3200 theottle issues ongoing

deano

deano

Junior Member
Messages
235
Hi, i am hopeing you maybe sble to help me, over the years ive had various throttle issues with this car, and the most recent is complete loss of throttle responce,
I cannot believe the throttle body has failed again so ive fitted a contactless pedal potentiometer and still have no responce,
Having looked further into this the block connect on the loom side for the pedal potentiometer appears to have what i think is non OEM wireing, as in there are 2 grey wires going off to the ECU from pins 3 & 6. There is also 1 grey wire that has been tapped up in this loom as can be seen in the images this has a 5 volt supply with ignition on, can anybody suggest as to why this has been done and the bestway to rectify,Whilst in this area i have the following
Pin 3 grey 0 volts ign off and 0.006 on
Pin 6 grey 0 volts ign off and 0.006 on
Pin 5 red 0 volts ign off and 5 volts on
Pin 4 red/orange 0 volts ifn off and 0.006 on
Pin 1 red 0 volts ign off and 5 volts on
Pin 2 red/green 0volts ign off and0.007on
Help please 88860
 

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Gecara8183

Gecara8183

Junior Member
Messages
74
deano said:
Hi, i am hopeing you maybe sble to help me, over the years ive had various throttle issues with this car, and the most recent is complete loss of throttle responce,
I cannot believe the throttle body has failed again so ive fitted a contactless pedal potentiometer and still have no responce,
Having looked further into this the block connect on the loom side for the pedal potentiometer appears to have what i think is non OEM wireing, as in there are 2 grey wires going off to the ECU from pins 3 & 6. There is also 1 grey wire that has been tapped up in this loom as can be seen in the images this has a 5 volt supply with ignition on, can anybody suggest as to why this has been done and the bestway to rectify,Whilst in this area i have the following
Pin 3 grey 0 volts ign off and 0.006 on
Pin 6 grey 0 volts ign off and 0.006 on
Pin 5 red 0 volts ign off and 5 volts on
Pin 4 red/orange 0 volts ifn off and 0.006 on
Pin 1 red 0 volts ign off and 5 volts on
Pin 2 red/green 0volts ign off and0.007on
Help please View attachment 88860
Click to expand...

8886488864
 
deano

deano

Junior Member
Messages
235
Oneball said:
There was a Maserati fix that bypassed part of the loom. That grey wire should be connected to another I think, rather than just disconnected
Are you anywhere near Manchester?

Autoshield told me about the fix and I’m sure would be able to help.

Some pics here https://www.sportsmaserati.com/index.php?threads/3200-throttle-pedal-sensor.27268/
Click to expand...
Cheers for the information, looks exactly the same as mine, in one of the replies it mentions up the voltage to 0.37 on what colour wire or pin would i be looking to see this on
 
davy83

davy83

Member
Messages
2,824
Hi Deano. Sorry to hear of your woes.
The odd wiring may be Maserati's work as there was some shorter ground wires added to a number of cars mine included, and it looks rough but may well be correct.

Attached here is the pin functions for one of my pedal sensors ( I presume that's what you have fitted?)
The two outputs should be between 0.35 and 0.65 volts with the ignition on and the pedal in the idle position. You have more or less 0v so something is wrong. So we need to find out why you don't have some volts on the two outputs. I am thinking either no gnd connection, ECU wiring is short to ground or pedal sensor is goosed, or cable on pedal sensor side has an open circuit, but two at the same time seems a little unlikely. could be bad connections in the connector so check the contacts look ok and don't move or push out when its plugged in
Can you check a couple of things for me. Measure ohms between each wire in the connector and the car body and establish that two of them give a very low reading (these are the 0v or earth pins). This would at least remove a little of the worry that the wiring loom is not right. You have the two power supply pins measuring 5v so that indicates that is ok. if both of these get to the pedal sensor you should have voltage on the output pins.
Measure the voltages with the pedal sensor plugged and and also with it not plugged in. 88863
was it working and then stopped or has it not worked since fitting the pedal sensor?

If it helps you can send the pedal sensor back here and I can check its 100% make sure there are no issues there.

Note that i think if the lever on the end of the pedal sensor gets forced and moves round from where it should be it still produces like 0.2v so that possibility seems less likely to be the issue here.
 
deano

deano

Junior Member
Messages
235
Hi Davy,yes it was one of uours,i never actually got around to fitting it when i bought it from you until now.i went and bought a grantourismo instead,lol.
But it has sat to long now and i need to gte it running again then decide what im going to do with it,
Thanks for the information,ill go and pin it out in the morning
 
deano

deano

Junior Member
Messages
235
davy83 said:
Hi Deano. Sorry to hear of your woes.
The odd wiring may be Maserati's work as there was some shorter ground wires added to a number of cars mine included, and it looks rough but may well be correct.

