Sure don't, all I have is a scan tool & a voltmeter - nothing special, I do have an elm-usb OBD2 for a laptop but my software doesn't seem to support-report flex info on this truck but there is a PID listed as : % Alcohol but selecting yields nothing...

 

I'm using the 5volt line

 

As you should be.

Did you double check the bulkhead wiring connector under the truck?

 

I tested all the way to the ecm connections,


I have a question about the diagram, the pnp transistor going to the 555 output blows up in simulation software- multi-sim -11, and a few others, it also blows out the #3 on the 555 timer.

I showed this diagram to several people and they all said that it's a dead short and will blow those parts instantly. I'm confused...LOL

 

That is confusing. Maybe I made an error in the diagram, but I don't think that I did.
I guess I am confused as to where the short is. The 555 is just wired as an oscillator in astable mode with a 5 volt square wave output, and the dual PNP transistors invert the waveform.

Let me see if I can find my old copy of multisim. I didn't simulate this, but I did test fairly extensively on my scope.

There are probably other ways to do it as well. I'm a mechanical engineer, not an electrical engineer

 

Also, where are you located?

 

I'm in Illinois, I just downloaded the 30 day Multi Sim 11 Demo, sadly I think I have about 11 days left, but I have lot's of computers and OS's

 

Well, I wish you luck. I don't really know what is going on.

You did build the circuit, did it fry anything? If it is frying things, perhaps the base current for the PNP resistor you chose exceeds the current limit for the 555 output pin. You can add a resistor between the 555 chip and the PNP transistor to prevent this. I didn't add one (although it probably is good practice) because I used a transistor with a very low base current.

 

This is a pretty good website for that

Transistor Circuits

 

Here's a screen from MS11 built to diagram...I didn't add the reg I just dialed down the voltage but with a regulator it's the same and it blows out without the 2nd power supply and wiring

 

Just tried it in multisim: You need to add a resistor between the base of the transistor and the 555 timer for it to work in simulation. This may or may not be true in real life, depending on which components you use.

 

I already tried adding a 2k thru 10k resistor there and I tried adding a 10k between the V1 and Q1.

So I just tried it again and #3 still blows out.

I can email you the file if your still interested in helping me I know I'm probably a PITA... my email is net_sale@comcast.net

What I did notice about this software is if you change stuff around it quits happening even though you are back to the same design that showed problems before...frustrating.

I was looking at buying an Equus 3340 that reads hz and ms and duty cycle cause I'm definitely working in the dark...I could use it for many other things as well, do you think that would help?

I did have luck -sort of with a different design and my P0178 code went away....but then I had P0179 freq. too high but at least the circuit was recognized, should have been around 50hz


Here's what a guy told me on a "circuit" forum:
Here is the answer to your question.
First have a look at the internal schematic diagram of the 555 with the help of this link:
NE555 Datasheet pdf - Timer - Philips
Download the Philips data file, and go to fig.3.
You will notice that the output stage is built in a push-pull configuration. You will also immediately understand that the Q24 transistor and the base-emitter junction of the first 2N3906 transistor were destroyed the very first time the circuit tried to work: a short-circuit between +5V and ground!
According to the scheme published (http://img706.imageshack.us/img706/1621/42239973.jpg), the only thing you have to do is to connect the 10K resistor between the V2 +5V supply and the output of the IC without any transistor, and you will be done, as both parts of your circuit are powered by +5V.
I guess you confused the output stage of the 555 with an open-collector configuration, but it is not.
Kind regards,
B.B.

 

I don't mind emailing you; we'll get it working! I know the circuit has the potential to work, as I have made a few for people and the light always went out. I think there must be something strange going on. I work at a pretty big company and have access to scopes and soldering equipment. If it comes to it, I'll build the circuit again and see if I can scope it out.




On your PNP transistors, did you make sure to connect the Vcc to the emitter, not the collector as you would an NPN?

 

Yes, the package came with clear illustration of which pin was what and I double-double checked the pins

I've been using Radio Shack parts as I 'm only a mile away from 2 of them and it's the only place local to get them...

So far the only parts that blew out were in software, you can't tell by looking at the 555 or PNP transistors if they were damaged but I bought new ones just in case, till I can test the circuit physically

 

I have a 2000 Ford Ranger Flex and I'm having the exact same issue. I've looked at the diagram over and over, but I'm sure I can't build it. Any help would be greatly appriciated.