I have a coolingmist progressive alky injection system. The progressive controller uses the GREEN wire from the map sensor as a reference to determine boost. I have a A P&P blower, P&P 2.4 head, secret cams and a header as flow mods. I am using the stock size 2.8 pulley on the m45. I see just a hair over 3psi of boost on my stewart warner boost gauge. (this gauge seems accurate as it rests perfectly at 0 with the car off). This is also the amount of boost I would expect from my setup. I am sure this is what my car is truely building for boost.
Here is my problem.
BEFORE With the wire for the progressive controller hooked to the map sensor I was seing 105kpa (1.16psi) acording to hp tuners. Hp tuners just displays what the pcm is seeing for boost. I was running lean acording to my brand new AEM wideband. I also used another AEM wideband I borrowed before I bought mine. Both widebands read the same. AFR would climb to 13.6 at about 6800rpm Alky injection would not kick in even though it was set at 2psi and the gauge was reading 3psi
AFTER
I unhooked this wire I instanly saw 125kpa (3.62psi) via hp tuners. Same abient air temp, same IAT readings, ect the only thing I changed was unhooking the alky controller signal wire from the green wire coming off the map sensor. Now with the pcm reading more boost (and adding fuel accordingly) the leanest it went was 12.9 at about 6800rpm
So it appears that tapping the map sensor wire for the signal is NOT OK. I will be calling coolingmist tomorrow to get there thoughts on this.
So now my options are
- no longer use the progressive controller instead using a 2 psi mechanical boost switch
- or see if I can wire up another seperate map sensor just for the progressive controller
Thanks to wrenchmonkey for his over the phone help with hp tuners ?s and for converting kpa to psi for me while I was in the middle of nowhere driving down the interstate.
Thanks to Chris Taetsch for mentioning that it does not seem like a good idea to hook another wire to the map wire as it could affect the voltage to the pcm. He was 100% right on this. I had originally thought this but dissmissed it saying to myself "coolingmist would not reccomend doing it this way if there was an adverse reaction".
Feel free to share your thoughts on this matter.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
tapping a wire can alter the output of the sensor you are tapping....absolutely.
especially depending on what method you used to tap it with (straight splice, splice with solder, 3m scotch lock...etc).
I would not advise doing it for sensor information at all. I was going to do the same thing for the boost retard on my MSD, but when I had asked MSD if I could use the signal from my car's MAP to ALSO use with the MSD box, they said there would most likely be voltage loss, and it would not read correctly.
I bought a seperate 3-bar map soley to use on my MSD. Since it is there to only pick up boost, I have it fed off the intake piping right before the TB, therefore I would not have to modify the TB or intake mani.
As mentioned, tapping off of sensors always alters the voltage... with a sensor like the MAP you do not want this.
Just pick up a universal 2 bar sensor and harness and get a separate signal for the coolingmist setup.
Good luck man!
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
To splice the wire I used what I think is called a scotch lock. It is the peice thaty ou lay one wire through it and then the other wire right beside it, then smash this litle metal razor blade looking thing down. This metal peice cuts through the sheathing of both wires and transfers the electricity.
I am sure I the method I use to splice it will have an effect on the volage. The only difference being how bad. I don't think I should do anything that will affect the voltage of that wire. To make matters worse I used a 16g wire for the signal wire for the alky controller and I think the map wire is a 18 or 20
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
I guess I just need to know how I wire up a 2nd map sensor. They operate in a 0-5v range so would I need to make sure that the votlage going to the senor is only 5 volts? Then the other two wire would be signal and ground?
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
the gauge of the wire SHOULD not make a difference on voltage.....but current and resistence instead.
you need a 5 volt source, and a ground to go to the extra sensor. usually the controller will already have this....but if they are suggesting tapping the wire, it doesnt sound like it does.
I would NOT do it like that...
In the Marines i learned that KISS is a GOOD idea.
Keep IT Simple Stupid.
I would get, and have used. This.
I would only use this.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
Do I need to make sure the voltage going to the map sensor is five volts? If so How would I step this down coming from the battery which is 12.6v?
Chris
I might go with a mechanical boost switch as it would be simpler and less wiring in my engine bay to run and hide. The only downside is it would not be progressive.
I am trying to weigh my options here.
