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1990 Dodge Ram Van B250 Question: No fuel flow to throttle body

 

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Visitor, 5.9L V8, Giltner, NE, March 22, 2011, 20:41

I have no power to the green wire on passenger side under rear bumper with ignition on. Should there be constant power there or just a pulse until key is in cranking position? Also, can pump relay on firewall be replaced with a standard automotive relay? I see the stock relay has no connector in the middle position as on a standard relay. Lastly, there is an empty gray relay socket near the center of the firewall. Before knowing the location of the fuel pump relay, I plugged a standard relay into it--could this have fried the fuel pump relay, fuel pump, or another component that would cause no fuel to get to the throttle body?

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  • Answer #1

    patrick mannion from Greg Solow's Engine Room, March 22, 2011, 23:19
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    Don't swap relays, even if the pins physically fit in the socket, some relays are naturally open some are naturally close and pin configuration may be similar but the internals can be wired differently. I wish I had time tonight to research your question. I can only right now direct you to information that may be useful. Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info.
    and get an online repair manual subscription. There is a company that independent auto repair shops buy their information from that the same information inexpensively to do it yourselfers. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online
    I like Alldata, it has good explanations of the theory of how things work.

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    Visitor, March 23, 2011, 09:28

    Thank you for the response. I did register at Auto Zone, and it does have alot of helpful information, but no real details about the relays. They talk about testing the injector harnesses on the throttle body for voltage, and there it states that the fuel pump will run for just a few seconds when the ignition is turned on, and then the ECM ungrounds the pump until cranking and/or engine is running. I was testing by myself so I couldn't check for voltage when cranking, but if the ECM disconnects ground, perhaps the power is hot all the time with ignition on, and if not then that would indicate a bad fuel pump relay. I will check the power and ground with some helping hands and if that all checks out then I will know the pump is bad. I would love to get the Alldata subscription for the van and another vehicle but I am scraping pennies as it is for the parts I will need at this time. I have used Alldata when working for a repair shop as a service writer/biller and their info is very thorough, so once I am back to normal financially I think I will definitely make that investment.

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