ECU Light on and no revs - running like a 1.2

[tarmac terrorist]

Here's some info from the Manual:

GENERAL INFORMATION
The accelerator pedal potentiometer is incorporated in
the accelerator pedal. Its replacement therefore
requires replacement of the accelerator pedal.
There are two types of pedal: with or without
kickdown point.
These cars equipped with cruise control/speed limiter
have an accelerator pedal with a point of resistance at
the end of their travel (kickdown).
This point of resistance makes it possible to quit the
speed limiter function if the driver has to speed up.
REMOVAL
Disconnect:
the battery,
the accelerator pedal connector.
Remove:
the three pedal mounting bolts,
the pedal.
REFITTING
Refitting is the reverse of removal.
CONNECTION
Track Description
1 Track 2 earth
2 Track 1 earth
3 Track 1 signal
4 Track 1 feed
5 Track 2 feed
6 Track 2 signal
Note:
A fault on the accelerator position potentiometer
causes changes in the idle speed or engine
operation (see Section 17B, Idle speed
correction).
17B-26

MOTORISED THROTTLE VALVE
The motorised throttle body carries out idle speed
regulation and engine air intake modulation functions.
It is composed of an electric motor and two throttle
position potentiometers.
When the engine is idling, the throttle position is
adjusted according to the idle speed setting. This
setting takes into account the major power consumers
(air conditioning) and operating conditions (air
temperature and coolant temperature).
When the driver moves the accelerator pedal, his
request is translated as a call for torque which causes
the throttle to open and the ignition to advance.
To eliminate misfires, facilitate gear changes and
perform the safety functions, the throttle valve
modulates the engine torque.
MOTORISED THROTTLE BODY DEFECT MODES
The motorised throttle body has three types of defect
mode.

Reduced Performance Mode: this mode covers
electrical faults for which there is a viable backup
solution for the injection system (loss of one of the
two tracks on the pedal or the throttle body).
This mode results in reduced acceleration and limits
the maximum opening of the throttle.

Driver Override Mode: this mode is also called
"Electrical Limp-Home". This mode is applied when
the accelerator pedal signal disappears completely,
but the injection computer still controls the intake of
air to the engine (automatic throttle control is still
operational).
In this mode, the injection computer imposes a set
engine speed for each gear ratio and imposes the
idle speed when the brake pedal is pressed.

Mechanical Limp-home Mode: this mode covers
breakdowns which result in loss of the automatic
throttle control (the throttle can no longer be
controlled).
In this case the throttle is in the mechanical rest
position and the injection computer limits the engine
speed by cutting off the injection.

 

[tarmac terrorist]

And regarding the throttle pot connections:

CONNECTION
Throttle body connector
Track Description
1 Engine - control
2 Potentiometer sensor earth
3 Potentiometer +5 V power supply
4 Engine + control
5 Potentiometer track 1 signal
6 Potentiometer track 2 signal

Accelerator potentiometer connector
Track Description
1 Potentiometer track 2 earth
2 Potentiometer track 1 earth
3 Potentiometer track 1 signal
4 Potentiometer track 1 supply
5 Potentiometer track 2 supply
6 Potentiometer track 2 signal

 

[WONGY]

Yes I'm going to find this connector thing as well, or rather ask my Porsche mechanic to do it plus the pedal potentiometer per the info above!

I changed my piper x filter recently after finding the foam had never been cleaned or oiled cos it was on the car when I bought it. When I took it off it was as hard as cheese so swapped it for a bmc. My throttle body butterfly valve is actually black on one side with dirt cos of the filter so must be part of my problems, so going to get this cleaned plus also the map sensor on the inlet manifold!

Something I noticed when my plugs were changed was temp gauge was one bar lower plus it took 2/3 times to start after that service. Since they have to take everything off it could be something not connected properly - I think others have said something similar with temp gauges going pear shaped after engines been out?

 

[tarmac terrorist]

Eng temp gauge being off after engine out would point towards an airlock in the water system to me....
I would assume it is a thermocouple tapped into the water jacket on the head somewhere which measures the coolant temp.

Have you tried flushing the coolant system through or getting it pressure filled and bled?

The only connection i can think of with start probs is the ECU thinks eng temp is cooler than reality so the fuel correction is out....

 

[k1ano]

The only connection i can think of with start probs is the ECU thinks eng temp is cooler than reality so the fuel correction is out....

Which ironically, as some will know, is sometimes a way that so called 'chip' tuners adjust fuelling by putting a potentiometer in the ECU to allow the relative adjustment of the engine temperature sensor output to enrich the fuel mixture across the board ... Very crude :s

Martin

 

[WONGY]

For my car engine out and back in, no probs with temp gauge but I've seen others post problems on the forum which is why i mentioned it.

Only when I later had the spark plugs changed did the gauge read 1 bar lower on the temp gauge on the dash when fully warmed up, though the fans kick in no problems and there is no overheating. Not sure where the temperature sensor is plus the connectors e.g. is it part of this set of connectors we are talking about near the air filter?

Since that service, I've found my car harder to start when cold e.g have to turn it over twice to start it. Then last few weeks I've found it sometimes groggy / misfiring when cold at 1-3k rpm, and a misfire sometimes under light load, sometimes under heavy load at 4k sometimes 5k rpm which is intermittent.

Renault looked at it = no faults recorded on the ECU, and i changed all the coils last year as well as fuel pump.

So thats why I'm thinking some kind of connector needs cleaning or putting back together properly because it was different after that spark plug service?

Plus my air filter was knackered, so the butterfly valve on the throttle body is dirty and probably clean the map sensor as well the put in some injection cleaner.

So if I do all the above hoping this fixes it otherwise will try taking it to a dyno / rolling road or something.

 

[Fat_Board]

So after experiencing the same problem myself a couple of times I finally found this thread.

I think my problem is very much the same as described above. I've just had the cambelt changed so the engine should have been out and there might be some problems with the connector.
I haven't checked it yet as I finally got to record the issue last night.

Are there more people who have experienced this or have found a solution? The errorcodes I got was P0120 and P0220 which is throttle body sensor related.

https://www.youtube.com/watch?v=72AYnMp ... e=youtu.be