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Fuel Pump relay is hot when car is running?

Discussion in 'Technical Q&A' started by 308GTS, Jan 15, 2004.

  1. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    My fuel pump relay is quite hot when the car is running. Is this a sign of a problem with the fuel pump or just the relay. Thanks.
     
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  3. Darolls

    Darolls F1 Veteran
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    Jul 2, 2003
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    Sparky
    Normal, they do get quite warm.
     
  4. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    I highly recommed checking the old F-chat archives first for your questions, there are a number of threads on the fuel pump relay. There are also threads on installing the throttle cable too. :)
     
  5. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    Dave in the time you took to write this you could have answered normal or not. JMHO. Not going to argue archives with you but to be honest they don't always work the way they are suppose to. Just looked and didn't see the answer to either question. Anyway, let me know if you find something in the archives. If so, email it to me.
     
  6. rivee

    rivee F1 Rookie

    Jan 20, 2002
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    308GTS,

    How did you notice it was hot?
    Did you just happen to feel it?
     
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  8. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    Hey Rivee its Richelson with my new name 308GTS. I was in the fuse panel just checking it out and touched it. It was pretty hot. Not sure if it is normal or not. It was hotter than I would think it should be though.
     
  9. rivee

    rivee F1 Rookie

    Jan 20, 2002
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    Hey Richelson, I have never felt the relays while the ignition is on so can't help you. They do conduct electricity so I would imagine they would get a tad warm at times.

    rivee
     
  10. jselevan

    jselevan Formula 3
    Rossa Subscribed

    Nov 2, 2003
    1,854
    308GTS - I have a bit of experience with this issue. I wrote a piece on F-Chat concerning heat eminating from the fuel pump fuse block in the Boxer. I suspect the same situation exists in all F-cars of similar vintage.

    First, it is normal for the relay to be barely warm. It is not normal for it to be hot. Second, I would touch the fuse suppling the fuel pump to see if it is hot. I suspect that you will find the same issue.

    The culprit is likely the contact resistance between the male and female tabs that the relay plugs into, and the contact resistance of the fuse in its holder and the male-female tab of the wire connecting to the fuse block. I suggest that you remove the relay, and use sandpaper or a dremel with a copper-brush wheel to clean the male tabs. Try to run sandpaper in the female side of the tab, and gently pinch the female side tighter with needle nose pliers. Clean the fuse ends, the fuse holder where the contact is made, and the tabs. Also, many of the fuse blocks have a copper-bus-bar that is riveted to each fuse holder. These rivets become loose, increasing contact resistance and heat.

    Careful attention to the contact resistance will significantly lower the I-squared-Resistance loses (the toaster effect). If, after cleaning these tabs and tightening all female connectors around the male tab, you still have a hot relay, then the problem is likely in the relay itself. If you are adventurous, you can carefully pry open the relay container, and clean the relay contacts using the same technique.

    Finally, a tired fuel pump may cause excessive current draw, but the failure mode for pumps is usually catastrophic, not gradual. If the pump suddenly draws large current, the fuse will open protecting the circuit. I would look to the pump as a last resort.

    Jim S.
     
  11. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    Thanks Jim. I will try all of these. Also I think there might be another relay similar to this one in the box that I could swap out after I cleaned all of the contacts. Thanks Again for the help and hopefully this will do the trick.
     
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  13. Newman

    Newman F1 World Champ
    Professional Ferrari Technician Consultant Owner

    Dec 26, 2001
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    Newman
    You'll notice the relay block is hung on two pins, I would simply lift it up to unhook it,(you dont have to unplug anything) turn it around and inspect the back of the plastic block, you may find scary stuff. I did on mine.
     
  14. f355spider

    f355spider F1 World Champ
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    I'm not offended in the least, but I do believe you are being a little lazy to not check first. I didn't recall the answer, but knew it to have been discussed serveral times in the past. I also believe you don't understand how to use a search engine. I just ran "fuel pump" and made sure to use "and" instead of "or" in the "keyword options" section, just below. When I did this, I immediately found the following threads you may find helpful:

    1) http://www.ferrarichat.com/discus/messages/256120/1963.html

    2) http://www.ferrarichat.com/discus/messages/256120/11515.html

    You could do more searches to narrow it down...

    "pump relay hot", or "pump relay warm", etc.

    I think Newman and James have you on the right track though


    Good luck
     
  15. TOM B

    TOM B Formula 3

    Jul 24, 2003
    1,038
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    Thomas Buckley
    Newman and Jim S. are on the right track. After fighting hot relays and burned out terminal strips for 3 years I finally replaced the entire fuse block. This solved a number of electrical issues. Try to find a used one as I did. New costs $1500.00 US.

