Check Engine light in 2002 575M

If I do not drive my car for 2-3 days, when first started it idles rough, and the engine light comes on. After a couple of minutes it runs smooth, but the light stays on. Have taken it for service, they found an air leak in the intake manifold once, and fixed it, it ran OK for a few hours, then light on again. Second time I was told it was a mass air flow sensor, which was replaced, and the car ran OK until I left it parked for 3 days, then same all over again. A friend told me his BMW M5 does the same thing, and that it it the result of "bad gasoline", and he solved it by adding an "octane booster" and a chemical to clean his injectors, since which it has not happened again. Any truth to this?

 

A lot of things can cause the CEL - ideally you need the code - it could be ignorable such as gasoline emissions P0440 - it might not be

 

An independent guy told me it was "the throttle motors", but the Ferrari people did not mention this.

 

If you believe in magic go ahead and give it a try.

Then when you get tired of playing games take it to someone who knows what they are doing and get it fixed. It ain't rocket science.

 

Like the Ferrari dealership, which has not been able to figure it out? I am not a millionaire, and certainly don't "play games" with my expensive toy. Just asking for ideas.

 

Then spend twenty bucks on one of the code readers recommended here and report back - the P code list has about 500 possibilities

 

I spent a lot of years in Ferrari dealerships and to assume they are gifted with any god like powers is naïve.

From your description of events I wouldn't know how to characterize it any differently

If you fill out your profile we may be able to give some useful advice based on among other things your location.

 

Try a double start and see if that eliminates the problem. On the first start, as soon as she catches, shut her down, wait for the Check OK lamp, and start her again. If a smooth start this time, one more thing you can tell a talented tech who can diagnose the cause of the initial rough start. This is not unusual and, like Brian said, can be easily diagnosed and repaired by an experienced tech. Mine never gave a CEL, though.

Or pour in a can of Techron (gas tank) and see if it fixes the problem. Snake Oil.

Maranellos with older intake manifold seals have a habit of backing off their fasteners, which are very lightly torqued. A new metal seal with plastic/rubber coating was introduced that has proven to be more leak resistant. My old one, at 10 years of age, was badly deteriorating and bits were being sucked into the intake. I have my techs torque the intake manifold at every annual because of the very light torque value.

 

Terry the way that you answer and always try to help the sometimes foolish,
sometimes the naivety of our fellow members ( me included) is to be complimented
you are a prince.
Daniel.

 

Daniel- I learned most of this from listening to Brian. But mine had the rough start problem and, unbelievably, a can of Techron cured it, so it was probably injector leak-down. but maybe just coincidence. Can be caused by so many things, though, like Brian said, best to let a pro diagnose.

 

Injectors can certainly cause a rough start and from time to time a can of good cleaner can help but with a CEL it will set a fault code. A fault code is only a piece of information, not a diagnosis and there are no fault codes that can suggest an injector problem or a MAF problem or an intake manifold gasket problem or throttle motors. I was these guys boss for a lot of years and I can tell when someone is incapable or too lazy to perform a diagnosis and just resorts to throwing parts at the problem and getting a few billable hours. In most cases it is lack of ability, just not very many diagnosticians out there. Too bad, used to be a prereq. And like I tld the OP, just because the guy is standing under a big yellow sign is no reason to think he is any better or wose than any otherguy.

 

Brian- Affirmative, no CEL on mine, just the rough start. No problem now, but she has had a 10 year (lock and swap at 5 years) and new intake manifold gaskets since then. I am lucky my techs learned their trade in the olden days when you had to have diagnostics skills. They were the ones that fixed the carbs (actually sent them out) and other problems on the Daytona in the last issue of Forza.

 

Terry. Would you recomend a can of Techtron every now and then as to prevent future injector issues?

 

There are 2 things that count and really only 2.

Read up on Top Tier Fuel. Use it.

More importantly is use the car. Sitting is the single most destructive thing to a fuel system.

We had a 360 engine sitting here on the floor for a while that had well over 100,000 miles on it. It was out of someone's daily driver. We used to take the injectors out of it to put in other cars as a diagnostic test. The high mileage injectors worked perfectly and the bad injectors we were pulling out typically had 10 or 20k miles.

 

If the car isn't driven regularly, then along with the periodic addition of Techron or other good fuel system cleaner, you ought to consider having all the injectors pulled and professionally cleaned and their flows checked whenever you have your major service done.

This is common practice for other makes, so it's surprising that Ferrari doesn't have a specific recommendation for it also - however, neither do they have a specific recommendation for flushing the cooling systems, and we all know how important it is to keep the cooling system well maintained for an aluminum engine & aluminum radiator........don't we?

 

Eli- Like they said, cannot hurt. I even dump a can in Jan's GL 550 every year or so since she fills it at a Smiths that likely does not use a really good additive package.

 

Next time, before your replace a mass airflow sensor, try cleaning it.
Any advance auto parts or similar store has products that will do the job.
They are very sensitive and can get you that CEL
While doing that make sure the air filters are absolutely clean.
If you use K&N filters they could give you a CEL as well.
Don't get discouraged: it is all part of the "experience"...one CEL at the time

 

It really works and I was not a believer at first

 

Just finished reading the entire toptiergas.com website. Thanks for the education, I always thought "Top Tier" was just more marketing jargon.

Greg

 

Thanks and greetings also from Switzerland to the ever so helpful Terry
(but also of course to the rest of the gang),
FrankieS