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Discussion Starter · #1 ·
the F1 pump activates kind of normal, like every 120 seconds with when engine off, ignition on, but goes crazy when engine is running, coming on every 20 seconds or so.
Any ideas?
I disconnected the e-diff, but it didn't make a difference. everything is bled properly and no apparent leaks.

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Discussion Starter · #4 ·
the leakages were 144/150 cc/min, I changed the clutch solenoid. first one started to go down (it doesn't go down immediately because TCU averages it over time).
Valve on leak didn't go down. Where would that leak be? I don't have any external leaks?
I disconnected both quick couplings for the E-diff to isolate the problem. it didn't help.
I am having difficulty understanding how idle would cause such rapid drops in pressure?
 

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Discussion Starter · #6 ·
Door opening (new): motor runs for a six to seven seconds. this is consistent all the time, it may take less sometimes but not more.

Key on but with engine off -dash lights on: Motor runs for one second, cycles every two and a half minutes or so. (at 65F) it takes about a second to get to full pressure. this is consistent all the time.

Engine running in neutral : Motor cycles every 80 seconds or so today at 65F. it takes about a second to get to full pressure. this is not always consistent. Yesterday, the pump was cycling every 10 seconds, warm??

Then shut car off but put key into on position again: Motor cycles every two and a half minutes or a bit more (160 to 175 seconds). it takes about a second or less to get to full pressure.

Then how many shifts do you get before you get pump to cycle ..: Every shift causes massive pressure drop, to 30 bars or so, causes pump to cycle each and every time. It takes about a second or less for the system to get to full pressure.

Shift from 1 to n to 1 and let me know how many shifts before pump turns on ..also note the same as above duration .. Every shift causes massive pressure drop, to 30 bars or so, causes pump to cycle each and every time. It takes about a second or less for the system to get to full pressure.

Do the same shifting with engine running.. Every shift causes massive pressure drop, to 30 bars or so, causes pump to cycle each and every time. It takes about a second or less for the system to get to full pressure.

thank you so much for your help, I am puzzled why idling would cause additional pressure drop. I attached some screenshots of system pressure.

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Discussion Starter · #7 ·
I also get "P1773 clutch beyond PIS" code and frequent random drops to N when shifting, with "P1770 Gear engagements with wrong shifts".
no sign of clutch slip.
tried different PIS settings, no change
 

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Discussion Starter · #11 ·
clutch wear shows 12.2% with the scanner, the position measurements come out to (21.157-18.708)/5.6 = 44%
I got only 23k miles but I have seen clutches go bad with even less than that...
 

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Discussion Starter · #12 ·
Does the quantity of total available hydraulic fluid decreases in the reservoir? If not, you definitely would have an internal leak at the actuator allowing the fluid to flow back instantly depressurized as soon as the actuator is operated (failing teflon seals). It can also be a leaking solenoid valve at the Power Unit blocked open causing a big instant drop. EV #1/#3/#5 are all 3 used for N and 1st gear engagements.
the fluid level moves as expected, higher when left overnight, drops when pump pressurizes.
shifts operate as expected at rest, with scanner.
shifts often get missed when driving, dropping to N, both during upshifts and downshifts.
dropped shifts used to be rare, like once a day, now like every second time.
Thanks!
 

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Discussion Starter · #13 ·
Usually if cycle times and run times are good with engine off but not good with engine running ..that points to solenoid ..also he changed it already iirc

All that being said . Never a perfect science
I just installed a brand new EVF, but I don't know hot to diagnose the rest of the solenoids. they do seem to operate fine and perform all the shifts at rest?
 

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Discussion Starter · #20 ·
OK, as advised, I changed the accumulator and everything is fine now Thank you for all the kind support.
lesson learned, F1 ACUUMULATOR NEEDS TO BE CHANGED EVERY 10 YEARS, regardless of mileage, the rubber membrane inside just disintegrates, ait trapped inside helps retain some pressure reservoir function, but the fluid aerated and pressure erratic, all kinds of weird shifting problems happen.
 

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Discussion Starter · #24 ·
Now that it is working fine
.you should post some graphs and cycle times (on and off ) so other will have a reference of a "good" system

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below are pressure (bar) versus time (sec) graphs with good and bad accumulator. I am surprised that the system gets to a higher pressure with the bad accumulator.
the pump motor turns on at the same low press. setting, but with bad accumulator it appears that pressure overshoots due to lack of pressure buffer. I think pressure loss is slightly more rapid at idle even with good accumulator but not significant. I didn't take good data to compare idle vs ignition on with new accumulator.
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