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Re: Winter Operation
The glow plug system needs to be in good operating condition. klhansen has posted a sticky on the top of this forum on how to check them.
What's that noise? One of two things and probably both. If it's coming from under the hood, it's the engine cooling fan. The engine fan's thermo coupling is suffering from “morning sickness” (Ford's term, not mine) and is more noticeable in cold weather. This will quieten down in a few minutes as the silicates or what ever they are, get back to where ever they belong.
If it's coming from the tail pipe and sounds like someone has stuffed a potato up there, it's the Exhaust Back Pressure Valve (EBV). This valve closes in a cold engine to create a load which will help the engine warm up a little quicker.
RPM increases. In the cold weather and the vehicle believes it has been parked for 90 seconds to 2 minutes the computer will increase the engine rpm. I understand the standard transmission equipped need the park brake set for this to kick in. How much increase depends on the ambient temperature and barometric pressure. My truck will idle up from 700 to 1300 rpm. You will notice that engine temperature has no bearing. The reason for the rpm increase is to prevent a condition called “wet stacking”. A diesel engine produces little heat while idling. Sucking in cold air doesn't help matters. The combustion chambers don't get hot enough and a sticky deposit remains on valves, valve stems and guides eventually causing engine damage. At least that's the story. I doubt you will find case of it actually happening to a 7.3 on this forum. Maybe it works. [img]/ubbthreads/images/graemlins/smile.gif[/img]
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2 quick things, on the RPM ramp-up and exhaust whooshing noise, it's called CAP (Cold Ambient Protecion) and it's main input is the IAT sensor, cold intake air usually turns it on. Make sure the EBP sensor and tube are not clogged or the whooshing will be worse and cause alot of cold driveability problems. Also, with glow plugs, my 10 years experience (most with IH diesels) and a wise old tech for a teacher hs taught me that when replacing the glowplugs, use ONLY Ford or Navistar (Bosch) glowplugs. I have seen alot of guys put champions in and within 6 months they pop like zits on a teenager. I know Bosch costs more, but it's worth it. Anyways, there's my 2 cents. Cool Canuk has hit the nail on the head for how to handle your 7.3 in cold weather. [img]/ubbthreads/images/graemlins/smile.gif[/img]
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