Engine/Transmission (1994 - 1998) High EGT when towing

[dodgeguy44]

When I'm towing my 5th wheel on level ground at 105 kph the egt's are around 800 degrees and when pulling a hill at 35 to 40 lbs boost the egt's climb to 1000 quite quickly. I let off the fuel and ease on it but the temps won't come down till I let right off. If I keep pulling hard the egt's will keep climbing, I have seen 1100. It does smoke when pulling hard.



Could it be timing? Maybe too far advanced? Too much fuel?



Pyro is post turbo. 105 kph = 2000 rpm. GVW 21000 lbs. Air temp 30 degrees Celcius.

 

[FordCummins]

If you are seeing those exhaust temps with with a post turbo pyro, they are definitely way too high. As I was reading it I was thinking "thats not too bad really", until I saw that those temps were after the turbo. What is your timing set at now, and why do you think it is too advanced? You are moving a fair amount of weight there with a GVW of 21000.

 

[GAmes]

Sounds normal to me. I use 20 psi boost as my shift point when pulling trailers, in other words when I hit 20 pounds I shift down to 4th while coasting down to 50 (85kmp?) unless I am near cresting the hill. It keeps my temps at or below 1100* preturbo and gives me better mileage. Black smoke is unburned fuel.

 

[bmoeller]

Adavancing the timing will lower EGTs, not raise them. If timing is still stock, advance it 2 degrees (or to 15. 5- 16 degrees). Will lower temps about 150 degrees F.



If the cam plate is slid forward, move it back.



Need more air for the fuel and load.

 

[Will Manchester]

EGTs are way too high for being post turbo in a sustained towing situation. The fact your seeing smoke confirms you don't have enough air, and likely VERY high EGT's pre turbo.



I used to run a 2 pyro's, on pre and one post turbo. If memory serves, I couldn’t hardly get my EGT's over 1000-1100 post turbo. Pre would easily peg my 1500 deg pyro in a matter of seconds - and that was when I had a LOT less fuel! Rule of thumb is pre turbo temps = post turbo + 10deg F per psi of boost - but you can pretty much throw that equation out the window past about 20psi boost.



In my opinion, the only thing post turbo EGT's are good for is determining when your OK to shut down your truck (you can see when you have removed most of the heat form your turbine). Other than that, its a useless gauge. I'd promptly move your pyro, or install a 2nd thermocouple and hook it up to an A/B switch.



I'm guessing you just have too much fuel. My dad has a 97 truck with the 215 pump, #10 plate, 3k govenor springs, hybrid 40, and an AFE (stock injectors and DV's) - this is still too much fuel for towing WOT as 1500 deg pre turbo is pretty easy to hit. However, this observation is from 5500+ feet elevation. I'm guessing your 40 hp injectors are hurting you. You may want to verify your timing is up around 15-16 deg, make sure your intake and exh are breathing freely (intake not dirty, exh brake not fully opened, etc), and maybe try adding a 2nd turbo under your BD

 

[dodgeguy44]

This is the same setup I had on my 94 2500 except for the pump, it was the only part I left on when I sold the truck, and the pyro never went near 1000 let alone past. I will check the timing and pull the fuel plate back.



I know I have to wash the right side of the trailer alot with this truck where I didn't with the 94. Guess I should have switched pumps too.

 

[Champane Flight]

Wrong!

At 1000' post, if your probe is set at the nipple in the elbow, you are approx 2" from the turbo. An old time diesel mech once told me rule of thumb is 100' drop per inch. I had been told by some of the guys here to put my probe pre and some had stated post. I went post, then decided to see what pre was, so I drilled both, I have them switched and can read either side on the fly.



The pre probe always is much more sensitive and climbs and drops quicker, my egts range full throtttle with a load pre-no load to load600-1350, post 600-1000. When you take a look at what is really happening in your cylinders on each firering cycle you would know that there is little chance of causeing any damage at these temps. If you had a probe in each cylinder you would see a spike , this spike is short lived, so damage only occurs if sustained high temp is held for a longtime. Most meltdowns occur in extreme fuel loads, under lugging conditions (engine cannot acelerate at any RPM). That same old timer (who was right with his rule of thumb) that 1350 was as high as I would ever want to hold for any extended time. I now have well over 100,000 miles with no problems, it runs better than it ever did, finally broke in.



