TechTalk8141

Hard Cold Start
Corey Magnus 28 posts since Sep 8, 2015
Hard Cold Start Feb 11, 2021 8:13 PM
i have a 04 Freightliner columbia DDEC 5 vin/N30344 /06R0761748 when it is inside it will start just fine but
take it outside for a couple hours and it starts really hard and smokes a lot i have egr code of 39 boost power.
i think that is a different problem i do have the ambient air temp sensor is reading 30 degrees F differents from
all the others so 66 in shop it is reading 35 and out side it was -5 but the sensor was reading -25. does the
ambient air temp sensor affect a 60 for start up or does it use the inlet temp sensor for that
i am with a western star dealer
Scott Trippel 4,094 posts since Dec 13, 2014
Re: Hard Cold Start Feb 11, 2021 11:33 PM
No S60 does not use the ambient air sensor for any fueling.
What is the crank speed
what is the fuel pressure
and what are your compression readings?
Could be just the cold air
Robert Cadell Jr 2,837 posts since Nov 9, 2014
Re: Hard Cold Start Feb 11, 2021 11:43 PM
That's confusing Scott drawing a06-47470-001 shows a ambient temp sensor on the engine wiring supplied by
freightliner ill upload the print
Robert Cadell Jr 2,837 posts since Nov 9, 2014
Re: Hard Cold Start Feb 11, 2021 11:46 PM
see attached use revision -001 right above the ecm up about 8 inches, if equipped the sensor should be tied
off to the metal fuel line.
Looking something else up real quick. Wanted to get this out there.
• ddec 5 engine print.pdf 1.2 MB Preview
Robert Cadell Jr 2,837 posts since Nov 9, 2014
Re: Hard Cold Start Feb 11, 2021 11:55 PM
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the print shows a ambient temp sensor, but on the engine side only thing I can see is a Barometric temp
sensor.
and to be honest at this point I dont remember, can you take a pic of the screen where you are seeing this?
I would start with Scott Trippel request
Robby Dabernig 123 posts since Nov 14, 2014
Re: Hard Cold Start Feb 12, 2021 12:22 AM
We see this problem quite a bit in glider kits with reman Detroits. We never really had one come in with that as
a complaint though. But I remember hearing something about a cracked head causing this issue. Causing low
compression when cold but sealing up when its warm.
Steve Reppard 168 posts since Jun 29, 2020
Re: Hard Cold Start Feb 13, 2021 1:54 PM
Well I would make sure it isn't flowing egr when cold, that will cause excessive smoke and poor running until it
is up to temps where egr starts flowing. I would look into that code for egr and rule it out.
Brett Hall 12 posts since Jul 25, 2020
Re: Hard Cold Start Feb 13, 2021 6:01 PM
what is fuel pressure while cranking when cold? does it have a fuel knock when it first starts to crank? what are
fuel pressures at idle and 2100 rpm? any air in return line?
Corey Magnus 28 posts since Sep 8, 2015
Re: Hard Cold Start Feb 15, 2021 8:21 PM
i just got back on the truck today i have put sight glass on the out of fuel pump and then on the return line
i have a pressure gauge on and at idle i have 18 and at 2100 i have 28 that is in the shop i have it out side
cooling down in the sight glass the is some small micro bubbles that i have been told not to worry about in the
past but maybe i should be i have put pics of the temps one is in the shop and one is out side before starting
it after two hours. after i get it back in the shop i will start going after the egr code if i dont find anything from it
sitting out side
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Robert Cadell Jr 2,837 posts since Nov 9, 2014
Re: Hard Cold Start Feb 15, 2021 8:59 PM
ok, I have a silly thing to ask, Run the unit out of a 5 gallon bucket, make up somelines, run your inlet and
return to the bucket, fill 3/4 full of fuel prime the unit start and let run, you may have to add some to your 5
gallon bucket, if BY CHANCE this resolves your issue then go over your fuel lines to the truck, does the unit
have cut off valve for a dual tank set up? those will leak over time and you wont know it.
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