I need some serious help here...... First thing first, the truck is a 2002 F250, 4x4, 7.3 liter with 145k miles, auto trans, AFE intake and exhaust, Dp Tuner and triple gauge pod.
The following all started pretty suddenly while my wife was driving the truck back and forth to work with the tuner on stock setting. The situation is at first startup of the day with temperatures near 70 degree the truck will smoke bluish white accompanied by a knocking sound coming from the engine most noticeable from the passenger side wheel well. The smoke goes away after a few minutes or sooner if I drive it and the smoke doesn't start again until the engine has cooled.<O</O
The knocking on the other had has come and gone depending on my driving habits. I have driven it really hard and the sound seems to go away until recently. Now the knocking is worse and does get slightly less noticeable when the truck is at operating temp. The sound can be heard from inside the cab, under the truck and passenger wheel well. The knocking seems to start seconds after the engine starts, almost like a short delay. Also, when decelerating from about 50 mph with the converter locked the sound is quieter, but still there. When I rev the engine at an idle the sound goes away only long enough for the engine to idle back down. It pretty much always makes the sound now and maybe always, I just can't always tell because of road and engine noise. It has been making the noise for about 500 miles.<O</O
<O</O

Here is what I have done:<O</O
Removed fuel <NOBR style="FONT-SIZE: 100%; FONT-WEIGHT: normal" id=itxt_nobr_10_0>tank</NOBR> and cleaned filter and eliminated the stock hose connectors.<O</O
Pulled valve cover and re-torque all accessible bolts and checked the wiring harness. I didn't check the pushrods for straightness.<O</O
Ran a tank of B20 bio diesel through it along with STP injector cleaner.<O</O
Added a quart of Marvel Mystery to the oil.<O</O
Checked turbo tolerances which were good.<O</O
Changed the CPS back to the original.<O</O
Had the torque converter and flex plate checked.<O</O
Disconnected the belts and started the engine with no change.<O</O
Took it to 3 mechanics and all were stumped. One ran it through a bunch of testes and said it was good.

<O</OAny help diagnosing this problem would be much appreciated.<O</O

 

Here is a test that was suggested to me by Pocket for a similar noise. Drive the truck at about 60 mph on a flat section of road. Listen to the sound. Take your foot all the way off the throttle. Does the noise go away? If it goes away, your noise is related to the injectors. If it stays the same, or a little less, then is is probably mechanical.

I have had a noise from my #7 injector (rear cylinder, passenger side) for a long time. Using the above test, I determined that is was injector related. It was there when I bought the truck, so I paid a price that reflected a bad engine. I have replaced all the injectors with Ford remans, new UVCH, and checked all the torques and pushrods. Everything checks out OK, but it still has the knock. I did make a "redneck breakout box" out of an old UVCH and rocker cover gasket, which is how I confirmed that it is #7.

I don't have any smoke like you do. You could have a bad injector. Do you have anyone who can do a cylinder contribution test? With the smoke, a CCT while cold should identify the weak injector. If it is a mechanical noise, a compression test should tell which one. Another quick test is using a non-contact (infrared) thermometer pointed at the exhaust manifold at each cylinder. This has to be done right at cold startup, since the whole manifold will transfer the heat rapidly and hide the cold cylinder pretty quickly.

I hope this has helped you.

 

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