Cold weather and smoke when starting

[eembry]

Well I changed the fast idle a little to the fast side and thought I would see if it made any difference. Also changed the fuel filter. If I don't depress the accelerator it's not too bad with the smoke but if I depress the accelerator to set the advance and the fast idle look out it is smoke city. This has to give someone a clue as to what's going on here. I started to advance the timing a little to see if that would help but if when you depress the accelerator advances the timing and that makes the smoke worse would it be the same if you manually advance the timing or is it a different situation? I'm confused. I still think it is something simple because the truck runs too well and starts too well under warmer conditions. Could there be anything in the wiring harness that could be breaking down? What do you think?

Eddie

[Robyn]

I am suspect of the injector pop pressure being too low and the spray pattern being poor.

How many miles on the squirts??
Were these rebuilts or >>>?????

The issue of more smoke with throttle is about right as the amount of fuel increases too, hence more smoke..

What was the POP pressure set to??

Have you turned the IP slightly to advance the timing a tad ??

RC

[midniteplowboyy]

Is your cold idle/advance switch working? You should have 12v to the cold advance solenoid and high idle solenoid when engine temp is below 100ºF with ign sw on. If you have power, check to see if the advance solenoid clicks when you remove/apply power(might be a low voltage problem also).

I think it is in your cold advance system. Its been awhile since I had the top off of one of them, IIRC the advance solenoid restricts the fuel return outlet on the top of the pump, you might unscrew the return nipple and see if you notice anything wrong(seams like it has a pressure relief valve in it for when the solenoid has the main return blocked).

My 93, when the temp switch was bad, it would miss and blow alot of fuel smoke, untill it gradually warmed up. My 92 is a different animal though, it still cranks good without it, I think it works now(got me wondering, I'll have to check). 6.5's are like people, there's no two the same and they got there own personality.

[eembry]

Robyn, I replaced the injectors with oem gm new injectors about three thousand miles ago.I don't know what the POP pressure you are referring to even is much less what it is set at,sorry. I looked at the IP but didn't move it. It was already right of the factory mark so I thought maybe it had already been moved. Also I need to get a different wrench to loosen the bolts boy are they TIGHT! All I had was a regular length end wrench what do you use to get those things loose? Kinda close quarters unless you take a lot of stuff off to get to them. As far as the temp swith plowboy is referring to I have not checked any of that stuff but guess I need to. I really don't know what all I need to check and what it is suppose to check anyway. Guess I need to try and find a book but even then don't know what all intersects with what. I really appreciate all the help I would love to get this problem solved wish some of you were closer so we could get together and scratch our heads over this. I know some of you would figure it out as you know a whole lot more about these engines than I do! Anyway don't give up on me I will try whatever I need to just stay with me. Thanks, Eddie

[BamaChief600]

So does the cold idle/advance need a full 12v? I have about 10v and I get alot of smoke and rough idling. It clears up when it gets warm. I know I need glow plugs and injectors as they are original.

[JohnC]

They're solenoids, so either they pull in or not. So, 10 volts is probably enough, but I'd be curious why it's not higher.

[midniteplowboyy]

They're solenoids, so either they pull in or not. So, 10 volts is probably enough, but I'd be curious why it's not higher.

I'd think it should be within 0.5v of battery voltage, if not I'd try to find the voltage drop. I think 10v would be sufficent though.

[BamaChief600]

Well I looked at the connector on the coolent sensor and they are gummed up with old caked oil so cleaned them up and the sensor is bad. Oreillys,auto zone or advance had no such sensor. Anyone have a parts #? Its not the one on the block but the one on the coolant cross over pipe.

[midniteplowboyy]

Here's the P/N for that cold start switch for you 1992 and 1993 guys.

GM/AC-Delco P/N 10154649

HTH,

[eembry]

Hooray! I finally got the truck starting without the smoke, only problem I'm not sure which cured it. I went over all the glow plugs and checked to make sure they were not burnt out, noticed some of the spayed connectors were not really all that tite so I pulled them all off tightned them up as best I could and put some electrical grease on each of them so they would make contact. I also went ahead and changed the oil pressure switch which I had changed not all that long ago. When I finished and started it ,just like it was suppose to start hardly any smoke and smooth like it was suppose to be. I don't know which did it but I am a happy camper as I have been fooling with this thing for a couple of winters trying to get it figured out. Thanks to each one of you for your suggestions and for helping me out. This is a great board and it is so hard in my area to find anyone that is very good on troubleshooting problems on the 6.5's. Everyone wants to tell you it's the Injector pump no matter what your problem is. So I appreciate this board very much. Thanks again, Eddie

[Robyn]

Often the connectors can get slightly corroded as well as loose and with the glow plugs,can cause poor heating or some to not work at all.

This is usually not an issue when the weather is warm.
The engine can start as long as it has a few plugs that are getting hot and as soon as the RPM comes up the compression temp will get the fire lit in the rest but you get the smokey Joe's while it's doing it.

Glad to hear the little creature is working well again.

Best


Robyn