no throttle response

steve 99

New Member
Messages
3
#1
Drove home ok, next time I started the engine there is now no throttle response, just idles but will some time creep up to 2000 revs. I have checked the faults there were 9 recorded. I have cleared them and 3 throttle faults do come back. P0120,P0220,P0221. I have 5volts on pins 2 and 5. Pins 1and 4 read .40 volts off throttle and 3.20 volts full throttle. do these look ok. before I delve any deeper
 

Trev Latter

Centenary Club
Messages
1,108
#3
Here you go.

Pedal pot probelms.
P0220 Throttle/Petal Position Sensor/Switch B Circuit Malfunction
P0221 Throttle/Petal Position Sensor/Switch B Circuit Range/Performance Problem
P0222 Throttle/Petal Position Sensor/Switch B Circuit Low Input
P0223 Throttle/Petal Position Sensor/Switch B Circuit High Input
P0224 Throttle/Petal Position Sensor/Switch B Circuit Intermittent
P0225 Throttle/Petal Position Sensor/Switch C Circuit Malfunction
P0226 Throttle/Petal Position Sensor/Switch C Circuit Range/Performance Problem
P0227 Throttle/Petal Position Sensor/Switch C Circuit Low Input
P0228 Throttle/Petal Position Sensor/Switch C Circuit High Input
P0229 Throttle/Petal Position Sensor/Switch C Circuit Intermittent

error codes normally thrown up by throttle body problems
P0120 Throttle Position Sensor/Switch A Circuit Malfunction
P0121 Throttle Position Sensor/Switch A Circuit Range/Performance Problem
P0122 Throttle Position Sensor/Switch A Circuit Low Input
P0123 Throttle Position Sensor/Switch A Circuit High Input
P0124 Throttle Position Sensor/Switch A Circuit Intermittent

Your codes point to faults on both pedal pot and TB circuits.

Davy83 is your man for the pedal pots and well worth the money and effort. Chances are you have a worn pedal pot and a TB problem. Best course of action is replace both with contactless. Be aware faults can cross over on the code read. The CEL will trigger if there is a difference between the two halves of the pedal pot circuit and likewise the two halves of the tb circuit. For diagnostic purposes only, you can join the yellow and white wires on the pedal pot to average the readings. If the CEL and limp mode still present, TB is your likely culprit.
 
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1,579
#4
If 3200, with the engine off remove the air pipe from the throttle body and open the butterfly with your finger.
If it's binding or if you feel uneven force when opening it will likely be dirty or the internal magnet corroded
 

Contigo

Centenary Club
Messages
17,259
#5
Ok so you have done some diagnosis and your voltages are actually in spec at 400mv idle and 3.2V at full throttle so I see no reason that your pedal pot is the issue here. It points to Throttle Body as being the culprit.

I would check for an air leak too and my guess is that the Inlet Manifold pipe has blown off the throttle body, it happened to me and resulted in no power or revs.
 

StuartW

Centenary Club
Messages
7,877
#6
The same thing happened on my 3200, they can work loose with the temperature change and at least that one is a very easy fix
 
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1,946
#8
I would tend to agree that the throttle body is the most likely candidate, however i would also urge you to check both outputs on the pedal sensor as it is VERY sensitive to these being even very slightly different. The ECU will throw up an error if the two outputs are different by more than 0.015v it will throw up an error. Most of the failed sensors I have seen are down to not total failure of the output but either intermittent output (hitting bumps causing momentary bad output) or differences in the two outputs down to uneven wear on the carbon tracks.
 
Messages
1
#9
G'day , my experience was after filling up was engine light came on then she went into leap mowed , started and rev as normal . Ieft it for a day and she came good. The following day it started ran normally but no exceeration no throttle response at all ????????? Hope some one can help
Cheers Rob
2001 6 speed Maserati
 

Contigo

Centenary Club
Messages
17,259
#10
It will either be throttle body or pedal pot. Measure the voltages as mentioned in this thread and check the butterfly on the throttle body isn't sticking.
 
Messages
2
#12
Ok so you have done some diagnosis and your voltages are actually in spec at 400mv idle and 3.2V at full throttle so I see no reason that your pedal pot is the issue here. It points to Throttle Body as being the culprit.

I would check for an air leak too and my guess is that the Inlet Manifold pipe has blown off the throttle body, it happened to me and resulted in no power or revs.
Hi Phil, I can see the 2 large air intake pipes to the throttle body but can't see the inlet manifold pipe you mention. Could you point me in the right direction . Cheers, Bill.
 

Contigo

Centenary Club
Messages
17,259
#13
The main pipe that connects into the throttle body!!!!

You can't miss it. It's held on by two jubilee clips too. You need to loosen it off to get access to the throttle body butterfly.
 

allandwf

Centenary Club
Messages
7,456
#15
Where about are you? Perhaps someone could help out by substitution to pinpoint. I agree with previous posts TB or PP.
 
Messages
188
#16
I have this same problem - but intermittently. I had a throttle body rebuild and the pedal pot checked at MaseratiShed a few weeks before. Problem seems to occur when I drive a few miles, wait 1/2 hour and then try to drive home. Battery reset and throttle reset seem to clear it for a (very) short while. It's happened the last 3 times I've driven the car - so now I don't drive it any more. It's pretty embarrassing driving 5 miles home at 25 mph in 5th gear on tickover in an Italian exotic!

Steve.
 
Messages
1,946
#17
Do you get an error code? I would have thought an error like this would throw a CEL?

I have this same problem - but intermittently. I had a throttle body rebuild and the pedal pot checked at MaseratiShed a few weeks before. Problem seems to occur when I drive a few miles, wait 1/2 hour and then try to drive home. Battery reset and throttle reset seem to clear it for a (very) short while. It's happened the last 3 times I've driven the car - so now I don't drive it any more. It's pretty embarrassing driving 5 miles home at 25 mph in 5th gear on tickover in an Italian exotic!

Steve.
 

Contigo

Centenary Club
Messages
17,259
#18
Yes it sounds like it is in Limp mode if he is only managing 25 mph!

Clean all contacts, throttle body end and pedal pot end, measure voltages at idle and at WOT. (Yellow and White wires on the pedal , 350-650mv idle to 3.2V at full throttle)

Send the TB back if it's been reworked.
 

conaero

Forum Owner
Messages
28,202
#19
Just a thought, might be worth checking the TDC sensor, they are classic at upsetting the ECU when getting hot or cold.

If the ECU cant interrogate where the flywheel is, it will throw a paddy.
 
Messages
188
#20
Do you get an error code? I would have thought an error like this would throw a CEL?
Yeah, I get a CEL but clear it with the resets. Must get a code reader!

TDC sensor might be a good call. I'm reluctant to believe it's TB or PP as they've just been done/checked by Mike.

Thanks,
Steve.