Hey guys, just wondering if anybody here has any experience with Haltech and external MAP sensors. I have a GM 3 bar sensor and just can't get it to work (part #12223861). I would like to use an external becaue my on board sensor is off. With the engine off it reads -1.1psi (-2.2hg), so when I am in full boost it would read 4.2 and not 5.5 which is the wastegate spring pressure.

I just can't get it calibrated. I found this map here: http://hhscott.com/93tmv/3-bar_map.htm and tried the numbers out. The boost/vac guage and the Haltch reading (on the laptop) are about right but my A/F goes to 10.5:1 at idle where it usually sits at 14.7:1 when internal MAP sensor is activated.

Any recomendation?


I notice that when I downloaded the 1.03 firmware there is a "calibrations" folder in there. In this folder I found the GM 3 bar calibration map but can't get it to work. Maybe I am missin something.


Help is greatly apreciated.

I want to bump the boost up to 8.5psi but would like to straigten this out first.

 

Did you select Manifold Pressure Source = External? What does 'Load - Fuel' show with the engine off with external map select? What about when running?

 

Hal,


I did select the "External" MAP sensor. I went to the "Setup" / "Main Setup"/ "MAP" menu and put the values in the "Volts" and psi/inHg boxes from that chart in and the original post.

So for Volts, I put .1V= -15 and for 4.8V I put 27.2psi.

With the engine running and these values the gauge on the laptop reads -15.


When I go back to internal MAP the car runs fine, it's just that the onboard MAP sensor reads -1.1psi with the engine off.



The car does not run properly though, when I turn the car off it continues to run for about 3 seconds.



How do I run the "Calibration" file that comes with the 1.03 sofware? I see that the GM 3 bar map sensor is there.

 

Any more input/suggestions?

 

To use the calibration file, go to Main Setup, MAP, and press the Load icon (a folder). I am not sure if this works in 1.03, try upgrading to latest if not. All it is going to do is set 0v = -100kpa, 4.90v = 198.7kpa

Again, same question as last time.... What does 'Load - Fuel' show with the engine off with external map select? What about when running?

 

Sorry Hal, I thought I had posted the load readings in post #3.


Well I did the calibration via "Load icon" and the car runs fine now with the external sensor. Same as it does when the internal is selected. So no porblems there any more, however, it is still not reading correctly. It reads just like the on board sensor:


Load with engine off: -10.4Kpa
Load with engine idling: -73Kpa

I took the hose off and it didn't make a difference.

 

Do you have a separate boost gauge that can confirm that the Haltech values are off? I suppose you can calibrate the curve to whatever you want with the external sensor but it seems odd that both the internal and external MAP sensor are reading 1 psi off.

 

Well, I do have a boost gauge (new Autometer) and I know it is reading corretly. How I know is when I am in boost. My w/g spring is 5.88 psi and it gets it's reference at the turbo. My Autometer gauge reads just a hair over 5psi (manifold pressure) when I am in full boost, so this makes sense and the .8 psi is lost through the intercooler.

While the boost gauge reads just over 5psi my Haltech log reads 4.2psi, again one psi below expected. My gauge and haltech are on the same vacuum/pressure line.



EDIT:

I just adjusted this setting: 4.90v = 198.7kpa to 4.4V = 198.7kpa and it seems to be maching the boost gauge. I can't really go out for a drive as it has been raining all night, so very slipery roads. I will test it all out tommorow I guess. Last night when I played with these numbers the car would do all kinds of funny stuff and run really rich, don't know what that is all about. It seems to be ok now.

I should also have some track times for my build thread by Saturday, I am heading to the track on Friday night.