Hesitation / Throttle Response spotty - Bad Fuel Filter?

[6SPD]

Issue continues to persist when engine is cold. I can feel the engine not getting enough fuel when driving it and all the sudden it will come to life out of now where and will drive normally. Best way I can describe the issue after observing it off and on now.

Any more ideas with this newer description?

Fuel pump or tps?

[ParsedOut]

I'm finding out the hard way, that engine management issues can resemble fueling issues. I miss the good ol' carb days...

It's really impossible to say what it could be. The Bentley has testing procedures for all of the management sensors, I'd start there. Then get a fuel pressure gauge and see what it shows when you get the cutoff. Keep in mind the Bentley test for the AFM is flawed...

[Quadrajet]

The cold start injector could be non operational, or the Engine temp switch not working or reading correctly.

[6SPD]

Stopped by E30 Motorwerks last thursday to check up on some parts that are going into an engine build for me and explained the issue to Robert.

He lent me a known working AFM and Fuel Pump straight from a spec e30 car.

Swapped both of them in and to my dismay, they aren't the root of the issue.

[6SPD]

Measured the fuel pressure today at idle and ran the car on the street for 30 minutes with the gauge installed.

At a cold idle it metered at 30PSI
At a warm idle it metered at a little more than 25PSI
On throttle it metered around 35PSI and didn't move when the issue occurred or left. It stayed at constant pressure until throttle input was removed.

Going to try and clean my throttle position sensor next.

Any ideas, I believe the test that I've just ran eliminates fuel system issues, is that true?

Thanks,

D

[Vtec?lol]

Check your engine temp sensor.

[6SPD]

Check your engine temp sensor.

Which sensor exactly is it, the coolant sensor? What is the best way to go about testing it?

[6SPD]

Ok. So far I've swapped my AFM, Fuel Filter, Fuel Pump, Engine Temp Sensor, and the just finished swapping the Throttle Position Sensor. The issue is still there.

I have several ECU's that I may swap out if that may be the issue, just in case. I've noticed my fuel pump before and after swapping makes an audible noise if you were to stand near the rear portion of the vehicle, is this normal?

The only two things left that have been suggested are the fuel pump relay and the ECU. The issue comes and goes in an unrecognizable pattern, does anyone have any additional ideas or thoughts. I'm currently at a loss and just want to plant my foot for the next month before my stroker gets swapped in.

Cheers peoples,

D

[Tom.]

I'm having the same issue, except eventually my car quits starting altogether after bogging in and out for a while. I've replaced similar parts as you have too. I think my problem might be my non-OEM CPS (crank pos. sensor)?

[6SPD]

I'm having the same issue, except eventually my car quits starting altogether after bogging in and out for a while. I've replaced similar parts as you have too. I think my problem might be my non-OEM CPS (crank pos. sensor)?

Spoke with a mechanic this weekend, he recommended changing out the ignition wires. I figured I'd just order an ignition system kit and swap it all out for good measure (coil, plugs, wires, cap, rotor).

[SlamedIAm]

This isn't a common cause for your symptoms but I had a mystery bogging situation that ended up being a terribly corroded engine ground from the pan to the chassis.

[Holland]

I am having the same issues with my M10. I have replaced pretty much everything you have replaced, and am pretty much at the same stage as you. let me know what you find.

[6SPD]

Just installed a new rotor, cap, bmw performance wires, and coil...

Ran nice and smooth, but still looses power while driving from time to time. It doesn't seem to be as bad but is definitely not fixed.

Like previously stated the car looses power while accelerating or looses it's ability to fully accelerate almost as if it's only getting 5% throttle input. It's feels like a kinked garden hose, when it becomes unkinked it's all there with full acceleration.

I'm just about to give up on this until I have the whole engine swapped in a month at E30Motorwerks.

[Tom.]

I'm having the same issue, except eventually my car quits starting altogether after bogging in and out for a while. I've replaced similar parts as you have too. I think my problem might be my non-OEM CPS (crank pos. sensor)?

Just installed a new rotor, cap, bmw performance wires, and coil...

Ran nice and smooth, but still looses power while driving from time to time. It doesn't seem to be as bad but is definitely not fixed.

Like previously stated the car looses power while accelerating or looses it's ability to fully accelerate almost as if it's only getting 5% throttle input. It's feels like a kinked garden hose, when it becomes unkinked it's all there with full acceleration.

I'm just about to give up on this until I have the whole engine swapped in a month at E30Motorwerks.

I replaced my CPS and my issue went away.

[Chilezen]

I'm having this issue too.. was there ever a distinct verdict to this unusual problem?