How To? I narrowed it down.

[Big Swole]

Ever since I rebuilt my truck I've had this dang P0236 Code (Boost Sensor too Low / Boost Sensor Performance Rationality)

Thought it was the dielectric grease..Cleaned all the connections under the hood....Still happening..

Here's what it's been doing.....
Completely cold engine...Key it one...Immediately throw's the P0236 Code...Clear it...Drive it a bit...Sometimes it'll throw the code again (BTW it causes a CEL and cuts powers WAY down)......Clear it again.....I can drive ALL DAY without ever throwing another code......BUT, soon as I turn the key off for a min or two and then crank again, The code comes Right back within a mile or two.....Clear it and I can drive All day again without trouble...
Park it for the night...Let it cool down completely...Turn key on...Immediate Code P0236...

Well, Here what I narrowed it down too.....I have to pull my power for my TS shift master from my MP8 harness....Been this way the whole time before...BUT, I replaced the harness with a new one during the build so I had to tap the power wire again...

The truck won't shift right or driver well with the MP8 harness off due to loosing power to the shift master But I unpluged everthing (mp8 harness, Quad boost fooler, & my RP guage harness) anyway just to see if the code came back when cranked cold like normal. I just plugged up the original Boost sensor and RP sensor.

Cranked it and got a P1749 code ( which I'm pretty sure is Tranny related due to the SM not getting power) BUT NO P0236 code....So it has to be in there somewhere...I'm guessing it's from pulling the power off the mp8 harness...Why it changed from before..Who knows....

Here's where I need you Smart guys to help:

-I need another 5v power source under the hood
OR
-I went to Radio Shack tonight to see if they could help me find a way to Reduce 12V from the batteries down to 5V's and just run the SM off the battery.... No luck with those goones...

Any electrically smart guys know how I can reduce the V's down to what I need???? It would be nice to run it just off the battery. I am SO tired of having to pull over to clear code's Everytime I freakin wanna drive my truck.


Thank Guys!

 

[White Knight]

just an idea...

Maybe you could wire it in series with a resistor. I'm just not sure whats the best way to limit the current. If you measure how much current runs through the shift master you could use Ohm's Law (R=V/I) to determine what size resistor you need. You need a 7volt power drop so just divide 7 by the number of amps the SM uses.

Make sure to use the power law, P=I*V, to ensure the resistor will handle the power and not just melt.


Or maybe there is another way, but that's what comes to my mind. Good luck!

:Cheer:

 

[dieselduck]

Swole

My Banks 6-gun has a lead that comes off the diagnostic port that goes to the PDA (Looks like a phone cord) that has a 5v plug in for charging the PDA. I am guessing that the power (5v) is comming from the diagnostic port, I am not sure on this though. You might be able to take a volt meter and probe the port to see if thats where the power is comming from. For referance the 6-gun stays plugged in to the diagnostic port at all times (this is how the PDA reads all the trucks vitals). Hope this helps.

 

[Big Swole]

Maybe you could wire it in series with a resistor. If you measure how much current runs through the shift master you could use Ohm's Law (R=V/I) to determine what size resistor you need. You need a 7volt power drop so just divide 7 by the number of amps the SM uses.

Make sure to use the power law, P=I*V, to ensure the resistor will handle the power and not just melt.


Or maybe there is another way, but that's what comes to my mind. Good luck!

:Cheer:

Man! That is WAY over my head...lol...Seriously, I'm a DumbA$$ about electricity.....I don't even like Static elec....lol

I'd need some help with this, I'm sure......

Thanks though.....Hope I can find someone round here that knows this stuff like you do...

Swole

My Banks 6-gun has a lead that comes off the diagnostic port that goes to the PDA (Looks like a phone cord) that has a 5v plug in for charging the PDA. I am guessing that the power (5v) is comming from the diagnostic port, I am not sure on this though. You might be able to take a volt meter and probe the port to see if thats where the power is comming from. For referance the 6-gun stays plugged in to the diagnostic port at all times (this is how the PDA reads all the trucks vitals). Hope this helps.

