3200 throttle body - lock down project.
- Thread starter davy83
- Start date
jluis
Member
- Messages
- 1,703
In your tests with different throttle bodies have you ever came across an issue where the throttle body makes a buzzing noise that remains after the engine has been shutdown for 1 minute. During this time while it’s buzzing I cannot start the car. Once the noise stops it starts without issues. Only does this when it’s hot (both the non starting part and the buzzing after shutdown)
davy83
Member
- Messages
- 2,821
Ah interesting problem. I have not really come across this no. Have you had a look at the throttle body while its doing this? I would be interested to know if the throttle flap is actually vibrating causing the noise or if the flap is static and the electronics is somehow buzzing. The electronics do make a whistling or buzzing noise in normal operation perhaps its just this noise getting louder? you can hear the normal sound here
If i had to guess i would say the flap is likely vibrating and its likely an issue with the position sensors, but quite hard to tell.
Regards
Dave Shanks
If i had to guess i would say the flap is likely vibrating and its likely an issue with the position sensors, but quite hard to tell.
Regards
Dave Shanks
jluis
Member
- Messages
- 1,703
Yep that’s exactly the noise it makes. Don’t remember what the flap does, I will pull the intake hose to have a look
jluis
Member
- Messages
- 1,703
Out of curiosity, do you know how the ECU commands the throttle body? Is it a PWM signal or a CAN message? I was thinking that a permanent solution for this recurring problem with our cars is to adapt the dumb Bosch throttle bodies such as the one in the 4200 to the 3200 ECU by building a custom electronic circuit that can translate commands from the ECU into movement on the dumb units. If the protocol is known, an MCU based device can be built cheaply and easily.
davy83
Member
- Messages
- 2,821
Well if thats the noise its making then its meant to make a noise! Its really a question if it sounds louder than it should.
I have also wondered about making a personality module to convert a Modern Bosch unit to work with this car. Its CAN bus and I don't have all the CAN bus comms structure and commands and of course Magnetti-Marelli wont give out that information, so the communications protocol would need to be reverse engineered and then the code to not only make it work but make it always meet the loony tight rules the ECU places on the behaviour would need to be done. I can probably get some of it from my programmer, maybe, but there would still be a fair amount of work in this.
To be fair to the throttle body it is not this unreliable in the Volvo cars it is used on, the problem is down to Maserati setting unrealistic tolerances on the performance of it, same problem with the pedal sensors.
I have also wondered about making a personality module to convert a Modern Bosch unit to work with this car. Its CAN bus and I don't have all the CAN bus comms structure and commands and of course Magnetti-Marelli wont give out that information, so the communications protocol would need to be reverse engineered and then the code to not only make it work but make it always meet the loony tight rules the ECU places on the behaviour would need to be done. I can probably get some of it from my programmer, maybe, but there would still be a fair amount of work in this.
To be fair to the throttle body it is not this unreliable in the Volvo cars it is used on, the problem is down to Maserati setting unrealistic tolerances on the performance of it, same problem with the pedal sensors.
jluis
Member
- Messages
- 1,703
Small update.
I had an old throttle body lying around that I tried to convert to the sacer module a few years ago and shelved it because i failed and it was throwing codes.
Today I decided to spend some time with it again tweaking the position of the magnet and it now does the self test, the humming and doesn’t throw any code.
However, if I press the throttle pedal before starting the car the throttle body with the sacer module stops buzzing while my original throttle does not.
Tomorrow or during the weekend I will swap the throttle bodies and see if my hot start issues persist.
I had an old throttle body lying around that I tried to convert to the sacer module a few years ago and shelved it because i failed and it was throwing codes.
Today I decided to spend some time with it again tweaking the position of the magnet and it now does the self test, the humming and doesn’t throw any code.
However, if I press the throttle pedal before starting the car the throttle body with the sacer module stops buzzing while my original throttle does not.
Tomorrow or during the weekend I will swap the throttle bodies and see if my hot start issues persist.
craigs3200gt
New Member
- Messages
- 6
Hello All,
I’ve owned a beautiful Maserati 3200GT Manual for over 20 years now with only 40,000klm on the clock. I have finally been confronted with the dreaded Throttle Body problem.
My car was recently suffering with intermittent throttle hesitancy and a jerky driving response.
I removed the air intake pipes to observe the reaction of the TB butterfly and confirmed that it was intermittent and unstable during the slow depression of the accelerator pedal.
I also had a CEL indicator on the dash for the last 6 months.
I did not have the equipment to analyse the CEL yet, but nevertheless decided to upgrade the TB to use the contactless Sacer parts. This was successfully done by me, following all instructions, and by my local soldering expert.
