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MAF Tuneup


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Old 08-25-2010, 07:31 PM   #1
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Default MAF Tuneup

Well, she is still running like a WWII tank when I start her from cold. So much so that she stalls 2-3 times in less than 2 minutes. She rev up to 1500 RPM then down to 500 RPM, up down, up down until after 3-4 minutes then falls to 1100 RPM and when warm flat a 1000.

So I decided to put my Eleanor fears aside and dive in.

MAF is a Bosch 0 280 212 018

I removed the plugs on the MAF sensors, then I took those 2 tiny flat head screws out that hold the MAF to the air box (I believe that flat head screw don’t belong on a car, they should have been Philips screws). Then I removed the clamp (again a stupid flat head screw on the clamp arghhh).

Once removed, I cleaned the inside of the MAF with cleaner then used compressed air to remove and dry the insides. I then took a multimeter to pin 1 and 6 and it should read 383 ohm’s. So 1-4 read 389 ohm’s and 5-8 read 391 ohm’s….too lean.

I removed the silicone around the top and removed the cap. I moved the S screw counter clockwise to reduce the resistance that richens the fuel. So I was at 389 and 391, too lean and probably why she was stalling when cold.

I then put the caps back on, silicone, reinstalled the MAF’s back in nice and tight. While I was there I checked the air filter and it looked pretty clean so I took the air hose to it and barely any dust came out.

The engine was hot (took her for a drive before) and got pissed because she stalls ONLY during the initial warm up. Even after a few hours she start fine, but start her up the next day when totally cold and she acts up.

So if this doesn’t fix it im thinking maybe a temperamental plug when cold. Absolutely no hesitation when warm and climbs the revs easily without issues.

I will do more testing with the MAF's if she is still acting up to find the right spot because I have an aftermarket exhaust and cats.



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1990 348 TS (87284)

“I build cars for young men that only old men can afford” - Enzo Ferrari
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Old 08-25-2010, 08:11 PM   #2
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Mario another thought.
Have you checked the ICVs?
Sometimes they get gunk in them and the idle suffers.
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Old 08-26-2010, 05:02 AM   #3
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No I haven't, where are they located?

I'm going to take a look in the repair manual and see...



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“I build cars for young men that only old men can afford” - Enzo Ferrari

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Old 08-26-2010, 05:31 AM   #4
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Is it called the throttle position microswitch?


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Old 08-26-2010, 05:41 PM   #5
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Idle Control Valve
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Old 08-26-2010, 07:15 PM   #6
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a1exander,

Where is it and what does it look like?


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Old 08-26-2010, 08:10 PM   #7
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The Ferrari name is Idling Speed Regulator.

I am trying to recall its location from my Mondial t which is some 7 years ago.......so please do not stone me if I send you in the wrong direction.

It is normally a silver round canister type of thing with an electronics plug in the one end and a hose out the other which hose is connected to the intake manifold.

I recall that the ICV are located in front of the intake about mid point on the manifold center line. (So if you look at the motor side view and in line with the center of the manifold you will see them just infront of the big rubber intakes)
You have 2 of them as your engine electronics operate as though you have 2x 4 cylinder engines (that is why you have 2 ECU's as do the early 355's 2,7 Motronic)
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Old 08-27-2010, 06:19 AM   #8
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Quote:
Originally Posted by a1exander View Post
It is normally a silver round canister type of thing with an electronics plug in the one end and a hose out the other which hose is connected to the intake manifold.

I recall that the ICV are located in front of the intake about mid point on the manifold center line. (So if you look at the motor side view and in line with the center of the manifold you will see them just infront of the big rubber intakes)
You have 2 of them as your engine electronics operate as though you have 2x 4 cylinder engines (that is why you have 2 ECU's as do the early 355's 2,7 Motronic)
How big is this canister? the size of your thumb? beer bottle or 2L Coke bottle? LOL

When you say front of the the intake, meaning between the Intake and passenger wall? of between the intake and muffler?

What year is your Mondial?

P.S. no stone throwing from me....



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1990 348 TS (87284)

“I build cars for young men that only old men can afford” - Enzo Ferrari

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Old 08-27-2010, 06:51 AM   #9
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This is the closest I could find in the Repair Manual, is this what you are talking about???


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Old 08-27-2010, 07:11 AM   #10
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That is what you are looking for as per the manual.
It sits between the firewall and the throtle body on the inlet manifold side.

The mondial was a 1990 convertible and was a real pleasure to drive with better handling characteristics then one would expect from a 4 seater.
I still miss the genteel manners that the car had.

Remove the idle valves and rotate them in your hand close to your ear.....you should feel and hear the "guilotine" move......if it does not there is your problem.

A bit of petrol in the holes with a bit of a swirl will do the trick to loosen any gunk......I am not sure about carb cleaner but where I have used it on my BMW ICV it has worked. That does not imply that I am advocating the use of carb cleaner so take care.
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Old 08-27-2010, 07:26 AM   #11
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Ok, so I'm on the right track....only thing left to do is finding it !!!!!!!!!!!!!


Much appreciated a1exander


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Old 08-27-2010, 09:40 AM   #12
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You may have a Throttle Position Sensor (TPS) that is failing to tell your Idle Air Control Valve that your car is at idle RPMs

Johan
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Old 08-29-2010, 10:18 AM   #13
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Mario
Did you come right with the idle?
Was it the Idle valves?
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Old 08-29-2010, 07:37 PM   #14
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Hahahaha....cant find it!!!!!!!!!!
Either that or it's in my face and it doesn't match the picture....


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“I build cars for young men that only old men can afford” - Enzo Ferrari
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Old 08-30-2010, 07:02 AM   #15
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Quote:
Originally Posted by johandc View Post
You may have a Throttle Position Sensor (TPS) that is failing to tell your Idle Air Control Valve that your car is at idle RPMs

Johan

Once warm, the engine is perfect!!!!! Absolutely no issues with Idle.



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Old 08-30-2010, 09:33 AM   #16
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Can you take a photo of the engine side view and post it?
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Old 08-31-2010, 06:55 AM   #17
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Yes, will do tonight when I get home.


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“I build cars for young men that only old men can afford” - Enzo Ferrari
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Old 08-31-2010, 07:08 PM   #18
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Here are the pictures....By the way, what it that black cap in the center of the top Intake?


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Old 09-01-2010, 12:48 PM   #19
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Mario it is easy
Look at the second photo you posted

You have the large intake ridged hose which comes from the air filters through the MAF and then connects to the throtle body which is attached on the inlet manifold.

From the inlet manifold you have a small curved rubber that connects onto a silver canister.
You also have a small rubber hose leading of the BIG ridged hose that connects onto the small silver canister.
THAT canister is your Idle Valve. There are 2 of them 1 on each side of the inlet manifold.

On the last photo you have posted they can both be clearly see located closer to the firewall (front of the motor) with rubber hoses leading out of the air plenums just infront of the throttle bodies.

Let me know please?

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Old 09-01-2010, 12:55 PM   #20
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With regards the black cap in the center of the plenums I suspect it may be for vacum or air measurement purposes?
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