Thanks, understood, but the internal maps of the Motronic ECUs are designed for a particular flow. That's one of the main concerns. Do we know if better atomisation won't result in, say, premature detonation? See also what James (INTMD8) said. Is it being ignited in the right places? Unfortunately, these injector companies are not going to pay for a new engine and exhaust if it is adversely affected. If the new OEM injector is within 2~3% of the flow, I think I'll be going with that. Note that I'm not doing the work myself and meanwhile the car is taking up space in my local Ferrari tech's garage, so time is not on my side. I can't send injectors half way around the world to have them repaired (The injectors have already been ultrasonically cleaned several times to see if that would help). At the moment, I don't have the garage space to do my own work.
Looking at a cross-section of the engine, I see that the injector is quite far from the valve. Image Unavailable, Please Login Looking at the diagram above, it looks like the jet is hitting the inlet tract walls, unless the airflow bends the jet towards the valve opening or the injector already has a built-in angle. Considering the length of the tract, I'm wondering if a lot of the fuel/air is already mixed before it enters the cylinders.
After seen that cut away I would say that the air would probably pull the fuel down as it comes out but still some if not most are hitting the back wall I should be doing a major this winter maybe I’ll use a bore scoop to see if there is “fuel wash” or witness marks of fuel hitting on the back of the wall across from the injectors Never thought to check it but let’s see Sent from my iPhone using FerrariChat
Well, some good news (for me at least). The new single OEM injector was put on a flow test machine and it matched the flow rate of the old ones perfectly. The test machine consisted of a row of measuring jars. The injectors were mounted on top and squirted vertically downwards into the individual jars. Interestingly, the spray was quite wide and the atomisation really good. My tech said that when he put the non-OEM type (4 hole) injectors on his machine, they appeared to squirt directly downwards in a more focussed jet, causing splashes on the surface of the fuel in the measuring jars. This was the opposite of what I was expecting. Hopefully my car will be back together again by tomorrow. As mentioned in my other message thread, my tech believes that the rough running may be responsible for the rattling noise coming from the transmission.
Actually, your maps will handle a range of operating parameters. I was told that a 20% range is the norm. As for the atomization, I have had 0 predetonation on my 348, and believe me, that is a far greater concern on our engines than your 355's since we lack antiknock sensors. Your ECUs are pretty flexible. They were designed to meet a variety of operating environments and conditions.
There's such a huge difference between what these diagrams show statically vs what's happening when the engine is running...355's especially have incredible volumetric efficiency for a NA engine and by the time the intake air charge is passing the throttle plate and passing the injector, it's moving at the speed of a hurricane. That's what the fuel mist is being sprayed into. Ferrari didn't get NA 110hp/liter by accident. I personally wouldn't mess with injectors unless I knew a lot more than I do about engine design.
Retrofit an extreme high pressure pump like a diesel, blend a scooch of oil and really watch it light up. Folks are doing some really trick stuff and getting amazing mileage too
Spoke too soon... The engine is still running rough, despite the injector change (and all injectors cleaned). There is an intermittent problem. The left bank is running 100C hotter than the right bank. No change with thermocouple ECU replacement. The temperatures were confirmed with an infrared heat gun. Coil pack tried. No change. With an SD1 tool plugged in, it was noted that the car took a long time to go into closed loop mode, but it eventually did. When it was in open loop mode, the coolant temp was 88C. I have a few spare parts to throw at it. Fuel pressure regulator. Secondary air check valve. My tech will look for air leaks and things like spark plug leads tomorrow.
So the tech thinks it’s running lean on one bank How do the plugs look ???? Sent from my iPhone using FerrariChat
I'm not sure at this point what are his theories. Apart from one, the plugs look good (and are only 1200km old). I believe the slightly blackened one was the one with the faulty injector. Unfortunately, there seems to be more than one fault here. By lean, do you mean air is getting into the system, downstream of the MAF?
