I have a 2001 F250 CC with a new factory rebuilt Ford 7.3L engine with less than 100 miles on it. In general it runs quite well, has plenty of power, is smooth etc. However....it has noise at idle that is driving me nuts. It sounds like one injector on the right cylinder making a clanking noise when at idle. The sound changes with speed and goes away above 1000-1100 rpm. It also does not occur when the engine is cold and when warm it takes probably 5 seconds for it to develop after the engine decelerates to idle rpm.

I have had a 7.3L before, it is not cackle like air in the fuel line. I did fill the truck up to get above the mixing valve in the tank just to be sure we did not have a fuel tank air problem.

Everything is stock except for the 4" exhaust. There is no chip on the truck right now. I have a Scan Gauge II and have entered the parameters for ICP and IPR. When cold and without the knock the system is running about 600-630 on the ICP. At warm idle the system is running: 470-480 ICP and 10.5 IPR. I am not sure if the scan gauge updates quickly enough to be accurate but I start to hear the sound as the ICP goes below 560. Twice when holding WOT I got a check engine light that cleared after a few minutes but the Scan Gauge showed no codes.

I took it to the dealership today, the technician confirmed the noise and had a concern about the oil and level so we changed it as a first step. The oil level was a bit high but had no fuel smell and was quite clean. He refilled it with dino 10W30 vice 15W40 as it is cold up here in Maine. We still have the same noise, no one offered a potential solution so I am trying to gather information and guide the effort before bringing it back next Tuesday.

Anyone have some thoughts to try out over the weekend? Thanks.

 

Is there any warranty with the new engine? Can you run a cylinder contribution test with your scanguage? (Do you have the aeroforce scan gauge that is compatible with the PSD or do you have one of those little rectangular things?)

 

IS there a way to prime the High pressure oil lines? if you were not getting oil all the way back yet, would it not make the same noise, you wouldnt be dumping fuel yet..Seem a 100 miles though it should have worked itself out by now.. but I dont know.

 

What parts were used off the old engine? (ie HPOP,ICP,IPR)

 

The engine has a two year warranty from Ford. The HPOP, injectors etc were all rebuilt by Ford as part of the engine. ICP and IPR look new as well as the other sensors. The ICP does read 10 on the Scan Guage when the key is turned to on. I only have the rectangular simple Scan gauge II and have not figured out how to do a cylinder contribution test with it yet. The turbo, uppipes etc were reused.

 

What parts were used off the old engine? (ie HPOP,ICP,IPR). IDK but you may still have air in your HPO rails.

Ops double post

 

It could easily be one of the rebuilt injectors that is causing the noise. If you've got a 2 year warranty from Ford, I'd suggest you let them hook it up to their fancy scanner and figure the issue out themselves. Just make sure you're dealing with a dealership that has a qualified diesel tech.

 

The tech seemed pretty good. The oil level was high and the installer had to change an injector on initial startup so the tech was affraid the high oil level was caused by a leaky oring or when they changed the injector. The dipstick tube also had been routed incorrectly so he wanted to make sure we were getting the right oil level reading. The dip stick proved accurate after refilling with 15 qts and a new filter. I did not have a ton of time today so we did not take it too far.

My gut tells me it is an injector as well. Part of this effort is trying to really get to know the truck and make sure that Ford lives up to the warranty.

 

A simple test, as long as you can hear the knock, is to get the truck up to 50 or 60 mph so the torque converter is locked (or any speed if you have a manual) and let your foot off the accelerator and coast. When you do this the IDM stops firing the injectors. An injector knock will go away when you do this, a mechanical knock will not.

 

It goes away when the injectors are not fueling.

 

Then let Ford use their scanner to determine which injector is causing the problem and replace it. This is not unheard of with rebuilt injectors.