[balljoint]

Runs Rough Cold for short Time

When engine cold,the heater grid has power going to it and works with the wait to start system ,

Up date -the heater relay heats -up and cycles properly,so now I need to figure out why the blue/white smoke when cold and running rough for 30sec to a minute with a rpm drop of 200 rpm,could a bad injector work and not work ,and why only when cold,I have 11-12psi fuel pressure ,even replaced the fuel filter,checked the lines for leaks,no codes,purrs like a kitten the rest of the day after its little fit in the morning. I am stumped

 

[nkfry]

Fuel pressure?

As far as the truck running rough, does it only do it during warm up? If so I'd say there's an issue with your grid heater relay.

 

[Wy Elk Hunter]

I see your in Co. I'm in Craig Co right now and it's been pretty warm. Between 15f and 59f your grid heater will only come on for 10 seconds before you turn the key to ignation. After that it may not cycle at all. Perhaps it is working fine. What is your OAT ( Outside Air Temp) when starting your truck??? You say your truck doe's not load down like it use to. Well things are warmer now.

 

[balljoint]

What it does when it is cold is you crank it and when it starts it just billows out smoke,acts like it run on 5 cylinders and the engine rpm is about 200 less than when warm,then after about 30 seconds to 1 minute depending on how cold it is outside it comes out of and purrs like a kitten.has 12psi fuel pressure. I know diesels do not like cold but the smoke is horrible,it is almost embarrassing to start it when it is cold out. Could the IAT sensor be going bad ? I did clean it but it seemed it made no difference . if sits during the day and it is warm out you can hit the key and runs great,so it is cold related,I did check the grid with a test light and it is getting power.:S:

 

[Wy Elk Hunter]

What it does when it is cold is you crank it and when it starts it just billows out smoke,acts like it run on 5 cylinders and the engine rpm is about 200 less than when warm,then after about 30 seconds to 1 minute depending on how cold it is outside it comes out of and purrs like a kitten.has 12psi fuel pressure. I know diesels do not like cold but the smoke is horrible,it is almost embarrassing to start it when it is cold out. Could the IAT sensor be going bad ? I did clean it but it seemed it made no difference . if sits during the day and it is warm out you can hit the key and runs great,so it is cold related,I did check the grid with a test light and it is getting power.:S:

A quick check to see if your grid heater is working is to cycle your key a couple of times without starting your truck, Then feel where the grid heater is, and it should be warm to the touch. If so, I wonder if you could have a bad injector. If your injector is not atomizing properly it may not be fireing until it warms up a little. I'm not the expert, but I have been around a lot of diesels, particularly in the marine industry. When ever an engine was starting to wear out it would do as you describe. There are compression gauges for diesel engines. There a little pricy.
One thing we would do to find out which cylinder was the problem was to crack the injector line, one at a time while it was running bad. When the smoke cleared up we found which cyclinder or injector it was. I'm sure you can do the same on our trucks. What color is the smoke???
I'm sure someone who knows more will chim in.
Hope that helps some.

 

[irish power mad]

A bad grid heater shouldn't cause the engine to billow out black smoke or idle rough for a minute.Might take an extra crank or 2 if it's cold out but should fire up with no issue's.More then likely you have a bad injector or bad injectors.

 

[balljoint]

A bad grid heater shouldn't cause the engine to billow out black smoke or idle rough for a minute.Might take an extra crank or 2 if it's cold out but should fire up with no issue's.More then likely you have a bad injector or bad injectors.

The smoke is not black ,it is a blue /white ,The heater grid checks out fine I tested it it gets power and does heat up,After it has its little fit when cold and runs rough with about a 200 rpm drop for 30 sec-to may-be a minute ,it purrs like a kitten the rest of the day and beats you to the key when starting.would a bad injector show up just when cold or all the time?

 

[Shainer]

Check for codes.

