Right hand bank cold exhaust on startup idle. | FerrariChat

Right hand bank cold exhaust on startup idle.

Discussion in '365 GT4 2+2/400/412' started by Britward, Jan 8, 2023.

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  1. Britward

    Britward Karting

    Sep 8, 2021
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    Rob Ward
    #1 Britward, Jan 8, 2023
    Due to some bad planning 2 weeks ago I was forced to put the car into the garage whilst still wet, and as today was the driest day since then I ran the engine for 15 minutes or so. Did the same to its friend, the E-Type, next to it, too.

    Some good reasons to do so, and some equally good ones not to, but I couldn't resist. Forgive me.

    It's been bizarrely wet ever since and I wanted to make sure the cars were as dry as possible. I'm near San Francisco, and it's been abnormally moist underfoot recently. House flooded last weekend, happily the garage did not.

    Priorities.

    Sadly it started to rain again before I could take either of them out for a spin.

    Anyway, my 6 year old pointed out that the left exhaust was soon warm whereas the right was noticeably not.

    Is it as simple as being too rich on the left? I melted some catalytic converters a few weeks ago, predominantly on the left bank.
     
  2. Britward

    Britward Karting

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    #2 Britward, Jan 8, 2023
    This is the same 6 year old who, when 3, came in to interrupt the zoom call I was leading to tell me he had helped me wash the E-Type by "filling it with water Daddy, with the hose".

    It was a roadster with the top down - no point in putting it up to wash it as it doesn't fit anyway - and so I had visions of him having filled the car to the brim.

    Happily (?) all (?) he had done was fill the petrol tank with water.

    He was lucky he made it to the age of 4...
     
  3. raemin

    raemin Formula 3

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    #3 raemin, Jan 9, 2023
    If you have the single ignition distributor, check the lead order: given that the rotor finger are 180 degree apart, the order of the cables on the distributor head is not the firing order...

    You should also check that the k-jet pump is working ( ideally with pressure gauges) .
     
  4. raemin

    raemin Formula 3

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    #4 raemin, Jan 9, 2023
  5. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #5 Steve Magnusson, Jan 9, 2023
    Last edited: Jan 9, 2023
    Could be if very soon and unreasonably hot -- and are you confirming that you just had fresh cat(s) put on the left side of your 1986 412? If so, replacing a melted cat, and not checking the AF/fuel delivery behavior, is a bit strange/incomplete repair. Does your 412 have anything (thermocouples) mounted in the (added for US) cat outlet areas to detect overheating? Unfortunately, ICE run beautifully set rich (or even very rich), but the cats need it to be set just slightly richer than stoichiometeric in order to survive.

    Losing a bank (for either fuel or spark) should be smooth running, but low RPM and weak power -- was it? Easiest first thing to do is determine if both banks have ignition present by using a timing light or spark tester.
     
  6. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
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    #6 SouthJersey400i, Jan 9, 2023
    Assuming it is a 400i or 412, first thing to check is the that the RH fuel pump is running. It makes a ticking sound.
    Ken
     
  7. Britward

    Britward Karting

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    #7 Britward, Jan 10, 2023
    Sorry for the delay in responding, sadly been pumping an atmospheric river out of my house.

    When I bought the car it had (obviously) passed smog but much of the exhaust was in poor shape so I had it largely removed, replacing it simply with off the shelf parts without really thinking through what I was doing. At one point I just had straight pipes, which was awesome but also a little too much, so I had fitted single silencers on each pipe and then 2in/2out cats on each side. It was these latter that fried in 500 miles or so of admittedly enthusiastic uphill twisty driving - both sides went, but worse on the left.

    Taking them off again wasn't intended to be any kind of "fix" other than to stop the horrible rattling that my wife teased me about, and was/is intended to be temporary until I could get the car into my friendly (but busy/slow) mechanic to tune the car properly. Once that's done I intend to put cats back on, although I'm reliably informed that most people run the cars without until the car needs to be smogged.

    Current situation, prompting this thread, was simply the cold exhaust on the right bank while idling/warming up. There was an equal amount (nothing excessive) of smoke/condensation coming out of each bank, and certainly last time I drove it there was no issue with the right bank being down. I've experienced that before and it's very noticeable, but it could be that the fuel pump chose the last startup to die.

    Ironically, of course, as has been suggested, the car as it stands - running rich and no cats - runs incredibly smoothly. I had an engine rebuild done last year (which is why I was numb by the time it came to what to do with the exhaust) and I have to say that being dumb enough to wring it out to 6000rpm is both a privilege and absolutely spine tingling.

    If it ever stops raining I'll take it out for a run and check the right bank is doing what is expected of it, and also check the exhaust temperature when hot.

