Fuel Mileage Drop?

[rteig]

I tried to post this once but believe it failed. I have a 92 X-cab, 4X4, auto, CTD with 205K on it. Last summer I had the valves adjusted and the pump turned up (all the way) and the turbo adjusted. For the first few months the mileage stayed about the same, then within the last few months it dropped dramatically from 17-18 to about 10-12. I drive it the same, service every 3K with Rotella. About a year ago it wouldn't start one day so I talked to one of the guys at NAPA that has had quite of bit of experience with the 5. 9 CTD and he told me to tap on the pump, I did and it ran great until about a month ago I was leaving the post office and when I hit the bump from the curb to the street it quit and would not restart so I tapped on the pump again and away it went and has run ever since. Any ideas? Lift Pump going out? Injectors? Any ideas would be great. Thanks. Also I have I have a Jacobs exhaust brake for a 24 valve that I would like to sell or trade for a smaller turbo housing for quicker spool up and more boost and/or a 4" exhaust.



Oo.

 

[MMiller]

As far as the no start, and tapping on the pump. Look at the wires on the shut off solenoid. The connections are probably loose. My truck would run down the road and shut off, and then start back up(5spd would keep the engine spinning). The connections were loose, and would shut the engine off from time to time.



What kind of turbo is currently on the engine? Is it wastegated? It must be aftermarket-cause stock there is no "adjustment" on the turbo. I'm just asking, wondering what you have.



AS far as the mileage, has the power been dropping off? Is it still running the same as before? Have you been running any mixed winter fuel? The mileage on my truck usually drops a bunch this time of year, because of the poorer winter fuel, longer idle warn up times, and not shutting it off as often. Notice anything differnt about the truck, mayde the trans is starting to slip a little??



Hope this helps



Michael

 

[phillips5]

Do you have a boost gage and pyro what are the readings. Does it smoke more Is the side of the engine wet with fuel. If the pump is coming apart it would put junk in the injectors and they would not adomise properly. Is the trans full of atf. assuming it is an auto. Maby overdrive is not engaging. Need more info.

 

[rteig]

I guess I have to plead ignorance on the turbo. To the best of my knowledge it is stock, and the guy that adjusted the valves adjusted what he called "the turbo to give full boost" (round pod upper left hand side of the motor and the pump was adjusted on the back side of the pump on the left side). The turbo is not waste gated. I can get the numbers off of it if that would help. As far as gauges I have a tach, boost, and pyro. At 67mph on the flat it runs ~1800 rpm, 2-5 # manifold/boost press. ,~800 degrees F. However when it was first turned up, you could pull a good hill at 80 mph at 2100-2200 rpm, but the pyrometer would shoot up to 1100-1200 like nothing. It has a K&N air filter and the stock exhaust. I know it needs a bigger exhaust and the prices they get for those I think I may try to build my own and I am sure more air into the airbox would help also. The transmission was just rebuilt with all of the updates a little less than a year ago. I suppose the winter fuel could be some of it, although I run Power Service year around. It does feel as though the power has dropped off. I used to run 120 miles round trip everyday for work but now I use it mostly for hunting, snowmobiling and errands around town, I am sure this may have some relationship too.

 

[phillips5]

800 degrees on a flat run at 65 mph. sounds very high to me. I don't have a piro so I don't know what the no load 65 # should be. On a mack semi empty with loboy 27000 total empty at 60 mph the pyro only read 300 degrees.

 

[JLEONARD]

800 degrees on a flat run at 65 mph. sounds very high to me. I

Sounds high to me as well.

I am non intercooled and I see more like 600 degrees.

Jay

 

[cerberusiam]

It sounds like you have plenty of fuel and maybe not enough air. What is the max boost you see when you really load the motor?



The 1200 degrees max EGT under a hard pull is about right. Will it climb over that if you stay in it or that the absolute top temp WOT?