Engine Issues

[dwyant30]

So I have a list of symptoms and was hoping someone could help me figure out what is going on.
My CJ started backfiring on the freeway the other day, pretty bad in fact. It also starting smoking pretty bad. I've checked the timing and the settings on my Webber Carb using some great info from other threads. I pulled the plugs and they all have black tar attached to them, which one would assume is oil. I put new plugs in and after running the jeep for 15 minutes I checked them again, and the black spawn of satan had already started reattaching itself to the new plugs. The oil also has a fuel smell to it. I'm just not sure what would cause all 6 plugs to foul at the same time with oil. My fear is that I have a spendy problem to fix. Lamesville.

thanks guys!

 

[dwyant30]

I also had oil pooled around the flange on the carb. Forgot that part.

 

[gert]

Is the oil coming from your PCV valve? or crankcase breather? there should not be any oil aroud the carb unless it being sucked to the carb. Do you have a high mileage motor? With you having a fuel smell in the oil it sounds like you could be running rich and if its a high mileage motor the PCV vale could be sucking blow by into the carb which would carry oil with it.

 

[dwyant30]

The breather from the rear of the valve cover is the one that was running into the carb. It appears the hose with the PCV valve is running into a port a few inches below the carb itself.

It is a high mileage motor as well. the odometer says 220k, but I was told it was rebuilt recently. Not sure though.

 

[IOPort51]

fuel smell in oil?? check fuel pump for leaking diaphragm. you may find the oil level is higher than it should be. drain the oil and replace the pump ASAP.


back fire could be vacuum leak.
have you replaced the PCV valve in recent memory??

 

[dwyant30]

fuel smell in oil?? check fuel pump for leaking diaphragm. you may find the oil level is higher than it should be. drain the oil and replace the pump ASAP.


back fire could be vacuum leak.
have you replaced the PCV valve in recent memory??

I have not replaced the PCV valve yet. It does rattle when I shake it, but it wouldn't hurt to replace it. The back firing only happens when held at full throttle on the free way for awhile. It has never done it on any short trips I have taken.

 

[IOPort51]

I once had a problem with back fire at speed that was a bad connection at the coil. good enough backfire to split the muffler wide open at the seam! BANG!!!

 

[dwyant30]

Brutal!!!
I'm thinking of starting a book titled "Things I Learned the Hard Way".

 

[dwyant30]

I once had a problem with back fire at speed that was a bad connection at the coil. good enough backfire to split the muffler wide open at the seam! BANG!!!

Speaking of connection at coil. Mine has a red wire and a red and white wire connected to one side, and the black wire to the other. Does that seem correct to you?

 

[IOPort51]

nobody ever learns anything the easy way.
I can help with a couple of chapters.

Brutal!!!
I'm thinking of starting a book titled "Things I Learned the Hard Way".

 

[dwyant30]

You realize that now that you have reponded to my post, that I will be like the stray cat that you feed once and then can't get rid of right?

 

[JR74CJ5]

You realize that now that you have reponded to my post, that I will be like the stray cat that you feed once and then can't get rid of right?

:laugh:

And I could help with a few of those chapters too...

My 2 guesses have already been mentioned... PCV valve sucking in oil with air, vac leak of carb issue (mechanical or settings) on the backfire...

 

[dwyant30]

:laugh:

And I could help with a few of those chapters too...

My 2 guesses have already been mentioned... PCV valve sucking in oil with air, vac leak of carb issue (mechanical or settings) on the backfire...

When you say vac leak, do you mean vacuum tubes, or more on the manifold side?

 

[JR74CJ5]

Not sure exactly where myself... I would check intake and carb, all lines, and even the exhaust system all for leaks...

I know I had bad backfiring issue when i had some bad leaks on headers and collectors before...

But i also had some carb leaks, and timing needed adjustments... So not sure how much of it was the exhaust leaking causing it...

 

[dwyant30]

So a leak down revealed a 30lb drop in cylinder 1, and a 50lb drop in cylinder 5. After that I didn't see much point in wasting the guys time on testing the rest of them. All the pressure loss came through the valve cover.
Looks like a rebuild is on the horizon.