Need Some Help

[robban]

I have got a ls400-91and i loved it!

Got some problem tough.

Didnt pass the Swedish MOT because of bad emmsion.

Co 1.7 (0.5)

co2500 1.6 (0.3)

HC 165 (100)

lambda1.01 (ok)

I check the codes and got

Engine 41,28

Trac 45

code 41 (throttle position sensor signal) is it broken? ,can it be cleaned?Wouldent the car run badly?

code 28 Main oxygen sensor signal Right bank i guess its the first one ,before the cat!But the lambda is ok accurding to MOT!

Trac code45 when idle switch is on main throttle positon sensor signal is 1.5v or higher.Whats does that mean?

The car runs ok, trac-light come sometimes when i start the car ,if i turn the engine of and start it again the light goes off!!

Anyone having the same problem?Some ideas?

[steve2006]

Two of the fault codes are indicating either a faulty or misadjusted TPS there is a set up proceedure for these and for testing the oxygen sensors on the link below.

http://www.lexls.com/tutorials/EFI/

Is the idle speed correct when the engine is fully warmed up,should be around 650 RPM with the air con off.

Other things to check are the condition of the air filter and the plugs and leads.

Another thing is to check the EGR pipe is not leaking as this can upset the emmisions as can a leaking exhaust system.

Also check the crankcase ventilation system ( take off the oil filler cap with the engine running and then check how much blow you get out of the filler it should be very little unless there is a problem)

As I said before you really need to get some sort of manual they are fairly cheap on eBay

[robban]

Two of the fault codes are indicating either a faulty or misadjusted TPS there is a set up proceedure for these and for testing the oxygen sensors on the link below.

http://www.lexls.com/tutorials/EFI/

Is the idle speed correct when the engine is fully warmed up,should be around 650 RPM with the air con off.

Other things to check are the condition of the air filter and the plugs and leads.

Another thing is to check the EGR pipe is not leaking as this can upset the emmisions as can a leaking exhaust system.

Also check the crankcase ventilation system ( take off the oil filler cap with the engine running and then check how much blow you get out of the filler it should be very little unless there is a problem)

As I said before you really need to get some sort of manual they are fairly cheap on Ebay

thanks for the info ,ill check it tomorrow.

[bazgtr]

code 41 (throttle position sensor signal)

If this has never been off the car and you have a signal from it, I would say it's very fine nut just the computer getting the wrong signals from the sensors on the exhuast sensor. Some cheap new ones on eBay USA.

As for emissions, new cats maybe on the way being a 1990 model. Try sensors first and reset the ecu.

[robban]

code 41 (throttle position sensor signal)

If this has never been off the car and you have a signal from it, I would say it's very fine nut just the computer getting the wrong signals from the sensors on the exhuast sensor. Some cheap new ones on ebay USA.

As for emissions, new cats maybe on the way being a 1990 model. Try sensors first and reset the ecu.

Thanks Bazgtr,steve2006

The cats are brand new,installed myself,magnaflow cats,maybe its the sensor as you say.

The sparks are new,also the filter, oil, etc

The search goes one!

[robban]

code 41 (throttle position sensor signal)

If this has never been off the car and you have a signal from it, I would say it's very fine nut just the computer getting the wrong signals from the sensors on the exhuast sensor. Some cheap new ones on ebay USA.

As for emissions, new cats maybe on the way being a 1990 model. Try sensors first and reset the ecu.

Thanks Bazgtr,steve2006

The cats are brand new,installed myself,magnaflow cats,maybe its the sensor as you say.

The sparks are new,also the filter, oil, etc

The search goes one!

The car past the MOT :winky: but i still have the trac code 45,i have reset the truble codes! Trac code45 when idle switch is on main throttle positon sensor signal is 1.5v or higher.Whats does that mean? why is the signal 1,5v or higher?

[steve2006]

Ok I'll try and explain.

You will no doubt own either a radio or a Hi-Fi system which will have a rotary volume control if you turn the knob clockwise the radio gets louder if you turn it anticlockwise the sound level goes down until you cannot hear it.

This is the principle behind the TPS but in this case it is connected to the throttle butterfly so as you press the throttle pedal in the car the engine speed increases and as you release it the engine speed falls.

The reason for the TPS is it tells the engine computer the position of the throttle butterfly i.e closed ( idle speed) fully open( maximum revs) or somewhere in between.

It does this by varying the voltage from the TPS which is normally between 0 volts at idle and 5 volts at fully open throttle so for example when the engine speed is 2000 RPM the output voltage from the TPS might be 2.5 volts.

However when the throttle is fully closed (at idle speed) the engine computer needs to know this as air required by the engine is still needed to maintain tickover even though the throttle is fully closed so a switch is incorporated within the TPS to do this which in turn tells the engine computer to supply the air via the IAC ( Idle Air Control) valve.

If it did not have this air supply with the throttle closed the engine would stall.

The error code you have is suggesting the voltage at idle from the TPS is too high which could indicate adjustment is required.

BTW what is your normal tickover speed when the car is warmed up fully with the AC turned off?

[robban]

Ok I'll try and explain.

You will no doubt own either a radio or a Hi-Fi system which will have a rotary volume control if you turn the knob clockwise the radio gets louder if you turn it anticlockwise the sound level goes down until you cannot hear it.

This is the principle behind the TPS but in this case it is connected to the throttle butterfly so as you press the throttle pedal in the car the engine speed increases and as you release it the engine speed falls.

The reason for the TPS is it tells the engine computer the position of the throttle butterfly i.e closed ( idle speed) fully open( maximum revs) or somewhere in between.

It does this by varying the voltage from the TPS which is normally between 0 volts at idle and 5 volts at fully open throttle so for example when the engine speed is 2000 RPM the output voltage from the TPS might be 2.5 volts.

However when the throttle is fully closed (at idle speed) the engine computer needs to know this as air required by the engine is still needed to maintain tickover even though the throttle is fully closed so a switch is incorporated within the TPS to do this which in turn tells the engine computer to supply the air via the IAC ( Idle Air Control) valve.

If it did not have this air supply with the throttle closed the engine would stall.

The error code you have is suggesting the voltage at idle from the TPS is too high which could indicate adjustment is required.

BTW what is your normal tickover speed when the car is warmed up fully with the AC turned off?

Thanks for the reply ,me like

Cold engine 1000-1100rpms

varm engine 600-650rpm.

The trc light only comes on when the engine is cold,never hot!But not every time thou, go figure!