Blue smoke is oil check back side of turbo going to the aftercooler.
White smoke is incomplete combustion usually related to timing issues that could be created by either the VP-44 or injectors that are wore out.

 

[balljoint]

Fuel pressure?

As far as the truck running rough, does it only do it during warm up? If so I'd say there's an issue with your grid heater relay.

All checked out with the pre-heater ,it has power when cold and heats-up.
Only when cold ,it has its little fit ,has blue/white smoke ,runs rough ,then come out of it and is fine the rest of the day.

 

[balljoint]

Check for codes.

Blue smoke is oil check back side of turbo going to the aftercooler.
White smoke is incomplete combustion usually related to timing issues that could be created by either the VP-44 or injectors that are wore out.

I have a 50 hp power puck in-line between the vp-44 and the computer,could it be acting up when cold? or when vp-44 going bad or an injector going bad do these show only when cold ? It has no codes.....

 

[Wy Elk Hunter]

Blue/White smoke. Then clears up when warm. Plus no codes. Plus drops rpm. To me that sounds like you have a cylinder thats not firing. Hence the drop in rpm. Likely a bad injector. Like I said before, Crack loose each injector line at the head one at a time while it's running bad. The one that doesn't drop rpm, and clears up when crack the line open will be your cyclinder. Pull that injector out and have it tested.
Let us know, I'm interested.

 

[balljoint]

Blue/White smoke. Then clears up when warm. Plus no codes. Plus drops rpm. To me that sounds like you have a cylinder thats not firing. Hence the drop in rpm. Likely a bad injector. Like I said before, Crack loose each injector line at the head one at a time while it's running bad. The one that doesn't drop rpm, and clears up when crack the line open will be your cyclinder. Pull that injector out and have it tested.
Let us know, I'm interested.

I will let you all know what I find,the injector test you described sounds good ,but by the time I get around to crack open a injector the engine is already running smooth,I will eventually figure it out and will let you guys know what I find,may-be someone who had a similar problem will chime in on what fixed there problem,thanks

 

[balljoint]

A bad grid heater shouldn't cause the engine to billow out black smoke or idle rough for a minute.Might take an extra crank or 2 if it's cold out but should fire up with no issue's.More then likely you have a bad injector or bad injectors.

I agree ,after further testing ,the the grid was found to work fine ,it is cold related and for some reason it is not burning all the fuel when cold for the first few secounds.

 

[Shainer]

I have a 50 hp power puck in-line between the vp-44 and the computer,could it be acting up when cold? or when vp-44 going bad or an injector going bad do these show only when cold ? It has no codes.....

Take the power puck off. Reduce variables while trouble shooting.

 

[huntin'fool13]

I have the same problem...hope its not the injectors. If it was an injector would it matter if it was plugged in or not? Because when mine is plugged in it starts and runs like a top

 

[irish power mad]

I have the same problem...hope its not the injectors. If it was an injector would it matter if it was plugged in or not? Because when mine is plugged in it starts and runs like a top

When you first start without plugging in does the motor stutter a bit for a few seconds and stutter even more if you give it a small bit of a rev.If it does then more then likely your injector tips are worn or the pop off pressure is down.

 

[balljoint]

I have the same problem...hope its not the injectors. If it was an injector would it matter if it was plugged in or not? Because when mine is plugged in it starts and runs like a top

I think I may have found the cure,it is nothing to do with the injectors ,or the heating grid,popets or nozzels,or grid relays,If my hunch is right I may have solved this gremlim,before I commit to this fix ,Give me another day or two,to prove myself wrong or right ,I will let you know.

 

[huntin'fool13]

Yes it does! And I look forward to hearing it balljoint!

 

[huntin'fool13]

Do you have to replace the whole injector if the tips are bad?

 

[Wy Elk Hunter]

Do you have to replace the whole injector if the tips are bad?

\
No, you can replace the nozzel. But then you will have to have it flow tested. That's still cheaper than replaceing the whole injector.