power that the relatively weak 1.4 diesel could muster.

Because it happened relatively infrequently it was difficult to be absolutely sure, but this was our suspicion.

Dom

i have a thread labeled "1.4 TDCI DuraTorQ Injection/glow plugs loom." i havent linked it still learning the rules of what is and isnt allowed in a post. anyway its more or less how mine was at the start then over time it got worse and worse until eventually it threw up the COG symbol with ! mark in it and went in to limp mode. then and only then could i get any codes to try help. mine were related to open/short circuit on an injector. anyway bottom line of it all to fix mine i had to fit 2 new (2nd hand) injectors and change all of the wiring on the injectors. I dont know if i am right or not but my assumption is that the loom gets damaged and then over time it damages the injectors its running. there's full info on the post i put up with a diagram of how i done it. i need to add more pics to it but havent had time to sort them out. if however you NEED some let me know and i'll make a point of doing it.