POD injectors in, Truck smokes BAD!

[TexasTurbo]

I'm moving this question I asked BushWakr to a new topic. I got the POD's injectors in with few problems, BUT, my truck smokes like mad now. Not just at idle, but also running down the road, warm or cold. As far as I know, the pump had never been tweaked ( I never tweaked it, I puposely left it alone in anticipation of installing different injectors). From a reply by BushWakr;



"I had POD's put in a couple weeks back. I had some smoke at idle issues which were corrected today. Seems they came with the wrong washer thickness. Piers put in a brand new set, new washers, (thinner) and presto"



I installed the thick washers, the same that came off the old injectors. Also, my Cummins book called for 0. 06 in. thick, which are the large washers. Are you saying I have to run the medium thickness washers or the thin washers? And is a pump retiming necessary? Any help is appreciated.

 

[CToney]

The thickness of the washers affects the timing. This has to with the type of injectors installed. Some injectors need thinner or thicker washers. My truck used to smoke real bad when the pump wash turned up, bigger injectors, and timing off. I would get the same washers as bushwacker as long as the same cpl or try them anyways. I would also get the truck timed to 14-15 degrees or 1. 4-1. 5 mm. This should stop the smoke. Also check the max fuel delivery screw to see if the cap is still on if it is pump has been left alone.



Good luck



CR Toney

 

[Scot]

The starwheel was 5/8 of a turn off max from the factory as best I could tell. If it had been tweaked, someone did a real good job hiding their work.

 

[BushWakr - RIP]

I'm certain that Piers put in the "medium" washers. I think they are the . 040 thou. The . 060 thou. is what was put in when my first set of POD's went in. They had the thicker washers because, like you, thats what we thought would be right. NOT! When my second set was just starting to go in Al noticed that these one's came with washer actually already on the nozzle tip. The first ones did not. That made us curious since they were obviously thinner than the ones coming off.

Piers also made it plain that his experience was these injectors liked to have about 15* timing advance. Thats were mine is now.

I was able to back out the smoke screw alot more than previously with the 180 injectors and still had smoke. Now, with the thinner washer, and 15* timing, and no other changes its just fine. My smoke at start-up (plugged in overnight) is less than it was when at full running temp before the change to thinner washers. Even cool start at the shop was better than running temp smoke.

We have freezing temps here right now. Its at or just below freezing. I'm going to leave it unplugged tonite and check how it is in the morning. I'll let you know how that turns out too.

Like you I was really surprised at the smoke at idle when warm sitting at stop lights for example but Piers/Al fixed it up just fine as far as I can tell.

Don't give up, hang in there.



Regards, Bob



edit: I'm almost positive you'll be able to ease up on your pump adjustments and still get better power. That will also help with smoke too.

 

[TexasTurbo]

Thanks for the help all, looks like I'll be pulling injectors again this weekend.

 

[nascar mark]

Try backing out star wheel or turning diapham back slightly. Noticed smoke at idle and heavy on power. Backed off alittle and cleaned up alot. Boost is same.

 

[Power Wagon]

If you get smoke when NOT under load, then there's something physically wrong. Either you have an injector with dirt in it, or your timing is off.



I would advance the timing a ways, that should clear up any smoke at idle and cruise... . IF the problem is timing. If you have a stuck injector, it should shake bad at idle, and cracking the lines will show one that spews foam while the others squirt fuel.



Changing the thickness of the washer has absolutely no impact on timing. What it does do, is position the tip of the nozzle inside the combustion chamber. Be careful about trying to use really thin washers, like on the 215HP injectors. The injector will hang up on the little orienting ball on the side, and will not seat solidly.



Advancing the timing is likely to work well with lower nozzle positions, since the piston will be farther from the nozzle at injection time, and lowering it will put it more cleanly in the center of the air pocket.



Even if you have the wrong washer (way too thick) it won't smoke at idle or not under load from it. It will smoke more under load...

 

[BushWakr - RIP]

BushWakr wrote on 03-23-2002 12:52 AM:

Hi PW,



I read your post re: wahsers, timing, smoke on NO load condition.

I'm a little confused here.

When I had the POD's put in my timing was advanced (15*) before hand, then the injectors went in.

Afterward I had smoke at idle, when warm/cold. Even at running temps, in gear at a stop light. It did decrease slightly if I went to "N" while at a light.

Idle was fine, no roughness, in fact slightly better than the 180 BD injector idle.

I lost about 3 MPG as well.

Last week we pulled the orig. POD's and put in a new set with . 040" washers instead of the . 060"

The smoke decrease noticably across the board. Even on cold start at 32*F +or- I had less smoke than when truck was warm with orig set of POD's.

So, the only difference I see now is:

A) Far less smoke

B) Idle is slightly lower with new inj. & washers.

No changes have been made to pump that I'm aware of.

If the seating depth didn't help me (due to . 020" difference) what did?

