m50 power loss :(

[Cook318IS]

Coming home from college tonight, revving at about 3k. Put my foot down a bit and absolutely nothing, revs stayed where they were (pretty much). Changed down a gear and put my foot down - nothing until all of a sudden all the power comes back and scares the shit outta me! I left it cruising at the same revs and i could *feel* the power coming on and off. It was fine after that

The car also has a very much on/off feel to the accelerator when the engine is cold. Only really notice it though when the revs are running down, it slowly lowers then will lower really quickly (with a strong jolt its that quickly). The throttle butterfly valve isn't sticky.

I've got a new lambda sat in my living room anyway to go on the car anyway (car is only doing about 18mpg).

Any ideas guys? Car is a facelift 316i with e34 m50b25 non vanos(405 ecu)

[DanThe]

I would say lambda, have you tried the engine with it unplugged? Usually runs much better without a faulty lambda plugged in

[Cook318IS]

That was my initial guess too, but i thought i would post it up incase it isnt. Luckily my brand new lambda arrived yesterday I haven't tried it unplugged yet to be honest, its something that ive wanted to replace anyway.

Cheers dan

[Bob_S]

it'll be your lambda sensor mate, mine did the same

[bumhole]

where is the best (cheapest) place to get a new lambda sensor? Sounds like a good idea to change it? Ta

[Cook318IS]

Depends on what you buy. The oem supplier is bosch iirc. Bosch ones are about £70 each from euro car parts. You can obviously buy other makes for about £35, or a universal one that you solder yourself is about £15.

hth

[booomer]

I have this problem with the M50 in my e34 but it did it the same before and after i fitted a new lambda!
When its warm it doesn't do it though.

[Cook318IS]

Its now running a new lambda but it still struggles to start. I didnt notice the snappy throttle though tonight. It turns over fine, and it starts to fire up but then it'll just keep turning over until it finally starts (if that makes sense )

Car was only serviced about 1.5-2k miles ago with new spark plugs, etc etc. Any ideas what it might be? crank sensor?

[bumhole]

My tranny van had a similar problem to what you are describing and it was the maf sensor. But then it is a Ford and I'm sure it won't be long till something else breaks on it!