P0102 Mass or Volume Air Flow Circuit Low Input

This is a continuation from the thread http://www.ferrarichat.com/forum/showthread.php?t=201140
Since I only have one remaining issue, I decided to start a new thread.

My 97 F355 Spider is showing the DTC "P0102 Mass or Volume Air Flow Circuit Low Input." I have cleaned the MAF and the electrical contacts and still have the issue. I resolved a mounting problem that allowed the idle regulator to come out of the Y pipe and still have the issue.

I have now disassembled the entire post MAF air system and verified that all the hoses/tubes are connected properly. Here's a picture.
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Here's some pictures looking into the intakes on top of the motor.
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Here's some pictures looking into the idle regulator.
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Finally, some pictures looking into an air box. I'm not sure the purpose of this box, but it may be suspect. There is an O ring that apparently is supposed to create a seal. The connection seems like a bad setup to prevent air leaks. I noticed that if there is an air leak after the MAF, I immediately get the P0102 code. With everything connected, I don't get the code until I drive for a few minutes.
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Any pointers? Does everything look normal? As I keep claiming, I'm and Engineer, not a Mechanic.

BTW, here are some plots from the MAF.
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After checking all of the hoseclamps and connections, I reset the computer, idled the car for 10 minutes and went for a drive. I kept the RPM's under 5000 and P0102 showed up less than 5 minutes into the drive.

 

The square box after the Mass Airflow Sensor is called a "duct" by Ferrari (P/N 168783, Table 12, #40), I think that it's a muffler to decrease intake airflow noise. There is an O-ring sealing it (P/N 153628, Table 12, #22). When I replaced the corrugated rubber tubing and Y-pipe with FabSpeed's silicone air hose kit, there was a block-off plug included for that aperture so you could get rid of the "duct". I don't think it serves any real function other than to decrease noise. Maybe an air leak at this level is the cause of your problem. Get a little piece of thin rubber and try to seal it to see what happens. Did you use CRF's Mass Airflow Sensor cleaner? Also, when I pulled the electrical connection to the MAF, there seemed to be a lot of corrosion. I cleaned it with CRF electrical contact cleaner, used Stabilant A contact enhancer, and wrapped a couple of turns of Teflon tape around the connector threads to seal it. Best of luck with this problem.

 

Does the MAF connector need to be airtight as well? If so, this may be the problem. I will try some teflon tape tomorrow. I will also try putting a ballon or something over the hole for the duct and clamping it with the clamp that is already there. Hopefully I'll have another update tomorrow evening.

 

My guess is that the better the integrity of the system (i.e., no external airleaks) the better the function and the less probability of having some non-filtered contaminant enter to air:fuel mixture. I noticed that you had some "dust" in your air intake tubes. While the system is mostly apart, why don't you finish the disassembly and cleaner everything with Simple Green, rinse very well, and treat the corrugated rubber tubes with a good protectant like Griot's Garage rubber protectant. I would only use a damp, lint-free cloth/Q-tips to gently wipe-out the mechanical parts (e.g., idle regulator) and wipe from the inside-out to prevent pushing any debris into the intake system. I also use K&N sealing grease on my BMC airfilters. Ferrari air boxes have a tendency not to apply equal pressure on the entire perimeter of the air filter. The sealing grease (applied as a thin film) will prevent any non-filtered air from entering the air stream. An experienced Ferrari mechanic in LA told me that a reasonable amount of fine dust can get by the air filter system of Ferrari air boxes without the sealing grease. As far as the MAF output charts - you're own your own. Your an engineer and I'm a doctor/attorney, so you are certainly are far more sophisticated in this area that I am! Your ideas in your last post seemed very logical - give it a try. But, hey, I'm certainly NO expert. Best of luck!

 

I have heard of a "smoke test" where smoke is added into the intake system (or vacuum system) to find air leaks (engine off of course). I am not familiar with the procedure, but you may need to find a shop that is.

 

I tried blocking the duct and using teflon tape on the MAF connector. Neither one made any difference. I still get P0102 less than 5 minutes into a drive. I am cleaning the connector again to see if it helps, but I may need to take this one to the shop. The shop won't work on my car right now the because it has a modified Motronic ECU, so I need to get a stock ECU first.

