Hi guys,

I am wondering if anyone can help me to solve a couple of problems I have with my 52 plate ST170.

Problem 1:

Fuel Gauge - This does not display the correct reading. For example, on a full tank of fuel the gauge will display as full. However it will stay on full for a long time until it will start moving to 3/4 then 1/2. Between 1/4 and 1/2 tank on the gauge means that the tank is empty (the gauge does not move past 1/4 tank even when the tank is totally empty and the car will not start, the fuel low light does not come on either).

I have been told that Focus dash panels can become faulty as confirmed by Ford, who will replace them under warranty. All instruments/ gauges on my dash appear to work correctly, apart from the fuel gauge. Could this be the offending item?

I suspect that it could also be the fuel sender unit, which maybe sticking, thus sending an incorrect reading to the gauge?

Could it be something else electrical?

Problem 2:

Occasionally when driving the engine will begin to surge/ fluff when accelerating (sometimes it can jerk the car like I have hit the rev limiter and drop power until I change gear) usually it is only fluffy and I simply change gear. This usually happens at around 4,500RPM. Although recently it has started happening at 3,000RPM, but since filling the tank and adding either STP or REDX injector cleaner the problem either goes away or isn’t as bad.

I guess this could be one of many things:

Dirty fuel – although I only full up at Shell stations (one of 2 in my area)

Faulty fuel injector

Blocked fuel filter

ECU / Electrical

Faulty fuel pickup

Fuel filter

I think my best bet would be to get it into Ford or some type of performance specialist so that they can run some diagnostics. I am just looking for some clues if anyone has had a similar problem, so if you could give me a heads for what it could possibly be, that would be appreciated!

Cheers,

Jamie

Hi Jamie,

As for your problem 1, I can't help, perhaps it is a faulty/poorly calibrated sendor unit - but im only guessing.

But for problem 2, I have this same problem.

I have had the car for over 18months and this summer it developed the issue, engine light came on. I took it to a local garage and the fault code was the MAF sensor, so they ran an air leak test, checked it over and replaced the Lambda. The car seemed to feel good again, but every now and again it'd stutter on acceleration asif I was taking my foot off and back on the throttle when I had the pedal buried.

This has now got worse, and it always does it. If I drive conservatively then the car is smooth. If I try to accelerate at low revs it is fine until the revs reach around 4000rpm approx then it is like I have hit a rev limiter, although if I keep foot buried the revs will climb - not pretty though. If I am on the motorway in 6th, at 70mph I can't accelerate to 80mph with foot buried, only at mid throttle, but from 80mph it will only perhaps accelerate to 85mph, no more, just feels like its hit a limiter.

But this time, there is no ECU fault codes.

The car is serviced regular anyway, but it has just been serviced - oil, oil filter, air filter. It is on a standard ECU map, has standard paper filter in which has been replaced during a recent service.

Have also now replaced leads, plugs, Crank shaft sensor, coil pack.

Driven with MAF unplugged = no change. Driven with Lambda unplugged = no change. No air leaks, the valve thing is functioning, exhaust note is normal - no blockage at cat etc.

I am really at the end of my patience, it has been doing this for over a month now and it can;t be diagnosed. I took the car to Tony McQuire at Pumaspeed (very helpful, recommend to anyone) who also cannot diagnose it easily. It is currently in garage at home and will do whatever it takes to solve this.

Any ideas, advice, suggestions, please come forward. I'll appreciate it, try it and respond.

Chris

Hi Jamie,

As for your problem 1, I can't help, perhaps it is a faulty/poorly calibrated sendor unit - but im only guessing.

But for problem 2, I have this same problem.

I have had the car for over 18months and this summer it developed the issue, engine light came on. I took it to a local garage and the fault code was the MAF sensor, so they ran an air leak test, checked it over and replaced the Lambda. The car seemed to feel good again, but every now and again it'd stutter on acceleration asif I was taking my foot off and back on the throttle when I had the pedal buried.

This has now got worse, and it always does it. If I drive conservatively then the car is smooth. If I try to accelerate at low revs it is fine until the revs reach around 4000rpm approx then it is like I have hit a rev limiter, although if I keep foot buried the revs will climb - not pretty though. If I am on the motorway in 6th, at 70mph I can't accelerate to 80mph with foot buried, only at mid throttle, but from 80mph it will only perhaps accelerate to 85mph, no more, just feels like its hit a limiter.

But this time, there is no ECU fault codes.

The car is serviced regular anyway, but it has just been serviced - oil, oil filter, air filter. It is on a standard ECU map, has standard paper filter in which has been replaced during a recent service.

Have also now replaced leads, plugs, Crank shaft sensor, coil pack.

Driven with MAF unplugged = no change. Driven with Lambda unplugged = no change. No air leaks, the valve thing is functioning, exhaust note is normal - no blockage at cat etc.

I am really at the end of my patience, it has been doing this for over a month now and it can;t be diagnosed. I took the car to Tony McQuire at Pumaspeed (very helpful, recommend to anyone) who also cannot diagnose it easily. It is currently in garage at home and will do whatever it takes to solve this.

Any ideas, advice, suggestions, please come forward. I'll appreciate it, try it and respond.

Chris

Hey i joined this fourm because i was having the same kind of problems as problem 2.

i have read your problem and have been struggling to find an answer to the above its driving me crazy.

the more i think about it the more it points to the fuel pump as all the mechanics seem to be sound.

i re-set my ECU and the car drove without any shuddering the only indications were at 120-125 mph range so at least the annoying power drawback has gone when at 3000 rpm. However i think this will only be temporary and in no time ill be back to where i was.

i would appreciate it if you could give me an update to how you are getting on with this problem as its not the easiest to diagnose

Cheers Michael

The same problem has happend to mine recently. Iv read if you keep.fuel above half a tank it helps but wont stop it from.cutting out. Had mine put on a computer today to.find out it's the fuel.sender unit inside the tank so ordered up 1 from.ebay as cheep.if it last a little while il know to buy new but at least il know exactly what to change. Hope this helps 

Welcome to the forum,I commend your eagerness to share your experience and help others on a 10 year old thread👍