Engine/Transmission (1998.5 - 2002) need help with high exhaust temps

[smote]

From the beginning:

I bought this truck used, 98 3500 4x4 5spd 4. 10LS quad cab, with 161,000 miles on the clock back in late February. When I bought it I knew that it had a bully dog torque computer, a bully dog exhaust temp gage with the probe after the turbo, looks like a new exhaust manifold was put on and the muffler had been eliminated and replaced with 4” flex pipe exiting out the rear.

I removed the bully dog computer but left everything else alone for the time being. The first time I pulled our 30’ high profile fifth wheel camper the truck had very little trouble getting up to speed and could fly down the road at 60 or 70 mph with no problems. The highest exhaust temps I saw on acceleration and climbing small hills were in the 700 to 800 range. I had some black smoke on acceleration but none while cruising. The only bad thing was I had taken the turbo silencer ring out and while pulling the camper the screaming of the turbo was ear piercing. Climbing hills on the interstate the pitch of the turbo would get so high it would go out of my hearing range.

A couple days later I decided to put the silencer ring back in. As I was doing that I discovered that the waste-gate was unhooked. The hose was zip tied to a wire loom and the hole in the outlet elbow was plugged off. After talking to some guys here at work about how the turbo could possibly over-speed I decided to hook the waste-gate hose back up. I got an elbow, some new silicon hose and new clamps.

Now when I pull the camper my exhaust temps climb to 900 degrees all to easily. I have to take it easy when accelerating and also when climbing hills while cruising or I can hit 900 degrees in an instant. I’m glad I have the gage. I’m also getting some black smoke when going thru the gears even when empty.

I don’t feel like I’m down on power that much and my fuel mileage is 16-17mpg, but my temps sure do rise fast.



Should I hook the bully dog torque box back up or will that make things worse?

Should I get one of those boost elbows that have the restrictor in it?

Should I just take it extra easy when towing?

I’m sure a complete 4” exhaust would help.



Thanks,

Scott

 

[Bandit1]

i would be careful, i have both egt probes pre/post and the pre can spike really high really easy. the most dif i have seen between the 2 was climbing a long hill and nailing it, i then saw a dif of 500 degrees, my post was on 700 and pre was 1200-1250. that only happens rarely. the average that i see in dif is about 250. if you hook the box back up take it easy on the towing, or you can upgrade turbos, that would help.

 

[duaneparks]

Smote,



FWIW, I have the PE Comp and it came with a more restrictive boost elbow to allow more boost. Sounds like the previous owner may have had the same problem you did and "fixed" it by completely bypassing the waste gate. I would call Bully Dog and consult them about your issue.



HTH.



Duane

 

[OL RATLR]

You didn't say what kind of air cleaner you have but you

could go to a Scotty11 and really help with egt's.

 

[RustyJC]

You must increase boost (mass airflow) to utilize the additional fuel. Find a boost elbow.



Rusty

 

[Bully Dog]

Its always a good idea to get a larger exhaust system or get a new intake.



I've seen as much as a 200 degree drop in EGT's with new exhaust.



If you do call bully dog and consult them.

Talk to russel 208-397-3200 ext. 113

Russel is a good guy and he will be able to help.

 

[RustyJC]

Wait a minute, guys. Let's read his post again.



With the wastegate hose disconnected, EGT's are OK (from his perspective). With the wastegate hose connected and no boost elbow, high EGT's. The problem is that the boost has dropped significantly because the wastegate is functioning at stock levels with the hose connected. The air filters and new exhaust systems might have technical merit, but only after the root cause of the problem has been corrected.



If he increases his boost above stock levels (i. e. , a boost elbow), the EGT's will come back down. If they don't come down enough (i. e. , boost with the boost elbow is less than boost with the hose disconnected), then maybe the add-ons are warranted.



JM2CW



Rusty

 

[TowPro]

As I read this is sounds like you took the bullydog off, so now you think the truck is pretty stock. Once you hooked up the waist gate now you have a high EGT (900 ain't really that high. I think 1200 is starting to get high if I recall)



Anyway, now that the waist gate is hooked back up, your not hitting that high a boost, Not sure if the bullydog has a wire that attached to the MAP sensor (DS near fuel filter). If it did that was a system that would stop the ECM from turning down the fuel when you go above 19psi. If the bully dog did have this wire, once you removed it and was running with the waist gate unplugged the ECM was turning down the fuel for you when you hit above 19psi, which would lower the EGT, as well as make you run out of power.



Anyway, Now that your stock again, you might find that the truck has had the injectors upgraded as well, but I am not 100% sure. Maybe someone in here with just an injector upgrade and nothing else can tell you what they see on EGT's.



Maybe you should run the bullydog again, but if your worried about damage, just keep your foot out of it. It will raise the MPG a little, and lower the EGT a little.

 

[RustyJC]

Re: Re: need help with high exhaust temps

Originally posted by TowPro

Once you hooked up the waist gate now you have a high EGT (900 ain't really that high. I think 1200 is starting to get high if I recall).

That's 900 degF Post Turbo!!



Rusty

 

[smote]

I just talked to the guy at TST.

He recomended that before I do anything else I should relocate my temperature probe to the manifold so I can get a better temp. reading. I think I'll do that tomorrow and see what my temps show then.

I'm thinking the easiest thing to do next would be to find one of those aftermarket boost elbow's to increase the boost.

Anyone know where I cna get one quick? How much?

 

[Bully Dog]

Have you ever heard of a J-hook



It holds the waste gate closed to allow engine to recieve more boost as modifications are added to the engine which helps keep exhaust temperatures down.



It fits an 01 and 02 automatic transmission.



$49 at www.bullydog.com

 

[duaneparks]

Originally posted by wantmoreHP

Have you ever heard of a J-hook



It holds the waste gate closed to allow engine to recieve more boost as modifications are added to the engine which helps keep exhaust temperatures down.



It fits an 01 and 02 automatic transmission.



$49 at www.bullydog.com

But his sig says he has a 5 spd... It won't work for him.



Duane

 

[Bully Dog]

Yep I realized my stupid mistake after it had already be commited.



Reeeeal sorry about that one.



I know some one who can help him out.



If you look up muddy mess on the tdr members list and send him a private e-mail he can definitly help you out.



he is very devoted to the cause and knows alot.

 

[TowPro]

You also need the electronic piece to hide the over boost from the ECU. I think you already have it as part of the Bully Dog box you removed. If its the Bully Box based on the EZ edge, the boost piece is part of it. That same box may also have jumpers. If your worried about the extra power, move the jumper to the lowest setting and reinstall the box would be my advice.

Originally posted by smote

.

I'm thinking the easiest thing to do next would be to find one of those aftermarket boost elbow's to increase the boost.

Anyone know where I cna get one quick? How much?

 

[Scrappy]

high EGT's

if he is going above 19 psi and de-fueling, then you will also probably also set a code for overboost. All it takes is a restrictor in the wastegate sensing line. A spent . 22 shell with a really small hole in it will do the trick.