Is this injector likely to 'hang up' on the orienting ball? I see no sign of sepage or leaking. Boost is good at 25-26 psi.



The rationale was, perhaps too much of the fuel cloud was missing the bowl and not being burned properly. ( abbreviated explanation)

Were is the thinking wrong??

Any ideas?



Thanks in advance



>>PW reply.....



Re: POD's and washer question...



If it works for you... I'll gladly say I'm wrong...



I'm guessing that those injectors are highly marginal, when it comes to being sufficient atomization.



I studied them on paper, once I found the part number, and found they have incredibly large holes... This is consistent with low speed smoke and somewhat less economy at light load. That should improve if you run higher RPM's, though. Speed causes the fuel rate through the injectors to climb, and rate is what makes the atomization work.



This being the case, apparently moving the tips down further does as you say, get the fuel into hotter air farther from the head surface...



If you haven't, post this on the thread...



Mark





edit: . . Thanks for your info PW... I appreciate it.

So far I'm having fairly good result with the lowering of the nozzle tip. I'll know how my mileage is in a few days.



Bob

 

[nascar mark]

I'm with Bush Wakr. The POD's smoked at idle and through the rpm band. You can not advance the timing more than my set up as i have it maxed. I talked to Piers on this subject when i picked up the injectors. Quote" You can not advance the timing too much on the first gen's. T he only way i have found to cut back on smoke is to retard the diapham to 11 o clock or unscrew the star wheel counter clockwise all the way. I haven't tried thinner washers as i put the POD's in with the washers that were on the injectors when handed to me. Piers did supply me with other washers as a install kit. Piers would be the "man" that knows best.



I do believe not all trucks from the factory are set up the same. When i bombed my truck it would smoke under heavy foot with stock injectors also. I have reduced the smoke quite abit by retarding. Smoke does mean power though. Don't think for a second, the pullers try a set up too reduce smoke.



"SMOKE" IS POWER. Two thinks happen with smoke. Helps seal ring to piston wall and also lubes cylinder walls. Too lean is trouble. When we race 1000 hp + trucks its a fine line but fat is always better than thin. Nothing eats a engine faster than thin. Start fat then work backwards til you can live with it. Work on egt's more important.

 

[Power Wagon]

Originally posted by nascar mark



I do believe not all trucks from the factory are set up the same. When i bombed my truck it would smoke under heavy foot with stock injectors also. I have reduced the smoke quite abit by retarding. Smoke does mean power though. Don't think for a second, the pullers try a set up too reduce smoke.



"SMOKE" IS POWER. Two thinks happen with smoke. Helps seal ring to piston wall and also lubes cylinder walls. Too lean is trouble. When we race 1000 hp + trucks its a fine line but fat is always better than thin. Nothing eats a engine faster than thin. Start fat then work backwards til you can live with it. Work on egt's more important.

Smoke is carbon... carbon is abrasive. Heavy smoke dumps soot in your oil and soot in your oil increases wear rates.



If you shove in enough fuel, raw fuel will strike the cylinder wall, cutting the lubrication of the engine oil and causing scoring on the cylinder wall and piston, and burning to the rings, causing stuck rings. Simply idling a lot will wear it faster, as the very low combustion temps increase the unburned fuel going past the rings. The larger your injectors, the more it does it. If you smoke at idle, it means there's unburned fuel in the cylinder after firing.



The more fuel you put in a diesel, the hotter the egt, up to a point. Lots of boost + lots of fuel = high EGT. A naturally aspirated engine without a lot airflow won't go too high, simply because there's not enough air to burn enough fuel to get that high... but it will belch a completely opaque explosion out the tailpipe.



In a diesel, the cure for high EGT is enough air to cool the cylinder temperatures to acceptable levels. Once you reach a certain point, then compression ratios must be reduced, as well. In other words, MORE air cools, not more fuel. This is why people use the PDR or B1 or other turbo mods, to get more airflow - which reduces the EGT.



I hope this all makes sense.

 

[nascar mark]

I was simply stating don't worry about small smoke even if its at idle. They don't call these injectors "PRINCE OF DARKNESS" for no reason. You get lots of smoke with these high power injectors. I do agree with the way to lower egt's is more air. As i will when $$ allows. Prioritys,prioritys. For now i chose to have the power and drive by foot and keep egt's in check. Diesel carbon is a lot less abrasive then gasaline carbon. Diesel fuel is quite slippery and so is the black carbon which helps coat the exhaust tract. Diesel engines and exhaust components last up to 10 times longer then gasers partialy due to this. Valves, cylinders, pipes and mufflers are prime examples of this.



Yes you should change your oil more often as any high output engine should. We change oil on the race trucks after every weekend race which consists of 4 - 2. 5 to 3 second passes down a 200 foot mud track. The oil is contaminated easily with lots of boost and lots of fuel as we have blown a few brand new intake gaskets from high boost before finding the cure with special sealant. We don't have heat problems as our heads are filled with cement, not water and straight piped.