I did not catch what year you are running, if you have the stock exhaust, it is probably time to go four or five inch.

 

[Matthug]

Are you running the stock plate?

You never said what timing you were running...

Unless your timing slipped you should not have EGT troubles at all with a super B turbo, stock plate full forward, and 40 HP injectors with 4'' exhuast.



Also check for a clogged air filter.

 

[TGibbs]

A single B turbo is good for 400 hp and you shouldnt be even close to that something doesnt seem right with the air supply

 

[Champane Flight]

Question?

Is your pac brake opening all the way?

 

[Howard Durand]

What gears are you using for hill climbing? The 3. 54 rear end will force you into lower gears to maintain speed and lower egt with that much load.

 

[Cooker]

A single B turbo is good for 400 hp and you shouldnt be even close to that something doesnt seem right with the air supply

What kind of air a turbo will move to support HP and what kind of air a turbo will move to keep EGT's cool at a given HP are two very different things.



Howard asks a good question about gearing. You also need RPM's to keep things cool. What RPM's are you towing at?



As menioned I would be careful with your post EGT's. I personally would stop at 900 degrees post turbo for any sustained period of time. When working the engine hard it is not uncommon to see in excess of 500 degrees difference between pre and post turbo temps.

 

[Champane Flight]

Rpm?

You are lugging the engine ANYtime the engine cannot accelerate, I don't care if you are turning 2200 RPM. If you are still throwing smoke at these RPMs, and spooled up, you need to defuel a touch, move the plate back a little. Like I said before, (really, two diesel degrees under my belt and ignored) 1000' post is not a problem, 1100 is on the edge for any extended period of time.

 

[Will Manchester]

Personally, I'd never pull for an extended period at 1000 deg post turbo as I know my truck is past 1500 deg pre at that point. Bottom line, the only way to know for sure if you are safe is having a pyro pre turbo. I think you will be unpleasantly surprised to see how high you EGTs are if you make the change. I know I was!

 

[Cooker]

Like I said before, (really, two diesel degrees under my belt and ignored) 1000' post is not a problem, 1100 is on the edge for any extended period of time.

In your opinion what do you feel is a safe EGT to sustain pre-turbo?



On my 12 valve I had both a pre and post turbo EGT probe so I was well informed as to what both pre-post temps were. Depending on how I was using the truck there were certainly times when there was no way I could have safely, IMHO, made it to a sustained 1000 degree post turbo EGT's based on my preturbo EGT's.

 

[Champane Flight]

All depends...

Distance from turbo to post probe, distance from exhaust manifold to pre probe, amount of fuel being delivered, ambient air temp, engine coolant temp, and if engine is being lugged. I have seen 1500' pre temps before for a short period, at the time the post was at 1100', fluctuations in pre turbo temp are quick to take place, a light roll off the throttle showed a drop to 1300' pre, while post sat at 1100' for awhile. Myself I know what my pre is, so I hold it under 1350', post is usually sitting around 1000' at this time. I am talking sustaining temps for awhile, not a quarter mile run, or pulling a sled down the dirt. I feel perfectly safe at these temps, I have pulled most of the passes in Colorado at these temps without a problem.



My best advice is that if you are at 2000 rpm, and doing around 60mph, you are most likely in fifth and have 4:10s. Let it go on down to fourth and keep it cool.



I am only speaking from experience on the B engine, with pre and post probes in normal locations. It does sound as if he is throwing too much fuel for prolonged towing situations, or he may have a breathing issue. As far as EGTs go, I have heard some here claim to have a private line to Cummins who state 1000 post is too high. I say it is OK for a time, as long as the engine can accelerate. I think for some reason people think their pistons are melting at 1350-1500 EGT. Like I have stated before cylinder temps themselves are very peaky, you have three strokes for them to cool between firing cycles. Most meltdowns happen when a whole mess of fuel is added in a unbalanced manner, stuck injector, hung valve, turbo failure, all this under extreme loads, high RPM, and general abuse.