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Since: 9/8/2009
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Thankyou to member boomerang's great work http://www.maseraticlub.nl/board/index.php?topic=2380.0 there is now a solution to repair a faulty 3200 GT throttle pedal potentiometer. Thankyou to Luuk (boomerang) for the information below -
Don't forget the Throttle Pedal Potentiometer!
After gaining some experience in solving 3200 GT CEL/Limpmode problems, I would urge everyone to carefully check the Pedal Pot in those cases.
The SD2/3 tester would point out any problem with the Pedal Pot of course, but not everyone has such a tester lying around I'm afraid.
The Pedal Pot can be opened, modified and cleaned inside.
The last thing to do, is to delete the connector at the Pedal Pot and solder each wire instead, isolating every wire afterwards of course.
Bad connections/polloution inside the Pedal Pot can trigger CEL easily.
If someone was to send in a TB for overhaul/modification for contactless, you could consider sending the Prdal Pot with it, if you would not trust yourself with the modification/cleaning of the Pedal Pot.
As you can see, the Pedal Pot can be opened, the little round circuit board can be deleted after removing the three dots of glue after that, the resistor tracks on it can be cleaned, as well as the little wiper. (Be very careful not to harm the tiny wiper) Use a greasy kind of contact spray.
Mark the position of the little board in its housing, it should be glued back in exactly the same position.
Then solder a bridge between the yellow and white wires inside the Pedal Pot.
Close the Pedal Pot and put it back in its place.
It would be wise to delete the connector and solder the wires afterwards as is said before.
Following are some pictures of the internals of the Pedal Pot:
The Pot Meter Unit (Bosch) has two internal Potentiometers.
After disassembly - it sits on a hernia place - remove the unit from the linkage to the ball joint. Make no adjustment to the linkage between the pedal and unit.
Now carefully remove the lid (careful with the plastic latches).
You will see the back of the Potentiometer Board.
Now, with the wires deleted, you can see the 3 drops of rubber glue. (One deleted already at the opposite side of the existing two)
Mark the position of the resistor board in its housing, delete the glue and try to delete the board from its housing.
The resistor board deleted from its housing with a little screwdriver.
Again, be careful not to damage anything.
Now showing the little wiper that has to be cleaned with pressed air or a tiny brush, but again be very careful.
The resistor tracks where somewhat dirty because of some debris, just remove the dirt and apply some greasy contact cleaner.
If the resistor tracks look really worn/scratched, please do yourself a favour and order a new Pedal Pot.
When you did NOT mark the position of the resistor board in its housing properly, read this:
The ECU will open the ETM for idle when the Pedal Pot sends a signal between 350mV and 600mV.
Max throttle will be applied at 2900-3700mV from the Pedal Pot.
By gently rotating the board in its housing, you can achieve these values at idle then bond the board to its housing again woth three dots of glue.
If you did not mark the position of the board in its housing, you will have to measure these values, or nothing will go at all anymore!
Marcel had a setup created with 5V 100mA max power supply, + between pink and - at the brown wire (of the potentiometer unit), then measure between white and brown.
If you do have to calibrate, try to achieve a 450mV reading.
Carefully turn the potentiometer shaft to max and then measure again, should be about 3400mV.
Check these values for potentiometer 2, so 5V between + green and gray - and measured from yellow. If everything is okay, you should be 'in range' here as well.
After this, apply the dots of glue and solder the new connection between the white and yellow 'reading wires'.
Now there can never occur different readings from the two potentiometers again, causing the ECU to go in limp mode!
A well known Dutch Maserati specialist told me this modification was applied by Maserati all so later on.
Can some UK specialist confirm this, just curious?
Put everything back on its place again, delete the connector and directly solder the regarding wires to each other.
After this and a proper TB mounted, you should be freed from throttle problems.
DO NOT FOR GET TO DO THE THROTTLE RESET PROCEDURE AFTERWARDS!
Hope this is of some importance to you guys.
boomerang
 Attachment (6)
< Message edited by AD -- 7/10/2010 0:41:50 >
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Tension Not. Stay Positive
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