Guest mck2 Posted June 23, 2003 Share Posted June 23, 2003 I just replaced my suspect 1983 turbo fuel pump with a Walbro 392. The 83 was 36psi at idle, 30 at cruise, and 43 max under 12psi boost. The 392 is 56psi at idle, 57 at cruise, and 43 max under 12psi boost. Yes 43! It decreases as boost increases. At 0 manifold pressure the FP is 50. At +5 thru 12 the FP is 43. I now wonder if the stock injectors are demanding more fuel than the small 240Z fuel lines are able to allow. I have some 3/8" AL tubing I could use for supply and use the old supply as the return? HAs anyone had this problem? Perhaps the old pump was OK? Quote Link to comment Share on other sites More sharing options...
Nigel Posted June 23, 2003 Share Posted June 23, 2003 The stock 240Z 5/16th supply line is ok but the stock return line is way too small . That's why your pressure went up with the high flow pump. The pressure went down under boost because you are effectively bleeding off the excess pressure through the injectors. Definitely use the 3/8 line for the supply and the 5/16th for the return. However, you are also going to have a problem with the fittings on the tank (not to mention the stock tank is not properly baffled for FI applications - assuming you still have the stock tank installed). I would recommend having a sump welded to the bottom of your tank. Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
Guest mck2 Posted June 24, 2003 Share Posted June 24, 2003 Thanks for your reply. I made the changes I described above and the FP is 40 base, 30 cruise, and 50 at 11 boost. Quote Link to comment Share on other sites More sharing options...
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