Upon re-installing the upgraded TB, I was devastated to find no improvement! In fact, the TB butterfly now shows almost no movement at all with the depression of the accelerator with ignition on. The only movement occurs when turning the ignition to the On(MAR)position, and is identical to that shown in the video from Davy83 in #103 of this thread……ie a tiny cycle of only a few millimeters. With ignition off, the butterfly moves freely, so I think the motor and magnet are OK.
I have already done the TB reset and pedal calibration procedure as per the manual, a few times….. but with no improvement.
I doubt if the problem is the pedal pot., as the pre-modified TB butterfly did move all the way open on slow depressing of the accelerator pedal (albeit with sticking and jerky movements).
Also, I have now successfully analysed the fault codes using the UniDiag KWP 2000 software, and cleared the codes. The codes haven’t come back……yet(?).
The diagnosis had the following results:
P0110 (Intake Air Temperature Circuit Malfunction),
P0220 (Throttle/Pedal Position Sensor/Switch B Circuit Malfunction),
P0121 (Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem),
P0500 (Vehicle Speed Sensor Malfunction),
0x1172 (item not found on list).
The car starts easily and drives OK for speeds up to 30kph. Any quick depression of the accelerator pedal causes immediate ‘choking’ and spluttering and loss of power.
Does any forum member have any suggestions to help fix the TB problem?
By the way, I have not yet re-potted (with neutral-cure silicone) the soldered contacts in the upgraded TB. So, I could test the contacts with a multimeter, if I knew the values.
Thank you in advance…
I’ve owned a beautiful Maserati 3200GT Manual for over 20 years now with only 40,000klm on the clock. I have finally been confronted with the dreaded Throttle Body problem.
My car was recently suffering with intermittent throttle hesitancy and a jerky driving response.
I removed the air intake pipes to observe the reaction of the TB butterfly and confirmed that it was intermittent and unstable during the slow depression of the accelerator pedal.
I also had a CEL indicator on the dash for the last 6 months.
I did not have the equipment to analyse the CEL yet, but nevertheless decided to upgrade the TB to use the contactless Sacer parts. This was successfully done by me, following all instructions, and by my local soldering expert.
Upon re-installing the upgraded TB, I was devastated to find no improvement! In fact, the TB butterfly now shows almost no movement at all with the depression of the accelerator with ignition on. The only movement occurs when turning the ignition to the On(MAR)position, and is identical to that shown in the video from Davy83 in #103 of this thread……ie a tiny cycle of only a few millimeters. With ignition off, the butterfly moves freely, so I think the motor and magnet are OK.
I have already done the TB reset and pedal calibration procedure as per the manual, a few times….. but with no improvement.
I doubt if the problem is the pedal pot., as the pre-modified TB butterfly did move all the way open on slow depressing of the accelerator pedal (albeit with sticking and jerky movements).
Also, I have now successfully analysed the fault codes using the UniDiag KWP 2000 software, and cleared the codes. The codes haven’t come back……yet(?).
The diagnosis had the following results:
P0110 (Intake Air Temperature Circuit Malfunction),
P0220 (Throttle/Pedal Position Sensor/Switch B Circuit Malfunction),
P0121 (Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem),
P0500 (Vehicle Speed Sensor Malfunction),
0x1172 (item not found on list).
The car starts easily and drives OK for speeds up to 30kph. Any quick depression of the accelerator pedal causes immediate ‘choking’ and spluttering and loss of power.
Does any forum member have any suggestions to help fix the TB problem?
By the way, I have not yet re-potted (with neutral-cure silicone) the soldered contacts in the upgraded TB. So, I could test the contacts with a multimeter, if I knew the values.
Thank you in advance…
davy83
Member
- Messages
- 2,821
if you have moved the magnet around and not managed to get it to work yet then there is one of three things going on. 1. the throttle body has a fault that's not connected to the position sensors and replacing these will not have fixed it, they are known to have power drive problems. sensor input failures caused by faulty position sensors and/or people tinkering, and very commonly the magnetic rotor starts to break up and cause friction. 2. The Sacer kit you have fitted is not right, they do make mistakes some times and the magnets are 180 degrees out and occasional hall sensor failures, and sometimes the magnet is just off. The only way for you to test this is to try another one. 3. You have unwittingly done some thing wrong or silly during fitting the Sacer sensors and with no way of testing any thing you have assembled it wrong and/or broken the electronics and will need to replace them to get it to work again.
I would try the friction test again and be honest about what you are feeling
Its the most likely fault after the position sensors. If there is friction the current will go up when you try to move it and it will shut down, and this sounds like your problem (maybe?)
