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348 348 Odd throttle response issue - high revs - engine bogging etc

Discussion in '348/355' started by Ravens_Shadow, Nov 20, 2023.

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  1. johnk...

    johnk... F1 World Champ
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    John Kreskovsky
    #26 johnk..., Nov 23, 2023
    Nothing to do with fuel pump. Pressure in the tank is normal for the Evap system.

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  2. Ravens_Shadow

    Ravens_Shadow Karting

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    Nick Seavert
    #27 Ravens_Shadow, Nov 23, 2023
    Seems to rev higher than it should and then bogs down and speeds increases. However, I am definitely gaining some speed during this period of high revs and perhaps compared to the bogging down it feels out of place. It revs high enough where it sounds like I've missed a shift when I haven't and then bogs
     
  3. johnk...

    johnk... F1 World Champ
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    #28 johnk..., Nov 23, 2023
    Can't say for sure, but that does sound like the clutch is slipping for whatever reason. Either warn, oily or otherwise contaminated, or perhaps something is preventing it from fully engaging immediately when you release the pedal.
     
  4. Ravens_Shadow

    Ravens_Shadow Karting

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    #29 Ravens_Shadow, Nov 23, 2023
    I'll do the definitive clutch test soon and see if that can be ruled out. The clutch isn't exposed enough for an oil leak or something to get in there is it? For what I guess is my oil intercooler I have a pretty decent leak coming out of that pipe. Maybe a drop or two per day is my estimation. I also have a oil leak on the top of the engine from one of the pipes and there's a small bit of oil in a casting crevice of the plenum. Maybe 3 or 4 drips worth.
     
  5. Ravens_Shadow

    Ravens_Shadow Karting

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    #30 Ravens_Shadow, Nov 25, 2023
    I think I've pinpointed the source of my fuel smell.

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    The two circled connectors are both leaking as far as I can tell. I started the car for about 30 seconds to let everything cycle through, then touched all fuel connectors and found both of these were pretty soaked in fuel. Now i'm not sure if its just the one that's higher leaking down into the other one causing the 2nd to be wet. I tried as hard as I could to tighten the connector to no avail.

    The second thing i've noticed, this being the first time, is a couple of fresh fuel drips directly in line where my camera here is pointed. I'm not sure if this thing directly in the center of the photo is related to fuel, but the lines on it are extremely chewed up and it almost looks like it's "wet". I put my hands on it and got a bunch of stuff on me, but it was hard to tell if it was fuel.


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    This may be one of the few jobs I take to a professional, but curious to hear what you think.
     
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  6. Qavion

    Qavion F1 World Champ
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    #31 Qavion, Nov 25, 2023
    There doesn't seem to be any o-rings in the parts diagram for the fuel pressure regulator or the hoses. See items 63 and 60.

    https://www.eurospares.co.uk/Ferrari/348/348_(2.7_Motronic)/PartDiagrams/009/Fuel_Pump_and_Pipes

    Are the pipe ends cracked or threads worn?

    That's related to brakes. It's possible it's brake fluid (unless something is dripping on it from above).

    See item 22 and 23

    https://www.eurospares.co.uk/Ferrari/348/348_(2.7_Motronic)/PartDiagrams/037/Brake_System
     
  7. Ravens_Shadow

    Ravens_Shadow Karting

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    #32 Ravens_Shadow, Nov 25, 2023
    It smelled pretty potent like fuel on this brake line piece, well at least directly below it. My car is leaking so much **** its hard to decipher what's what. Car doesn't even need an engine out but feels like I might as well just yank the engine out and replace every tube, pipe, and connector on the car.
     
  8. Zamboniman308

    Zamboniman308 Formula Junior

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    #33 Zamboniman308, Nov 26, 2023
    I wouldn't start that again until you solve the fuel leak. Otherwise this could end in a disappointing and hot way.
     
  9. carnutdallas

    carnutdallas Formula 3
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    #34 carnutdallas, Nov 26, 2023
    Wow! This has been a painful thread to get sucked into! But the OP is working hard to learn about it. Kudos for the effort! Please don’t Hoovie your Ferrari and fix the fuel leaks asap! Clutch is toast. Pretty sure of that. The Ferrari clutch does most of it slippage at high RPM, unlike American cars, etc. Small disc and centrifugal force at the high RPM seems most likely based on description. The guys responding know a hell of alot about the cars, so heed their counsel!

