Duty cycle and dwell testing

[Funracer]

Mine jumps around too. I equate this to a dwell meter dither. You are looking for the average.

[joe912/62]

I can't seem to make mine work correctly. I'm getting power to the frequency valve ( changed the relay) but it's not buzzing or vibrating. I connected the scope and I'm getting over 100% frequency and duty cycle in the 20 range. I can't get the graph to look anything like yours. Also it seems like my RPMs surge now that the valve is getting power. If I disconnect the plug to the valve the RPMs are at 950. Any suggestions

[Schulisco]

The FV is electrically nothing else than a coil. So you measure its resistance. Don't remember the exact value but it shouldn't be neither endless nor a shortcut, guess 5 Ohms or less afaik If its far more or a shortcut the FV is bad. Don't put +12V on them directly - the coil will burn due the current it consumes because of the low resistance.
In operation it will be cooled by the fuel....

Thomas

[AndrewCologne]

the FV comes with 2 to 3 ohms

[joe912/62]

Here are my results with the oscilloscope. Red to green wire and black to ground

[AndrewCologne]

Originally Posted by joe912/62

Here are my results with the oscilloscope. Red to green wire and black to ground

As statet times before and also explained on my site: From oscilloscope or DMM the red to vehicle ground and black to signal/green, otherwise the duty cycle value is inverted.

[joe912/62]

I thought that by using a oscilloscope you didn't have to reverse the wires. I have read many replies
from you that you should not reverse the wire's but I could be wrong. I will test with the wires as you suggest. Thanks

[AndrewCologne]

proper wiring can be tested easily.
When engine is cold below 15°c you should read 65% duty cycle :-)

[joe912/62]

Results with wires correctly installed and O2 unplugged.

[AndrewCologne]

OX Sensor unplugged should give you an "open loop" 50% duty cycle, that's the value needed for i.E. CO measuring and set up. This won't show you if the osci ist connected properly as its ... the middle value, means 50%.

Pull the plug/wire from the 15C° switch on the right keychain housing and check if a 65% duty cycle is present in the output/reading of the oscilloscope.

[joe912/62]

I don't understand if I connected wrong the first time and connected it correctly this time how do I get a different result if I pull off the 15 C wire on the switch? I'll do that and re-test

[AndrewCologne]

Read my lines carefully :-).
With the sensor plug connected and the 15C° switch disconnected you get a proper 65% reading, if you get a 35% reading then the connection of the Osci is wrong.

[joe912/62]

Thanks

[joe912/62]

With 15 degree switch unplugged, black to green and red to ground. O2 unplugged

[Damon88]

interesting.. when I set mine, I did not unplug 15C.

[joe912/62]

I think it's to test if you connected the wire's correctly, but I'm not the expert.
Would like to know where to go next with these results.

[Funracer]

Originally Posted by joe912/62

I think it's to test if you connected the wire's correctly, but I'm not the expert.
Would like to know where to go next with these results.

That is correct. So now you know your scope is set up right and you can plug the 15 degree switch back in and set you frequency as desired.

[joe912/62]

Is there a post which details the setup process?

[AndrewCologne]

Originally Posted by joe912/62

I think it's to test if you connected the wire's correctly, but I'm not the expert.
Would like to know where to go next with these results.

Exactly.

With OX sensor plug connected and 15°C switch unplugged: If connections of the Oscilloscope are connetcted wrong then you get a 35% duty cycle result. Cause the signal gets inverted.

[AndrewCologne]

Originally Posted by joe912/62

With 15 degree switch unplugged, black to green and red to ground. O2 unplugged

I see your amplitude is only about 9.53v but should ba about 12v.
Check your voltage at the relay terminals at 30 and at the 87 ones which lead to the FV and the ECU.