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eembry
10-25-2010, 18:18
I have posted a couple of times about having smoke at cold start on my 1992 2500 pu over the last couple of years. I have replaced the injectors the ip the glow plugs the glow plug controller the ops I have probably have put less than 4 thou. miles since all this was done. I still have rough starting and smoke when I first start the truck cold even when the weather is fairly warm out. After the inital start it is good to go all day no matter how much or how little you drive it. I don't see any evidence that I have a fuel leak and would be loosing pressure but I don't have any timing advance or fast idle at cold start, I know there are some sensors or something that control this but would this be what would causing this problem or is there something else I need to check? I am limited on finding anyone in my area that is really good on the 6.5's. This truck runs and drives great except for this nagging problem I really need some advice from some experts as to what to do next this is very annoying! Also if I plug the truck in when it's cold it starts great so I suspect there is something not working in the electrical part of the system dunno?
Thanks in advance for any help

Big Green
10-26-2010, 06:31
Have you checked your compression numbers?

low compression can make them really hard to start.

JohnC
10-26-2010, 08:15
I don't have any timing advance or fast idle at cold start, I know there are some sensors or something that control this but would this be what would causing this problem or is there something else I need to check?

Nope, that's it...

Follow the wires (green?) until you find a coolant temperature sensor switch. Likely it is not working.

eembry
10-27-2010, 21:22
thanks will check it out I have not checked the compression #s but as quick as it started this I don't think thats what it is I'll do the simple stuff first then if can't get it straightened out will check it. Thanks for the help.

suburbanK-2500HD
10-28-2010, 10:52
Nope, that's it...

Follow the wires (green?) until you find a coolant temperature sensor switch. Likely it is not working.

Would agree, experienced the same issue.
Accidently bumped into the temp sensor, and bearly cracked the top.
when i started the engine i would not settle as it was getting hotter.

1629dill
10-28-2010, 12:57
Just reading the posting and started to have questions about the coolant temperature sensor switch. Is this the same item that feed information to the temperature gage on the dashboard or is there a different sensor that takes that reading? The other question I have is there two idle speeds on the engine? My suburban only idles at 700 rpms hot or cold. Just wanting to know if I need to add another item to my shopping list to get ready for the winter.

suburbanK-2500HD
10-28-2010, 13:24
Just reading the posting and started to have questions about the coolant temperature sensor switch. Is this the same item that feed information to the temperature gage on the dashboard or is there a different sensor that takes that reading? The other question I have is there two idle speeds on the engine? My suburban only idles at 700 rpms hot or cold. Just wanting to know if I need to add another item to my shopping list to get ready for the winter.

Look at this picture: if this is defect it wont idle normal when hot, stays high on idle. Thats what mine did.

racer55
10-29-2010, 08:40
Just reading the posting and started to have questions about the coolant temperature sensor switch. Is this the same item that feed information to the temperature gage on the dashboard or is there a different sensor that takes that reading? The other question I have is there two idle speeds on the engine? My suburban only idles at 700 rpms hot or cold. Just wanting to know if I need to add another item to my shopping list to get ready for the winter.
There are 2 seperate sensors for coolant temp information.
The ecm snsor is located in the coolant crossover manifold shown in the picture above.
The gauge sensor is located in the drivers side cylinder head near the front.
There is a high idle mod that can be done to raise the idle with the help of a toggle switch and some ecm wiring.But depending on the temp the ecm will raise the idle in really cold conditions but it may not be noticable in your area.