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Crazy high EGT

5K views 34 replies 6 participants last post by  dirtydozen97 
#1 ·
Ok. So when I bought my truck 8 years ago I tried blocking the waste gate actuator. Pegged at 45 psi so I hooked it back up. Egts wod barely go past 1250. I blew that charger and replaced it with one from a manual. My egt seemed higher. . The turbo was quieter and slower to spool. The waste gate was already blocked off and I didn't have the line handy at the time to hook it up. Took it got a drive and it struggles to hit 35 psi being blocked and I can cruise right past 1400 egt empty with no problem. I have 4.11 gears also. I was wondering if it's waste gate problems. It seems to move by hand but still is not hooked up. There are no boost leaks either. I also heard larger DV will make it hot. I never changed them but how do I know if they are stock or not? Or could something else be my culprit? I'm stumped right now.


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#3 ·
How bad does it smoke? I would think you need to tune your afc to limit the fuel. It should spool right up to 35psi no problem. Used turbo? Did you inspect it before install?
 
#5 ·
Doesn't seem to be any leaks. And it smokes pretty good from a dead stop but clears up pretty fast. And a slight haze. And it boosts all the way to 35 but that's it. And it only gets past 1200 when it shifts into lockup. 1200 all the way till then but when it does it gets warm fast.


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#6 ·
Loosen up the preboost screw, tighten the AFC and let us know what that does. It sounds like it is getting too much fuel. I can't push mine past 900 during hard acceleration. It is a haze the whole time, no black smoke.

It you had a bad boost leak, the AFC would limit the fuel. You may have a small one. Try building a tester if the above method doesn't work.
 
#8 ·
Yep, the starwheel. Seems like you have everything adjusted correctly.

It's an odd problem if all you did was change the turbo, unless a wheel is damaged on the turbo or you have a boost leak. I'd check for a leak, see if you can borrow a turbo or upgrade the turbo.
 
#9 ·
I'm going to try the ore pre boost screw again in the morning. Maybe I was wrong but it's been adjusted that way for 6 years. What seems to baffle me is I have a friend with a 95 manual. And 3.55 gears and he pulls a 30 ft gooseneck with a tractor. 100 plate full forward and 3kgsk and 50 horse injectors and never gets above 1250 degrees. Pre turbo. Ran into another guy with 150 injectors and stick turbo and says he barely gets to 1300. So I though maybe delivery valves. Also at idle my truck is way louder than any of my friends with 12 valves and still louder when driving. Straight pipe to stacks.


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#20 ·
Also at idle my truck is way louder than any of my friends with 12 valves and still louder when driving. Straight pipe to stacks.
Checked your timing lately? Slipped timing will make it run hot too...
 
#10 ·
I'm no help on the DVs. I have too much fuel as it is. If you didn't change them, it should be the turbo as it is the only thing that changed. Or didn't you have gauges before you changed the turbo? Either way you have too much fuel, a turbo problem, or a boost leak.

The AFC controls the fuel until you hit full boost so unless the spring is really loose and experiences coil bind when you tighten it, the plate doesn't do much. I have a 0 plate to control fuel at full boost.

You can snag a box turbo, T3-T4 adapter and downpipe for ~$900 if you want to upgrade.
 
#11 ·
So I decided to go out and check the pre boost screw. It was turned in a little bit. So I unscrewed it out with only about 3 threads left. Still gets hot. I have always had gauges on the truck . And yes the turbo is the only thing I changed. It's from a 98 manual though. I tried putting my old compressor housing on a few weeks ago with no change. If I had a leak would I sill see 35 pounds? Just doesn't make sense to me. The truck had a fuel plate upgrade when I bought it and I installed a 100 shortly after. With having previous mods that lead me to think it maybe had DVs or even injectors. I need to figure this out because I'm supposed to pull later this month.


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#12 ·
The old turbo did 45 and it was the smaller one from an auto so there is 10psi+ you're losing. Search around for how to make a boost leak tester if you like the stock turbo. It'll cost you maybe $10 to make. 35 is the max you want to go with a stock charger if you want it to last.
 
#13 ·
I understand the lower boost. I had the older one limited back to 35 for a few years before it blew. But why would 35 psi form one charger be diffident than 35 psi for a diffident in? And a larger one at that? The truck runs great otherwise but at wot it sill gets hot and I have rode in others that don't. Still stock chargers with more fuel ungraded than I have.


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#14 ·
I thought the old charger made 45 and thats why it blew up. What kind of gauge do you have and where is it mounted? Could it be an issue with your gauge?
 
#16 ·
Boost numbers can be the same or even lower from a larger turbo and still produce better power as you are moving a larger volume of air CFM
 
#18 ·
Sounds like you have to find the leak. Unless there is an actual issue with that Turbo, you must have a leak causing the high EGT's. Other than hight EGT have you noticed any other symptoms of an issue?
 
#19 ·
It's just the egt. There isn't very much smoke and I figured it would smoke way more with the higher egt. Also what makes me think it isn't a leak is that my boost pressure is measured at the intake on the side. Not the intake horn but below that. Not much after that to be leaking but I'll check when I find a air source to use.


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#21 ·
I have not checked it. Never changed it myself. Would it slip if never taken apart? Been wanting to do the timing anyhow but can't find the dial indicator adaptor. And would slipped timing cause a loss in fuel mileage also? Because to think of it. I get horrible milage also.


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#22 ·
Yep and yep. The timing gear is just tapered onto the pump input shaft. Even when torqued to spec they have a habit of slipping.
The horrible fuel mileage is another dead giveaway. I can't remember now where I got the dial indicator adapter I have, but I know they aren't that hard to find. Check Ebay or some of the vendors that advertise here.
 
#25 ·
There are several good articles on here as well as a couple of Timing videos on You Tube. One is actually called Timing in 40 minutes I believe.
 
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