Jump to content

knocking engine on acceleration


fats_40
 Share

Recommended Posts

advise sought please,i own a p38 with 116000 miles on clock.on pulling away you hear a knocking sound under load,it then stops when you hit 15-20mph.i changed the main bearings,decatted it,but noise still there.i have now read that it could be a detonation problem,ie,spark knock.are p38s fitted with an egr valve and if so where would i find it.oil and leads and spark plugs changed 8 weeks ago.any help !!!!ps,engine 4.6 thanks

Link to comment
Share on other sites

Does it only do it when cold or at all temperatures ?

A little bit of piston slap isn't unusual in both the 4.0 and the 4.6 when cold although it normally goes away when it's warm.

hot or cold it doesnt matter,its only when i pullaway then dissapears

Link to comment
Share on other sites

hot or cold it doesnt matter,its only when i pullaway then dissapears

P38 engine’s have sensors which keep the ignition just off the pinking point to make it as economic as possible they are called knock sensors (dugh) the crank sensors may also be playing up. Best to pop it into a specialist to plug it into some diagnostic equipment.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy