T444E cold weather "safe mode"

[Brad S.]

Among other things I do I drive school bus for our local school district, the bus has the T444E engine. 1997 model year. Temps last couple days have been single digits and some below zero, (F)
After I start it will idle at about 700-800 rpm but the pedal DOES NOT rev the rpms at all until it's run for about 5-8 minutes. Then I can set the idle higher to warm it faster.
Then until the temp comes up 130 - 150 degrees if you take off it acts like the filter is plugging, no power etc.
It is plugged in overnight all the time, so its not starting completely cold.
Before the outside temps got below 20-30 degrees, it also acted like the turbo was bypassing any built up pressure, the engine would rev but little power.
Just wondering if anyone has ideas. I'm guessing these are all factory settings meant to protect the engine in cold weather.
If this should be in another area sorry, just figured most of the experts are in this section.

 

[rjjp]

Yes, it should be in the powerstroke area for people who know more about the T444E to view it. But every big (F650+) truck that I've seen, with the T444E, the owners claimed that when cold the computer wouldn't let you rev it up.

 

[DragRag]

My 01' does the same thing. Let it warm up, and the pedal eventually responds. Just the way they are.

 

[trackspeeder]

EBPV is closed when cold. This gizmo is to help heat the engine faster.

When the valve closes it will make the engine feel like it has no power.

 

[93turbo_animal]

stop trying to rev it up the more you mess with the pedals gas clutch and brake included the longer before the computer sees an extended cold idle. If left to idle and everything is functioning properly the computer will increase the idle on its own. I don't beleive the IH version has the EBPV or atleast not all of them do but the computer will not let the engine rev when cold either way

 

[Dieselcrawler]

every one of our 7.3 busses from IC have EBPV on them. let it sit, she will idle up and warm up.

 

[93turbo_animal]

must be by application our fuel truck does not

 

[Brad S.]

So does that mean if you leave alone it will idle up all on it own. Or is it better to set the high idle when it will let you.

 

[Goofyexponent]

I'm not trying to pick a fight...but the words cold start and rev shouldn't be in the same sentense.

I NEVER rev up a cold engine. As most will tell you. When cold the oil is not being pumped where it should be, most of it is in bypass mode.

Let that thing warm up for 5 or 10 minutes before you try and gain ANY rpm. My truck is standard, so I can ride the clutch to back it out of the driveway, and then just let it coast in neutral down the hill to the main road. I usually sit at the firehall away from houses for 10 minutes to let her warm up.

Just my .2cents, but revving a cold engine is asking for reduced engine life.

 

[Dieselcrawler]

atfer a few mins it will idle up by itself.

 

[rjjp]

I'm not trying to pick a fight...but the words cold start and rev shouldn't be in the same sentense.


Just my .2cents, but revving a cold engine is asking for reduced engine life.

http://www.youtube.com/watch?v=6slibTD9MF0

 

[RyanDamo]

there should be a switch near the air brake button that says throttle on it that you can usually idle it up when cold starting. maybe it was just an option?

 

[OLDBULL8]

If your school has a dedicated bus mechanic like our school's here do, they may be crackerjacks on gas engines, but most don't know beans about diesel engines. If the tube from the exhaust to the EBPS is plugged with soot or cracked, it will not get the signal to go into Hi idle. Being the bus block heater is plugged in, that indicates to me the engine oil is warm, that is one signal to the PCM to stay in normal idle, and the EBPV stays open. The EBPS has a diaphram in it and can be easily damaged or also plugged. Link below says 2002, but also applies to all T444E DIT 7.3 engines. IIRC.


http://www.guzzle7pt3.com/ebps.php

 

[Brad S.]

Goofyexponent
Your right, when you say no revs, what I mean is from 600 to just under 1000.
With my own vehicles I leave it alone until it warms up on its own. Thanks for the reminder,
RyanDamo,
Right, the cruise switch or switches let me set the idle higher, thank goodness no airbrakes. But here again when I first start it runs at 600 -/+ rpms and even the switches to set the idle higher wont work right, but thats normal ecm stuff.
OLDBULL8
Our "Bus Boss" just started this year, he has been working at school for quite a while. I think if they get something that deep they take it to a dealership. The bus runs fine but 20-25 minutes of idling, slow or high, and the temp is only 110-120 degrees seems a little "off". Even with the engine being plugged in. Maybe I'm expecting to much when the weather is cold.

 

[RyanDamo]

still not right though, maybee thermostat stuck open? those busses do have huge radiators also