    I will emphasize “do not ride the clutch pedal.” It is not a foot rest. On or off is the rule. Neutral after stopping. Pay attention to rear view mirror and be ready to engage. I typically go to second and then engage first. I do tend to fiddle with the selector, bad habit. But I like a smooth easy engagement and straight to first can sometimes be tight. After 9 different 355’s and a 348, they are tight on first. Granted, second is tight when cold, but just the nuances of the tranny. That is ranging from 8k mile cars to 75k mile cars. All of them on second clutches (8k was toasted by first owner)

    Anyway, brave of you to share, learn and ask. We all love these cars and they are fun to learn about. Go back to some manual video training and look for anything from Bob Bondurant. Or even better, buy and read his original book. How I learned and always refer back to. He treated the shifter like an egg and the clutch was never meant to scramble it! Read his book. Excellent for the racer or the average Joe who cares to learn. Cheers!


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  10. Ravens_Shadow

    Ravens_Shadow Karting

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    #35 Ravens_Shadow, Nov 26, 2023
    I'm here to be completely honest so I can learn from my mistakes, and ultimately learn everything I can about the car to keep it in good shape for decades to come. Money is a pretty good punishment, and I'm emotionally attached to my "trophy".

    Regarding the fuel leak. I vented my garage last night due to how potent the fumes were. Once I undo the lines what exactly should I look for? What should I do about all the gas that's spilled all over the alternator etc? Do I just wait a few days for it to evaporate? What can I do to prevent things from getting even more saturated in fuel? Just a number of towels stuffed under the area?

    Unfortunately I don't have a lift or anything yet and the car has about 3/5 of a tank full.

    I'm considering just getting it towed to a well known shop here, but at the same time want the experience of fixing this too. I just don't know what to look for minus cracked threads etc. I'm pretty unfamiliar with fuel lines and the prices of this little piece have my head spinning at what the cost could blow up to be just for a piece of tubing. I watched some videos on how to make your own fuel plumbing with AN connectors and such and it doesn't seem like a bad project to undertake. Just not sure if Ferrari has special requirements or not for flanges and angles.
     
  11. steved033

    steved033 F1 World Champ
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    #36 steved033, Nov 26, 2023
    You need to know what part is cracked.. is it the fitting or is it the rail?

    You want a wrench on both sides of the fitting to help not stress the male side. It's not a bolt, you don't just go "crack it loose" (possibly why it's cracked and leaking). NEVER use any sort of thread sealer or tape on these fittings.
     
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  12. m.stojanovic

    m.stojanovic F1 Rookie
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    #37 m.stojanovic, Nov 27, 2023
    Last edited: Nov 27, 2023
    The threads on the fuel system connections are metric so AN will not fit directly but would need metric-AN adaptors.

    The points of leaks you have shown are on the fuel return line, at its connection to the FPR (low pressure line that goes back to the fuel tank). It appears that the return line (marked with a blue line) on your car is not original but someone's modification involving a few adaptors, i.e. a few additional points of potential leaks. You will need to disconnect the line from the FPR and inspect its connections/adaptors. You may need to have this return hose redone or look for a good used original hose (147290 RH, 147291 LH).

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  13. Ravens_Shadow

    Ravens_Shadow Karting

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    #38 Ravens_Shadow, Jan 31, 2024
    Fuel leaks were eventually fixed by simply retightening them and I had the clutch replaced. Yowza, my wallet!

    We had a ferrari club christmas party in the hill country of TX early last month. Car was struggling to make it up the hills from a slipping clutch disc, then the fuse under floor board burned up for the radiator fans, so they stopped working unbeknownst to me and the car overheated. Overall bad night for her.

    Point your fingers and laugh at the state of the clutch after its tragic setup. Why didn't we tow it? Both phones we had on us died, it was 11PM, and the towing service we use went out of business so for the 3 percent battery we had, we used it trying to call them. By this point we were 1/2 mile from my house so we limped it home.

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    I've since had some 1 on 1 training on how to drive this car. So this shouldn't happen again!
     
  14. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #39 fatbillybob, Feb 1, 2024
    Really have a hard look at the fuel lines. Go oem if you can. To my memory the 348 lines were fine. If you use AN fittings only use the best like earls or other made in usa. Do not use Chinese fittings and don't mix brands because of slight manufacturing differences. Consider this because fuel leaks come with high penalties. Either on some routine put a wrench on the fittings or paint mark them for visual check.
     
  15. Ravens_Shadow

    Ravens_Shadow Karting

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    #40 Ravens_Shadow, Feb 1, 2024
    Good idea on the paint. I had a local ferrari shop that specializes in this sort of thing handle all the fuel line woes and they gave me the green light for the current lines.
     
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