Another CAT C13 with poor fuel mileage. Looking for advice

OK, I've been running an 05 International 9200 for a bout a month now. It has a C13 Acert, with an Eaton Fuller 10 speed manual. Not sure on the rear gears yet, as the previous owner painted over everything with a thick coat of black paint. It's a mid-roof with the big bunk like found on the 9400. In fact, you'd be hard pressed to find a difference other than the hood.

The truck has had it's fair share of issues. Most are just the nickle and dime stuff that comes with a used truck with 650,000 miles on it. The ECM going out after a week, that was not a nickle and dime issue. But it's replaced and all is good. Except for the fuel economy.

I really struggle to get above 6mpg. Most of my loads are on the fairly flat roads of Illinois. Most are under 20,000lbs. And a large portion (maybe 40%) of my miles are empty. I pull a reefer, by the way.

Now when I say I struggle to get 6mpg. I mean I'm at or below 55 mph ALL the time. Occasionally, I'll run 62 if the wind is at my back and I'm light. I don't run the engine past 1500 rpm. In fact, I rarely get much over 1300 with the exception of 9th (and 10th on times I run 62). 9th I have to go to 1400+ or it drops off too far when going to 10th. The truck just doesn't feel like it's using anywhere near the 430hp it's set at. I came out of a 430hp Mercedes that could just walk away from this one.

This is the first truck I have owned (as if you couldn't tell). Always before, I dropped it at a shop and told them "This is what it's doing. Fix it. My company will pay for it". Now that I own it, I have to figure out what's wrong and fix it myself (if I can) or find some place to do the work.

So, if this were your truck, where would you start looking to find problems that affect fuel mileage?


(A few things that are planned)
Almost due for a PM (will send oil for analysis)
Will be having an over head done. (probably gain some there)
Going to install a boost gauge to compare with what others are getting on their C13 (maybe a boost issue. It spools up. But who knows)

Any and all help is greatly appreciated.

 

Bout Z: Thanks for the reply. I took the truck to The Diesel Doctor in Effingham, IL. They were the ones who found the error codes that led to the replacement of the ECM. Maybe I'll swing back down there and see what they can do with it now.

tenevin225: Thanks for the reply. I had Altorfer in Champaign, IL do the work on my ECM. There was, also, a bad oil pressure senser and one bad Intake Valve Actuator that they replaced. I've not heard anything bad about their work. But, on the other hand, I haven't heard anything good, either. I took some time to look into the scangauge you mentioned. Will do some serious thinking on that. Looks like it could be very beneficial for no more than it costs. Thanks again!

Helowrenchturn2: I will check into your suggestion as well. I was told that, if there were problems in the past, there could also be build up inside the plumbing that could cause power loss. Not sure what those problems could be. Or if the truck ever had any of those issues. I didn't get much info from the place I got it from. International and CAT didn't have much history on it in their systems either. So, guessing it was pretty much maintained by in house mechanics.

If anyone else wants to chime in, I'm all ears. Well, seeing as this is the internet, I'm all eyes.

 

I followed up on tenevin225's advice and ended up getting a ScanGauge. I hooked it up today for the first time and was given some data that has been troubling me.

I didn't get into the whole fuel tank size mpg stuff today. I just wanted to see how certain aspects were (or were not) performing.

The fist one I was interested in is the boost. This one really bugs me. It goes up to 31.5 and stops dead in it's tracks. I can back out of the throttle and let the boost come down to 25 or so. Then mash the throttle and it will shoot right up to 31.5psi. No 31.6 and then drop to 31.5. Just 31.5 and done.

The other is the horsepower. The ScanGauge is reporting that my horsepower is roughly 320@1600+-. That was with a 12k in the reefer up hill in ninth gear with my foot on the back of the engine. I know that's not how to drive a CAT but wanted to see what numbers I could get.

What could cause the boost pressure to stop right at the same 31.5psi over and over again?
I'm assuming the lack of boost is why the low HP numbers too. The truck ECM is set to 430hp.
No error codes, by the way.

Thanks for any suggestions/advice.

 

Well, I've been searching the web for info on the issues I'm having with lack of turbo pressure and low horsepower. And I think I have come across some info that may lead to a solution.

I read a page by a CAT Master mechanic where he stated that the ECM on this engine does not throw an error due to low fuel pressure. It merely recognizes the fact that the motor is starving and cuts the boost and horsepower to compensate.

It was suggested to start with changing the fuel filters. My truck is about due for a PM anyway. However, it's been sluggish since the last PM when the filters were replaced then. So, I am going to skip that and go straight to the pressure test. If the pressure test shows there is low pressure, I will change the filters and retest.

If there is still a pressure issue, I will need to dig into the fuel lines to see if there is any blockage, kinked lines, etc. I've never messed with this stuff on a truck, but I am guessing there would be a "pick up" (or 2) that could be clogged.

He then suggested replacing the pressure regulator as they have been known to have issues. It's, also, much cheaper to replace than the fuel pump. Which would come next.

I'll update this as I find out more in hopes that it will help someone in the future.

If anyone has any tips for my endeavour, I'd be very appreciative.

 

I have pages and pages of info printed from CAT when they changed my ECM. Nothing states exactly what the torque is set at. Just "Rated Peak Torque: 1550/1750 @ 1200rpm". That may well be part of the whole fuel economy deal. But I'm sure not being ale to access all my horsepower is part of it too. Especially when it takes 2 miles to get 25000lbs up to 62mph because the truck wont make over 275hp and gets 2mpg while doing it.


The truck goes in this Thursday to get the exhaust manifold replaced. I found a crack in it while doing my pretrip. I would change it myself. But I'm not set up to deal with broken bolts. Which, I'm sure there will be at least one. Always seems to be that way. If that repair isn't too pricey, I'm having the overhead done too. I will see if they can give me any more info on the current setup. I, also, plan to have them do a fuel pressure test. As, I really think that is where my horsepower/turbo issue is stemming from.