    This may be something about nothing, apologies for the distraction.
     
  8. raemin

    raemin Formula 3

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    #8 raemin, Jan 11, 2023
    If you do have a 412, you do have two separate ignition systems and two separate injection system.

    First check for the fuel pump fuses and while doing so check for burnt components as the 412 relay fuse panel is the most unreliable upgrade Ferrari did to the 400. If you could subsequently check the voltage that reaches the pumps that would be great. Unlike other 400, the 412 fuel pumps are in the tanks (not under the frame), if you remove the carpets you should be in a position to access the harness easily. Once this basic test is done, you could proceed to the following steps.

    For the ignition you could try to swap coil and ECU and see if the problem moves from one side to the other. As a less aggressive approach a spark tester could help. If a spark tester is not available you may disconnect one of the ignition lead and test it against a spare spark plug (this is crude to say the least...).

    As far as the injection is concerned, best approach is to use pressure gauges, but you could also make a basic test with an allen key (a long one with a T-bar shape). If you hear the injector hissing, at least you know there is some flow. See post https://www.ferrarichat.com/forum/threads/ferrari-412-extreme-exhaust-temperature-difference-between-left-and-right-bank.665809/#post-148755318.

    Hopefully this will allow you to isolate your problem.
     
  9. Britward

    Britward Karting

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    #9 Britward, Jan 12, 2023
    A dry day between storms.

    Must....drive...cars...!

    Right bank is certainly working, no power issues at all, and after a drive the RHS exhaust is, of course, pumping out warm/hot air, however:
    1) RHS is still certainly cooler than the LHS.
    2) LHS is noticeably louder.

    Likely just down being richer on the LHS (the side that fried the cat more than the other)?
     
  10. raemin

    raemin Formula 3

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    #10 raemin, Jan 12, 2023
    No guess work, just check the k-jet pressure, and once it is acceptable validate that each injector does spray an equal amount of fuel (unplug the injectors from the head and place them in a plastic container) . Once done, the CO screw can be adjusted.

    You could also use a laser gun and check each cylinder individually. This would let you know which does not work (less heat ~ less combustion?)
     
  11. Al Campbell

    Al Campbell Formula Junior
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    #11 Al Campbell, Jan 13, 2023
    Sounds like a stretched timing chain meaning the left side is more retarded than the right and combustion is pushing out into the exhaust. Has the camshaft timing been checked recently?
     
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  12. raemin

    raemin Formula 3

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    #12 raemin, Jan 13, 2023
    Good catch on the stretched chain.
     
  13. Ak Jim

    Ak Jim F1 Veteran
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    #13 Ak Jim, Jan 14, 2023
    Also maybe the chain needs to be adjusted.
     
  14. raemin

    raemin Formula 3

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    #14 raemin, Jan 14, 2023
    As the car has not been used for a while the tensioner could also be stuck. While the timing chest covers are open, it would be a good idea to check it (use a pry bar to push the tensioner).
     
  15. Britward

    Britward Karting

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    #15 Britward, Jan 14, 2023
    All great suggestions, thanks. I'll let you know what happens.

    Car had only been sitting 2 weeks, other than that i drive it daily. No idea of course how long it's been like this, the performance is fabulous though.
     
  16. 365GT4 2+2

    365GT4 2+2 Karting

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    #16 365GT4 2+2, Jan 17, 2023
    It may come as no consolation to those with fuel injection but I have seen many pictures and videos of carburettor cars with vapour out of one exhaust only. Mine does it shortly after start up but always clears before normal running temperatures are attained.


    Sent from my iPhone using Tapatalk
     
  17. Britward

    Britward Karting

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    #17 Britward, Jan 19, 2023
    It's going to be 3-4 weeks before I can get this looked at, but in the meantime are any of the potential causes above reason not to drive the car?
     
  18. Ak Jim

    Ak Jim F1 Veteran
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    #18 Ak Jim, Jan 20, 2023
    Not claiming to be an expert but I read somewhere that if the timing chain is too loose it can cause accelerated wear on the sprockets.
     
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  19. raemin

    raemin Formula 3

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    #19 raemin, Jan 20, 2023
    Last edited: Jan 20, 2023
    As a bare minimum I would drop the timing chest covers and check the chain & timing marks. That's 2x6 blind nuts to remove, so quite a simple task.

    Image Unavailable, Please Login
    (funny, the paint of the cam-covers has changed quite a few times since this photo...)

    Have a look at this discussion, looking at my naked engine you can get a pretty clear idea of what to remove and what to look for: https://www.ferrarichat.com/forum/posts/147859375/
     

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