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Boost Fooler Adjustment Question

MBBOB

MBBOB

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Location
Conneaut Lake, PA
I have the turbomaster set at 10 psi at WOT and for some reason it started throwing 78 code recently, so I installed the 10k boost fooler as outlined in the stickys. My question is what setting am I looking for? Is there any harm in turning it to max if I have the boost known to be set at 10 psi? If so, what is the adjustment I am looking for?

PS. I have it set with a gauge

Thanks
 
I run a 10k pot on both my baro and my MAP. Forgive my improper verbiage but 94s have a baro and if you don't tweek it as well, the ECM will notice a differential out of range discrepancy and defuel/code. I run my baro at the full setting and the MAP at 2.5 largely because that's the threshold before it codes. I also run a "F" chip as I've removed the vacuum and blocked the EGR.

Your signature would seem to indicate you've spent your money well.
 
Do you just measure the resistance across the pot when running? or just back it off until code and then turn it up a bit?

Where did you wire it into the baro? I think this may be my problem because the code usually does not trip under boost, it seems more atmospheric ( if that is possible)

Excuse my ignorance, I am an electronics dork.
 
Thanks Guys for the support, the money was spent with tears in my eyes, but I read and learned from the people here.

Just getting tired of trying to "fool " this thing:

Switch to fool it about starting temperature

POT to fool boost pressure

Now maybe a POT to fool the baro

Just need to pull the plug and buy the GL4
 
MBBOB said:
Do you just measure the resistance across the pot when running? or just back it off until code and then turn it up a bit?

Where did you wire it into the baro? I think this may be my problem because the code usually does not trip under boost, it seems more atmospheric ( if that is possible)

Excuse my ignorance, I am an electronics dork.
Click to expand...

I'm a bigger electrical dufus. I caused an entire wiring harness I'd spent 2 hours building to go up in flames.

Measure? That's for the other guy. Kennedy Diesel confirms that the 94 needs to have the baro tweeked as well or you'll code. I've attached a photo of a baro. It has a green connector and is located next to the wiper motor and above the brakes master cylinder. The baro wiring works the same way as the MAP - input reference signal, output signal and ground - so wire it the same way. A fixed 10k resistor is viable here.

Again, I run the baro full up on the 10k pot and while driving run the MAP up SLOWLY until the truck codes and then back it down slightly. Also attached are photos of my pots on the dash. The one on the left is the baro; right pot is the MAP.
 

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I cant hardly believe you would need to fool the Barometer, but maybe it makes more power if you do. That is supposed to be the exact Barometric Pressure not fooled, as it gives the engine an idea of your elevation/atmospheric pressure, and how much actual boost you have because N/A would be at the atmospheric pressure, anything over that is the amount of boost.

Now if you fool it to make it think that atmospheric pressure was much higher than it is, then you might accomplish the exact same thing, because you would be subtracting this amount from the total pressure the boost sensor sees. However I dont think it is necessary, and could be degrading to performance.

The boost sensor is what causes the codes becuase your out of the stock ECM's boost schedule, more pressure than it would be telling the vacuum wastegate solenoid to be allowing.

I use an F chip on my S engine, and all I did was pull the vacuum hose off of the firewall Baro sensor.
 
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buddy said:
I cant hardly believe you would need to fool the Barometer, but maybe it makes more power if you do. That is supposed to be the exact Barometric Pressure not fooled, as it gives the engine an idea of your elevation/atmospheric pressure, and how much actual boost you have because N/A would be at the atmospheric pressure, anything over that is the amount of boost.

Now if you fool it to make it think that atmospheric pressure was much higher than it is, then you might accomplish the exact same thing, because you would be subtracting this amount from the total pressure the boost sensor sees. However I dont think it is necessary, and could be degrading to performance.

The boost sensor is what causes the codes becuase your out of the stock ECM's boost schedule, more pressure than it would be telling the vacuum wastegate solenoid to be allowing.

I use an F chip on my S engine, and all I did was pull the vacuum hose off of the firewall Baro sensor.
Click to expand...

On OBD-II S baro is only looked at at start up, then the baro reading becomes the feedback of vac applied to EGR, and from feedback PCM guesstimates the position of the EGR, which is why when I went S to F PCM before I reflashed I kept EGR functional, but blocked off flow with a plate under the EGR valve . I was able to run MAP(boost) fooled only and not code
 
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I didn't tweak the baro sensor on my old 94....there was no need to in order to reach 10 psi....

When I wanted more than 10 psi, then I had to screw around with other things....
 
Tell you what, I'll turn off my baro BSer on the way to work today and report tonight as to whether it codes. I'll do a full throttle pull at 11 psi through the gears...for science. Of course that'll be just anecdotal evidence.

Honestly, with your mods, if you have the means to chip it that would end the discussion and likely reap the benefits of much of your upgrades.
 
Dan Hunter said:
Tell you what, I'll turn off my baro BSer on the way to work today and report tonight as to whether it codes. I'll do a full throttle pull at 11 psi through the gears...for science. Of course that'll be just anecdotal evidence.

Honestly, with your mods, if you have the means to chip it that would end the discussion and likely reap the benefits of much of your upgrades.
Click to expand...

Please try it Dan, as I have limited experience with fooling for the OBD-Is and would like to know for the next go round this question comes up
 
Should be no issues at 10 psi max.....been there done that...

Unless baro from SK to OK is significantly different.....
 
Keep in mind that I was lazy and just spliced at the sending unit rather than chase the wires inside the cab so there may be some resistance across the wires effecting results.

With both dials turned full down, and cruising at 65 mph, I turned the MAP pot until it coded. Interestingly, it coded at 4.5...when I set it on installation in the summer, it was 2.5 but that was enough to allow me to set the TM at 12 psi under a load.

With the MAP set, I adjusted the BARO pot full up - both cruising and at full throttle and noticed no changes on boost and no coding. Back cruising, I was not able to adjust the MAP threshold by adjusting the BARO.

Finally, I went full off with both pots and at full throttle I rapidly dialed up the MAP to my present 4.5 limit. I noticed a smooth increase of about 2 psi which essentially allows me to hit the TM limit.

Now, I'm at 1300 MSL but the current altimeter is 2995 which puts me effectively at sea level. I wonder if the results would have been different if the pressure altitude was higher.
 
From Kennedy Diesel's Website:

"While this unit works on all model years, it is particularly effective on 1996 up trucks with HD "F" engine programming. It is my suggestion that 94-5 trucks take advantage of the TD-Max Performance Chip Prior to installing this unit as it will likely be unnecessary to ad the boost control with the proper chip calibration. Use on the 94-5 trucks and 96+ LD "S" engines may require a second controller on the firewall mounted MAP sensor to avoid an aggravated DTC 78 (wastegate solenoid) fault code." - JK

I believe the "firewall mounted MAP sensor" he's refering to is the BARO.
 
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