Possiblity.....Thanks!!

Anyone see a problem with this?? Would this cause a problem elsewhere??

 

[06 DIESEL]

I kept getting the P0236 code also after installing the HTT 62/71/14. I have found that I get it more when the RPM are low while driving or when it is sitting there at 750-1100 RPM out of gear. If I keep the Smarty turned up it basically eliminates the code except for every now and then, which was last about 3k miles or so ago. I have just learned to live with it and associate it with too little fuel and too well of a breathing charger. Who knows though.

 

[Garland]

All engine opperating sensors are 5v, IIRC. Best ones to tap are the boost, coolant or RP. Sounds like you are on the right track!

 

[White Knight]

Man! That is WAY over my head...lol...Seriously, I'm a DumbA$$ about electricity.....I don't even like Static elec....lol

I'd need some help with this, I'm sure......

Thanks though.....Hope I can find someone round here that knows this stuff like you do...

If those ideas don't work I think we can build you something simple. I was over-thinking it when I first responded.
After thinking about it I think a simple voltage divider like this would work:

And I think this 50ohm resister in place of R1 and this 100ohm and two of these 10ohm resisters (all end to end in series) would work for R2

 

[Joesixpack]

If those ideas don't work I think we can build you something simple. I was over-thinking it when I first responded.
After thinking about it I think a simple voltage divider like this would work:

And I think this 50ohm resister in place of R1 and this 100ohm and two of these 10ohm resisters (all end to end in series) would work for R2

Thats a pretty poor voltage supply for digital circuits....... If your going to build something from radio shack might as well build a regulated supply with

+5V Fixed-Voltage Regulator 7805 - RadioShack.com

$2 bucks.

Instructions and how to......

http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html





But don't think Swole is to interested in getting the soldering iron out....


David sounds like your on the right track, the two boxes must be pulling too much from the one line.......

I'd try tapping a different sensor, oil, water with 5V. 3 wire sensors, not the two wire....

Oh...and I'm pretty sure there is only 12V on the obdII port.

 

[joefarmer]

Use a 7805 and be done with it. Just make sure you use a heatsink with it if you're pulling any sort of load on it.

 

[Big Swole]

Thank you all for the replies!! I do believe I saw some of those 7805's there last night...

Joefarmer - Whats a "heatsink"?...... It's just going to power my TS Shift master..I can't imagine it has much load...

Thanks Sixpack for the links!!


So I just hook up the three leads from the 7805 as the instructions say and WA-LA, I'll have 5v's direct from the battery?? It'll be nice if it works!!! Thanks you guys!

 

[White Knight]

Thats a pretty poor voltage supply for digital circuits....... If your going to build something from radio shack might as well build a regulated supply with

+5V Fixed-Voltage Regulator 7805 - RadioShack.com

$2 bucks.

Instructions and how to......

http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html





But don't think Swole is to interested in getting the soldering iron out....


David sounds like your on the right track, the two boxes must be pulling too much from the one line.......

I'd try tapping a different sensor, oil, water with 5V. 3 wire sensors, not the two wire....

Oh...and I'm pretty sure there is only 12V on the obdII port.

I've never seen one of those before, that's pretty cool :bow:

 

[joefarmer]

Thank you all for the replies!! I do believe I saw some of those 7805's there last night...

Joefarmer - Whats a "heatsink"?...... It's just going to power my TS Shift master..I can't imagine it has much load...

Thanks Sixpack for the links!!


So I just hook up the three leads from the 7805 as the instructions say and WA-LA, I'll have 5v's direct from the battery?? It'll be nice if it works!!! Thanks you guys!

It's a large metal plate that snaps or bolts to the 7805 and dissipates the excess heat from the chip.

THe big metal wavy thing on the upper right:

 

[Big Swole]

Ah!!!! Sorry for my ignorance!

I'm hoping to try this tmrw or Thurs while I'm off...

Thanks for the help!!!

 

[Big Swole]

Just wanted to say thanks to JoeSix and Joefarmer!

The Radio Shack 7805 worked like a charm!!!

Good lookin out!!!!