1998 4.6 pinging bad.
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Junior User
Joined: Dec 2009
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1998 4.6 pinging bad.
I have a 1998 4.6 extended cab with flare side bed. The motor pings real bad.
It has new motorcraft plugs, good wires, just cleaned the maf sensor. Installed a new pcv valve and hose and evap hose. the hoses were changed due to some previous codes that were being thrown. It looks like the ecm was changed since it has a seperate sticker on the door jamb. any input?
It has new motorcraft plugs, good wires, just cleaned the maf sensor. Installed a new pcv valve and hose and evap hose. the hoses were changed due to some previous codes that were being thrown. It looks like the ecm was changed since it has a seperate sticker on the door jamb. any input?
Laughing Gas
Joined: Jan 2006
Posts: 1,098
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From: Minnesota
Next to the MAF is the IAT sensor. Clean that and see if that helps. I replaced mine years ago because it really knocked when it got cold out. It was rather inexpensive and simple to change. Solved the problem for me.
Senior User
Joined: Jan 2008
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Before jumping to the conclusion, I would check vacuum leak first, because it's simpler than replacing knock sensor. Connect a scanner and read fuel trim. If numbers are high, vac leak is suspected. Vac leak will make engine run hot and cause pinging without throwing codes. YOu can replace knock sensor after that.
Laughing Gas
Joined: Jan 2006
Posts: 1,098
Likes: 11
From: Minnesota
I would sure check other things as mentioned first, EGR, IAT.....can really screw it up. When my IAT was bad I got no CEL....but A LOT of ping. Very well may be the knock sensor in the end, but that thing is a pain to get at if it's the same as a 4.6 in Mustang. I pulled the intake because I wanted to change it to an updated one any way ( aluminum coolent crossover).....this was on a car though. Not sure on your truck if you can get at it.
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Junior User
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Ok new knock sensor in, new air temp sensor. And still pings with 91 octane. I know the heads were resurfaced when I got the truck. Is it possible I need to run a different spark plug. I change the DPFE, for a different code. But also checked for vac leaks and found none. The erg was work as well
Lead Driver
Joined: Sep 2006
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With no codes set, the only thing that will cause pinging assuming it is not an internal engine issue is the EGR is opening.
This will advance the ignition timing and lean out the fuel.
Both these togather is a no no under load.
Check out the EGR control vacuum regulator for leaking or hanging up not allowing the EGR to close once it has opened and the vacuum lines are on proper.
Clean the vacuum regulator filter under the round cap.
Normally the PCM will detect an issue in this system and set a test failure code but you never know.
Good luck.
This will advance the ignition timing and lean out the fuel.
Both these togather is a no no under load.
Check out the EGR control vacuum regulator for leaking or hanging up not allowing the EGR to close once it has opened and the vacuum lines are on proper.
Clean the vacuum regulator filter under the round cap.
Normally the PCM will detect an issue in this system and set a test failure code but you never know.
Good luck.
Junior User
Joined: Feb 2007
Posts: 51
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From: Becker MN
Had mine do the same thing. It did turn out simple plug wire was arching inside the head not a good connection mine has cop's and did it. But my wifes truck also did it and she has standard wires . Get the holes cleaned out. they will fill up with dirt and may not let you get a good connection. Maybe put some of the greasy stuff they make for plug fittings. Its cheap