my 91 Q45 dies after replacing fuel pump

[cpoage]

We replaced the fuel pump but now the car starts then dies. Do I need to set the pressure in line? eeeek

[Q45tech]

Did you replace with brand new oem Nissan pump and a working Fuel Pump Control Unit...............new pumps might stress an already failing FPCU.

[cpoage]

eeek no, I dont think so, is that also the regulator?

[maxnix]

Assume you also replaced the filter with OEM one and used a new O ring.

[goody90q45]

We replaced the fuel pump but now the car starts then dies.

Was the engine running before you replaced the FP or has it been down for a while? Any other recent maintnance? How does the connector look on the FPCU? Burned?

[cpoage]

the pump was humming bad and finally went out, no other recent work done. I'm confused where the FPCU is (sorry). I think I'll bring it into the shop for this one.^^ Thank You all so much!

[maxnix]

Look at the FSM. It is on your right under the parcel shelf in the trunk. Trace the pump wires.

Don't do anything until you read the fuel pump posts in IOM and answer our questions please.

[goody90q45]

the pump was humming bad and finally went out, no other recent work done. I'm confused where the FPCU is (sorry). I think I'll bring it into the shop for this one.^^ Thank You all so much!

If you've changed out the fuel pump the hard work is done. Testing the FPCU is easy stuff. The link will take you to a recent thread showing how to ground the fuel pump to check the FPCU. The FPCU is in the background in the pic. Save yourself a couple hundred bucks and do this yourself. Good luck.

zer...18625

[Q451990]

the pump was humming bad and finally went out, no other recent work done. I'm confused where the FPCU is (sorry). I think I'll bring it into the shop for this one.^^ Thank You all so much!

If the noisy pump stopped working, it's more likely that it just stressed the controller too much, rather than technically burning itself out. So you probably need to replace the FPCU (fuel pump control unit). There should be several available in our classifieds, and on eBay. Going price used seems to be about $50-$75, and new is maybe $300?

As the earlier posters said... you can test the pump and replace the controller, and it's much easier than the work you've already done.

Good luck!

Heath

[Q45tech]

For the past 10 years Infiniti dealers have always replaced pump and FPCU as a group because experience has shown that a high percentage have a subsequent failure.

[elwesso]

yeah you're probably looking at a fuel pump controller... Does the pump come on?

FPCU are one of those things that Q owners should have on hand as spares at all times (in trunk---> FPCU, injector, MAF, etc)