Why do I constantly need to clean the MAF

Things to check:

1) idle air control valves
Remove them and clean them out with throttle body cleaner

2) vacuum lines
Check to make sure you don't have any that are leaking, and that they are all hooked up properly

3) coolant temperature
Make sure that once your car has warmed up it is operating near 190°F. If it runs cooler (below 180°) the Motronic will stay in the secondary enrichment, and that can cause lambda issues. This would be a result of a bad thermostat

4) coolant temp sensors
If the Motronic thinks the car is running colder/hotter than it actually is, it won't run the correct fuel mapping. New coolant temp sensor would be needed.

5) O2 sensors
If your O2 sensors are bad they won't send the correct info to the Motronic and it won't be able to regulate the fuel mix properly. Swap the sensors from bank to bank, and see if the problem jumps sides.

6) check your fuel injectors
It wouldn't be a bad idea to remove them and send them out for testing and cleaning

7) fuel pressure regulators
If these go bad the fuel lines wont have the proper pressure needed. The usual indication is the car having a hard time starting.

8) spark plugs
Throw in a set of new plugs. Gotta have good spark to burn up the mixture

9) check the mafs
Make sure that the resistance on both of them is set to 383/ohms

If all those check out just fine................then it may be a sign that the EPROMs in the Motronic ECUs need to be replace. I had replace practically everything in my car I just mentioned (minus the fuel pressure regulators) and it was still running crazy. Replaced the stock EPROMs, with a new pair I got from Eric, and it has been running great.

Check those out and get back to us.

 

Do you have an oil bath air cleaner like a K&N?
Is your oil level ok or is it overfilled?
Something is fouling the MAFs apparently. What's happening upstream from them?

 

Another thing worth checking is the connector to the MAF. Years ago, I had a "wandering" idle on my 355 (sometimes it would idle at 800 rpm, instead of around 1000 rpm), and cleaning the connector occasionally would temporarily fix it. Eventually I replaced all the pins on the female connector, and that fixed it permanently.

 

+1 on this. I was chasing down a 5-8 light that has been intermittant since I got the car. After the major in April, the car was CEL free for around 6 months and reappeared intermittantly. I was swapping MAFs a couple of weeks ago to see if it is the MAFs since the O2 and RPM sensors were swapped L/R a couple of weeks earlier. I had cleaned the MAFs and connectors a couple of months earlier, but didn't check the actual contacts for alignment. I found one of the contacts on the 5-8 MAF ECU connector were misaligned so that it didn't have good contact. I took a small metal probe and pushed the misaligned connector into place and rechecked all other connectors on both MAFs. I haven't had a 5-8 CEL in the past 6 drives. Hopefully it will not reappear. If it does it is Gold Connector Kit time.

 

Sounds like mine. Will have my tech look into this.

 

I had that same problem on my 348, some of what Erie posted fixed the issue every time.
MAF dirty, idle control valve, fuel pressure regulator.
And one more thing which took me some time to find. When the car is running try and wiggle the connectors to the MAFs see if the idle holds steady. obviously ferrari has problems which connector but I don't understand why.

BTW, I fixed a rough idle issue on a 355 checking the same things.
dirty maf and connector, been a yr now no issues.

 

Your ghosts will likely return. We went down this path over 15 years ago going from contact cleaners, contact enhancers like s21, and finally the scuderia rampante gold connector kit. Funny, Ernie did not mention the most important thing while Ghostbusting...CONTACTS! Ingnor your contacts at your own peril

 

Dave Helms includes new connector pins for the MAF plug in his gold connector kit. They are not actually gold plated for that application (the O2 sensor pins are not gold plated either), but freshening them up and cleaning the wire where it connects to the pins, makes a big difference.