 

I think the issue may have something to do with the connector. I tried the teflon tape idea, but it didn't work. I used some di-electric grease on the connector and I was able to go about 15 minutes before the P0102 code showed up. Today I took apart the MAF sensor and found that it had two O-rings in it. I cleaned the sensor plate with MAF cleaner again and rubbed some dielectric grease on the O-rings. I have driven for about 45 minutes total drive time over two trips without seeing the P0102 code. I have been keeping the RPMs under 5000 though.

 

Spoke too soon. 10 minutes into my third drive, I noticed the RPM's drop to 800RPM while at a light, then I saw the P0102 code appear and the RPMs went back up to 1000RPM. I am going to pull the idle regulator and try to clean it tomorrow.

 

Tom,
I had intermittent idle drops and found that cleaning the connector to the MAF would be a temp fix. After dealing with this off and on every two to three months, for the past couple years (no CE light though) I had my local dealer replace the plug and pins. My idle is steady ever since. Prior to this, I replaced the idle control motor, cam position potentiometer and Motronic water temp sensor to no effect (was dealing with a cold start idle issue, that is still unresolved). If you need a known good idle control motor, I can send you my old one for testing purposes.

(btw, you might also clean the connector to the air temp sensor just ahead of the idle control motor.)

My friend "aeroengineman" found that his idle drop was directly attributed to the activation of the radiator fan motors. As they age they seem to draw excessive current, blowing fuses and causing the idle drop from the alternator working like mad. New motors has corrected his issue.

 

I actually had a cold idle issue just the other day for the first time. I started the car to let it warm up and it idled at 600RPMs. It hasn't done it since though. This occurred immediately following my replacement of the alternator belt tensioner bearing, belt, and rebuilding the alternator with a new voltage regulator and diode bridge (old brushes stayed).

I also had idle drop on activation of the left side fan, but that went away after I replaced all four O2 sensors. I'm not exactly sure why though. Maybe it was because the car was running open loop until I fixed the O2 sensors. Now the ECU is able to correct the idle drop due to the excess current.

As far as the MAF connector, every time I try something with the connector, it changes the time duration until I get the P0102, so I really suspect that this is the culprit. I can't seem to find a replacement connector though. I only found the entire wiring harness. Maybe I need to call the dealer.

 

If you disconnected the battery (which you should have) when you replaced your alternator, the first time you start the car the ECU will run on open loop and have to re-learn its operating parameters - this takes 10-15 min. at idle.

 

Tom,
Remember the MAF and connector was commonly used on tens of thousands of BMW E34 540 sedans in the mid 1990's. I would suspect it is availabe either from BMW or a Bosch parts center. I did not inquire, but my dealer seemed to have no problem sourcing it.

 

I've called the BMW dealer and the local Ferrari repair shop to try to find the connector and neither one sells just the connector. I have to buy the entire wire harness which is very expensive. Is there a Bosch part number that I can use to search for the connector? I have already tried "0 280 217 800 Bosch MAF Connector."

 

What does the repair manual say about the circuit? How can we test it? How much is a smoke machine? I'll check.

 

I sent you a PM.

 

Tom:

Check-out this website they may have something: http://www.eagleday.com/ampconnectors.html. I also had a catalog from a company that sold all type of OEM electrical connectors, pins, etc... I'll look for it and post if I can find the name. Good luck!

 

I think I found the parts here: http://www.realoem.com/bmw/showparts.do?model=GJ83&mospid=47531&btnr=13_0437&hg=13&fg=15
PLUG HOUSING 4-POL 1 61131392224 $7.92
ONLY IN CONJUNCTION WITH
RUNDSTECKH 1,0-2,5 MM 4 61130007571 $1.95

They didn't have any more though. So I found an alternate source at: http://www.ecstuning.com

I'm not sure if they are the correct parts though and it's going to cost me $43.68 to find out.

 

I am waiting for the new MAF connector to arrive. If it doesn't resolve the issue, I will probably take you up on borrowing your idle regulator. The MAF connector should arrive early next week.

 

The idle regulator seems like a good bet since you mentioned the idle variation. Try the valve first if someone would be so kind as to Fedex a known good one. Been so busy lately and my car gets neglected

 

I received the connector. It is the correct connector. However, after replacing the connector, I still get the P0102 code. Now it's time to try the idle regulator.

f355spider, I'll send you a PM.