Attached here is the pin functions for one of my pedal sensors ( I presume that's what you have fitted?)
The two outputs should be between 0.35 and 0.65 volts with the ignition on and the pedal in the idle position. You have more or less 0v so something is wrong. So we need to find out why you don't have some volts on the two outputs. I am thinking either no gnd connection, ECU wiring is short to ground or pedal sensor is goosed, or cable on pedal sensor side has an open circuit, but two at the same time seems a little unlikely. could be bad connections in the connector so check the contacts look ok and don't move or push out when its plugged in
Can you check a couple of things for me. Measure ohms between each wire in the connector and the car body and establish that two of them give a very low reading (these are the 0v or earth pins). This would at least remove a little of the worry that the wiring loom is not right. You have the two power supply pins measuring 5v so that indicates that is ok. if both of these get to the pedal sensor you should have voltage on the output pins.
Measure the voltages with the pedal sensor plugged and and also with it not plugged in. View attachment 88863
was it working and then stopped or has it not worked since fitting the pedal sensor?

If it helps you can send the pedal sensor back here and I can check its 100% make sure there are no issues there.

Note that i think if the lever on the end of the pedal sensor gets forced and moves round from where it should be it still produces like 0.2v so that possibility seems less likely to be the issue here.
Click to expand...
Hi Davy, Ive just been out and measured the voltages at the Throttle pedal potentiometer,
0 volts ground has 7.1 ohms resistance to vehicle body
+5v has 5 volt supply
out 1 has 0.56 volts at idle position
out 1 has 3,54 volts at WOT position
out 2 has 0.571 volts at idle position
out 2 has 3.57 volts at WOT position
any thoughts ?and do you have any data as to what i should be seeing at what pin on the throttle body connector end?
cheers for your help
 
davy83

davy83

Member
Messages
2,824
Ok that's confusing.
First the 7 ohms to the car body seems quite high I would expect less, more like 1 ohm maybe. what does your meter read when you just join the leads together? can you make sure you remove the resistance of the leads and also make sure you are touching bright metal that's in good contact with the body in the footwell area.
The pedal sensor voltages look to be within the spec (see below here an extract from the Maserati workshop manual) I suspect if anything they are just a little on the high side. at 0.57 volts this is only 0.03 volts from the limit of 0.6v and so I think it might be more comfortable if this was lower. I think the simplest way to do this would be to use the two small adjustment screws on the sensor body and just rotate it to get more like 0.4-0.5 volts at idle. If this is already as far as it goes then you need to adjust the big bolts on the pedal lever itself.
Once you have done that run the calibration sequence a couple of times and try again.
Calibration sequence goes like - car in neutral, ignition on, don't start car, don't touch anything for 2 minutes and 10 seconds, ignition off. then repeat but press the pedal to the floor and hold steady for 12 seconds. ignition off. Repeat just for good measure,

The only other thing that is a possible issue is that the two outputs are 11mV apart (0.571-0.56) and the limit is 15mV so while this is ok its not ideal. If everything else fails you can send it back and I will fix that FOC, I have a method for improving that now. However it is within the limits so it should be ok, and indeed fixing that issue may not be the source of your problem.

88897
 
Oneball

Oneball

Member
Messages
11,129
I had mine adjusted right to the bottom limit and although within spec it started to throw errors. Adjusted it a little and it was all good.
 
M

MUC3200GT

Junior Member
Messages
127
About the initial Statement
I cannot believe the throttle body has failed again so ive fitted a contactless pedal potentiometer and still have no responce, <
Click to expand...
Was there in attempt to figure this out whether the throttle body is really still OK, I mean is it generating the click when tuning itsself and the high feeeeeep when ignition is on (but motor not yet started) . Are there error codes in the ECU ?
 
V

vulcan1208

Member
Messages
172
Well I have had more than my fair share of throttle problems over the years, just after I got the car at 3 years old Maserati did this "grey wire" fix which cured the problems for a while. I then had to have the TB replaced a couple of years later ( contactless fitted ) and after a few more years this started to fail and it was fixed (twice) I then bought one of Daveys' pedal pots and things improved but the TB again needed looking at, this time by David Askew, with fixed TB and new pedal pot things were good except for the sudden surging to 6000 RPM with no warning !!!!. Another member mentioned that they had a wiring problem in the footwell that seemed to cause the same problem so I cut out the connector, soldered all of the wires together and sealed in shrink down sleeving. In summary a refurbed TB ( reliably done ) together with a new pedal pot and the removal of the pedal pot connector seems to have done the trick for me, in fact almost all of the jerkiness associated with a manual model has also gone and the car now drives better than ever. The only thing now is that after having a recent repaint it now needs more paintwork as my wife sideswiped it when parking her car today :(, it wouldn't be so bad had she not done the exact same thing to my Volvo a few weeks ago :mad:
 
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