how to test TDC sensor?

[geesus69]

can anyone tell me how to test that the tdc sensor is working correctly and sending the right signal to the ecu?

cheers

 

[R1XPH]

Not sure whether you mean the Crank Position Sensor? Thats the one that tells the ECU where the pistons are. Its an inductive sensor, only 2 ways i can think of is to find the manufacturer data on what it should be, get an osciloscope and cross ref the information shown.

Or unplug it and see it it makes any difference to the running of the engine?

Whats happeing for you to suspect the TDC or CPS?

 

[geesus69]

yeh tdc or cps as its otherwise known

nothing is happening, thats the whole problem lol just finsihed converting 172 engine into mk1 clio. cranking over but not firing. originally having a problem with fuel pump relay, as in it wouldnt close the circuit when cranking (the ecu is supposed to actuate that) so bridged the connection to see what difference that makes, fuel pump will run and i get 12v at the coil feed, but still wouldnt run!

so that leads me to the cps sensor (although it is a brand new one i have fitted) or the ecu. and i wanted to rule out the cps sensor before i mess about with the ecu

the only thing i can think is that the ecu isnt getting a signal from the cps sensor, or its getting a signal but doing sack all with it! (ie not firing injectors or coil)

any suggestions welcome

 

[R1XPH]

Oh right lol

Well as I said, try and see what signal the CPS is putting out and try and find something to refer it back to?

Got any mates with a 172? Could borrow the ECU from theires n see if it works :rasp:

 

[geesus69]

cant borrow ecu's due to the immobiliser code

thing is i have had my ecu decoded and an emulator fitted, tested it on a ph1 using uch and it ran that car. but theres not alot else i can think of

 

[bmh.01]

I'd be looking at the ECU seeing as it isn't closing the fuel pump relay. Would've gone down the route of the immobiliser not being decoded properly but seeing as its worked on another car its wierd it doesn't work now.

 

[BRUN]

not sure if its the same, but on the Mk1's it should read 150-250 ohms

 

[bmh.01]

200-270ohms according to the Siruis 34 renault troubleshooting manual.

 

[geesus69]

I'd be looking at the ECU seeing as it isn't closing the fuel pump relay. Would've gone down the route of the immobiliser not being decoded properly but seeing as its worked on another car its wierd it doesn't work now.

thing is on initial ignition it closes the relay momentarily, thus priming the fuel lines ready to start

but then doesnt seem to close it again under cranking, so im wondering if its a sensor not telling the ecu the engine is being turned over, want to rule this out before i set about messing with the ecu again

 

[bmh.01]

Well as far as my understanding of it is that as soon as the immobisiler authorises and ignition power is recieved by the ECU the relay is closes and primes the fuel pump and puts power onto the coil pack.

If the CPS wasn't getting the crack pulses then afaik it just not spark and the injectors wouldn't pulse but the relay should still stay closed. Does the injector lock relay close and stay closed?

 

[geesus69]

injector lock relay? which ones that?

you'll have to bear with me here electronics was never my strong point lol