Edited 2 time(s). Last edited Thursday, June 26, 2008 8:36 AM
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
Taetsch Z-24 wrote:I would NOT do it like that...
In the Marines i learned that KISS is a GOOD idea.
Keep IT Simple Stupid.
I would get, and have used. This.
I would only use this.
Chris
that might use a 12v source insead of 5...i cant tell since i can not get page 3 which is the schematic.
otherwise you need to pull a regulated voltage from somewhere other than your battery.
The only things I can think of with a regulated 5 volt are sensors that need all 5 volts. You have any ideas of what I could use for a regulated 5v source?
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
EGR is 5 volts from what I can remember...
why not snag the 5 volt power from the map sensor power wire near the PCM... ground it there too at the map ground wire... and then send the signal to the progressive controller?
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
BTW Sorry wade i did not get back to you last night.....
But i was right about the computer being in the wrong fuel cells and thats why its running so damn lean.
Wrench Monkey wrote:BTW Sorry wade i did not get back to you last night.....
But i was right about the computer being in the wrong fuel cells and thats why its running so damn lean.
True No wonder it was running lean. How is it supposed to provide fuel for 3psi when it only think it is fueling for half that.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
Wade Jarvis wrote:Wrench Monkey wrote:BTW Sorry wade i did not get back to you last night.....
But i was right about the computer being in the wrong fuel cells and thats why its running so damn lean.
True No wonder it was running lean. How is it supposed to provide fuel for 3psi when it only think it is fueling for half that.
Yep.... now you need to get a smaller pulley on and tune it
IM Tom to send ya my tune, I told him to Add 10% Fuel across the board. watch the W\B and ADJ from there.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
Taetsch Z-24 wrote:IM Tom to send ya my tune, I told him to Add 10% Fuel across the board. watch the W\B and ADJ from there.
Chris
I am looking to reduce some fuel actually right now. I am in the 10's for an AFR until about 4500rpm. The leanest it seems to get now is high 12's just before redline (7000rpm) I want to tune for my 440's and go from there with a smaller pulley.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
then take the tune as is.
it was set up for 36# injectors, but my M\sec was on the higher side..... so 440's would be that much better.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
John Benham wrote:tapping a wire can alter the output of the sensor you are tapping....absolutely.
especially depending on what method you used to tap it with (straight splice, splice with solder, 3m scotch lock...etc).
I would not advise doing it for sensor information at all. I was going to do the same thing for the boost retard on my MSD, but when I had asked MSD if I could use the signal from my car's MAP to ALSO use with the MSD box, they said there would most likely be voltage loss, and it would not read correctly.
I bought a seperate 3-bar map soley to use on my MSD. Since it is there to only pick up boost, I have it fed off the intake piping right before the TB, therefore I would not have to modify the TB or intake mani.
^The method of splicing makes no difference at all....none. The sensor pushes a voltage based on the analog measurement and the "reading" device (PCM) completes this circuit with a A-to-D or a resistor inline with the circuit. When you throw another "reading" device on the same circuit(splice in the coolingmist controller) which has its own A-D or resistor it changes to total resistance of the entire circuit, lowering the voltage drop across both senor reading devices (PCM & coolingmist controller) making the voltage output from the MAP sensor look lower than it really is. The ONLY way you can splice sensors like that is if you have the ability to calibrate both reading devices to the new total resistance......systems like the Megasquirt allow you do stuff like that because you can calibrate the MAP input to the MS and just lower the pressures required by the Coolingmist module to come on when you need it to. Anyway, enough of that, just put in another MAP or boost pressure switch as others have said on here and you'll be good to go.
I was refering to the quality of the connection made when doing the splice. Not just the type. If a good solid splice is made, reguardless of method, then I agree with Josh about the type of connection.
The rest of his statement is dead on.
^I figured your post just read wrong but I didn't want anybody to get the wrong idea......I know you know your stuff there John.
thanx for bringing out the clarification
Avoid Scotch Locks if you want to insure reliable connections over time. Make sure that you use whatever size wire is reccomended by cooling mist, larger is ok. If you go smaller you will run into higher resistance, its minimal over a short run but it will be higher.
Thanks for your help guys. This wiring thing is not my area of expertise as you can already tell. LOL
It is kind of frustrating to me that coolingmist reccomends tapping the map sensor wire. A progressive boost switch would be nice, but I doubt they make that.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