Yes air behind MAF but even more questions then that 1) is the tech sure that one bank that is running warmer (leaner possible) or is it that one bank is running cooler (richer possible) what should the temps be on a good running engine (I never check mine so I don’t know maybe someone here does) 2) has the tech check for vacuum or exhaust leaks (before O2 sensors) that can create either a lean or rich condition on one bank 3) did the tech do a thorough check of the valve timing, ignition timing and cooling system And when the plugs where out maybe a compression test I’m asking because a little confused what you mean by running rough is it missing at some points or just a imbalance at idle or low speeds No one likes it when the cars are not right but there’s a lot going on with them so all info helps no one has a magic wand (I wish) and chancing problems can be costly I’m just looking at all angles here hope you find it and let’s us know Sent from my iPhone using FerrariChat
This was about the highest the EGT went at idle on my 348 (top number is left bank). The difference shown was, most likely, due to my left intake cam being one tooth late at the time which caused the compression in the left bank to be 150 psi as compared to 180 psi in the right bank, also resulting in richer mixture in the left bank. I have just completed my major service and the compression left-right is now equal. I have yet to check the EGT-s with the cam timing corrected. Image Unavailable, Please Login
When it happens, it's a constant wobble, like one cylinder is going down. It may slightly improve at higher rpms, but I would expect that (more inertia). Same here, I don't know what's normal. I took two photographs of the SD1 tool readout during idle, but there is nothing helpful other than the exhaust temperature: Left 395C Right 297C Left 438C Right 356C (possibly after a longer idle period). This is with an identical idle speed. The LTFT and STFTs didn't seem to be showing on this screen. I'm not sure it was working. That was his intention. I hear you can squirt starter fluid (?) around the engine to see if the engine behaviour changes. I don't know if he has an exhaust gas analyser. This problem seemed to start after a long period of not driving (3~4 months). I'm assuming the timing hasn't suddenly gone awry. Also, the problem comes and goes. The car has no leaks, oil or water. I assume it's not a compression issue as the problem comes and goes (?). Thanks for your suggestions
Interesting. Only one value of mine is close to that. I do have free-flowing cats (if that makes a difference).
On one occasion, the car took a long time to go into closed loop mode. Before it switched, the temperature was noted to be around 88C (Motronics value). The coolant temp sensor is obviously working. Are there any other things which control closed loop? The SD1 tool was attached at the time. I don't know if this was interfering with the switchover. The SD1 tool sometimes makes the engine stall.
I'm not sure how the thermostat would cause this problem. The coolant temperature was more than adequate to put the car into closed loop. Coolant temp only needs to be 60C for closed loop. After reading the WSM, an O2 heater problem might cause this, but I recall heater failures illuminate the CEL. Temp below 572F/300C = fail.
FYI Closed loop is achieved when the O2 sensors are at a temps around 500deg and up the heating Element is to assist in bring up the temp when cold start up , extended idling or slow driving where the temps are not high As long as the O2’s get heated to those temps it will go into closed loop if not open loop The porcelain and precious metal material used in the sensor will only react to O2 in the exhaust stream when hot enough there is a pumping cell build in the sensor that measures outside O2 to the exhaust stream O2 which then makes a voltage read by the ecm If a engine is running rich that can cool down the cylinder temps and not help the O2’s reach operating threshold leaving the car in open loop Sent from my iPhone using FerrariChat
Wobble ok meaning a unbalanced feeling But at higher rpm it seems ok I would more into something in the rotating assemblies pulleys accessories etc ???? When it is happening driving or at idle does it change if you put the clutch in or is it the same Sent from my iPhone using FerrariChat
Not ok. Just slightly better because of inertia. I didn't do much driving with the rattle coming from the transaxle. I can't recall if there was an improvement with the clutch in. Sometimes it's not there at all and sometimes it happens when the car is cold, sometimes when it's hot. I can't see how cambelts, pulleys, etc, would cause this.
You are right belts and etc probably not the problem But I would like to know if it is effected but the clutch or load from the engine driving the transmission or the other way around transmission driving the engine Because I have seen bearings and gears that had play in them have different characteristics under different circumstances (loads) And with you saying there is a rattling noise and running rough can be the engine trying to work with Unbalanced in the gear set ? On my zo6 one of the clutch springs broke off and some rivets inside the clutch plate and made a noise , i had vibration in some by not all gears and not all the time I would try to make it happen and then push the clutch to have it stop immediately it would not always happen after release the clutch again some times yes others times not but after see the clutch made a difference we removed the torque tube (vette trans in rear of car) check the aka drive shift joints and remove bell housing and pressure plate to find the disc to be bad I know Ferrari are way different drive train but just something to think about Sent from my iPhone using FerrariChat
My tech just gave me some numbers for Co2 and hydrocarbons: CO2 ( Fuel mixtures ) Left side is running at 1.43 & HC at 0400 Right side is 0.81 & HC at 0320 I may need to do some Googling on what this means.
i thought on open loop the injectors were running at full cycle I also thought your non 5.2 injectors flow more at full cycle So what you are saying is in open loop it still checks as per the wsm and adjusts fuel even at open loop now that I say that out loud I think that was what the wsm did say