If I seem a little negative then I apologise but i am getting a lot of throttle bodies from people who have bought these Sacer kits simply worked on the throttle body blind without any measurements or way of understanding what is actually going on and destroyed the thing in the process, and are amazed or annoyed that its just not that simple.
The throttle body is a complicated processor based device with two position sensors, a voice coil motor with a feedback system, two adjustable springs to set the operating zones, a bunch of limits to all of the signals, a self test start up routine and also a handshake with the ECU in the car on start up to confirm its set up correctly. It is controlled via CANBUS and there is a lengthy and complex communication protocol between the ECU and throttle body. Without any vision of what the internal ETM processor is seeing, or indeed what its telling the ECU, getting it to behave 100% correct can be quite challenging.
You want a quick fix? It took me around 18 months with a CAN bus interrogator and my car ODB interrogator just to get one set up and working.
You could alternatively just send it to some one who knows what they are doing and has the tools to do it.
I would try the friction test again and be honest about what you are feeling
If I seem a little negative then I apologise but i am getting a lot of throttle bodies from people who have bought these Sacer kits simply worked on the throttle body blind without any measurements or way of understanding what is actually going on and destroyed the thing in the process, and are amazed or annoyed that its just not that simple.
The throttle body is a complicated processor based device with two position sensors, a voice coil motor with a feedback system, two adjustable springs to set the operating zones, a bunch of limits to all of the signals, a self test start up routine and also a handshake with the ECU in the car on start up to confirm its set up correctly. It is controlled via CANBUS and there is a lengthy and complex communication protocol between the ECU and throttle body. Without any vision of what the internal ETM processor is seeing, or indeed what its telling the ECU, getting it to behave 100% correct can be quite challenging.
You want a quick fix? It took me around 18 months with a CAN bus interrogator and my car ODB interrogator just to get one set up and working.
You could alternatively just send it to some one who knows what they are doing and has the tools to do it.
craigs3200gt
New Member
- Messages
- 6
Thanks for the response Dave,
Being in Australia, with no support from Maserati dealers, we have to make do with our own research.
Anyway, after reviewing the Sacer instructions and user videos, I decided to do the upgrade job. The throttle body has a known problem and a known solution, so if the solution is marketed to be user doable, then it should be worth the effort.
It turned out to be a relatively simple project, although time consuming. To be sure of quality, I had the soldering done by a hardware repair specialist. It's a shame it didn't fix my problem.
I was wondering if Sacer made only one version of the contactless sensor to suit both the MM Volvo and Maserati specs, or are there 2 different variants?
Also, I was wondering if there are any voltage multimeter testing specs for the various potted contact points on the 2 sides of the TB? Just a thought.....
When moving the butterfly, I have found no indication of friction between the magnet and the windings of the motor.
Anyway.....looks like my user options are now limited.
So, as Dave has said, I must now decide what to do as the next step! Either way, it's getting more frustrating and expensive.
Being in Australia, with no support from Maserati dealers, we have to make do with our own research.
Anyway, after reviewing the Sacer instructions and user videos, I decided to do the upgrade job. The throttle body has a known problem and a known solution, so if the solution is marketed to be user doable, then it should be worth the effort.
It turned out to be a relatively simple project, although time consuming. To be sure of quality, I had the soldering done by a hardware repair specialist. It's a shame it didn't fix my problem.
I was wondering if Sacer made only one version of the contactless sensor to suit both the MM Volvo and Maserati specs, or are there 2 different variants?
Also, I was wondering if there are any voltage multimeter testing specs for the various potted contact points on the 2 sides of the TB? Just a thought.....
When moving the butterfly, I have found no indication of friction between the magnet and the windings of the motor.
Anyway.....looks like my user options are now limited.
So, as Dave has said, I must now decide what to do as the next step! Either way, it's getting more frustrating and expensive.
davy83
Member
- Messages
- 2,821
Sacer only make one upgrade and its in their interested to make it look simple. The Volvo part this was made for originally has Volvo programming and its a lot more forgiving than the Maserati application. you might have got lucky with it, but its possible that's not entirely the problem.
Measuring voltages on the position sensors is possible but the problem is that the start up routine measures the angle or percentage opening from the end stop, and that's adjustable. So the reading that matters is what angle in degrees the ETM reports to the engine ECU, and you need to interrogate it over the CAN bus interface to get those numbers.
FWIW i can fix it for you, if that's some thing of interest. PM me if you want.
Measuring voltages on the position sensors is possible but the problem is that the start up routine measures the angle or percentage opening from the end stop, and that's adjustable. So the reading that matters is what angle in degrees the ETM reports to the engine ECU, and you need to interrogate it over the CAN bus interface to get those numbers.
FWIW i can fix it for you, if that's some thing of interest. PM me if you want.
