For the first time since owning the truck, I mashed the pedal to the carpet while in neutral.<br>The truck hadnt made it to &quot;normal&quot; operating temps yet, it was still a little around 140*.<br>The engine revved to about 2500 rpms and no further.<br>It also produced heavy gray smoke. The smoke was so heavy it covered the front yard.<br><br>After driving it a short distance and getting the temps to &quot;Normal&quot;, I stopped in a parking lot and revved it again at full throttle. <br>This time, it smoked the same gray smoke for about a second or two, but then cleared up.<br><br>Just wondering what would/could be causing this?<br>Is this normal?<br><br>I know Ive got a weak number one delivery valve in the injection pump... could this be the problem, or making another problem worse?<br><br>Just wondering what all you guys think.<br><br>Rich.<br>

 

Dont have an answer for ya, but mine will smoke like this going down steep grades in the mtns, and it smokes real good when cold. And like you when shifting if I take it all the way to wastegate function I will get a nice puff of blue smoke no matter what temp the truck is.<br><br>Ill be watching to see what the experts have to say.<br><br>This site is awesome.<br><br>Trickytrae

 

i have done some fuel mods to my 96 3500 CTD. From what the experts tell me black smoke means power, mine only does it right when i mash the pedal, nuetral or drive. a thick puff of smoke comes out , usually resultin in all 4 rear tires spinning like a camaro. So from what ive heard smokes ok and if your really making power , its just an added bonus to show off with

 

[quote author=3500workhorse link=board=16;threadid=13771;start=0#131850 date=1051291500]<br>i have done some fuel mods to my 96 3500 CTD. From what the experts tell me black smoke means power, mine only does it right when i mash the pedal, nuetral or drive. a thick puff of smoke comes out , usually resultin in all 4 rear tires spinning like a camaro. So from what ive heard smokes ok and if your really making power , its just an added bonus to show off with<br>[/quote]<br><br>Yeah, fuel mods usually result in black smoke. The more black smoke = more power.<br>But this wasnt black. <br>There was a puff of black smoke initialy, but it then turned to heavy gray smoke.<br>If it were blue, Id say I was burning oil.<br>If it were white, Id say I was getting water into my cylinders.<br>But it was gray.<br>Im wondering if I may have an air leak in my injection system, or perhaps my timing is off?<br><br> ???<br><br>Rich

 

My truck grey smokes after boost is maxed out every time, or if I sit there and hold it at WOT. Does not mean anything just the the fuel is not being burnt all the way. I would not worrie about it.<br>DM01

 

[quote author=dodgeman01 link=board=16;threadid=13771;start=0#131922 date=1051300603]<br>My truck grey smokes after boost is maxed out every time, or if I sit there and hold it at WOT. Does not mean anything just the the fuel is not being burnt all the way. I would not worrie about it.<br>DM01<br>[/quote]<br><br>This sounds correct. <br>I placed a call to my local Cummins shop and that is the same thing they said.<br>They also told me that if it has gray smoke while in gear at WOT, then maybe the timing needs to be checked. <br>However, my truck does not have the gray smoke at WOT while in gear. <br>Thus, they said the exact same, just excess fuel not being burned.<br><br>So, this brings me to another question. I was always under the impression (From members pics) that extra fuel not being burned produced black smoke?<br><br>Why does extra fuel produce heavy black smoke, and unburned fuel produce gray?<br>Is it based upon the load of the engine?<br><br>Just curious.<br>Thanks<br>Rich.

 

The more fuel the darker it gets. really dark black smoke = a lot of unburnt fuel. Grey smoke means a very small amount of unburnt fuel.<br>DM01

 

[quote author=dodgeman01 link=board=16;threadid=13771;start=0#131963 date=1051305604]<br>The more fuel the darker it gets. really dark black smoke = a lot of unburnt fuel. Grey smoke means a very small amount of unburnt fuel.<br>DM01<br>[/quote]<br><br>I guess Im gonna have to fix that eh? <br>Hmmm... maybe a cam plate, bigger injectors, and 3k GSK?<br>Yeah, I think that'll change the color of the smoke!<br> <br><br>Thank you all.<br><br>Rich.

 

<br>Yep that would work.<br>DM01

 

Grey smoke is a sign of low compression, and the combustion temperatures not being high enough to burn or &quot;coke&quot; the fuel.<br><br>Exceptions to this is an injector failing to deliver proper atomization (injector plugged, weak delivery valve, burned injector tip) and the fuel remaining in globules long enough to simply evaporate in the exhaust and create an oil fog.<br><br>A diesel engine will burn grey when it is not fully up to operating temperatures, because the pistons are slightly cam ground and must heat up to fill the cylinder bores before they will make full compression. That is also why a cold engine knocks more than a fully warm engine, and why to never rev a cold engine above 1200 rpm (it hammers the piston skirts and causes premature engine wear, and blows unburned fuel into the crankcase). A cold engine will have low compression.<br><br>Black smoke is excessive fuel for the air mix. What happens here is that the combustion temperatures get high enough, but that there is not enough oxygen to burn all the fuel. The excess fuel &quot;cokes&quot; and blows out as carbon black. Black smoke generally only happens if there is a pressure leak in the intake system or a stuck AFC, or if the injection is turned up and brief rich conditions occur until the turbo catches up. All my trucks make a couple of seconds of black smoke before the air pressure is high enough to provide enough oxygen for a complete burn.<br><br>I would start by getting the delivery valve repaired. If you have a grey smoke problem when the engine if fully warmed and has been operated under load for at least 15 minutes, get an oil analysis to check for coolant in the oil. Blown headgaskets almost always result in grey smoke.

 

Thanks RCW, <br>The engine wasnt cold, but it wasnt up to normal temps either.<br>... and yes, I do need to take care of that delivery valve. <br><br>Thanks again.<br>Rich.<br><br>

 

Don't forget. They will smoke in neutral and WOT if the enine is not up to normal operating temp. Also, these things run completely different with no load, IE neutral, than in gear and pulling the weight of the truck.<br><br>If your experiencing this in neutral and a not full hot motor, I'd say it's running normal.<br><br>2 cents maybe only 1 cent.