NEWB: mad PING... HELP!!!

[rustyrotor]

I have a 93 navajo with the 4.0 litre 6 in it... with 160k miles
I am really happy with the truck, I got it for free, and its been really good to me for the last 10k miles..

A few months ago it started pining under load. I seafoamed it, cleaned the throttle body and did a full tuneup. this masked the problem for about a week... then it started back.

Then I started running premium in it. This fixed it for about a month, then it started pinging on 92!

the current situation is horrible.. ANY hill, or spirited acceleration will yield the WORST pining I have ever heard... it sounds like its gonna come apart....

It's also throwing some sort of code when under load... when it pings really bad the check engine light comes on..

I have run through the search and haven't found much..

I am a newb to fords, but not to cars... I am a VW guy.. and Im trying to keep this thing running until I can finish my rabbit project:

any help yall could give me would be greatly appreciated..

 

[HahnsB2]

How are you driving it? Are you babying it? Seafoam fixed the grandpa induced ping in my friends 4.0 ranger, and it's stayed gone since he drives it fairly hard. Have you checked for vacuum leaks as well?

 

[69Mach1]

Pull your spark plugs. Any of them whitish? I'd bet you need new intake gaskets. I had a pinging problem with my 93 Explorer. Changed intake gaskets and no more pinging, none! I could feel the engine ran smoother and with more pep. Also gained 2mpg. It's a very common problem on 93 4.0 V6's.

 

[James909]

Pull your spark plugs. Any of them whitish? I'd bet you need new intake gaskets. I had a pinging problem with my 93 Explorer. Changed intake gaskets and no more pinging, none! I could feel the engine ran smoother and with more pep. Also gained 2mpg. It's a very common problem on 93 4.0 V6's.

I second this. I didn't have to replace the gaskets on my truck though. I just retorqued the lower intake with everything still on the truck. The middle bolts I could back out with my fingers with no effort. This stopped the ping and also stopped my oil consumption. Now I don't even have to add any oil during a 6,000 mile oil change.

 

[rustyrotor]

I do not drive it like a grandpa... in fact, I have tried running it close to red line for several minutes to try and blow out any carbon without any real luck...

When I did the tune up, I replaced the plugs with stcok motorcraft ones.. and when I pulled the old plugs, I was VERY surprised!

3 of them had very worn electrodes... infact, I have a pic of them:

there's a new one in the back for reference... note the HUGE gap....

and those arnt the worst ones either.. one of them was practically worn to a nub...

I figured that perhaps they were original plugs.. but i don't know..

 

[rustyrotor]

I have not checked for vac leaks.. I will give that a try..

 

[Kamel]

remember that bad plug wires can also cause pinging. pinging, aka predetination, can be caused by a number of reasons, not just excess heat/compression (reason for carbon buildup causing it).

It should never be pinging with 92 gas in it, I am guessing the problem is definitely not carbon buildup or excess heat but I'm no pro by any means.

Try what people here have suggested, and if all else fails try running your engine while it is dark and use the old spray water on your plug wires at night trick to see if you can find any sparking/arcing to the engine block. sometimes this can cause pinging.

one final note, try not to push the engine too hard to try and knock some carbon loose etc, as it is possible to throw a rod with a single horribly timed ping. don't wanna scare you just saying it's possible.

last but not least, it *could* be a timing issue, but generally a timing issue doesn't creep up like that and usually it is even worse but it's a possibility.

 

[arco777]

What CEL code are you getting?

I have found a lot of shop manuals don't list all the codes. The link below details how to pull/read the codes, and at the bottom of the page there are links to explanations of all 2 and 3 digit codes.

http://www.fordfuelinjection.com/?p=13

 

[rustyrotor]

I dont know what CEL code I am getting.. because the light doesnt stay on...


on the timing note: That was the first thing that I thought of... but its not like I can just turn a distributor and retard it... is there any way I can mess with the timing?

When I did the tune up, I replaced the wires with new ones...


Another thought that I had was this: could it be a knock sensor? if the EU doesnt know that the motor's knocking, it wont make any adjustment to take it away... does that make sense?

 

[MrShorty]

I dont know what CEL code I am getting.. because the light doesnt stay on...

When the CEL comes on during normal operation, the computer will store the code in memory (CM). PUll codes and see what information is there.

If you have searched this forum and haven't found much, you just haven't found the right search terms, because it is a fairly common problem. Lower intake manifold gaskets have been mentioned. A dirty MAF will cause it. Look for the Singleton pages in the useful threads forum.