Fixed my high EGT.. feel like a dumb-butt... Check your air filter, lol

[Detroit80]

Moral of the following long story - don't just assume a part is OK....If it's an air filter, especially the K&N oiled style, just cleaning it with their kit may not actually clean it enough....I wasted two years and $2,000 figuring that out...

So I feel like an idiot... Been wrenching on vehicles for years, I do _everything_ on my vehicles..I know diagnostic procedures like the back of my hand....and I still made a repair 101 blunder, lol.

So my '90 F350, with a Banks Sidewinder turbo, has been having high EGT issues for a while. Got bad enough that it was virtually impossible to keep it under 1100*, unloaded, accelerating to and cruising at 65mph, yet it felt like it was even under fueling as I never saw it smoking at all, even when doing WOT pulls from a dead stop. Coolant temps ran high, quickly going up with the EGT, to the dangerously high range Putting any kind of load on or behind the truck was simply not going to happen.

Timing was set at 9° with a pulse meter. I never had _any_ issue with starting it, hot or cold, never stalled, never skipped/missed, nor did it seem to have any driveability issues other than that dang high EGT problem. Changed out the EGT probe and gauge thinking maybe it went bad...Cleaned and reoiled the Banks cone filter multiple times too.

I eventually just lost all my patience with it, parked it, and bought another truck. It sat for about a year, then the other truck developed a massive fuel leak, so I went back to the Ford. While doing some maintenance things, I inadvertently grabbed a different air filter for it, but had yet touched anything else on the engine yet other than putting on a new glow plug harness.

The next drive - I had to work hard to get it to 900° EGT. Today, I pulled a trailer that weighed approx 6500lbs loaded...even pulling out from a stop WOT to 70mph, I never even got it to 1000°. Cruises at 70mph running approx 550°EGT, while pulling that trailer.

Son of a....that damn air filter. Rookie mistake - I assumed that it couldn't be the issue especially since I cleaned it multiple times...it had to be plenty clean enough by now!

Nope... obviously not enough close enough, lol. Two years and $2,000 (to buy that other truck) to find out I just needed a new $40 air filter....I'll be buying a new air filter for it now....

 

[IDIBRONCO]

I know that it's frustrating, but at least you figured this issue out.

 

[swald]

What filter did end up buying for it? I have a banks sidewinder too, and the existing filter is a cone style and about 10" long. Looks like the intake is ~4" OD. But I don't want to spend $70 for a new one.

 

[chris142]

Blowing out the paper ones does not work either. The dirt gets down in the fibers. Blowing one out only gets the loose stuff out.

Got bit by that myself. My Jeep would not go up a hill.

 

[The_Josh_Bear]

Thanks for sharing! It's always good to learn what not to do by others sharing what they learned the hard way. I did a similar thing when I added charge air cooling to my rig, bought a cheap spectra filter to get on the road and couldn't get over 5psi, high EGTs, low power...made the entire swap feel like it was worthless.
Took me about 3 weeks or so to finally figure it out-- the filter started to cave in from the vacuum! As it got dirtier it got worse. I moved onto a BHAF and now enjoy lots of clean airflow, though I want to find a way to box it up and make a cold air inlet for it so it's not pulling hot under hood air.

Was it always like that with the K&N? If it was working well and then never worked right again the cleaning process is broken. But if it never worked right then that would simply mean it's too small from the get-go.

 

[genscripter]

Detroit80 should be commended for posting this. Most guys hide these things, leaving the rest of us in the dark.

 

[frankenwrench]

Detroit80 should be commended for posting this. Most guys hide these things, leaving the rest of us in the dark.

I have seen Wes and a few others bring this up in build threads and when I would ask questions about them. I still run a k&n filter but I do see higher egts than others since I installed the turbo. I know I'm wrong but $ is tight with covid restrictions/fears as well as my main truck it is on is down with bad bearings

 

[MtnHaul]

Occam's Razor: The simplest explanation is likely the correct one.

Glad you got it sorted out.

 

[gandalf]

Occam's Razor: The simplest explanation is likely the correct one.

Glad you got it sorted out.

Isn't this sometimes known as the KISS Theory?

My working theory, when I don't know the answer, don't know what is causing the problem, is to start with the easiest and least expensive explanation. I actually try to apply a certain amount of logic.

 

[MtnHaul]

My working theory, when I don't know the answer, don't know what is causing the problem, is to start with the easiest and least expensive explanation. I actually try to apply a certain amount of logic.

^^^^^Exactly what I try to do. I would have said K.I.S.S. but undoubtedly there is someone out there offended by the word "stupid"