Map Sensor Mods?
FTE Leadership Emeritus
Joined: May 2001
Posts: 13,653
Likes: 6
From: Cabot, Arkansas
The diode isn't neccessary then (yet).
What happens is when the MAP sensor detects an overboost condition (~24psi, which is interpeted as an approx. 5 volt signal) it sends that information to the PCM which backs off the fuel map, reducing power. The zener diode (4.7v) installs on the center wire (the green one) of the MAP sensor, and shunts anything over 4.7 volts to ground, preventing the de-fuel.
What happens is when the MAP sensor detects an overboost condition (~24psi, which is interpeted as an approx. 5 volt signal) it sends that information to the PCM which backs off the fuel map, reducing power. The zener diode (4.7v) installs on the center wire (the green one) of the MAP sensor, and shunts anything over 4.7 volts to ground, preventing the de-fuel.
Fleet Mechanic
Joined: Aug 2003
Posts: 1,769
Likes: 95
From: Phoenix, AZ
Cookie,
Do you prefer the diode or the regulator?
Is that the regulator in your pix?
If you prefer the regulator, could you provide the source or manufacturer name of your regulator? Any special hardware, fittings, etc.?
What would Ford say if they saw this regulator set up and I am still under warranty? Kind of a dead give away huh?
Do you prefer the diode or the regulator?
Is that the regulator in your pix?
If you prefer the regulator, could you provide the source or manufacturer name of your regulator? Any special hardware, fittings, etc.?
What would Ford say if they saw this regulator set up and I am still under warranty? Kind of a dead give away huh?
Posting Guru
Joined: Feb 2003
Posts: 2,153
Likes: 1
From: Roseburg OR.
Cookie,
My buddy that I e-mailed you about a while back is trying to find the right diode but can't locally. He was going to have a buddy who does phone work order him one and he said there were several different wattages of that diode starting at 1 watt. I don't know anything about this so I can't comment. Would the 1 watt diode be fine or a larger one?
My buddy that I e-mailed you about a while back is trying to find the right diode but can't locally. He was going to have a buddy who does phone work order him one and he said there were several different wattages of that diode starting at 1 watt. I don't know anything about this so I can't comment. Would the 1 watt diode be fine or a larger one?
FTE Leadership Emeritus
Joined: May 2001
Posts: 13,653
Likes: 6
From: Cabot, Arkansas
Heatstroked:
That is a relief valve in the pics, but I do prefer the regulator. You can go to Lowes or Home Depot and pick up a mini regulator, and a couple of 1/4" barbed hose fittings. Then just splice it in next to the boost gauge tee. You will need an air compressor to set it initially. Adjust it to about 20# and lock it down.
RRMike:
A one watt diode will work fine. You can have Radio Shack order one (if it's not in stock) and it will ship to your door.
That is a relief valve in the pics, but I do prefer the regulator. You can go to Lowes or Home Depot and pick up a mini regulator, and a couple of 1/4" barbed hose fittings. Then just splice it in next to the boost gauge tee. You will need an air compressor to set it initially. Adjust it to about 20# and lock it down.
RRMike:
A one watt diode will work fine. You can have Radio Shack order one (if it's not in stock) and it will ship to your door.
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Fleet Mechanic
Joined: Aug 2003
Posts: 1,769
Likes: 95
From: Phoenix, AZ
Thanks Cookie,
Yeah, I went to the local RS and they had a 5.1 V zener nothing else even close.
So, if I install a regulator, the boost gauge will never show anything above the locked down PSI of 20 lbs. right?
What do you think Ford would say if they ever popped the hood to check out warranty issues?
I have a 2002 w/26000 miles right now.
The diode is more discrete but the regulator seems to be more accurate and adjustable.
Thanks for your input!
Yeah, I went to the local RS and they had a 5.1 V zener nothing else even close.
So, if I install a regulator, the boost gauge will never show anything above the locked down PSI of 20 lbs. right?
What do you think Ford would say if they ever popped the hood to check out warranty issues?
I have a 2002 w/26000 miles right now.
The diode is more discrete but the regulator seems to be more accurate and adjustable.
Thanks for your input!
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Tuned
Joined: May 2003
Posts: 303
Likes: 2
From: Kentucky
Hey cookie,,,I'm getting lost here. Where is the regulator and what is it for? My engine light comes on alot and I didn't know it was cutting back on the fuel. Be more specific as I am new to Hot Rod trucks 
FTE Leadership Emeritus
Joined: May 2001
Posts: 13,653
Likes: 6
From: Cabot, Arkansas
So, if I install a regulator, the boost gauge will never show anything above the locked down PSI of 20 lbs. right?
I'm probably not the best person to ask about warranty implications. When I put my first chip in at about 12,000 miles I became my own warranty provider. But since you asked.....I'd advise you to be up front with them. Tell them what mods you've made and why. They'll either honor it or they won't. If it's something that is definately not mod related they have to cover it, but it may be a fight convincing them to do so. It depends alot on your relationship with the dealer, and what part has failed.
FoMoCo:
What we're doing here is installing a miniture air pressure regulator in the MAP sensor line to regulate the amount of pressure the MAP sensor see's. It does the exact same thing as a zener diode (see description earlier in this thread), only you are fooling the computer by mechanical means instead of electrical.
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