Sudden loss of power/accel while driving:

[artguy]

Hey guys...need a little help.

Specs: 1994 530i, 193k miles, auto tranny.

I searched and found some similar situations, but no resolutions.

Here’s my story:

Driving home with the car running normal. Two miles from home...stopped at a stop sign...turned the corner...started down the road going about 40 Mph and suddenly a dramatic loss of power and acceleration. The check engine light came on but it didn't stall. As I pressed the pedal down it would not accelerate above an idle. Fortunately, there was a center turning lane I could get into and I slowly “idle-crawled” to a road I could turn down. Parked it and turned on the flashers.

I shut it off, waited a few seconds and then restarted it. It did start and ran rough at idle. I called a wrecker and he brought us both home.

An hour or so later, I can still start it and it idles rough, but if I give it gas it starts to sputter and die.

I tried to do the pedal diagnostic test from the Bentley to get any fault codes…but I can’t get it to work.

I turned the key on (so all the dash lights come on) then pressed the accelerator to the floor 5 times quickly and then nothing. I did it several times waiting longer each time...nothing. Am I doing something wrong here?

I’m going to try again in the morning. I was hoping to get a fault code to help diagnose.

A) I’m thinking clogged fuel filters?
B) Dying fuel pump (but the car does start and run at idle)?
C) Failing O2 sensor(s)?
D) I will also check all fuses tomorrow in the light.

HELP with the process for getting the fault codes!

Any other ideas are much appreciated!

[Coldaccord]

out of gas?

i guess just put a fuel pres gauge and see whats up

[artguy]

3/4 tank of fuel...I forgot to mention that.

[Macv]

Giving me your 320i will fix the problem.

[shogun]

Do you hear the fuel pump whirring? Is so, that is even not enough, it could not produce pressure. I once had a similar prob, pump was running but pressure too low, when I removed it and tested it I could stop it with putting my thumb slightly on the outlet.
"Poor man's fuel pressure test"
http://bmwe32.masscom.net/sean750/fu...Regulators.htm

[Brandon J]

As said, could be the pump. Try stomping the pedal to the very end even faster a second or 2 after the key is turned. It's a learn by experience technique. You might not get a code relating to the actual problem if it is a pump. The check engine light could jave come up b/c of sensors being affected by a dying pump, like the O2, knock sensors, or voltage.

Only other thing I can think of is a coil going bad and taking the computer with it. Lets hope for the pump. As said, try to hear the pump on the cover in the trunk and ypu can also attach a gauge to the valve along the fuel rail.

Good Luck.