Ok,
I decided to post this in the 24 valve forum before I start the downward spiral into bombs.

I pull a 40 foot gooseneck and noticed that I don't seem to have the power I did before. I really noticed it tonight on my way back from Memphis pulling 2 forklifts. It just seemed to have no guts. I hauled up a light load to Missouri and it seemed to struggle a little then too. I would like to be able to maintain my speed up hills and it just seems to belly up.

So my question is am I missing something that could be the culprit? My mileage still seems to be about right unloaded. I have 4.10's in the truck and it should climb a hill like nobodies business. I know I will have to address the 47RE later as it should be upgraded. It seemed to really struggle to maintain 50-55 up a grade . So do I need to check timing, sensors, etc? I straight piped the truck and can keep it below the yellow but the throttle just seems to be unresponsive. I noticed a mention of defueling on the 12 valves, does this also affect the 24's?
I usually get 15 around town and 16 on the highway, towing I was only getting 9. I am thinking that was due to my foot becoming part of the floorboard.

Am I up against the wall and need to look at maybe 275's or a box? I would eventually like to get my mileage a little better, but I gotta get up the hills and down the road a little faster too.

Chris

 

Yeah 275's and/or an Edge EZ would be sweet for towing but how is your fuel pressure? I've heard of people getting a lowwer power because of a dying Lp especially when under a load like towing. If thats good, then maybe yeah, some upgrades might be in order =D
TNutcher

 

Your boost guage can tell you a lot. What was your boost running? What exactly were the temps? The boost and pyrometer guages can tell volumes about power problems.

 

Boost running up to 20, egt in the yellow. I try to keep it just at the base of the yellow Fuel pressure is 13. A relocation kit fixed those FP problems.

If I disengage the OD, it just seems to "just" hold 50-55. I notice I have more pedal left, but it doesn't help.

Chris

 

Should have also mentioned the egt's do drop some when kicking back into high from OD. I can atleast control the EGT in high. It seems to get to a point where I feel I have no throttle and it is only gonna give me X amount. Is this the defueling taking place?

Chris

 

Boost at 20 lbs and egts in the yellow (what exactly is the temp?). At what throttle setting is this happening at? What kind of boost have you been used to seeing?

Fuel pressure has nothing to do with your problem.

 

Usually around 1050, depending on the hill size. I can run it up a little higher, but I don't get anymore out of the engine.

Chris

 

I assume this is a post turbo reading? If it is, sounds like you're not making enough boost. Look for a boost leak, bad turbo, plugged air filter, something along those lines. You're not getting enogh air.

If this is a pre turbo reading, then you're not getting enough fuel, because the boost sounds good at 1050* pre turbo temps. Your fuel pressure sounds good if it is taken post fuel filter. If it is pre filter, maybe the filter is plugged and fuel supply is the problem. Otherwise I'd guess the MAP, AIT, APPS, or finally a VP44 problem ... something on the fueling side.

As the engine builds boost, the ECM adds more fuel, but if the ECM doesn't see the extra boost or there's a fuel restriction of some kind, extra fuel isn't added and no extra power is made. So the interaction of the pyro and boost guages tells what's happening with you performance and tells where to look for the problem.

 

Ok so the main question here is how much weight total trailor and payload are you pulling ? Boost sounds ok it will start to defuel at 21 psi

 

The payload going up was about 10000 including trailer weight. The payload coming back was much higher. It acted the same with the lighter load, just not as noticable.
EGT is pre-turbo and FP is at the VP-44. I need to find the parts locator picture so I can check the mentioned parts. I think it was on the Cummins site.

Chris

 

You need to check for codes. Your egt and boost sound right for a stock truck. There is probably a fueling issue since I would expect a bit more egt from a stocker that is towing heavy.

 

I agree with CTD NUT the boost is ok the EGT is a little low mine when it was stock with 4" exaust on long steep grades would hit 1250 easy if there are no codes you may be over loaded I tow 15000 on a regular basis and some hills are a killer on your speed.I hope it does better with the 275rv's I have towed with them let. Good luck .

 

When I unloaded the trailer I did a few hill climb runs and these are the number I got from it. It still seemed to no be getting the power it use too.

Empty 40 foot gooseneck
EGT 950 Boost 18 RPM 1900- Throttle seemed to not add anything until I kicked it back into high gear, out of overdrive.

Now as I understand it, best economy is between 1500 and 2000 rpm. In this condition was I just lugging the engine down at 1900 rpm and it didn't have a chance to speed up? Also the highest I could get my boost was 19 pounds. It would hold the egt and speed and boost, but no chance of picking any speed up. If I kicked it back into high, the EGTs would start to run up and very little speed increase but boost still seemed to be maxed at 19.
I think I will check the MAP and IAT sensor tomorrow to rule out dirty sensors as my mileage on the whole trip was less than 10 mpg.

Once I get this all figured out then I will probably do the 275's as I really hate needing power and it not being there.

Chris

 

Once I get this all figured out then I will probably do the 275's as I really hate needing power and it not being there.


Me too

 

The way it sounds it could be your tranny slipping.