blueberry

Hey all,

I've started experiencing another problem with low power. Last year it was determined that the guide pin in the IP was sticking. I had that fixed and the problem went away... until 2 weeks ago. At first it seemed related to "summer fuel" in "cold weather". I would stop off and add additives, and all better... until next morning so I'd top off and add additives again. But now that doesn't seem to matter. Sunday was just not a very good day for power and it just sounds worse at idle. Is it a new ULSD?

So far I've changed the fuel filter, checked the air filter, pulled the intake hose and verified the turbo still looks good, pulled the fan belt to make sure nothing is very tight, jacked up the rear wheels to make sure the brakes feel okay, and pulled the bed and checked the tank (clean, clean, clean). Some of those things were just too easy not to check so I did them just as sanity checks.

The real surprise is that I've noticed what I think is higher than normal boost levels by 3-4 psi. I don't recall the truck running 5 psi uphill in 3rd at 30 MPH. I also don't recall it requiring 5-6 psi to run downhill on the freeway at 72-75 (used to 3-4) and 10-12 uphill (used to 8-9). However, maximum boost also seems lower... So it almost seems like the timing has been retarded except that smoke has NOT increased and max boost has NOT increased (and maybe decresed 1-2 psi). Is this ULSD??? Winter fuel???

Any ideas?

Thanks,
Brian

Boatnik

Are your egt's changing as well? Higher boost with an increase in egt to me would indicate a greater load on the engine. Something like a front brake, tranny problem, Someone put a house trailer behind the truck while you wern't looking?

blueberry

I don't have an EGT gauge, only boost. I haven't checked the front brakes but I would tend to think anything that makes the engine feel this loaded down would probably be glowing or smoking or excessive pulling and the truck isn't doing any of those things.

What kind of trans problem would cause this kind of load? It doesn't sound any different. I wondered if the clutch was slipping possibly because of a rear main seal leak but I don't notice any better or worse leak condition in the past 6 months. I did change the trans fluid earlier in the month using the same oil as last time. The truck is 4wd and I use it weekly.

Brian

johnny5.9

Sorry to hear about your problems. I don't think it would be the ULSD, mine runs like a champ on it. I'm no expert at trouble shooting but here's my suggestion. Check your AFC on your pump. Maybe the boost is blowing by your diaphram. It might have got damaged by whoever fixed it. Also, the banjo bolt might have been overtorqued and eventually cracked and now you're leaking pressure. Also, jack the wheels up off the ground and check to see if they turn freely. Maybe you have smoked bearings in the hubs and they're dragging. Hope this helps, if I think of anything else I'll post it. Let me know how you make out.

Redleg

Tranny slipping? I was loseing power and gaining boost when mione went out. The tranny wasn't old, so I though it was something else at first.

blueberry

I removed the AFC cover and inspected it and everything looked fine. I did not see any problems with the banjo fitting. Is there something I could be missing there? I'll jack up the front end and check that the tires both spin freely.

I had the truck in the driveway and start and stopped it a dozen times. It seemed that a few times the truck started and sounded good, but then settled into a worse sounding noise. One time it even surged back and forth until I pumped the throttle on the pump. Even more interesting was the fan. It is not warm by any means outside and the fan would start running at full speed. There is also a little play in the clutch bearing. I wonder if the clutch is shot and running the fan at full speed. That may account for higher boost pressures and engine drag.

Brian

blueberry

The truck pulls 4 psi of boost at WOT standing still in my driveway. I think it may be the fan clutch!

Brian

blueberry

Okay, I removed the fan clutch and at WOT standing still in the driveway it still runs at 4 psi boost... and without any fan belt at all it runs at 3 psi boost. Is this normal? Or is the trans or something internal to the engine causing some drag? Or possibly the exhaust causing some problems? I don't know how to troubleshoot any more possible problems.

Brian

G1625S

I don't quite dare go WOT in the drive in neutral, but I can hit 12psi at 1/2 throttle. How often does your truck get a good flogging? This is just my opinion, but it seems to me that these engines were designed for greater things than pushing a little dodge around as a DD. When I do a lot of in-town tooling around, the truck idles worse and performs worse...can't narrow it down to anything but the daily routine. I recently put my winter front on and closed the flaps, so the engine gets almost no cool air. I ran a 4% grade at 80mph this afternoon, and the coolant gauge finally came off the low point of being warm and the pyro held steady at about 900 for 5 minutes. Idle went up 50rpm and is smoother. Again, just a suggestion, but if you don't work the truck regularly and there are no other problem areas, you may want to put some heat to the old gal

Boatnik

This is just another SWAG, but are your head lights running a little dim? Is the volt meter indicating where it should be? The air heater puts a pretty good load on the altenator. But didn't you pull the belt and the problem remained? Man this is a tough one!

blueberry

I drive the truck mostly on the freeway between Nashville and Bristol so that's about 300 miles each way mostly at 72-75 MPH. The past couple of trips have been loaded with firewood or cresote railroad ties. I would say the truck gets a good working, but not like the guys that tow Sundowner horse trailers.

I think I determined by process of elimination that the injection pump is the problem. After I reinstalled the fan belt and tried to crank it over... it wouldn't fire. I tried again, and no fire. Then I turned the engine over a few times with the barring tool.... OK. I started bleeding injectors to check for fuel. #1 empty, #2 lots, .... I bled with the engine running rough and #2 pours fuel without any pressure. The engine would finally start running very roughly but #2 doesn't do much of anything except dump fuel.

I guess its time to pull the injectors and pump and have them all tested.

Brian

G1625S

hmmm, that's sounding like the ip is shot. mine went all at once in a parking lot. It failed to shut down w/o using the manual lever...I went into the store, came out and started it and drove about 50 feet and poof! Started running rough then wouldn't run w/o throttle, then nothing. Pulled the shutdown solenoid and found metal pieces

blueberry

I gutted the solenoid 2 months ago when it failed to shut off the engine and now have a STOP cable. Its a shame that I replaced the IP about one year ago today with a rebuilt because of an AFC problem. I never expected to get proficient at this!

Brian

G1625S

Dang, something doesn't seem right Unless your fule filter didn't have any media in it, your IP should be fine in that amount of time...anybody else with a thought?

wannadiesel

I'd try very hard to find an air leak on the suction side. They really do run like crap with bubbly fuel. Several guys have had problems with the line inside the tank being rubbed through by a screw in the pickup assembly. Your comment about topping off the tank making it run OK makes me suspect this.