What's the drill (and potential consequences) for in tank pump noise?
Of course we changed the fuel pressure regulator to note no performance difference or pump quieting. Changed the external pump, which I do believe was making noise, to note no performance difference, and the in tank pump making noise. Probably a duet before.
Starts six or more revolutions after sitting one day. (Have to wait 'til tomorrow to check again). Until up to temp, doesn't like accelerating, stumbles, and it trailer hitches. Gas pedal is springy, bouncy.
I swear it's timed right, no vacuum leaks, combo relay must be o.k., no suction noise removing gas cap ( vent hose plugged ? ) The idle cut off switch clicks off at the last possible instant. As I believe they are only on/off, it is working.
In tank fuel pump noise.
There is a fine nylon screen mesh attached to the bottom of the in-tank assembly which must be periodically cleaned, per the owner's manual. It keeps tank crud from entering the fuel system and does a remarkable job to the point of taxing the tiny motor into failure if not maintained. That's what that 'whining sound' from the rear is when you're in the cabin. Since it has been discussed here ad nauseum on the in-tank's relative importance with respect to the entire fuel system, I doubt that would have an impact on your overall complaint.
I would hazard to guess your engine is running lean while cold and during warmup, causing the drivability problems you describe. Your AFM setup could be off, your coolant temp. sensor could be bad, the wiring, connectors and ground all affect the signal sent to the ECU in the glovebox. And, of course, valve settings, timing, all the basics.
I have mentioned before the yellow Bosch booklet on L-jet that describes in complete detail the function, components, and wiring of the system is invaluable. I highly recommend digesting this system engineering information to understand the practice in real life.
Another couple of many pics:
I would hazard to guess your engine is running lean while cold and during warmup, causing the drivability problems you describe. Your AFM setup could be off, your coolant temp. sensor could be bad, the wiring, connectors and ground all affect the signal sent to the ECU in the glovebox. And, of course, valve settings, timing, all the basics.
I have mentioned before the yellow Bosch booklet on L-jet that describes in complete detail the function, components, and wiring of the system is invaluable. I highly recommend digesting this system engineering information to understand the practice in real life.
Another couple of many pics:
HTH
'80 528i
'80 528i
Many thanks. As my '79 driver is running great ( wood knock, knock ), next is screen clean, temp sensor, then AFM switch out.
On one hand the e12, M30 seems so simple and reliable I think I'm getting good. Only to find out the last ten points to be an expert come hard. To run great, everything under the bonnet has got to be doing exactly what it should. Sounds obvious, but I'll bet even when I find, fix the component to say," A Ha!," it may not have been just that one single thing.
Maybe I'm lucky to find it fascinating, how a fuel pressure regulator works and why, etc. Still, I wouldn't want to do it for a living. To much knowledge and hard dirty work for cheap ingrates.
On one hand the e12, M30 seems so simple and reliable I think I'm getting good. Only to find out the last ten points to be an expert come hard. To run great, everything under the bonnet has got to be doing exactly what it should. Sounds obvious, but I'll bet even when I find, fix the component to say," A Ha!," it may not have been just that one single thing.
Maybe I'm lucky to find it fascinating, how a fuel pressure regulator works and why, etc. Still, I wouldn't want to do it for a living. To much knowledge and hard dirty work for cheap ingrates.
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Brian Smith
- Posts: 85
- Joined: Tue Jan 06, 2009 9:12 pm
a crazy coincidence to check
This one bothers me, which says more about me than the bother.
I noticed my fuel pump occasionally sounding louder.
It was louder than the pump in my e28, so I figured that either the pump must be different, or my e12 pump was failing or strained.
The pumps seem to be the same stuff, no clues there, but then I encountered the noise with the lights on, driving at night, fluctuating.
I noticed the coincidence that my dash lights would slightly brighten in concert with the occasional increase in pump noise.
Without even a voltmeter check, I feel certain that my pump noise is being caused by a voltage regulator problem in the alternator. If I hadn't had the lights on to notice the voltage fluctuation at idle (or the wipers, or blower motor, they would show it, too) I would never have guessed fluctuating voltage, since the idle smoothness and speed never varied.
Perhaps if your pump noise is not independent of voltage, especially if it comes and goes, yours may be voltage related, too?
I noticed my fuel pump occasionally sounding louder.
It was louder than the pump in my e28, so I figured that either the pump must be different, or my e12 pump was failing or strained.
The pumps seem to be the same stuff, no clues there, but then I encountered the noise with the lights on, driving at night, fluctuating.
I noticed the coincidence that my dash lights would slightly brighten in concert with the occasional increase in pump noise.
Without even a voltmeter check, I feel certain that my pump noise is being caused by a voltage regulator problem in the alternator. If I hadn't had the lights on to notice the voltage fluctuation at idle (or the wipers, or blower motor, they would show it, too) I would never have guessed fluctuating voltage, since the idle smoothness and speed never varied.
Perhaps if your pump noise is not independent of voltage, especially if it comes and goes, yours may be voltage related, too?
Last edited by Brian Smith on Thu Oct 22, 2009 10:29 pm, edited 1 time in total.
We are talking about the in-tank pump, for clarification.
Whining noise, most noticable inside a quiet cabin, means the pump is straining to operate, usually caused by a dirty screen. I have removed the assembly from the tank, cleaned the screen (carefully, soap and water, gently scrubbing the crud from the screen without damaging it - blow or air dry) and replaced the assembly (with the old gasket, it's rather robust but the manuals always call for replacement for safety reasons) to quiet a noisy in-tank pump. I now do it as a maintenance procedure as the owner's manual indicates before there is noise (and I replace the gasket).
Previous discussion here indicates a failure of the in-tank pump may only affect performance when the fuel is below 1/4 tank.
Whining noise, most noticable inside a quiet cabin, means the pump is straining to operate, usually caused by a dirty screen. I have removed the assembly from the tank, cleaned the screen (carefully, soap and water, gently scrubbing the crud from the screen without damaging it - blow or air dry) and replaced the assembly (with the old gasket, it's rather robust but the manuals always call for replacement for safety reasons) to quiet a noisy in-tank pump. I now do it as a maintenance procedure as the owner's manual indicates before there is noise (and I replace the gasket).
Previous discussion here indicates a failure of the in-tank pump may only affect performance when the fuel is below 1/4 tank.
HTH
'80 528i
'80 528i