Rough idle at cold start/random question

My Scud does the exact same thing. I've read it's common 430 issue, but know one has really addressed how to fix it or if it's even a problem.

 

I had the same issue. MAF sensors was the cause.

 

May Scud has the same behavior and is completely healthy. I dare to say this behavior for 10-30 seconds during the cold start procedure is normal. Important; don't drive away during the car is in its cold start procedure! Otherwise the software goes crazy and will recover again only by disabling the car completely.

These are maxed out high tech engines, they need a few seconds for finding the rhythm.

 

Try fuel from a different gas station. I had the same issue, and was told it could be the ECU. I went to a different gas station and haven't had that problem since.

 

Our gas in California is the worst thanks to the idiots running our state, so that would make sense. Maybe I'll start mixing it with some VP every now and then and see what happens. Car runs great otherwise...

 

Usually caused by injector leak-down past the seals. Try a double start and see if that fixes it. If you start and she stumbles, immediately shut down and retry. If it works normally second time, may be time to have the injectors cleaned and resealed, about $200-300 plus labor to remove and reinstall.

 

Taz, do you have a reference for us DIY'ers to send them out once injectors are removed? -thanks.

Interestingly mine did this. I did a major ( cam belts and degreeing, intake manifold and upper air plenum gaskets, plugs). Then she roared to life on startup for like a year. Now stumbles again on initial start up. Tried a ecu reset, and Italian tune up, Techronification, sea foam injector cleaner - no luck). My plan was to "re-torque" the intake manifold. Really couldn't truly "torque" them because of location of bolts had to use a 1/4 inch drive extension with swivel on some, and open end wrench on some.

Next I would go after injectors, and then MAF's, and finally coils. Having heard what it is supposed to start like, I am not accepting the stumble. Quite a difference.


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Send the injectors to RC engineering in CA for blueprinting. You'll get back perfect injectors and also a test to show pre and post spray pattern

 

My '99 360 does the same thing after sitting for a week or so. I start it, let I idle (roughly) for just moment, then re-start. The 2nd time it usually goes to an even idle. If it doesn't, I re-start it again. I DON'T let it idle, stumble, surge etc the first time more than 5 seconds or so.

Of course when hot, it starts just fine.
And I am not concerned about it.

 

No. MAFs can cause odd problems and not trip codes. Also, if you have the capabilities, I would scope the MAFs from a stone cold start. Response time, as the throttle is blipped can very revealing.

There are many items that can cause the symptoms you describe. You can (easily) throw thousands at the problem and still not fix it. It would be nice to see STFT and LTFT values. Have you pulled codes? Anything interesting?

A proper ECU reset is done with an SD-2 or equivalent. Turning off the battery typically fixes nothing other than re-set learned values. That's not the problem here.

 

This link, specifically pages 10 & 11 give you the information for engine cranking and cold start up engine ecu logic. The Ferrari is using ME7.1.1 instead of ME7.4.4 as in here, but all EFI systems operate on the same basic logic for cranking and start up operation.

http://www.sidney.pro.br/ecu.pdf

There are a few, but only a few possibilities for the car only starting up on 4 cylinders. Unstable voltage at the ecu for the offending bank is a strong possibility. Testing all of the related factors isn't very difficult with good equipment.

The MAF sensor is responsible for helping the ECU calculate engine load during start up, the other factor aside from RPM and coolant temp which is used to calculate the fuel injectors timing for proper fueling. You want to look for the load calculation parameter and compare it to the good starting bank for reference as to differentiating good and bad values.

 

Thanks!


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Eric I use a wifi obd2 connector and EOBD-facile app on my iphone. Can get realtime readings and even graphs from sensors, and can read both ecu's.


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You probably meant to say, or a typo "The Ferrari is using ME7.3H4" instead of "ME7.1.1". There's a big difference.

 

You're welcome.
We use the factory SD-2 tool on the 360. As it was originally designed for that model, the diagnostic capabilities are impressive. However, much can be done with a "Kiwi-type ELM 327 " dongle and most EOBD readers. There are a few out there, but I use the one from Facile. It enables you to see data from both banks. Some do this better than others.

On the MAFs, we're use a multi-channel PicoScope. As it has a reference library, which makes it somewhat easier to determine good MAF from a bad one. Again, a pretty high end piece of gear. Any scope will work. Much data is online as well as good info from Bosch as to pin configurations. As to what you are looking for; once the secondary air system has stopped, watch the MAFs patrterns as you move the throttle. The wave forms should follow in synch with the air flow. So, as you blip, you'll see the trace move upwards. Conversely, when you release the throttle, the waveform should follow, immediately. It is helpful to map both MAFs at the same time, as comparisons aid in the diagnostic process. In essence, the throttle response/air flow should mirror what you see on the scope, with no delay.

Keep in mind that as the MAFs warm from engine heat, they can perform differently (oftentimes better.)

 

Eric,

I was using 93 octane ethanol free gas when I was having cold start problems. I tried 93 octane from Entec which they say has up to 10% ethanol and have not had any problems since. I don't think Ferrari prohibits the use of fuels with some ethanol.
How often do they get fresh gas at the station you have been using? I think ethanol free gas sits at gas stations for a longer time before it sells. Old fuel, regardless of ethanol free or with ethanol does not preserve well. I would find a high traffic reputable gas station and give it a chance. I also try not to get too much fuel in my tank, I put enough gas for what I'm driving that day. Next time I drive I'll put more fresh gas.
I still think you should start with the simplest end less expensive fix, before you pour a lot of money into injectors, ECU's, etc.
Just my 2 cents though. Good luck and keep us posted

 

Maybe it was a seldom ordered option on Euro cars.

On the pre-2001 MY US versions, that switch is actually installed and wired up, but the wires seem to terminate somewhere inside the car. On my car, I don't see any extra wires or unused connections near the rear lights.

Also, the action on the switch is a dummy, it doesn't really actuate the contact block.

 

Sure haha - in the uk we have lots of bad weather and "fog" lights are mandatory. They are high brightness extra rear lights that we have to have here when the weather is so bad you can't see your hand in front of your face! (So that's most days, then )

 

don't forget, there is also a lot going on!

On cold start up, like in the old days, a car runs a little rich (choke). the O2 senses are not active until they get hot. AND the cats (catalytic converters) are not converting when they are cold - so the emissions are higher! Thus, feedback control loops are not active when a car starts up. When they become active, there is a closed loop system that adjusts the fuel to airflow mixture. The mass airflow sensors are also involved in the "air" part (quantity i.e. PV=NRT). I am not exactly sure how they work in the feedback control loop, so I reserve comment. So depending on how well the system is optimized, its understandable that there could be discontinuities in the idle smoothness as the default values switch to controlled values as operating temperatures are reached. And this may be more pronounced at various temperatures, altitudes, and humidities than at others.

I, for one, ALWAYS warm all my cars up for at least a minute at about 1200-1500 rpm before driving - although this contradicts the BMW manual as does changing the life-time fluid in the transmission and differential, and the 10-15K oil changes. Thus, I do not drive until the idle reduces to the "standard" value on all my cars.

That is my compromise between a full warm up and a start and drive as advocated in many newer car manuals. That is how I live my life..

 

Rear fog lights are standard on Euro Ferraris. They are really, really bright red lamps and blind you on a clear night with no fog if you are behind a driver who forgot to turn them off. That is why they are banned here in the US. Drivers cannot be trusted to turn them off.

Fog in Europe, especially in the low countries, is a big problem and rear fog lamps are a partial solution. Still does not prevent the occasional huge pile-up in foggy conditions. The rear fog lights are incorporated into the tail-light assemblies