[huckers01]

Hello all, bit of a newbie here in search of help! I have a 1998 323i se auto that has developed a severe loss of power / torque when travelling at speed. When cruising in top gear at anything over 50 - 60mph+ there is no power or acceleration when I press the accelerator pedal, just the sound of the air intake sucking in air, it will only accelerate if i push the pedal hard enough to force it to down shift, (kick down).
From a standing start the car still pulls very hard and accelerates very quickly. Ive had a diagnostic test done, all ok, no sensors faulty, no codes, no dash lights! Full gearbox service, new cat converter.
The accelerator pedal does seem a little stiffer than it used to before this fault was apparent, but the cable seems to be free enough.
Fuel economy has also dropped dramatically, and when I take my foot off the gas altogether the engine braking is quite severe! Any help or advise on what to look at would be greatly appreciated. Thanks guys.

 

[billywhizz1984]

No luck on BMW Land?

Do you feel this is a power issue or the auto box failing to respond? Did this just suddenly happen or was it after work on the car? What equipment was used to do the code checks? Do you have an induction kit fitted? What happens when you disconnect the MAF?

A few items to ponder....

 

[huckers01]

No luck at all over there!
The gearbox people said it was fine at the service, didn't find any problems with it at least.
Issue just happened, literally while I was in Tesco's! Got back in to drive home and it was just different!
I had the diagnosis done at a local fuel specialist place, albeit not a BMW specialist, the only code they found was MAF, thats because I had previously disconnected it to eliminate it as the cause. MAF disconnected, ran like a bag of spanners! No induction kit fitted, all completely standard.
It seems worse when warmed up, it also takes ages to get to temperature, 25 miles down the M1 each morning and still not warmed up, so obvious to look at thermo, could it be related?

 

[pantzer]

Yes, it can be your thermastat causing the poor fuel. Not sure if it can cause the power issues though.

 

[TheEnd]

What's the idle like?
Have you changed tyres sizes recently?

Can you see the revs drop as it gets into 5th gear?

 

[huckers01]

The idle is nice, no lumps at all,
New tyres on the rear, like for like size,
Goes well through all the gears, can feel it drop into 5th ok, really pulls well through the gears until I try and cruise at 60 or 70, when i do kick down a gear it still really struggles to speed up, the plugs all look good, not lean or rich running so ruled out fuel starvation, new air filter, CAT, brakes and suspension all four corners.

 

[billywhizz1984]

Regardless of anything else you need to sort the thermostat, the car will be overfuelling until it gets to temp.

More questions...
Have you tried putting it in 4th instead of "D" to see if it pulls ok at cruise speeds?
What happens when you put it in Sport mode?
What is the mileage?
Have you checked the engine to chassis earth?
Does the car have ASC?

 

[huckers01]

Thermostat first, agreed!
Good questions,
Have put it 4th on the Motorway, just revs higher no torque,
sport mode just makes it drop down the gears quicker, doesn't pull any harder,
120K miles, car has got ASC,
not checked the earth.

 

[swaynie]

so this loss of power suddenly started aftewr filling up at a tescos??

could be mucky fuel thats go through a clogging soemthing up throw some nitro injector cleaner through or redex and give it a good blast

 

[huckers01]

Hi, thanks for all your comments, quick update.
Have spent the morning poking around the air intake and throttle body area and found a substantial tear in the hose between the MAF and throttle body! Could this be my nemesis?? have patched with silicone sealant for now and will test for results on the way to work tomorrow!

 

[steph323i]

Can't say for sure if that's the cause of your specific problem but it can't have been helping.

Keep us posted on how the car feels after your repair.

 

[xXxStKxXx]

Hi, thanks for all your comments, quick update.
Have spent the morning poking around the air intake and throttle body area and found a substantial tear in the hose between the MAF and throttle body! Could this be my nemesis??

Yes...

 

[Ferret]

Hi, thanks for all your comments, quick update.
Have spent the morning poking around the air intake and throttle body area and found a substantial tear in the hose between the MAF and throttle body! Could this be my nemesis?? have patched with silicone sealant for now and will test for results on the way to work tomorrow!

There's ya problem !

And you say that your idle was fine ?

 

[huckers01]

Idle never been a problem, ticks lovely at 600 ish rpm.
Have given it a good run out to work and back today, fuel economy definitely better although not really hammered it,
power seems better but not how it used to be, have sprayed all around the air intake system with carb cleaner and idle speed doesn't alter.
Will test for fuel economy over a (gulp £££) full tank of petrol!
Thanks again every one.
Dave