316I E46 1.9 2000 Power Issues

[rorocirca1989]

alright guys,

I bought a 316i E46 back in January for £950 - expecting some work to be done on it obviously. It initially had idling and power problems - the idling was all over the place and made it very easy to drop out and it had no power. After checking and fixing all the vacuum pipes and replacing the MAF the idling problem was solved and now shes steady as a rock at just under 1,000rpm. But now I've noticed a power issue - with the accelerator flat to the floor the car labors but the power is absolutely flat, it struggles to get above 4,000rpm with no power at all. It almost seems easier to ease the power in instead of flooring it. Its intermittent as well, and as far as I can tell might be worse from a cold start.

I've taken it to a few mechanics and they seem pretty confused by it. Although apparently its a common problem with this age and model? (its got the 1895cc engine)

Any help or if anyones got any similar problems would be much appreciated.

cheers,

Rory

[kee1173]

Still sounds like the MAF, did you get a new original bmw one, or secon hand or a pattern part because i had a van with a maf problem, i went thru 3 new pattern part ones in a matter of a month and stil the problem came back, so in the end i put on a original manufacturers one and the problem was solved

[rorocirca1989]

Unfortunately it was a second hand one (due to budget) from my local (but normally trustworthy) scrappy Trents. Were you experiencing power issues too? I thought after the idling problem was sorted that the MAF was decent, but I'll give it a clean and look into a brand spanking new one!

A mechanic also mentioned the throttle positioning sensor could be a duff at one point, would be good to eliminate some potential sources before I fork out for also sorts of bits and pieces!

thanks again

[IanIOM]

Have you had. Diagnostic on it? Could be the cat is getting bunged up

[kee1173]

with my van, i would be driving round the m25 say at 70mph then i would have to slow down for whatever reason but as soonas i put my foot back down the accelorator i had nothing, i would say break from 70mph to say 50 then as i say, foot down and would just about creep up then gradually start lose all power but very slowly , even with the foot flat to the floor, van was still running but revs would not raise at all.

So pulled over stopped van, idling perfect but when i pressed the accelerator not much at all, would slowly creep up to say 3000rpm but a real struggle... managed to get her back to my mechanic and he changed the maf for another one ( this is the 2nd pattern one now) and i drove off fine.... 2 weeks later same thing again, it was sort of like doing 0 to 50 in 15 minutes, Back at mechanics, this time it stayed there he checked everything, everthing fine, checked Maf sensor, it had gone again...so this time he got one from the main dealer (twice the price) fitted it to the van, never had a problem since but yes i had not idling problems with mine but mine was power issues as i say i would have foot flat to the floor and the revs would hardly raise, started out very similar to what your car is doing then over the coming weeks got worse.....but was all down to Maf sensor and my van does nt like pattern parts but my mechanic was saying it is really common on most cars especially with maf sensors that the pattern parts are not so good ( maf sensors) and only seem to perform on original parts....

[kee1173]

As Ian says def worth getting checked as could be something else but all i was trying to say is it just sounds similar to my problem i had which was the MAF an over a month i had 3 of them..

[rorocirca1989]

I did actually get it diagnosed a while ago - throttle position sensor, crank shaft sensor, MAF and a couple others came up, after reseting the system and diagnosing again just the MAF came up - so thats when I changed it with the refurbed second hand one. I thought initially it might be the lambda sensor, but as the exhaust system seemed to come up clean I put it to the back of the list.

I will probably get a new Bosch MAF when I have the money anyway - another thing I've noticed recently is that if I ease the power on and only go to about half way down on the accelerator it seems to pull with all its 105bhp (not a lot admittedly), could that suggest positioning sensor/throttle body problems? another weird symptom it has is if you come off the accelerator pedal quickly, or turn the cruise control off after a stint, the throttle pedal get jammed, and you have to stamp on it to get it moving again!

Bit of a mystery, still don't regret buying the car though.

cheers

[rorocirca1989]

Just as an update - I drove to Oxford at the weekend and on the way back the Engine Management light came on - I hope this might mean when I diagnose it in the week it may come up with something a little more specific to the problem, I will update this thread if I find out anything as apparently its a common problem.

[IanIOM]

Be interesting to hear the results!

[rorocirca1989]

Sorry for the wait - so I had noticed recently that when I turned the ignition to power the rev needle would bounce up and down for awhile then stop when I started the car - then I was driving back from work and it did it again and cut out completely and would not start again!

The RAC came out and used a diagnostic kit and the Oxygen sensor came up along with Throttle positioning - BUT we tested the Oxygen sensor and it all seemed to be reading correctly (It also came up with a secondary fan failure, but that apparently is due to the diagnostics thinking the car had air con).

Had a chat to the RAC man, asked if it could be a busted Cat and he said the car would be running a lot worse.

He recommended looking at the Water Temp sensor along with double checking everything else as a lot of them are closed circuit so if one fails it will revert back to default settings and obviously not run as well. He also tested the battery because of the Rev dial symptom suggested the car was cutting out and reseting itself - so we got a new bat and the dials stop bouncing!

The engine lights back on again and its still running really flat - this car is proving to be a mechanical mystery.