I just did some more testing. If I keep idle at 1,350 RPM there are no misfires and codes. The MAF reading at that RPM is 1.3 lb/min. Idle air flow is about 0.8 lb/min. So.... With about 55% more airflow and the underlying problem - weather it is an intake leak or another problem - becomes inconsequential. Does anyone know if a valve guide, valve seal, or any kind of other valve problem would cause the same symptoms? I'm tempted to just order the intake gaskets but maybe I should do a leak down test before I do that work. Wait a second, won't the leak down test show a loss anyway because air escapes through the faulty intake gasket at top dead center?
The leak-down test its a fantastic diagnostic measure when necessary. However it will not help you IF its a intake leak. The intake gasket replacement can be done within a normal working day, I would do that & a under the intake heat exchanger all at once & just consider it preventative maintenance wether it corrected your fault or not.
Before you start on the intake gaskets, I would at least check the harness connector to the ECU. Remove it and spray contact cleaner to it. On my spider, it took about 20 minutes. There is a ground point close to the ECU, might as well give that a good cleaning. The crank position sensor is worth swapping between banks. I doubt that it's the problem because the CPS does not discriminate between cylinders when it's intermittently faulty. But then, it'll only takes about 15 minutes to swap it. I R/R the intake gaskets a few years ago. https://www.ferrarichat.com/forum/threads/360-diy-how-to-replace-intake-runner-gaskets.425760/
I cleaned all the ground connectors and ECU connections already with CRC Electronic Cleaner. I'll clean the CPSs tomorrow and swap them. Do you think the valve timing may be out of adjustment? The belts looked tight and the bearings do not leak. The only way for valve timing to be out of sync would be if the belt had jumped a notch. But in that case all bank two cylinders should be misfiring, right? I read your intake gasket DIY. Great job. Thank you for putting that together. How many hours did it take you do the job?
I don't think it's the valve timing because the possibility of leaking intake gaskets are higher than a jumped belt. I replaced the gaskets with about 11K on the odometer if I remember correctly and took about 20 hours due to documenting the process. I have a spider, so I also need to remove the interior access panel in order to disconnect a few hoses that's in the back of the plenum.
The first thing to check before doing any ignition or fuel system/intake leaks is the mechanical integrity of the engine. You should do a compression test and a leak-down test on the engine before doing anything else. The method that you have been using so far is shooting from the hip parts replacement. You have to know what the condition of the engine is as a mechanical pump, and how each cylinder compares with another, and how the two banks of the engine compare with each other.
I had similar problems with my 360 and took it to the dealer- they did not get any codes after 2 hours of searching. Therefore they had no Clue and needed more time to diagnose. I ended up bringing the car back home with me and started searching by using a termograph camera- turned out that my cats temp were way off ( high imn temp) and uneven. Also the exhaust manifolds were uneven temps at two of the outlets( higher temp). Did a quick swap on those coils that was running too rich on fuel and the temp changed back to "normal". Ordered New coils and plugs- installed it AND reset the ECU according to a certain prosedure. After that my car has been running perfect. Have you reset your ECU`s??? Its an easy way to eliminate a potential cause and from what I understand a important procedure for the ECUs to re-learn the New info from the coil. Here`s how you reset the ECU`s and if you read closely please note that in the beginning the car WILL misfire. Do not know if this will cure your problem, but its worth a try before doing the gaskets. Good Luck trying;-) (PS I had my ECUs change a year prior the this) https://aldousvoice.com/2013/01/16/ferrari-360-ecu-reset/
I took out the intake. The gaskets looked pretty poor. Some had even started to disintegrate. I can't believe the super low quality. Makes you wonder how these cars ever perform right. A mechanic who worked on 60's Ferraris was quoted in a car magazine in the 80's as saying that "Ferraris had been put together by a bunch of communists who despised their future owners". He also claimed to have found old cigarette packs in the rocker panels. In order to get it out I had to take the red intake cover off the intake manifold. Toward the rear bumper there is a T shaped metal oil line that goes from the oil filler reservoir to both valve covers. It was just in the way since I had to remove the intake in a 45 degree angle because the other end could not be lifted up past the Spider body. Is there a trick to get the assembled intake including the red cover in there in one piece? If I remove the T metal oil line I might be able to get it in. I would need to cut the rubber hoses that connect it to the valve covers. I can replace them with new hoses and hose clamps. Any input by those who have done this job on a Spider is appreciated.
I did managed to take out and reinstall the plenum in one piece per my DIY. I tape up the rear of the plenum and the spider body weather seal strip with duct tapes to avoid scuffing the red paint. It wasn't easy but doable with a bit of maneuvering and heavy shoving in finding the right angle to clear the mounting studs. It would help tremendously if you have another pair of hands.
Thank you for your reply and the DIY you posted. I don't have a set of additional hands to assist me. I was thinking of removing the rear lid and putting up a hoist. My cover is getting powder coated right now. I know it is very difficult on a Spider to reach the rear screws of the cover when the intake is already in the car. Seems like either way it will be a %$#@ to get it back in. Was it easier to take it out or to put it back in? You don't by any chance remember the angle at which it came out?
It was equal in effort to take out and put in. I would say about 45-60 degree angle and rear of the plenum did rub against the rear weather seals/metal shield. An alternative method is to install the intake first and the covers second. Access the rear cover screws by means of the compartment access panel.
Hello how are you my name is Dany you still getting problem with misfire on Cyl #6? If you want call me to 954-614-5809 8-5pm eastern time. Have a good one! Sent from my iPhone using FerrariChat.com mobile app
UPDATE: All upper and lower intake gaskets were replaced. I also took this as an opportunity to get the intake refreshed with a new red wrinkle powder coat. I'm happy to report that there are no more misfires. For anyone doing this work I suggest removing all hoses from the oil tank to the engine for better access. Make sure to also remove the metal pipe leading to the right and left cam cover since it is in the way when you angle the 40 pound intake to pull it out and install it. I upgraded all hose clamps to reusable stainless clamps to make future service and tightening easier. The cheap clamps Ferrari uses only make sense to keep manufacturing time efficient but make no sense once the car needs to be serviced. It is just not smart to have to wait for an order of new clamps every time something gets removed, serviced, cleaned, etc. That is a total waste of time and money.
Very good. I was pretty sure you would have that result when I posted originally. I am happy to hear that you seem to have resolved your issues with that suggestion. Keep driving & enjoy.
