What fuel air ratio make for hotter exhaust?

T

Tree DR

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Oct 14, 2007
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Just trying to find out if my truck runs hotter at 65mph than most and if that helps explains mpg differences between trucks?
 
Stock had the ecm flashed a few months ago because someone left a 70hp down load on it. If my truck is running rich does that mean to much fuel or not burning properly because of bad injectors? The previous owner had the edge juice on it could that have caused injector wear? Any other ideas?
 
Hot like EGT or like coolant temp?

How hot are you running? How heavy are you loaded? Whats the weather like when you answered the previous?
 
Not loaded looking at EGT's My pyro is in the #6 exhaust manifold would that explain 700+ at 65 level ground no major winds?
I'll try to fill in my sig. My truck 05 g56 4x4 3500 dually flatbed.
 
Tree DR said:
Not loaded looking at EGT's My pyro is in the #6 exhaust manifold would that explain 700+ at 65 level ground no major winds?
I'll try to fill in my sig. My truck 05 g56 4x4 3500 dually flatbed.
Click to expand...

Nice Darin 700?:hehe: I hit 1500 for a min on the smarty tnt/revo tune today.
I think I burned my sbc 3600 a lil too.
 
Now what I'm talking about is crusing at 65mph light wind level ground. I've seen guys post stay below 600deg and I'm at 700deg at 65mph. Why is my truck running hotter? The water temp isn't high and everything seems normal.
When my truck was still moded I could hit 1500 when pulling my trailer.
 
Outside temp doesn't seem to make it change enough to really notice. About 600ft above sea level.
Thanks for the info.
 
do you still have that DL that you can't identify on there? A programmer will make it run a lil hotter.
 
Temps sound normal to me. Mine runs around 850-900* on level ground and has since the day I bought the truck brand new from the dealer. Quit worrying about it and drive it. It could be something simple as to your pyro probe placement, accuracy of the gauge, intake setup, exhaust setup, tire sizes, gearing, tranny, load in the bed, any accessories you've added, who knows. 100* is nothing.
 
Around 16 on the highway and 13-14 in the city. Big tires and tall gearing sucks for around town mileage. Truck has run 800-900* since the day I bought it so nothing's changed there. On a small hill I can tag 1200*.
 
If the probe is truly in front of the #6 exhaust port, then IMO, it is normal. #6 typically runs the hottest. I have my probe coming in the manifold in front of #4 whcih pretty much reads the back 3 cylinders and get around 650 degrees at 65mph.

Did the previous owner have a downloader on it or an Edge Juice or both? It shouldn't matter either way, just curious.

Quit worrying and keep driving.
 
I read somewhere sometime way back when that Diesel tend to make the most HP around 1200* and tend to get the best MPG around 600*.

I think it was in a bio-diesel article by the U of I. Comparing BTUs in the different fuels and what not.

I personally don't trust a $200 gauge with my $8000 engine. I have 2 gauges, 1 is a traditional gauge by autometer, the other is on my FMS box. They both usually have different readings by minute amounts. The FMS seems to react faster (digital gauge) then the traditional analog. Most of the time, I hover around 600* cruising on both of them (the analog may be a hair past 600, and the digital may read 625).

I will hit 1000-1100* all day long going over some of the passes here at 65-75. I've run right past 1450* many times.. I wouldn't worry too much about those temps.
 
djbikeman said:
If the probe is truly in front of the #6 exhaust port, then IMO, it is normal. #6 typically runs the hottest. I have my probe coming in the manifold in front of #4 whcih pretty much reads the back 3 cylinders and get around 650 degrees at 65mph.

Did the previous owner have a downloader on it or an Edge Juice or both? It shouldn't matter either way, just curious.

Quit worrying and keep driving.
Click to expand...

First I'm not worried about the temp. Just looking for the difference between trucks that might explain MPG differences.
The truck did have a down loader but I've had the ecm flashed. Temps haven't changed much though.
I'm deffinatly driveing about 400-600mi a week, just tired of paying more for fuel that the truck payment.
 
The variance could be from machining tolerances, valve lash's, cp3 differences, injector differences, piston differences, tolerances, gauge accuracy, probe placement, who knows. Maybe your injectors are .0001 bigger than the next guys and that's causing your slightly higher EGT's. Who knows. Either way, 100* difference in egt's isn't going to make a lick of difference in mileage.
 
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