MAF Question
Senior Member
Joined: Feb 2000
Posts: 1,544
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From: Kalamazoo, MI, USA
Nice 'Basics', Max.
From FAQ on the referenced site: "...1. [Problem]: My car won't idle properly.
[Solution]: Check TPS voltage, it should be 0.995 to 0.999 with the ISA disconnected, or KOEO. If the car won't idle with the ISA disconnected, then it will not idle with it reconnected. Always adjust the mechanical linkage with the ISA disconnected for the best mechanical idle and to prevent feedback from the EEC IV during adjustment. The thermostat should be 180 F. If the battery is in the trunk, a 12 gage wire needs to be run from the battery post negative to the engine block. If long tube headers are being used, make sure they are ceramic coated to prevent EGO drift lean. Open air breathers cause the vehicle to run lean at idle. Either use a stock breather cap with the throttle body hose connected, or add a nipple between the outlet of the MAF and the inlet to the supercharger. This will allow the MAF meter to measure all incoming airflow, and correct the lean condition. *Also check MAP sensor..."?
<Whew!>
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Y2K™ Jim - N8JG@Hotmail.com
Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"
From FAQ on the referenced site: "...1. [Problem]: My car won't idle properly.
[Solution]: Check TPS voltage, it should be 0.995 to 0.999 with the ISA disconnected, or KOEO. If the car won't idle with the ISA disconnected, then it will not idle with it reconnected. Always adjust the mechanical linkage with the ISA disconnected for the best mechanical idle and to prevent feedback from the EEC IV during adjustment. The thermostat should be 180 F. If the battery is in the trunk, a 12 gage wire needs to be run from the battery post negative to the engine block. If long tube headers are being used, make sure they are ceramic coated to prevent EGO drift lean. Open air breathers cause the vehicle to run lean at idle. Either use a stock breather cap with the throttle body hose connected, or add a nipple between the outlet of the MAF and the inlet to the supercharger. This will allow the MAF meter to measure all incoming airflow, and correct the lean condition. *Also check MAP sensor..."?
<Whew!>
------------------
Y2K™ Jim - N8JG@Hotmail.com
Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"
Senior Member
Joined: May 2000
Posts: 4,761
Likes: 0
Y2K 7700 4X4- Thanks for your seal of approval. Beyond the basics, pro-flow is gracious enough to provide technical information for all skill levels.
Joe T- The two questions that YOU asked can have some light shed on them here, as well as a few illustrations and products.
[This message has been edited by max mitchell (edited 11-04-2000).]
[This message has been edited by max mitchell (edited 11-04-2000).]
Joe T- The two questions that YOU asked can have some light shed on them here, as well as a few illustrations and products.
[This message has been edited by max mitchell (edited 11-04-2000).]
[This message has been edited by max mitchell (edited 11-04-2000).]
Senior Member
Joined: Aug 1999
Posts: 196
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From: Oklahoma City
Hello Joe T, welcome to the Board. I will try to give a very brief description of the MAF. It directly measures the mass if the air flowing into the motor. This tells the EEC how much fuel to deliver. Fuel delivery is fine tuned by other sensors i.e. O2 and throttle position sensors. Contrast this with the older type of fuel injection known as Speed Density (SD). SD motors used the manifold absolute pressure (MAP) sensor, throttle position sensor, and the known volumetric efficiency of the motor to determine amount of fuel to deliver. You probably find a better explanation in a Ford Motorsport catalog. Regards, m.a.t.
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1999 XLT SC, bright red, 4.2l, 5 speed, MAAP stainless nerfs, Prime Designs bug deflector, Astro Euro-Lid II, Mobil 1 Synthetic Oil and Transmission Fluid.
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1999 XLT SC, bright red, 4.2l, 5 speed, MAAP stainless nerfs, Prime Designs bug deflector, Astro Euro-Lid II, Mobil 1 Synthetic Oil and Transmission Fluid.
Senior Member
Joined: May 2000
Posts: 4,761
Likes: 0
Some nice basics can be found at www.pro-flow.com
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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
Class III tow/Payload #3/Convenience pkgs.,
4-wheel disc/ABS,Chestnut/Parchment 40/60,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification, Superchip,
Dynomax ultra-flow welded 3" cat-back,
3" exit Y-pipe, Hellwig rear anti-sway bar,
Rancho RS9000s.
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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
Class III tow/Payload #3/Convenience pkgs.,
4-wheel disc/ABS,Chestnut/Parchment 40/60,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification, Superchip,
Dynomax ultra-flow welded 3" cat-back,
3" exit Y-pipe, Hellwig rear anti-sway bar,
Rancho RS9000s.
Senior Member
Joined: Oct 1999
Posts: 554
Likes: 0
From: Trixters-Playground
I just want to clarify some things here.
M.A.T. is right.
The late model F-150s have EEC V. EEC IV diagnostic routines will not apply to the new F-150s. Bear in mind, some of the basics will apply.
Disconnecting the IAC will not affect TP voltage. TP readings change only when you open the throttle.
When the MAF is used, the MAP is not.
The PCV system definitely needs to remain closed. You will find the breather tube takes in filtered air from the intake duct.
M.A.T. is right.
The late model F-150s have EEC V. EEC IV diagnostic routines will not apply to the new F-150s. Bear in mind, some of the basics will apply.
Disconnecting the IAC will not affect TP voltage. TP readings change only when you open the throttle.
When the MAF is used, the MAP is not.
The PCV system definitely needs to remain closed. You will find the breather tube takes in filtered air from the intake duct.