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Serious EGT problem? And need overflow tank in Lubbock ASAP

I had started on B100 but by the time we got to Lubbock I had already refueled with petroleum Diesel so we were running maybe 12% tops at that point.
As a side note I was shocked yesterday when I stopped at a Flying J truck stop and found they were selling B15. I had thought those places only sold B2.
As far as the deal on the Excursion goes, they were asking about $3,000 over book. Kevin and my wife and I were texting furiously the whole time we were at the dealer so we knew things like to stay away from the 6.0 power strokes. Kevin also told us that the Diesel Excursions were highly sought after and that the "book" price and market value did not necessarily coincide. I bought the Suburban in 2000 for $14,500. I got the Excursion for $16,950. For trade in they gave me $1,500.

Leroy, I am sorry I never got a chance to get those pictures of the Walbro on the truck. With everything going on I just never had the time to get under it with the camera.

GM like all manufacturers made compromises in the design of the truck to make what they felt was the most appealing overall package to the widest market segment and of course do it as profitably as they they could. When I started re engineering the truck my primary focus had been performance as a daily driver. I had never imagined I would be pulling anything this heavy with it. With nothing heavier than the family and some luggage it ran like a scalded dog. But in my pursuit of daily driver performance I think I compromised the towing ability of the truck. My previous vehicles were such things as Z-28 Camaros, Turbo Trans-Ams and a police package Caprice. I tried to make the truck too much like them. I would not try to pull that trailer with any of those either. It is a matter of having the right tool for the job. My only previous experience with Ford products had been my first car (1968 Mustang) that I got burned by, and some tow trucks I have driven. As much as I hated Ford I was forced to admit they did know how to make a solid truck.
And it has ten cup holders.....
 
No worries I have plenty of pictures, just sucks you did so much work on it lately.
 
JeffMD said:
When I started re engineering the truck my primary focus had been performance as a daily driver. I had never imagined I would be pulling anything this heavy with it. With nothing heavier than the family and some luggage it ran like a scalded dog. But in my pursuit of daily driver performance I think I compromised the towing ability of the truck. My previous vehicles were such things as Z-28 Camaros, Turbo Trans-Ams and a police package Caprice. I tried to make the truck too much like them. I would not try to pull that trailer with any of those either. It is a matter of having the right tool for the job. My only previous experience with Ford products had been my first car (1968 Mustang) that I got burned by, and some tow trucks I have driven. As much as I hated Ford I was forced to admit they did know how to make a solid truck.
And it has ten cup holders.....
Click to expand...

Jeff, thanks for posting this as you're sorta confirming my concerns as I followed this thread. That is, my concern is that you were not driving it as intended when towing.

"With nothing heavier than the family and some luggage it ran like a scalded dog. But in my pursuit of daily driver performance I think I compromised the towing ability of the truck. My previous vehicles were such things as Z-28Camaros, Turbo Trans-Ams and a police package Caprice. I tried to make the truck too much like them."

I think most us here will confirm that if you mash the pedal while towing up a grade in 117 F ambient heat, you're going see temps sky rocket regardless of configuration. Anyone telling you otherwise is spewing BS.

I bought my '95 for the express purpose of towing boats down the Baja during the summer. There are significant grades on the highway and the ambient heat regularly reaches over 100 F in the desert stretches. I knew from driving the truck around in SoCal that it was not up to the task due to the heat generation I was seeing. I took years, several forums, finally this forum, to work through all the heat issues on that truck. Still, it's not something that you can mash the pedal on while towing up a significant grade. EGTs will alway skyrocket to above acceptable levels. It's why you have a pyro and boost gauge so that you can manage the EGTs in such situations. This is not just simple step and go driving. Rather, it active management of the EGTs and coolant temp.

This past weekend I towed a crate of slate stone up to Big Bear Lake. 1500' at the base and 7100' at the lake view summit. There was a 10 to 15 minute stretch there where my coolant temp stayed a tick above 210. I tried to manage it the best I could, but there were cars behind me. Speed limit was 40 to 55 mph depending on the signs, but mostly 40 mph. I could keep it at 45 mph and still had more left with the boost only at 7 psi, but I had to manage the EGT and coolant temp. I typically kept it at 35 to 40 mph and once I got to a flatter section, the temp dropped to 187.5. Again, simply mashing the pedal to floor was probably asking for trouble. It's all about managing the driving.

