Mondial Fuel Pressure too high | FerrariChat

Mondial Fuel Pressure too high

Discussion in 'Technical Q&A' started by rascalif, Aug 20, 2004.

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  1. rascalif

    rascalif Karting

    Dec 20, 2003
    82
    Southern California
    #1 rascalif, Aug 20, 2004
    Some of you may recall that my '86 Mondial 3.2 Cab started losing power, with the Slow Down light lighting up whenever it would happen. It finally got to the point that I was down to one bank of cylinders as I limped over to my mechanic's shop. Luckily, he detected no damage to the cat converters but told me that the fuel pressure appears to be too high. He's looking into various solutions but I was wondering if anyone has some insights they could share on this.

    Thanks!
     
  2. abarthracer

    abarthracer Formula Junior

    Dec 6, 2003
    373
    Falmouth, Cape Cod
    Full Name:
    david S.
    #2 abarthracer, Aug 20, 2004
    I would look into the fuel pressure regulator being defective. I think in your car it is integrated into the fuel distributor. Any competent mechanic that can check fuel pressure should be able to diagnose this one. Good luck
    David
     
  3. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,223
    TN
    #3 308GTS, Aug 20, 2004
    It could be your fuel pressure regulator in the fuel dist. but it would more commonly be the Warm Up Regulator. You also have a gold pressure damper on the side of the FD. It resembles an EFI pressure regulator.
    I think System pressure should be around 72 psi.
     
  4. rascalif

    rascalif Karting

    Dec 20, 2003
    82
    Southern California
    #4 rascalif, Aug 20, 2004
    Great thanks! I just talked to my mechanic and he's making good progress. Apparently the fuel pressure is just one of multiple issues. I'll keep you posted.
     
  5. rascalif

    rascalif Karting

    Dec 20, 2003
    82
    Southern California
    #5 rascalif, Aug 25, 2004
    Hello again

    Well we've determined that the compression on one of the cylinder banks is too low. However, we need the timing belt mark in order to fix this, which apparently isn't readily visible. Can anyone tell me where/how to find this?

    Thanks!
    Ray
     
  6. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,965
    Austin TX
    Full Name:
    Brian Crall
    #6 Rifledriver, Aug 25, 2004
    The only marks that should be used for timing the cams are under the valve cover on the back side of the front cam bearing caps.
     
  7. Matt Morgan, "Kermit"

    Matt Morgan, "Kermit" Formula Junior

    Nov 12, 2003
    405
    Ferndale, WA
    #7 Matt Morgan, "Kermit", Aug 25, 2004
    As I am in the process of setting up an '85 308 right now, I can share some of the fuel pressure part.
    308 GTS hit much of it as you can see by the Settings part of this post. I would imagine that the systems are identical, so that would make the small regulator he refers to is part of the Lamda system. It regulates the fuel pressures slightly, as it is tied to the Oxygen Sensor, and makes some small changes as needed. As you can see by the numbers, @72 lbs your system pressure is right about middle of the requirements.

    Fuel pump delivery at least 750cm³/30s
    Warm Up Regulator pressures
    Cold (@ 70 degrees) 1.4 to 1.8 bar or 20 to 26 PSI
    Hot 3.4 - 3.8 bar or 50PSI to 56PSI
    Primary pressure 4.5 - 5.2 bar 66.15 PSI to 76.5PSI
    Leakage test, pressure must be minimum 1.7 bar, or 25PSI after 10 minutes and 1.5 bar or 22 PSIafter 20 minutes
    Injectors opening pressure 2.5 - 3.6 bar or 36.75 PSI to 53 PSI

    One atmosphere equals 14.7 PSI
    One PSI equals .06805 atmospheres or bars
    Shim pressure value: .1mm Shim equals 2.2 PSI change.
    Less shims will richen the mixture, just as more shims will add pressure
    BTW: the K-jetronic an many forms has been on damn near every European Auto Manufacturer, and a few Japanese, so obtaining shims shouldn't be too hard. Make SURE toreplace the O-ring, as it will raise heck with setting system pressures if fuel is allowed to seep past it. The new ones arer slightly fatter, so it must have been a problem. As a matter of fact, I purchased mine thru a Diesel Fuel Injection shop, as they are an authorized Bosch Dealer.
    HTH
    Kermit
     

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