Engine/Transmission (1998.5 - 2002) EGT's seem too low

[cmills]

The other day when towing (Gross weight of 18,870) the highest the EGT's would get were about 650 after the turbo, I thought this was too low so I took the truck in to have the pyrometer checked and they said it was ok, So I got a new probe and came home and put it in and hooked up to the same load and got the same results. the truck has 275's and a boost fooler with the elbow in the turbo and it was running around 29 psi of boost. Do these temps seem normal?





Cory

 

[NWhitney]

more info needed

Since your prob is post turbo then this is close to right... add ~300*. That gives you 950*. You have bigger injectors, but you have more air too. Do you have an auto or a manual. If it is a auto the computer may be detuning the engine if it is seeing a slip in the trans. Fill out your sig so we can help. But for the most part... don't worry you are fine.

 

[juicedcummins]

Your boost is TOO high for just 275's. On my 99 you only needed 22 to control the egt's with 275's. The fooler is needed to get max out of the injectors. The newer trucks may se about 1-2lbs more @ most. If you had an adjustable elbow [not the pinhole one] you could dial it to the pyro. High boost #"s like that and you are loosing power to pumping loss unless you have the fuel to near max the egt's.

 

[rblomquist]

It depends on what the engine load is and rpms play huge in your reading as well. If you're "keeping the fire lit" (rpms up) then your post turbo reading will stay fairly down there. If you hadn't got the pyro tested and hadn't put a new one in I'd say it might be off by 50-100 degrees but it sounds to me like it should be telling you about what it is.



What could be throwing it off a tad is that with at least some pyros where the lead from the thermocouple connects to the wire running to the gauge is set for a fixed calibration at something like 70 degrees. So depending on where that wire connection is i. e. under the hood or inside the cab and the temperature around it in that location will skew your readings by a factor depending on how far off from that 70 degrees the ambient air is. On my Westach pyro the instruction paperwork clearly talks about it.



On my truck with the EZ and pulling 11-12k loads under a light pulling condition where I'm kind of freewheeling i. e. level road no wind etc it will indicate in the 650 range. As soon as the truck starts to "pull" the load though, the EGTs will climb and will keep climbing the more the truck is lugged. As long as I don't let it bog down the EGT post turbo reading stays pretty cool all the time.

 

[cmills]

EGT's

How does the adjustable elbow work? I assume it hooks up the same right. then how do you adjust it, do adjust it so the egt's are quite a bit higher and if so why do you want it to be hotter?

 

[darkhorse]

The adjustable elbows have a small allen screw that controles the size of the orifice. The smaller the hole the higher the boost can go.

 

[Yooper1]

I had the same problem and the real problem was the gage. . I swiched the gage and really saw the real temp. . Always watch your gages and question them if they seem low. . Had a problem with my boost gage and it was a fitting that was leaking. . It was off by 18psi.

 

[cmills]

elbow

thanks darkhorse, i just looked at the elbow that came with my boost fooler and it has a little allen screw in it, I didn't put it in because i still had the old elbow in that came with the edge box i used to have. How do I want to set this when i install it?

 

[darkhorse]

I got one from TDR member Don Troxil. It was pre set for 30# max. I just left it that way. If you get to much boost, screw the allen in slightly & make a test run.

 

[cmills]

hotter=Better.... Why?

Why are hotter EGT's better, I always thought cooler was better.

 

[NIsaacs]

I would question the accuracy of your pyro. Post turbo pulling, should be in the neighborhood of 900 degrees with the probe about 2" from the turbo. The further downstream you go with the probe, the cooler the temps.



"NICK"

 

[darkhorse]

Your 650* post turbo translates into about 950* in the manifold. If it's on a level road I think you are about right but if it won't go higher pulling a grade or at wot then you are definatly on the cool side. 29 lb boost is a lot for level cruise even with your tow weight.

 

[cmills]

Egt

I had the gauge checked and they said it was fine, and I installed a new probe just in case it was bad. When I checked it I pulled out on the highway and kept it floored through all the gears until I reached 70-75 mph and 650 was the highest temp I got, I was on fairly level ground. I put in the adjustable elbow and I messed with it all over the place and it didn't really change no matter how I had it set.

 

[NIsaacs]

Cory,



We need more information on your truck. Did you just install the guage or has it been on for several years? Has it always been on the low side? What kind is it? Is it mounted next to the radio speaker? Pyros can be very tempermental at times depending on the type. The speaker magnet can throw a false reading if too close. If the pyro is a direct wire mount with wire studs, remove them, wipe the wire terminals off then reinstall. Also check your main lead from the guage to the probe wire. If all this checks out ok, I would suspect a "gunnysacked" guage. On a good pull with that weight, you should see about 900 degrees. What is your idle temps?



"NICK"

 

[OTRPU]

Mo Fuel, then Mo Air In, then Mo Air out.



Cheers,

Steve J

 

[johncameron]

If you can only hit 650° post at wot merging on traffic I would say it's too low. When I had mine post turbo I was able to get her up to 1050° empyt climbing a 11% grade wot at 2200rpm with 33lbs of boost. I'm running mo fuel that you but it still seems low to me.



Fill out your sig so we know exactly what you are running

 

[cmills]

the gauge is on the pillar and I have had it for a few years, but i don't see how it could be bad because when they checked it with their gauge they said it was fine and reading just a little bit hotter than theirs, by the way it is an isspro gauge

 

[cmills]

what else

So if the gauge really is ok, which I was told it was, what else do I look for?

 

[dcamilleri]

How is your power, compared to normal? A slightly plugged fuel filter will cause low egt's due to low fuel delivery. Also check fuel pressure.

 

[cmills]

the fuel filter only has few thousand miles on it, I'll check the pressure tonight.