Have been struggling with a 13 year wake up of a 90 325i. Rounded up the usual suspects ICV, O2, CPS etc with no luck. Plugs are still looking rich and cold start up is poor and needs “ foot” help for the first 15 to 20 seconds unlike my 2.9l 86e. The fix revealed itself as a fuel leak. On the 90i there is a short rubber line that connects the hard return line ( body) to the tank. The small bend it had to avoid the fuel filter collapsed to a crimp, which started to leak. It appears the crimp was enough to cause the return line to become pressurized ( the leak shot 2 feet) resulting in the FPR to be unable to dump fuel to the return line to control rail pressure. Once the 4 inch section was replaced startups are good, plugs look normal.
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Last edited by PEZ2; 12-08-2023, 06:21 AM. -
Good job! At least it was cheap parts wise, just some time! -
Oh yes, not a huge surprise- this is why a fuel pressure test is so useful...
I found a return line blocked with sludge that way once...
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now, sometimes I just mess with people. It's more entertaining that way. george gravesComment
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Why was it crimped? Did someone use too long a hose?Comment
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Glad you got it! Wouldn't have expected a damaged return line.
'87 BMW E30 325is Turbo
'99 BMW E36 M3 - - - '98 BMW E36 328iComment
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there was another thread with blocked return line and if you just looked at fuel pressure you may conclude the FPR was faulty so proper diagnosis is key89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...
new build thread http://www.r3vlimited.com/board/showthread.php?t=317505
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