    Tom
     
  16. KurtK328

    KurtK328 Formula Junior

    Mar 6, 2001
    347
    Villeneuve-Loubet, France
    Full Name:
    Kurt Kjelgaard
    If you go to Bosch and ask for original part number relays, they will give you newer (revised) versions of some of them. I don't remember which - on the road at the moment. These new versions are in metal housings instead of the original black plastic dittos. This to cope better with heat according to my Bosch man.
    Could be that the fuel pump relay is one of them.
    When I get home (in a couple of weeks) I will post old and new partnumbers for the relays required for a 328, IIRC there is four different ones in the fusebox(es).
    Might be good info also for the 308 and other folks.
     
  17. Newman

    Newman F1 World Champ
    Professional Ferrari Technician Consultant Owner

    Dec 26, 2001
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    Newman
    The 308's, mine in particular, already has the metal relays. i didnt think they came any other way. I would say the connection in the relay block has high resistance due to age/ corrosion just like the fuse boxes do. Cleaning all the contacts or replacing the fuse and relay blocks is the safest thing to do to eliminate a fire in the future or getting stranded somewhere.
     
  18. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    May 4, 2001
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    You should have it looked at. About 4 years ago my 308 started running like s%@#. I immediately drove to my mechanic. My relay was hot as a firecracker. He made some repair to it and told me Fiats "do that all the time too". Anyway it solved the problem and it has never returned. A warm relay is one thing a HOT one is a problem waiting to happen.
     
  19. KurtK328

    KurtK328 Formula Junior

    Mar 6, 2001
    347
    Villeneuve-Loubet, France
    Full Name:
    Kurt Kjelgaard
    Re. my previous post as promised, I'm back.

    Newman, you are absolutely correct - I got it backwards.
    The old relays are in a metal housing, the newer versions are in plastic housings. Could be a simple cost question or maybe they get rid of the heat better? MAybe the new part number is only due to the new housing or did they improve the guts of the relay?
    Anyway, here are some Bosch numbers:
    a) Old: 0-332-014-113 substituted by new: 0-332-019-151
    b) Old: 0-332-204-101 substituted by new: 0-332-209-151
    c) 0-332-015-006 still supplied (metal housing).

    On the 328 there are 18 (a), 7 (b) and 1 (c) respectively fitted in the fusebox and the auxillary electrical board in the passenger foot well.

    The fuel pump relay is an (a).

    The fuel injection control unit in the trunk contains 3 relays, Ferrari part numbers 40130106 (2) and the often mentioned protection relay, Ferarri no. 61766200.

    Anybody got Bosch numbers for these 3?
     
  20. FerrariFrank1

    FerrariFrank1 F1 Rookie

    Aug 15, 2003
    3,887
    Chicago-Phoenix-L.A.
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    Frank
    I just replaced the Fuel Pump Relay on my '81 308. The car only has 18,XXX miles on it. I called a Bosch parts distribution center in Broadview,IL.,which is just a couple miles from my House.The guy said that the relay should not have failed. That it has a Lifespan of,something like 70million mega cycles,(or something like that). I got a replacement relay with a new Part #. But from an Auto Parts store that he reccommended. It was only a few bucks. This one is Black plastic. The original is Metal. But,it works fine. realistically,I'd like to replace all of my relays,as,they are 23 years old,but,only have 18,xxx miles worth of time on them.(and keep the original ones as "Spares" and to stay with the car.) But,some of these relays can get pretty co$tly. I had a Porsche,once. And,I needed a relay,(forgot what it was for...Power Roof,maybe???) and it was almost $100.00!
     
  21. ChrisfromRI

    ChrisfromRI Karting

    Jan 28, 2003
    230
    Foster, RI
    Full Name:
    Chris F
    When I first purchased my 308 GTB QV I noticed the bank of older Bosch relays when I was going over the car. Rather than trying to find the proper replacements I simply removed them one by one and serviced them all.

    I removed the metal cover (little tabs need to be bent out with a tiny screw driver to release the cover), cleaned the precious metal plated contacts with CAIG DeOxit contact cleaner on lint-free paper towel strips (no abrasives please), checked the contact spacing and operation of the actuator arm, re-installed the metal covers (little tabs need to be bent back in to secure the cover).

    The action of removing each relay from the mounting block and then re-installing them should somewhat clean the back connection electrical contacts, and reduce the contact resistance at the back of the block.

    It took me less time to do this than to locate the right replacements and I preserved the originals.

    Kind Regards, Chris
     

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