knocking 4L SOHC

[dreamcargt]

My 2001 explorer with the 4L SOHC has a persistent knock in mid-range acceleration. I have tried 93 octane gas and it still knocks. I just installed a JET performance chip, because I thought a new air/fuel program would help, but it still knocks. The only other modificaiton I have is an afermarket air filter and no air filter box.

Do you think it could be a bad oxogen sensor? Any ideas?

Thanks.

 

[alexefron]

try searching for seafoam. it has helped many an explorer

 

[Eneurb]

It's probably the primary timing chain slapping around. Usually happens between 2200 and 2900 RPM under a slight load.

 

[dreamcargt]

If it is the timeing chains, is there a fix? Surely there is some kind of tensioner that should keep the chains tight?

While it could be this, it sounds to me more like detination.

 

[Eneurb]

There is a TSB kit that includes the primary timing chain tensioner, chain guide, jackshaft and crankshaft sprockets, gaskets and a new chain.

 

[blue xlt]

dreamcargt-You could try cleaning MAF wire with brake cleaner.I think there is a Ford TSB on the subject about aftermarket air filters which use oil and that a light film of oil on wire will cause improper PCM readings.Ford advises not to use any filter that uses oil.Make sure engine is not running hot or overheating because this will hasten the onset of pinging.

 

[Katmandu]

There is a TSB kit that includes the primary timing chain tensioner, chain guide, jackshaft and crankshaft sprockets, gaskets and a new chain.

My 98 4.0SOHC has this "Diesel-like rattle" also.

Can someone tell me what the TSB# is for this issue ??

What is the MOST likely culprit ?? The Tensioner OR the guide going bad ??

 

[CDW6212R]

Run a search for "cam cassettes" and read the suggestions. Good luck,

 

[unclemeat]

Sometimes the 4.0 l engine builds up carbon on the exhaust valve. Usually when you run middle RPMs a lot (manual trans). Try running the engine under load at a minimum, 4000 RPMs for about 5 to 10-munites. Also a bottle of injector cleaner can't hurt. If it is the timing chain, then your on your own.

 

[aldive]

My 2001 explorer with the 4L SOHC has a persistent knock in mid-range acceleration. I have tried 93 octane gas and it still knocks. I just installed a JET performance chip, because I thought a new air/fuel program would help, but it still knocks. The only other modificaiton I have is an afermarket air filter and no air filter box.

Do you think it could be a bad oxogen sensor? Any ideas?

Thanks.

Is your sound the same with and w/o the Jet chip?