1998 CV MAF sensor/engine ping *SOLVED*

[monterey1962]

1998 CV LX w/4.6L. Engine has a ping and "rattle" on days 80+ deg. F., under acceleration/load, and is worse with the A/C running. Cooler days (including winter) the noise does not seem present. Not sure if there is any power loss since I am the passenger 99% of the time (it's my mom's car).

CVN has a fair amount of threads on this issue, but as with most of their threads, no one ever follows up and posts whether or not they found a fix. I followed the procedure listed here to test MAF voltage: http://www.crownvic.net/ubbthreads/u...73#Post2083673

The car has had a coolant flush, new Motorcraft spark plugs, new air filter, and new fuel filter in the last six months.

After cleaning the MAF sensor with the appropriate MAF sensor cleaner, I was able to get the voltage down to .81. CVN info states that .6 to .75 volts is correct, yet no one states where that information comes from. Is the .6 to .75 the correct range?

Any info regarding a fix or something new to try is appreciated. Ask if you need more details.

[Kodachrome Wolf]

My '97 has been suffering similar issues. I can clean it and it may or may not have an effect. The car hates regular gas. I can usually get away with mid-grade, but when it gets hot, it gets back to pinging. The times I've run premium in it, it stops all that business and pulls strong and happy all day. Needless to say, I'd rather not have to burn premium in a car rated for 87.

I've been thinking about grabbing a MAF off a junk car at the salvage yard and seeing if that changes anything. If that doesn't work, I'm going to try Seafoaming the engine and see if burning out built up carbon might help.

[knucklehead0202]

My '98 acted the same in the hot California summers. After experimenting with various grades and brands of fuel, I discovered it did better with 89 octane than anything else. Your experience may vary but try a top-tier fuel in mid-grade and see how she does. My experience with premium did not improve or degrade performance but mileage suffered in a way it did not with 89 or even 87. Just my $0.02

[sly]

+1 NPIs have this issue with E10. If you can find pure gas, you can run 87. The tune on those cars is so close to being lean that it will ping with E10. Replacing the injectors with the next size up just to get that much more fuel in may also help, but it's only an idea and not based on any application. The idea is going from 19# to 20# or if yours has those weenie 13#, using 14#. My engine got replaced before I ran through this idea and the 2000 doesn't have the issue.

[monterey1962]

Thanks for the info. Will try E-free 87 or 89 octane.

[monterey1962]

Last weekend, my mom ran the tank down to "Empty" and filled half a tank of Ethanol-free 87 octane. She drove it for the week, then let me drive it today.

No more "rattle" or "pinging". Weather today is hot and 84 deg. F. when I drove the car. I ran the car on the same stretches of road and under the same conditions as the last time I tested it. Even with AC running, there's no noise.

Thanks guys. Looks like we'll be feeding this car E-free from now on.

[porschpow]

Unfortunately where I live, we have no ethanol free gas, sux! But I am havig the same problem with my 1997 town car, even with premium she pings and chatters!!!!!!