mid range smoke

[rubberneck]

I installed POD's in a buddies truck over the weekend along with a 12 cm housing. We also turned the full fueling screw up about 1-1&1/2 turns (not sure exactly how much as i pulled the screw completely out to cut off tamper collar, and the lock nut moved when putting it back in). The idle was only up about 100 rpm if that gives an idea of how far up we went. We also advanced timing to 1. 5 mm. No other adjustments were made to pump as i wanted to drive it first to get a baseline. He loved it and didn't want me to do anything else. However after driving it for a few days, he wants to get rid of some of the midrange smoke. He still wants it there at full throttle, however he just wants to be able to control it a little more during shifts. Smoke right out of the hole seems to be manageable when driving normal, but will smoke like a train if you stab it hard. Where should i start. Star wheel adjustments, diaphragm or aneroid on top?? Do i need to back the full fuel screw out a tad. I think he would be a bit bummed if i had to do that, but probably would be worth the compromise.





PS have any of you experienced a rough or erratic idle from the POD's, this is the second truck I've put them in and the other truck does not seem to have this issue. Its not bad, just noticeable and he asked about it. TIA for all suggestions.

 

[BushWakr - RIP]

Hi rubberneck,



As for the POD's ... some have noticed a bit of 'roughness' or hard idle as I call it. Others have no problem. I think that there are some basic reasons for this. First there are some trucks/engines with their own "personality". I know that sounds simplistic but I'm convinced of it. Second there may be slight variations in the quality/health of fuel pumps that can affect this. Third, pump timing is pretty important in this situation. While one guy will have a good result with 15* advance, another might do better at say, 16* or 16. 5* advance. Heck some run up to and slightly over 17*advance. Generally 17* is the upper limit to retain some measure of head gasket life span, and also most pumps will hit the engine before they can go much further.

Fourth, you may need to coordinate all your settings with a proper valve set. Cummins calls for . 020/. 010 exhaust/intake.

Since we are pushing the trucks a little harder, running more fuel, and higher RPM's you may want to tighten up on those settings a tad, eg: 19/9



As for the smoke, here is a general description of what adjustment does what.....



1) Smoke only at full throttle/load - back out the full fuel screw.

2) Smoke at low end thru pull-up - back out the delivery rate setting. (AFC diaphram/cone) **Look in my readers rigs gallery for some pics on the AFC/cone and internal parts. Also jbolt has some good pics too. Look them over.

3) If smoke is heavy at immediate start-up - fine tune the smoke screw on top of the pump. (under cap, 13mm locknut, #25 torqs bit) Counter clockwise reduces smoke and fueling that is used in the first 60' of launch as I call it. Clockwise increases fueling for the same.

4) Starwheel - adjusts the amount of fuel per pound of boost. If you turn the SW down (clockwise) you will have more fuel coming on with low(er) boost. Counter clockwise will result in less fueling for a given amount of boost.



As I mentined, go thru some of the picture galleries and have a look around. There is some selfexplanatory things that can only be made sense of if you look at how it's arranged.



Good luck.



Bob.

 

[rubberneck]

Thanks bushwakr, sounds like i am going to start with the starwheel and see where we get.

 

[rubberneck]

while im here, whats the trick to getting more out of the high idle stop. there is still more travel left on the adjustment, but there is not enough travel in the pedal. Do you bend the pedal or the mount or something to that nature. right now it will go to 2800 rpm in neutral



Also, how sensitive is the starwheel, are we talking several clicks/turns to see a noticeable difference, or should i go a few clicks at a time. Sorry for what seems like such simple questions, i have looked at most of the info you mentioned, and it makes sense to me, i just havent had the "tinkering time" to really sort it all out. Hopefully after this weekend i will be a VE pro

 

[jbolt]

Think of star wheel adjustments in terms of 1/2 and full turns. I would run the star wheel CW to the bottom, count # of turns so you know where it is at now for reference then try backing it out 3-4 turns and see how it is. Tweak from there



What turbo does it have w/ the 12cm? Is the waste gate hooked up or disabled?



Jay

 

[nascar mark]

Ruberneck,

When you installed the injectors, you might of installed the lines with the inj nuts slightly off vertical. If the inj lines don't line up just right you will have a erratic idle. Loosen nuts and pull up on nuts so you can see lines and bend slightly so they look straight with inj and slide down nuts and tighten.

 

[rubberneck]

nascar mark, thanks for the tip, i will check that as soon as i get my hands on the truck. Jbolt, thanks for the advice on the star wheel. The turbo is the stock wh1 with an hx35 12cm wastgated housing. the wastegate is hooked up and functional, but i put a brass boost elbow on it off of one of the turbos i had for my truck. On my truck the elbow was adjusted for 36 lbs, but i dont know how much boost hes getting as he only has a tach and pyro. Thanks for the tips, im sure i will be asking for more before everything is just right.



Hey i noticed a lot of you guys are listing 4" exhaust from turbo back, I didn't know anyone was making these for a 1st gen. Or are these all custom jobs.