Testing S.a.d Off The Car?

[mrblonde 0]

hi ya,sorry if this has been coverd before.search thing still doesnt work well does it??...im just asking if you can test the s.a.d off of the car.because i have a spare one and dont know if its anygood?..and if its not anygood can you fix them up etc please?..cheers

[Tom Fenton 1,548]

Put 12v across the terminals, if it works you should see the small hole through it close up over the course of a few mins.

[returnofjim 0]

Put 12v across the terminals, if it works you should see the small hole through it close up over the course of a few mins.

 

Doesnt also depend on temperature? if its cold its closed and if its hot its open? or is it other way round

[Pugnut 9 1 Cars]

12v or temp , but i wouldnt like to chance submerging it hot water! so 12v it is .

 

basically its just a bimetal strip in there thats either heated via a 12v heater or the heat of the engine .

 

as tom said , cold open , hot closed

[pip470 61]

I Really dont think it works on temperature aswell, It is purely a timed closure and when i say timed it has been set up by peugeot to close within a certain time frame. Once it is closed I dont see any need for it to open again until the engine has cooled sufficiantly to need the extra air/fuel to run (choke) but that will be controled by the ecu. When you start the engine from cold the sad is open allowing extra air to bypass the airflow meter, 12 volts is being sent to the sad and slowly as the heater element heats up and causes the bi metalic strip to expand it slowly causes the disc rotate till there is no gap. This has been designed to coincide with the engine reaching its normal operating temperature although it doesnt always work like that. To answer the question as tom said just put 12v accross it and it will slowly close until if you hold it up to the light you should see no gap. It could take 3-5 mins. I dont think it matters which terminal you put the positive either as its only a heater element. Phill

Edited January 31, 2008 by pip470

[Pugnut 9 1 Cars]

I Really dont think it works on temperature aswell, It is purely a timed closure and when i say timed it has been set up by peugeot to close within a certain time frame. Once it is closed I dont see any need for it to open again until the engine has cooled sufficiantly to need the extra air/fuel to run (choke) but that will be controled by the ecu. When you start the engine from cold the sad is open allowing extra air to bypass the airflow meter, 12 volts is being sent to the sad and slowly as the heater element heats up and causes the bi metalic strip to expand it slowly causes the disc rotate till there is no gap. This has been designed to coincide with the engine reaching its normal operating temperature although it doesnt always work like that. To answer the question as tom said just put 12v accross it and it will slowly close until if you hold it up to the light you should see no gap. It could take 3-5 mins. I dont think it matters which terminal you put the positive either as its only a heater element. Phill

 

if it didnt work on temperature then you would return to your car after a 10-30 minute stop (engine still hot 12v been off for 10mins and as you describe the sad would be open again) and you would see a good 1500-2000 rpm !!

[pip470 61]

I understand, cheers Pugnut. The engine temperature determines how fast the bimetallic strip contracts after the engine has been switched off.

[mossy 0]

First check resistence between the two connections on the SAD. you are looking for between 45-55 ohms @20 degs.

Disconect the connecter and put a volt meter between terminal no3 (wire 48) and sutable earth, get some one to crank the engine and you see a minimum 9v if not check your wiring. If no voltage is recorded check the battery supply to the fuel pump relay (tacimetric) and te continuity of the electrical circuit. To check the earth connect an Ohmmeter between terminal 4 ( wire no M24) of the airflow sensor multi plu and earth the Ohmmeter shpould indicate less than 1 Ohm. An incorrect reading indicates a fault in the continuity of wire M24.

Put 12v across the SAD's connections after 5 mins the disc inside should be fully closed. ( Blocked off )

 

Info from Auto data

 

HTH

Al.

[CosKev 16]

if it didnt work on temperature then you would return to your car after a 10-30 minute stop (engine still hot 12v been off for 10mins and as you describe the sad would be open again) and you would see a good 1500-2000 rpm !!

 

The ECU engine coolant sensor will tell the ECU what temp the engine is at surely????

 

Then the ECU will control the S.A.D. depending on the temp reading from coolant sensor.

[pip470 61]

The ECU engine coolant sensor will tell the ECU what temp the engine is at surely????

 

Then the ECU will control the S.A.D. depending on the temp reading from coolant sensor.

 

 

The temp sender will tell the ecu what temp the engine is at and it will control the fueling, but this is where i fell short of understanding, If you leave a sad after putting 12v across it for five minutes it will open again, so if you switch the ignition off and go away for ten minutes, and the sad wasnt using engine heat to stay closed it will start to open. As pugmad pointed out this will leave you with high idle on an already warm engine. So it must use the engines heat to stay closed. Phill

[Pugnut 9 1 Cars]

the ecu is in no way connected to the sad . The +12v for the sad comes from the injectors, these are fed from the tach relay. Its the -12v that is 'pulsed' for the injector duration from the ecu. the coolant temp sensor and ecu only sorts out the fuelling side of things during cold start.

 

this is 1980 technology were on about here! the jetronic ecu only does fuelling .

[returnofjim 0]

the ecu is in no way connected to the sad . The +12v for the sad comes from the injectors, these are fed from the tach relay. Its the -12v that is 'pulsed' for the injector duration from the ecu. the coolant temp sensor and ecu only sorts out the fuelling side of things during cold start.

 

this is 1980 technology were on about here! the jetronic ecu only does fuelling .

 

Just what i was about to say, the s.a.d is such and old and simple device

[brianthemagical 1]

the extra air allowed through by the sad is metered by the afm, hence no cuting out of the engine. to test the sad, i used the reverse switch plug with the ignition on, safer then trying to get 12v on the the terminals.