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Discussion Starter · #1 ·
When driving 2 hours on the freeway mostly flat, my EGT sensor is running 9.5 and the floor is hot. You can feel the temp on the undercarriage etc.

I read 12.5 is the max before causing damage.

My question is what is normal EGT operating temp when driving 2 hour distances with no load or headwind? I am guessing there is a boost leak somewhere and is causing the elevated temps or is this temp normal on 7.3

Thanks for the help!
 

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Not normal, assuming the gage is correct. Should be around 700 depending on conditions...
 

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I see you have this listed at the bottom of your page:

(1999 F350 7.3 Auto 4x4 CC SB Lariat, 6 Position Chip

what tune are you running in? and have you tried setting it back to stock to see if your EGT is still high?

Normal driving (flat, no load) I see very little boost on my gauge, add a trailer or payload and boost increases, put my foot in it or hit hills and it really climbs. Around town and even on highway my EGT’s stay steady in 600 range.....with boost EGT’s climb up and come right back down.
 

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Your EGT is significantly influenced by exhaust flow, restricted ( as in stock with a stock muffler ) will push it up. A larger diameter exhaust system, or even a BTM flow throw muffler on a stock system will allow it to run cooler. At 2000 RPM unloaded 600 to 65O would be normal, unloaded on flat road with a BTM.
It's a 99, when did it start the high EGT?
 

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What speed are you running?
DENNY
 

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Discussion Starter · #6 ·
I ran the truck again on the same route and noticed a few things. The way out of town has a small grade and didn't have any boost or high readings as it was downhill/flat. On the way back I was increasing boost (small amounts) and the egt climbed immediately from 600 to 850-900. There was a small hill towards the end of the drive and boost reading was 13 with temperatures reaching 10,500 degrees if new gauges are correct. I left off the gas to allow the temperature to fall and immediately fell to 800 range.

I have only owned the truck for 10 months and recently installed the 4 cluster gauges to monitor boost, egt, fuel, and transmission. Not sure how long the truck has been running like this as I have not driven continously on inclines etc.

The exhaust is stick and has 6 position chip is on setting 4 - 75hp and I have not tried in stock to see if the results are different but will next weekend. Around town I will drop on the gas on inclines and my boost never has been higher than 21. The egt increases but never this high. It will immediately drop temp once I let off the gas.

I will do some more testing and see what I find. If I had a boost leak, I assume I would not hit 21 on the boost gauge?

Appreciate the advice..
 

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As you add fuel in that 75 hp setting you are going to increase the EGT's

Try a lower setting on the chip and see what it does, even the stock setting.
 

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1999 ford f250
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If you have the stock exhaust it probably ain't breathing enough for the extra power. And follow the advice bugman gives you too 👍🏻🙂
 

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Early or late 99?
 

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When driving 2 hours on the freeway mostly flat, my EGT sensor is running 9.5 and the floor is hot. You can feel the temp on the undercarriage etc.

I read 12.5 is the max before causing damage.

My question is what is normal EGT operating temp when driving 2 hour distances with no load or headwind? I am guessing there is a boost leak somewhere and is causing the elevated temps or is this temp normal on 7.3

Thanks for the help!
Do you have an Exhaust Back Pressure valve? The big butterfly valve in back of the Turbo. I had the retainer clip on the control arm come off and the arm fell down and limited the valve in a half closed position.
What changed? What were you working on prior to this condition happening.
 

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I used to get the hot floor (no egt gauge, yet) that turned out to be leaking donut gaskets on the up-pipes. A leak in the exhaust will also cause higher egt's right?
 
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