I have a crown victoria with 212k miles that started running rough and pinging at higher loads. I thought the engine was just shot. I learned at a website for CV's that if the MAF gets dirty it can through off your fuel injection system. The MAF tells the computer how much air is entering the engine. From what I've read, when a MAF gets dirty it indicates higher than actual air flow and causes the engine to run rich at low power and indicates lower than actual air flow causing the engine to run lean at high power .
At lower power levels (normal driving) your O2 sensor will update the fuel trim tables telling the computer to reduce the fuel flow to compensate for the richness. However, at high power the circuit goes open loop, disconnecting the O2 sensor and hence no updating. So when you jump on it, more air is going through the MAF than it is indicating to the FI system (causing the engine to run lean) plus the computer goes to the fuel trim tables and reduces fuel flow again (extra lean) causing low power and heavy pinging. At least on Fords the computer uses the fuel trim values learned at low power for high power (open loop) operation
When I cleaned the MAF on my CV the results were remarkable. It changed from a dog to a neck snapper. The increase in torque "made it feel young again". My cruiser doesn't have the mileage but it helped it too.
Here is a link to the cleaning procedure for a CV just to get the general idea, if you think you may have a MAF issue.
http://www.crownvic.net/tech/cleanmaf.html
You can also search the web for articles on MAFs. There is a good technical bulletin by Ford ( I think all the MAF's use the same detector design).
On my 95 LC the MAF is downstream from the air cleaner. If you take it out it looks like a jet engine. Look into the hole in the center with a flashlight and notice those two little wires that are the sensing elements for the MAF. If they are dirty you are in for a pleasant surprise when you spray them down with contact cleaner. I sprayed mine down and didn't have any negative reaction from the plastics, but proceed at your own risk. You might also have to disconnect your battery to dump the computer memory after you have a clean MAF to get rid of those old fuel trim values.
I'm no expert but this was very helpful to me and thought I pass it on.
Hope this is helpful for you guys with dirty MAFs.
Don't forget use electrical contact cleaner and not choke cleaner or other solvents. Also, compatability with the polymers in your MAF may be an issue, but it wasn't in mine.
At lower power levels (normal driving) your O2 sensor will update the fuel trim tables telling the computer to reduce the fuel flow to compensate for the richness. However, at high power the circuit goes open loop, disconnecting the O2 sensor and hence no updating. So when you jump on it, more air is going through the MAF than it is indicating to the FI system (causing the engine to run lean) plus the computer goes to the fuel trim tables and reduces fuel flow again (extra lean) causing low power and heavy pinging. At least on Fords the computer uses the fuel trim values learned at low power for high power (open loop) operation
When I cleaned the MAF on my CV the results were remarkable. It changed from a dog to a neck snapper. The increase in torque "made it feel young again". My cruiser doesn't have the mileage but it helped it too.
Here is a link to the cleaning procedure for a CV just to get the general idea, if you think you may have a MAF issue.
http://www.crownvic.net/tech/cleanmaf.html
You can also search the web for articles on MAFs. There is a good technical bulletin by Ford ( I think all the MAF's use the same detector design).
On my 95 LC the MAF is downstream from the air cleaner. If you take it out it looks like a jet engine. Look into the hole in the center with a flashlight and notice those two little wires that are the sensing elements for the MAF. If they are dirty you are in for a pleasant surprise when you spray them down with contact cleaner. I sprayed mine down and didn't have any negative reaction from the plastics, but proceed at your own risk. You might also have to disconnect your battery to dump the computer memory after you have a clean MAF to get rid of those old fuel trim values.
I'm no expert but this was very helpful to me and thought I pass it on.
Hope this is helpful for you guys with dirty MAFs.
Don't forget use electrical contact cleaner and not choke cleaner or other solvents. Also, compatability with the polymers in your MAF may be an issue, but it wasn't in mine.
Not a real good grade booster, trust me.