I seriously looked at an '02 Excursion with the 7.3. 110K miles and my buddy wanted $14K for it. I was willing to pay $12K. He eventually got the $14k for it. I ended up with the '99 Burb and have been very happy with the choice. I'm sure you will be happy with the 7.3 powered Excursion. I just think you did not give the Burb a fair shot. Many here would have snapped up that Burb for $2000 simply to get the mods you did on it.

Steve
 
Steve,
I was babying it the almost the entire way with the trailer. The only times I came close to "mashing it" was merging into traffic. As far as temps go, my coolant temp only got close to 210 once. The post 97 cooling mods did what they were supposed to do. The only issue I had with engine cooling was the leak in the surge tank.

What kind of EGT do you get on flat ground? Trying to just maintain 50 mph I was seeing 1200+ degrees post turbo.

As far as climbing grades the speed limits on the interstate outside Albuquerque are 70-75 mph and in West Texas 80 mph. Limping along at 40 mph in my suburban I would have a moving hazard, not to mention turning a ten day vacation into a month.
If I still had the GM-4 turbo and intercooler on things might have been different. If I had a 4 inch exhaust on with the ATT it might have been different. But the combination of parts I had simply would not tow the weight at highway speeds from near sea level up to 8,000 feet.
 
JeffMD said:
Steve,
I was babying it the almost the entire way with the trailer. The only times I came close to "mashing it" was merging into traffic. As far as temps go, my coolant temp only got close to 210 once. The post 97 cooling mods did what they were supposed to do. The only issue I had with engine cooling was the leak in the surge tank.

What kind of EGT do you get on flat ground? Trying to just maintain 50 mph I was seeing 1200+ degrees post turbo.

As far as climbing grades the speed limits on the interstate outside Albuquerque are 70-75 mph and in West Texas 80 mph. Limping along at 40 mph in my suburban I would have a moving hazard, not to mention turning a ten day vacation into a month.
If I still had the GM-4 turbo and intercooler on things might have been different. If I had a 4 inch exhaust on with the ATT it might have been different. But the combination of parts I had simply would not tow the weight at highway speeds from near sea level up to 8,000 feet.
Click to expand...

On the freeway highway at 65 to 70 mph pulling a 27' boat that weighs in at 8500 lbs loaded with trailer, I'll hit upwards of 200 F on the engine coolant at times. Boost will be 4 to 7 psi at 2200 rpm. EGT will be 700 to 900 at that is before the turbo. Going up a hill from a standing start I can get the EGT up to 1300. Something was wrong with your equation if it was hitting 1200 on flat level ground. Expecting to blaze up grades at 70 mph during the summer while towing is a bit unrealistic, just sayin.

The ATT is a dog at low speeds. This past weekend I was parking the Burb at a trailhead at 7800'. I had the truck in 4hi on dirt, wheels turned sharply trying to maneuver it to a space off the forest service road. The engine had trouble developing the torque to move the Burb from that position and it was rolling coal like no other. Just hard to get the turbo spooled up in that situation.
 
Lots of factors involved, none of them seemed to be in Jeff's favor.
1. larger turbo is awesome for pulling a load, but has other flow requirements, which is why I would not recommend it to people before a couple other things. Basically need the 4" exhaust and K47 or similar air box before a larger turbo.
2. Injection timing, I have personally reviewed a few older aftermarket programs from Heath, and they will provide good throttle response and better efficiency when not towing. However, I would never personally tow with programs like those I had seen, and he may not have either. Too much timing advance.
3. Bio blends, starting with B100 high cetane and low BTU is not good, especially with too much timing advance, and diluting it would likely have started making a difference. Its kind of like putting 85 octane ethanol blend in a corvette, going to ping all day until the good mechanic turns the distributor to retard the base timing.
4. IP timing, not sure what the TDCO was set at, or if it was set properly, but can have a profound effect if PCM really doesnt know what the timing is, as long as it was set with a good scanner and it was negative value should be fine.
5. Injectors, I assume the Heath injectors were still good, so thats not something I considered in this case, but low pop and poor atomization can hurt you.

