Hi all.

My 09 TDV8 has a very intermittent misfire or fuel starvation problem. I've had the fuel filter changed and codes read a while back, I think it came up as a pressure drop in the fuel supply system.

The symptom annoyingly only occurs on Haldon Hill on the A38, one of the steepest dual carriageways in the country heading South in Devon and always precisely at the same point on the hill which is at about 7/8ths of the way up, almost at the top.

It will manifest in two ways;

(Road speed around 55-60mph and roughly 2500rpm).

1. Reduced engine performance dash display as well as hearing what sounds like a misfire. If I stop, switch off and back on again the problem goes away.

2. Lots of warning lights and chimes and engine cuts out. Once stopped, ignition off and re starting clears the issue.

I've been to my indy and we've tried to replicate the fault but try as we might, it just does not happen anywhere else on the planet.
Any ideas as the last time it happened was a bit scary as the whole family were on board and we were in the outside lane overtaking trucks.
Avoiding the hill is not an option either

Thanks in advance.

Graham

I know of something similar years ago in a Jag, turned out to be sludge in the tank restricting the fuel at the pick up. It only manifested itself on the steepest hill in town as all the sludge slid back to one place. Would it be worth checking all fuel lines and filters. 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Sounds like the problem I had which was a crack in the plastic inlet manifold, it only shows up when the engine is under load, in my case when accelerating up a long stretch on a constant incline.

I eventually found the issue by pressurising the manifold, see my YouTube video.

&t=5s

Hi iforland.

I've had the inlet manifolds replaced a year ago as one had a slight oil leak.

There are plenty of steep hills with which I can put it under load but, none manage to induce the aforementioned symptoms.
The air leak on your video is really loud and I would definitely notice that.

It feels like a blockage in there somewhere but very odd its only shows up on the one hill!

Thanks

G

Brit Plumber wrote:

I know of something similar years ago in a Jag, turned out to be sludge in the tank restricting the fuel at the pick up. It only manifested itself on the steepest hill in town as all the sludge slid back to one place. Would it be worth checking all fuel lines and filters.

An odd question, perhaps, but does it do it at other speeds or engine revs on that hill? That is to say, if you went at 65mph would it do it? If you lugged up at 2000rpm or 3000rpm would it still do it? If you can drive around the problem in this way and it only happens in that situation, then maybe you'd be better off saving your money for other issues. Just a thought. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Hi RRSTDV8.

I've not experienced the problem at any other speeds despite trying to make it happen.

The road in question is a dual carriageway and steep, the inside lane is used by trucks lumbering up but I will certainly try ascending it at say a steady 50mph and see what happens.

The first time it occurred it sounded like it was a petrol engine misfiring accompanied by a reduction in power, this was also the case for the second occurrence.
The third time was more scary as we were in the outside lane overtaking and the dash lit up, warning chimes, engine cut out and suspension lowered. On such a steep hill, you very quickly loose momentum and I managed to drift over to the left and onto the verge, squeezing in between the trucks.

The read out said "low fuel pressure"which in turn would cause the reduced engine power message to prevent any damage to the fuel pump.
If it was sludge in the tank I would have reasonably expected it to happen at other speeds and road conditions.
The only thing I can think is that a slight extra demand towards the top of the hill induces a temporary partial blockage due to the extra flow.
I wouldn't mind but it's not like I've got it at +3500rpm and dropping through the gears.

Puzzling!

G

The aforementioned misfire was finally traced to a faulty injector on cylinder number 6. It finally packed up and had to be replaced curing the odd symptoms mentioned at the beginning of the post.

I think it had been only partially operational / tired throughout the time of my ownership as the power and smoothness of the engine is now markedly increased.

Gone also is a slight blue smokiness from the engine when cold from the left hand tail pipe which I subsequently found out was a symptom of a failing injector.

Mpg has also improved slightly too.

Glad to have finally gotten to the bottom of the problem.

Happy New Year!

Great that you have sorted the problem and well done for posting about the solution, it will assist others greatly should they suffer the same

Interesting that you mention the slight blue haze from one exhaust pipe. I remember mine did this for a while. Had an injector changed but I never had any of the performance symptoms you'd mentioned originally. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed