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Sooo sick of defueling!!!!!

Thats where a scanner would come in handy, so you can see what the MAP is reading the atmospheric pressure is, should be about 14psi with no boost. and monitor evereything real time.
 
buddy said:
Thats where a scanner would come in handy, so you can see what the MAP is reading the atmospheric pressure is, should be about 14psi with no boost. and monitor evereything real time.
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X2
Snap On scanner MT2500s on ebay are coming down in price, several lap top software tools reasonably priced these days as well.
 
I've figured it's best to get all the mods necessary done and out of the way before i get the GL4. I'm ready just don't have money to throw away...... yet ;) I'll have to get an ohm meter and check out the resistance and if a map sensor is cheap i'll just replace it. I don't really want an ic because Turbine Doc has liked not having his installed, just get an att later on.
 
Ok, Nothing wrong with the sensor. I'll have to se if i know anyone around me with a scanner to get the codes. I can generate it pretty fast if it's cleared, just have to floor it till i get to 90 and then it throws. So is there any way to fool the pcm about the iat safely?
 
If you think the IAT sensor is to blame, unplug it....

Truck will see IAT as low....

Better yet - a trick I learned was to take the IAT sensor out of the intake and wrap it in a shop towel. Set it somewhere that it won't get damaged and put a plumbing plug in the intake hole for the sensor...testing/drag racing purposes only of course :thumbsup:....
 
Their is no way that 8psi of boost will cause a problem. The truck runs that stock anyway. As Turbine Doc stated the IAT or MAP. You have checked the map so now is the IAT. I have also seen the throttle position sensor do this. I don't have my books any more and don't remember which side is the sensor. That will throw a code too. Codes will certainly help.

Greg
 
Put a resistor across the IAT sensor harness, you would fool the PCM to thinking its only 150 if you put in a 500 ohm resistor.

Maybe you shouldnt go 90MPH with 4.10 gears :)

What size tires do you have on there, noticed you had newer wheels. If you put on some massive tires the truck might not realize how fast it is going and you can mess up tranny controllings.
 
buddy said:
Put a resistor across the IAT sensor harness, you would fool the PCM to thinking its only 150 if you put in a 500 ohm resistor.

Maybe you shouldnt go 90MPH with 4.10 gears :)

What size tires do you have on there, noticed you had newer wheels. If you put on some massive tires the truck might not realize how fast it is going and you can mess up tranny controllings.
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True that! I'm scared at 70!
 
265/75/16. It's what was on the truck when i got it. The Speedometer is dead on to the exact mph. It goes to 100 :D just not since the vac pump died and i put a mech waste gate control on it. I know it's got the power, I just can't use it.

One thing i can think of that would cause it, When i put my boost gauge in I put a "t" in the sensor hole so i could have a barb fitting for the boost gauge line. Could that being raised up above the intake manifold get enough engine compartment heat to make a difference?
 
Anyone in West Michigan with a scan tool? I'll buy your lunch!!!!!

This is going to be a pain in the butt if i gotta pull a 4k trailer 600 miles with a half alive 6.5L
 
Hmmm, so you split the airflow at the MAP sensor, and you are fooling the PCM on the boost amount. That could affect its measurements and your sensor's. Put that back to normal. Just get an $8 tap and put the boost guage in somewhere else.

If youre fooling the boost that would lead me to believe the truck might also think you are at like 15000ft elevation, since you would be telling it the atmospheric pressure is lower too. On a 94-95 OBD1 you can fool the boost sensor, because our MAP or EGR/BARO sensor is separate on the firewall.

The PCM can screw with fuel and timing based on elevation.
 
Deere Freek said:
One thing i can think of that would cause it, When i put my boost gauge in I put a "t" in the sensor hole so i could have a barb fitting for the boost gauge line. Could that being raised up above the intake manifold get enough engine compartment heat to make a difference?
Click to expand...

You could be cutting the air flow across the sensor causing it to heat up more.

Leo
 
Deere Freek said:
.

One thing i can think of that would cause it, When i put my boost gauge in I put a "t" in the sensor hole so i could have a barb fitting for the boost gauge line. Could that being raised up above the intake manifold get enough engine compartment heat to make a difference?
Click to expand...

Hmnnnn interesting thought there, since you don't have ready access to a scan tool, run without boost gage, or drill/tap the intake like most have done for your boost gage and put IAT sensor back where the factory put it.

There is a LOT of underhood heat, look at last data set in ATT thread, +20-40F difference of air box temp vs outside air temps, and that is just heat soak on a plastic box, imagine how much heat soak a metal cased probe/tee can get.
 
buddy said:
Hmmm, so you split the airflow at the MAP sensor, and you are fooling the PCM on the boost amount. That could affect its measurements and your sensor's. Put that back to normal. Just get an $8 tap and put the boost guage in somewhere else.
Click to expand...

X2

read over your post my apology shoulda read thru to page 2 Buddy; but spot on.
 
Deere Freek said:
Anyone in West Michigan with a scan tool? I'll buy your lunch!!!!!

This is going to be a pain in the butt if i gotta pull a 4k trailer 600 miles with a half alive 6.5L
Click to expand...

Any Autozone, Advanced Auto, etc will read your codes for free. It'll at least get you started with what the codes are. They can clear them right away, too.
 
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