Hey y'all! I posted a thread back about 3 weeks ago asking for some help on performance parts and some pump adjustments. I finally got some of the pump stuff figured out and I don't think I need to buy a new injection pump!

I thought my fuel pin was stuck but it turns out that it was just hung on the horizontal pin that it slides against. Once I got it out, I found out that I have a factory fuel pin rather than an aftermarket one. I cleaned inside where the pin goes with a nylon brush and also cleaned the pin. By the way, the pin has the number "75" printed on the bottom of it so I'm not really sure what that means.

I've been having issues with smoke and high EGTs from day one with my truck so I decided to do a little tweaking. After doing some research, I figured turning out the smoke screw and the starwheel would fit the bill of what I was asking for. I turned the starwheel up 1/2 a turn and didn't touch the smoke screw then went for a test run. This lowered EGTs and smoke a tad but I wanted more. By the end of my tuning, I turned the starwheel up 3 full turns and the smoke screw out by 2 turns. This lowered my EGTs about 150-200 degrees permanently and helped the smoke out a lot.

I still push 650-700 degrees just cruising down US-25 through the northern Kentucky hills at 55mph and 600-700 while running down the interstate at 65mph. My question is what else can I do to lower EGTs? I don't really know if adjusting the full fuel screw would help any, I'm just looking for some insight about it. My goal is to be around 500-550 while running 55 and 600-650 running 70.

 

6-700 is pretty normal for cruising, why are you trying to get lower exactly? What is your boost at cruise?

Backing out your fuel screw should help.

 

On a hot summer day here in Texas i see about 800 cruising on the highway.

 

2 nights ago was maybe 90degrees outside and I was running 700-800 degrees @70mph. Ill have to see how it is after I've messed with my pump today and advanced the timing on it.

 

As the others mentioned, your cruising EGTs are perfectly fine. What are you seeing for EGT when loaded at full throttle?

With the mods you've got in your sig, I'm thinking about the only thing you could do to further lower EGT would be twin turbos and maybe a 24 valve head. That's a lot of money to spend for an EGT reduction that may not be of any practical help though.

 

Timing will help egts but raise motor temps if you go to high.

 

Whenever I'm hauling even small loads (1000-2000lbs.) and I put it wide open to the floor, I can hit 1200* easily. Especially if I'm not really spooling any boost (under 5psi). I plan on going from my 18cm exhaust housing down to a 16cm or maybe a 14cm in order to get the quick spool up I want. I plan on getting rid of my truck here sometime when I find a really clean 24V that I can trade towards or just sell my truck outright so I don't want it modded up too much.

Would that help the issues with EGTs any? What else could I try that might lower EGTs during a load?

Advanced timing? Bigger injectors? Turn the fuel pin?

 

There is nothing to gain from lowering EGT's any further than you have already.

I've seen a chart somewhere of what temps a cummins can withstand, and how long.

it reads something like: (this is from memory don't quote me)
all pre turbo:
1250* - constantly
1400* - 30-45 seconds
1600* - 15-20 seconds
1800* - 5 seconds ( don't try this)

 

I've heard similar numbers while searching around on here. I guess you're right, EGTs don't really matter unless they are getting too high. I guess I'm just freaking out about it. It just seems like whenever I have a load and there's no boost, EGTs rise awfully quick.

 

A load and no boost will cause high egt's. You either need to adjust your low boost fueling or increase spoolup (smaller ex housing). Start with your AFC tuning.