fuel pump 323i

[mcgyverjr]

I own a 86 323i, fuel injected, europe spec car. Recently the fuel pump started making noise after 5 minutes of driving. I replaced the pump, fuel filter, air filter, some vac lines and all fuel lines under the hood, because of dry rot. The pump still makes a whinning nosie after 5 mins driving. I replaced the pump again with a bosh one (a little quieter). I have also checked the fuel pickup in tank and it looks fine. The noise is still there after 5 mins of driving. A few things to note. I did have bad gas in tank but now corrected. Fuel tank is preasurized when I remove the fuel cap. Car is not worth much so any help would be greatly appriciated.

[mcgyverjr]

I have noticed that when I start the car it runs good for about 1 min then I notice a engine idle change and it surges and chugs untill it warms up. The cold start sensor ohms at 3 ohms when cold and when I check it after a min. it is 2 ohms. I am taking it to the dealer on Monday unless I am missing something obvious.

[mcgyverjr]

Is there no one that can help?

[jeffreyb4me]

thought about this a few minutes and might have an answer. from your desciption and the recent history, i think you might have a sticking 'Fuel Pressure Regulator'. this is the last valve in the line for fuel returning to the tank, when they stick closed, the pump 'dead heads' [max. possible pump pressure], this will cause all the symptoms you've described AND that fact you've experienced a BAD tank of gas makes it even more likely........The Most Common time of year for Fuel Press. Regulator failures is mid to late fall when the fuel blends change for colder weather. the added volitility apparently acts like an extra solvent, 'cleaning' the lines etc... and depositing the 'gunk' in the regultor.
'BAD' gas will do the same for different reasons. A fuel pressure test would confirm this and can take a while for the regulator to 'restick' after opening the lines to install the gauge. IF it acts up, still runs badly or the pumps' still noisy AND the fuel pressure is ok [ 32-40 psi ] then forget my idea here and move on.........................................jb.

[mcgyverjr]

Thank for the reply. As first suspected, it was the fuel preasure regulator. The cost was not worth a guess. Thanks for your help. I know alot more now about the BMW than I wanted too. Can not wait untill I get back to the states and have my chevy again. Thanks Again.