Pinging saga continues...4.0

[35Remmy]

I've tried everything to stop my 4.0 OHV from pinging...plugs, wires, cleaned MAF, lower intake manifold gaskets, seafoam, etc. Still pings, no CEL.

However, my #4 and #5 plugs keep fouling out...threads oily and electrode all white.

When I change these plugs, the ping stops for about a month...then the ping returns as they foul.

I ran a compression test on all cylinders, and all are good and within 5lbs.

I still think I have a lower intake manifold leak, to me it's the only thing that makes sense. Is there a test a shop can do to verify this?

I used the Fel-Pro metal 2-piece gasket set (includes upper intake gaskets, too) and I couldn't understand the directions when it came to lining them (lowers) up...so I positioned each side evenly and scribed both the gasket and the head to line them up. I'm thinking, well, they're still not lined up properly?

I've also retorqued everything. Any ideas?

 

[turbo cat]

The oil on tghe threads is probally oil that has seeped down into the spark plug holes from a seeping valve cover gasket. There not fouled if you said there white. That would indicate a lean or overheating condition in those cylinders. what kind of plugs are you running?have you checked the timing?

 

[35Remmy]

Turbo...I'm running autolite double platinums at .052 (APP103) I've ran the Motorcrafts but they "fouled" much sooner.

Yes, you're right on...those cylinders are definitely running lean. No, I haven't checked the timing as I am under the assumption that this is entirely controlled by the PCM and not adjustable.

Oh, for an update...I changed #4 and 5 plugs today...pinging is STILL there...

I LOVE the 4.0 OHV's but this one has me scratching my head. I'[m wondering if it's time for the FORD dealer...do you think they'd have a better chance of figuring this out in comparison to a regular garage? I'm leaning towards yes.

 

[turbo cat]

have you tested the fuel pressure, changed the fuel filter, or fuel pressure regulator, injector issues?

 

[aldive]

Have you installed an OBD II scanner and looked things over?

 

[35Remmy]

I haven't checked fuel pressure...fuel filter is pretty new (6 months)...I thought about the possibility of a sloppy injector, but I have no idea how to bench test injectors.

AL...I ran codes a while ago and I got a PO170 or 71 maybe? It was the code for a lean condition, but never triggered a CEL....If there is a stored code, why wouldn't the CEL come on?

 

[aldive]

AL...I ran codes a while ago and I got a PO or 71 maybe? It was the code for a lean condition, but never triggered a CEL....If there is a stored code, why wouldn't the CEL come on?

I was referring to sensor functioning, not codes.

 

[turbo cat]

how does it run overall. Does is have a rough idle, stumbles, surges....i would test the fuel pressure for sure you may have a bad FPR. But it can be a vaccum leak, blown gasket, clogged injectors, faulty electrical....I would start simple first as in a fuel pressure test

 

[35Remmy]

AL...the only scanner I've used was an OBDII scanner that reads codes, not how the sensors are functioning. I don't know how to get my hands on one of those...only way I know of to test a sensor is using a voltmeter.

Turbo...the truck runs great!!! When I first start her in the morning I'll get a little but of a rough idle but nothing bad. It's got plenty of power, sounds good, etc. I CAN tell of a loss of power up a hill when it's pinging, though.

The ONLY things I can think of that would cause a ping:
MAF sensor
EGR valve
Plugs/wires
Lower intake manifold gasket
Injectors
cracked block
O2 sensor
carbon buildup
timing
any other vacuum leak
cooling system

Am I missing anything?!

I appreciate your help guys!

 

[aldive]

AL...the only scanner I've used was an OBDII scanner that reads codes, not how the sensors are functioning.

Thats the difference in a scanner and a code reader.

 

[skoal_mint]

Go see a small shop and ask them if they could scan it and look over the reading... Even better, get a movie of all the reading when test driving and post them up.

 

[35Remmy]

Skoal...sounds like a plan...thanks.