Blowing my Fuel Pump Relay repeatedly - Any Ideas? Thanks! | FerrariChat
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Blowing my Fuel Pump Relay repeatedly - Any Ideas? Thanks!

Discussion in 'Mondial' started by paulchua, Feb 3, 2014.

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  1. paulchua

    paulchua Cat Herder
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    #1 paulchua, Feb 3, 2014
    So a recurring problem (that I've erroneously believed was fixed many times in the past) is my fuel pump relay (I believe behind the trunk liner in the back) keeps on blowing, making my car run only on 4 cylinders.

    This happened again to me last Friday while I was revving the engine and I had to embarrassingly tow the car back home with my buddy.
    Anybody ever run into this problem and have any ideas?

    Huge thanks in advance gents.

    Cheers
     
  2. porphy

    porphy Formula 3
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    Randall Gatz
    #2 porphy, Feb 3, 2014
    You must check the wiring to the fuel pumps as well as the wiring to the fuses for those relays. There was a similar thread several years ago with the same problem. Turned out to be a power wire to the fuel pumps with bad insulation in a spot shorting to ground under the chassis pan cover.
     
  3. paulchua

    paulchua Cat Herder
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    #3 paulchua, Feb 3, 2014
    Thanks Porphy,

    You know this is the third time the relay broke (does anybody know the exact one behind the trunk panel?) The first time, the mechanic just replaced the relay, the second time the mechanic did take off the bottom tray and said it was a short, they supposedly fixed it – I’m going to jack up the car and try to find this bad boy and fix it myself. If anybody has any other thoughts or suggestions – much appreciated in advance.

    Cheers
     
  4. porphy

    porphy Formula 3
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    #4 porphy, Feb 3, 2014
    You should also check the fuses and their wires next to the relay, one of my fuses was broken and causing lots of difficult to diagnose problems, i.e. shutdown of one bank.
     
  5. paulchua

    paulchua Cat Herder
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    #5 paulchua, Feb 10, 2014
    Thanks Porphy, just like you said – bad fuse! The car is back in business, I opened up the back panel in the rear trunk area. On the right side, there is a 7.5 fuse that was burned out. I’m thinking that my battery was weak and it caused it to blow. I can’t think of any other reason at this point on why it might have blown. Huge thanks buddy.

    Cheers
     
  6. porphy

    porphy Formula 3
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    #6 porphy, Feb 10, 2014
    Glad to be of service. Those fuses are carrying about 5 amps and any extraneous strain will cause the fuses to blow. Keep an eye on the fuses just in case the fuel pump on that side is increasing the current draw because its wearing.
     
  7. paulchua

    paulchua Cat Herder
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    #7 paulchua, Feb 10, 2014
    Thanks Randall,

    Very much appreciated - I'm assuming fuel pump replacement is not an easy job?

    Take Care
     
  8. porphy

    porphy Formula 3
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    #8 porphy, Feb 10, 2014
    Relative to other jobs, it is relatively easy. The painful part is draining the fuel tanks. The fuel splashes into the receptacle and its not pleasant. There may be better ways to empty it than my primitive approach. MY gas tank gauge was under a quarter tank and I got 10 gallons out. After that it is easy. A few small bolts and it drops right out. I got my fuel pumps from online for about $100 each. Once you get the pumps out there is a great thread from Ernie about what you need to do. http://www.ferrarichat.com/forum/technical-q/224988-348-fuel-pump-rebuild.html#post138263272

    You can get new o-rings from:Size Cross Reference I think I got Viton o-rings based on Ernie's thread.

    Its really not so bad.
     
  9. yelcab

    yelcab F1 World Champ
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    #9 yelcab, Feb 10, 2014
    You buy a cheap transfer syphon pump from HF for five bucks, and use that to transfer the fuel to a waiting 5 gallon plastic gas can. Stop when it is full, dump it into your other daily driver because all Ferrari owners must have a daily driver. Then come back for the rest of the gas from the Mondial.
     
  10. paulchua

    paulchua Cat Herder
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    #10 paulchua, Feb 11, 2014
    thanks gents - as always - you have my gratitude for the awesome info!
     
  11. porphy

    porphy Formula 3
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    #11 porphy, Feb 11, 2014
    You are right Mitchell, as I said, this was a primitive approach. I bought the syphon pump AFTER I emptied the tank! At least I'm ready for the next time.
     
  12. paulchua

    paulchua Cat Herder
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    #12 paulchua, Feb 20, 2014
    Hi guys, I'm pretty sure the fuse is blowing because spikes in power caused by bad alternator - I've noticed the battery is not charging..... Going to pull it out - rebuilt it and get a yellow top battery - from research the two must be done in tandem as the bad alternator pretty much craps out the battery and vice versa....
     

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