2000 F-150 4.2 L V-6 118K Miles

This engine has severe spark knock / detonation or ? when cold. The knock only occurs when the engine is under a load such as gradual acceleration. The knock does not occur when revving the engine while in park or neutral. Once the engine reaches normal operating temperature the knock is no longer evident. Also, once the torque converter locks up during cruise, even with a cold engine, the knock disappears. Upon unlocking the torque converter the knock returns. This problem does not generate any fault codes.

I had the engine scanned. The mechanic who performed the scan could not find anything abnormal. He scanned it twice. The first morning while idling in Park (noise not evident). The second morning he drove the truck duplicating the problem with the scanner attached. He suggested that it was a lifter that is slow to pump up. Although the sound is similar to a collapsed lifter, I have a very difficult time with his theory since the noise is only obvious during vehicle acceleration when the engine is cold. It does not occur when at idle or revving the engine in park. As stated above, once the torque converter locks up or the engine reaches normal operating temperature the problem goes away. This is very repeatable and very predictable. The problem is the most obvious after the truck sits overnight. The colder the night, the more pronounced the noise.

Sorry for the long post. Has anyone else experienced this problem?

I appreciate any suggestions.

 

What You're Hearing Is Spark Knock. Very Common On These Engines.

 

I'd like this thread to get a little more attention. I have this same exact problem. Though at idle and in parl, if I get out and lay on the ground I can just barely hear it from the bottom of the engine. I'm thinking I may have some bearings that may be shot. I find that kinda hard to believe at only 70k miles though. Anyone else have some other ideas?

 

Maybe your temp sensor is not functioning correctly, so the spark and air/fuel curves are slightly off for a given motor temp (cold) but right for another (warm).

If you baby your motor to much and never rev it over 2k, it might be carbon build up causing detonation.

My 4.2L sounds like a diesel when cold. It's smooth, but it's loud and clanky. Been that way since day one when cold.

 

Where is the temp. sensor sensor located? Is there a way to test it? After paying mare attention to the sound I guess it could be detonation.

 

To Get Rid Of The Detonation, Run Cleaner Through A Vacuum Hose That Runs Into The Intake. The "ping" Is Caused By Carbon Build Up. It Is Very Common On These Engines.

 

96fourbanger,

The ticking noise you hear while idling in park is most likely from the fuel injectors or the oil pump. Both have been know to occasionally be fairly noisy but are nothing to be concerned about.

Mooneyman9,

The ticking noise you hear while under load is certainly spark knock. As others mentioned, it is relatively common problem on the 4.2 engines. Poor gas quality, too low of octane, vacuum leaks, carbon buildup, too much spark advance, or a lean air/fuel ratio are the most common causes of knocking. How long have you had the problem? Is you truck stock or have you done any mods?

 

I Have A 2003 F150 4.2 With The Pinging, & A Ticking Sound From The Passenger Side Of The Engine.ford Replaced All The Lifters-pass Sise,checked Manifold&exhaust For Any Leaks-none.scanned It & Tested The Fuel Injectors,noise Is Still There?the Pinging Seems To Be From The Exhaust,but The Ticking Is Very Noticable From Inside The Wheel Well Mostly.

 

I was just getting ready to post about this same problem. My truck does this as well. I have a 97 with 117K miles. I tried running some fuel system cleaner and octane boost thru the tank, but to no avail. With these gas prices, I don't really want to shell out for high octane. Does this "pinging" harm the motor at all?

 

I believe this is something we just have to deal with.
Today's engines are typically tweeked to the max for 87 Octane.
My 2000 was not bad really, but the '05 is a bit more noticeable.
I have read a good bit about the subject and am content to deal with minor "pinging".
Winter seems worse which I attribute to different fuel formulations.

FWIW - there is a big difference bewteen preignition and detonation.
It's an interesting subject really.

You can Google the terms
"detonation and preignition" and find plenty to read.

One thing to note; as the miles build up, any carbon deposits in the combustion chamber (top of piston, valve, etc) can lead to a tendency for preignition to occur. The carbon deposits will increase the compression ratio and serve as a point - a hot point - to ignite the fuel/air mixture before the plug fires.

 

crack; the temperature change ( heat) eliminated the noise. I can hardly remember what I did to verify. I think I puled the plug wire to find the cylinder I am not recomendind this just another thought to consider MAX