Have to floor for acceleration sometimes

[Bimmerboycam]

I have a 1999 BMW 323i that has undergone a shit ton of work and now it doesn't "punch" like it should when i floor it. I suspect the catalytic converter as I have no codes and the car shifts just fine. Would cataclean help this problem? Would it do any damage to gaskets in my engine? Thanks guys

[MarcoZandrini]

Check the fuel pressure. It needs to be at least 45psi. There's a test valve under the black, plastic cover on the top of the engine. Item #2 is the cap.

http://www.realoem.com/bmw/enUS/show...diagId=13_0900

[Bimmerboycam]

Do I test while running or after warm up?

[Bimmerboycam]

I don't think it would be the fuel pump as I don't notice a drop in gas mileage, any odd sounds, codes, just doesn't accelerate fast sometimes. Do advanced auto parts have a rental tester?

[MarcoZandrini]

Check the pressure after the engine starts. Also, check it while the engine is revving at 3000rpm. The pump may be providing adequate pressure at idle but as the engine's speed increases the volume of gas required goes up linearly. A failing pump may not be able to provide a larger volume of gas at the proper pressure.

If it is the pump, but a Siemens/VDO pump from bmaparts. They have the best price on the pump. Do not install an aftermarket pump as it'll fail in short order. You'll also need:
- fuel pump seal ring
- fuel filter (Mahle or Keyser)
- 1 foot section of fuel hose for a fuel objected engine
- 6 worm clamps for the hose

Why the last 2 items? The live behind a metal panel under the car. They are exposed to all sorts of environment crap. After all these years they are ready for retirement.

The filter is behind a metal plate that's inboard of the chassis rail that runs next to the drivers seat.

[Bimmerboycam]

Check the pressure after the engine starts. Also, check it while the engine is revving at 3000rpm. The pump may be providing adequate pressure at idle but as the engine's speed increases the volume of gas required goes up linearly. A failing pump may not be able to provide a larger volume of gas at the proper pressure.

If it is the pump, but a Siemens/VDO pump from bmaparts. They have the best price on the pump. Do not install an aftermarket pump as it'll fail in short order. You'll also need:
- fuel pump seal ring
- fuel filter (Mahle or Keyser)
- 1 foot section of fuel hose for a fuel objected engine
- 6 worm clamps for the hose

Why the last 2 items? The live behind a metal panel under the car. They are exposed to all sorts of environment crap. After all these years they are ready for retirement.

The filter is behind a metal plate that's inboard of the chassis rail that runs next to the drivers seat.

Thanks so much man! Just finished it up today and it runs beautifully! Very well detailed although I didn't have the money to drop more than 100 bucks so an aftermarket one from Amazon does fine I'll reply to the thread if and when it stops working. 50 bucks for pump and 25 bucks for the filter!

[Critter7r]

Check the pressure after the engine starts. Also, check it while the engine is revving at 3000rpm. The pump may be providing adequate pressure at idle but as the engine's speed increases the volume of gas required goes up linearly. A failing pump may not be able to provide a larger volume of gas at the proper pressure.

If it is the pump, but a Siemens/VDO pump from bmaparts. They have the best price on the pump. Do not install an aftermarket pump as it'll fail in short order. You'll also need:
- fuel pump seal ring
- fuel filter (Mahle or Keyser)
- 1 foot section of fuel hose for a fuel objected engine
- 6 worm clamps for the hose

Why the last 2 items? The live behind a metal panel under the car. They are exposed to all sorts of environment crap. After all these years they are ready for retirement.

The filter is behind a metal plate that's inboard of the chassis rail that runs next to the drivers seat.

FYI, I installed an AutoZone pump at about 130k when the original failed. I'm at 225k now and no fuel pump problems.

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