Lower compression, could give you less torque, but in general should help lower EGTs

I know someone that uses their 95 burb to go 70mph up 8% grades with a 6000lb camper, and he drives by EGTs to keep them around 1100F or less preturbo. 3.42 gears though, so 70mph is like a sweet power spot.
 
It was fun while it lasted. But I don't think I am going to miss it too much. One of the things that really irked me about it the last few months was that the window switch in the front passenger door needed to be replaced. I checked several aftermarket sources (LMC etc) and never found one. They had earlier and later models but not the 1994.
I don't have to worry about that anymore.

Aces, I don't think the CR in and of itself was really a significant factor as so many other makes start off at 18:1 stock. But I could be wrong.
 
I thought CR because most people lower their CR to accommodate higher boost like 20+psi and from what I have read(and please correct me if I am wrong) the ATT runs lower boost psi than the GMxxxx. Also I will concur what Buddy said about Heath tunes. I have had two so far and both made the trucks run like a bat out of hell empty but egt's through the roof towing and noisy(advance). It would be interesting to know if anyone else is running an ATT with 18:1 and what the results are.
 
Honestly I feel these trucks/suburbans are not made to tow.....fast!

I do not like going above 65 MPH when towing myself.

When I pulled my camper no matter how big the hill was I never went below 50 MPH.

Of course I have almost zero mods!
 
I think they tow better with almost zero mods. So far the best of the bunch I have had is my burb and the only thing I did was open the exhaust up. No tunes on that one, it runs fine. In fact a better fan clutch and she'll be real good but make no mistake, these engines are at their limits towing. I had an 99 F350 7.3 PS and that truck was a brute. It could tow anything you could put behind it and then some in 100 deg heat and not even break a sweat. My Cummins towed better than the 6.5 but it got hot on the hills, had to keep an eye on it. That Stroke would not get hot no matter what I did to it or how hard I pushed it. I have said it many times, I personally think the 7.3 PS tows the best of them all. Of course the trade off is the day it needs injs hold on to your wallet and Ford Automatics suck. They always have and still do. Nothing alot of money and a phone call to Suncoast can't fix though...:D
 
Acesneights1 said:
I thought CR because most people lower their CR to accommodate higher boost like 20+psi and from what I have read(and please correct me if I am wrong) the ATT runs lower boost psi than the GMxxxx. Also I will concur what Buddy said about Heath tunes. I have had two so far and both made the trucks run like a bat out of hell empty but egt's through the roof towing and noisy(advance). It would be interesting to know if anyone else is running an ATT with 18:1 and what the results are.
Click to expand...
Slim has 18:1
 
DieselCash said:
Honestly I feel these trucks/suburbans are not made to tow.....fast!

I do not like going above 65 MPH when towing myself.

When I pulled my camper no matter how big the hill was I never went below 50 MPH.

Of course I have almost zero mods!
Click to expand...

but you also have the perfect towing foundation: five speed MANual transmission, and a 2 wheel drive.

I will leave that statement out in the open, and back away from the crowd, for fear of being clubbed with an auto trans. shift lever!
 
I would think 2wd makes a big difference. 4x4's draggin alot of extra gear around but in New England a 2wd is as useless as henshit on a pump handle...:rof:
 
I think it's more about what heath tune you have.

Before my piston crown stove in, I could easily manage the egt's below 1100 without water spray, and below 950-1050 with spray.

That's with a Heath tune in my 98.

But, there's a few other factors here;

1. I called Heath and told him exactly what I was looking for - a daily driver, not a "hotrod" and a weekend heavy hauler.

2. I have a Heath TM on my GM8 and it's set to blow off at 12-13 psi

3. I have a 4" exhaust and 2.5' crossover

4. I have a 98 water pump


@ jeff:

Glad you enjoy the Excursion, great beast!

I also think you're on to it with your problem being how you built it. For the use you intended, it sounds like it worked great. But once you stuck a heavy load on it, you were just too far outside your design parameters.....
 
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