355 sticking throttle issue on cold start up, car redlines
Discussion
Hi all, hoping someone will know the answer to this
Our 355 is normally a display piece, however on the odd occasion it's started it appears to randomly rev to the redline by itself from cold start up. I've looked at the throttle cables and the throttle housing and everything seems fine. If you push the throttle pedal half a dozen times before start up it's fine and it doesn't do it when driving
Weirdly the throttle is spring loaded so I don't see how it's revving by itself ??
Any ideas please
Our 355 is normally a display piece, however on the odd occasion it's started it appears to randomly rev to the redline by itself from cold start up. I've looked at the throttle cables and the throttle housing and everything seems fine. If you push the throttle pedal half a dozen times before start up it's fine and it doesn't do it when driving
Weirdly the throttle is spring loaded so I don't see how it's revving by itself ??
Any ideas please
The throttle cable must be routed correctly in between the hoses to the water pump or it may not slide freely inside its sheath and that can make the sticky pedal effect worse.
It sounds like the whole mechanism needs a thorough clean up, between the pedal box, the cable and even perhaps the throttle bodies.
It sounds like the whole mechanism needs a thorough clean up, between the pedal box, the cable and even perhaps the throttle bodies.
Thom said:
The throttle cable must be routed correctly in between the hoses to the water pump or it may not slide freely inside its sheath and that can make the sticky pedal effect worse.
It sounds like the whole mechanism needs a thorough clean up, between the pedal box, the cable and even perhaps the throttle bodies.
Hi Thom and thanks for your response. My issue that i'm struggling with is, the car ticks over lovely when we park it up at night. Nothing sticking and all is well. When we come to it in the morning it sometimes redlines when we start it up without touching any pedals at all so and this is why i'm scratching my head It sounds like the whole mechanism needs a thorough clean up, between the pedal box, the cable and even perhaps the throttle bodies.
Its possible its the cable - but I doubt it from what you said as the sticky throttle cable normally does not induce red line revs - just a fast idle.
2.7 or 5.2?
How is it running once its up to temp? Rough or as it should? Does it seem like its down a cyl?
How does the exhaust smell - rich or ok?
2.7 or 5.2?
How is it running once its up to temp? Rough or as it should? Does it seem like its down a cyl?
How does the exhaust smell - rich or ok?
355 is a simple cable throttle. You press the accelerator and the cable acts on a lever which is located in the V of the engine.
Tapping the throttle a few times before you start would indicate a mechanical issue, so before you start it next time, I'd lift the expansion tank and check the position of the linkage.
Secondary potential problems maybe the idle control valve (although that's ECA controlled, so pressing the throttle a few times wouldn't matter).
An air leak would give you persistent rough running, so I'd discount that for now.
Tapping the throttle a few times before you start would indicate a mechanical issue, so before you start it next time, I'd lift the expansion tank and check the position of the linkage.
Secondary potential problems maybe the idle control valve (although that's ECA controlled, so pressing the throttle a few times wouldn't matter).
An air leak would give you persistent rough running, so I'd discount that for now.
Gary C said:
ISC valve I bet.
Looks like a silver cylinder, gets stuck open.
If thats the cylinder in front of the V of the plenum chambers where they split (mechanically minded, I am not), then yes, I'd go with that as well. Mine had the same, although it would stick whilst driving as well.Looks like a silver cylinder, gets stuck open.
An ISV stuck open would be surprising as they are closed by default but cleaning them with WD40 can always help if they are extremely dirty.
Probably unrelated but did you disconnect the battery recently? If it was disconnected then the engine should be left idling 10 minutes upon the first start up after reconnecting the battery with everything else turned off (A/C in particular) so that ECU(s) can relearn all basic parameters (especially idle parameters). This is mentioned in the owner's manual.
I only leave the engine idle for a full 3 minutes then when manoeuvring the car I make sure to baby the throttle as to avoid sharp dips in revs, particularly when engaging the clutch. If the ECU(s) see wide RPM variations during the learning phase this may lead to an excessively high idle speed when warm after the 10 min relearn phase is over (observed on both my F355 and 550).
If the relearn was done correctly and if the issue is still there, what happens if you start the engine with ISV(s) disconnected?
Probably unrelated but did you disconnect the battery recently? If it was disconnected then the engine should be left idling 10 minutes upon the first start up after reconnecting the battery with everything else turned off (A/C in particular) so that ECU(s) can relearn all basic parameters (especially idle parameters). This is mentioned in the owner's manual.
I only leave the engine idle for a full 3 minutes then when manoeuvring the car I make sure to baby the throttle as to avoid sharp dips in revs, particularly when engaging the clutch. If the ECU(s) see wide RPM variations during the learning phase this may lead to an excessively high idle speed when warm after the 10 min relearn phase is over (observed on both my F355 and 550).
If the relearn was done correctly and if the issue is still there, what happens if you start the engine with ISV(s) disconnected?
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