Power Loss, Higher Egt's, Boost fine, Low idle
 

Hey guys, this has been an on going problem that I thought I had resolved, but it's still here. On a long drive in my truck colorado to texas I had this issue occur.
Noticed:
EGT's are higher, and climb much faster. Reach up to 1300 relatively quickly at WOT or under load
Truck takes longer than usual to "wind up" from the line and blows more smoke

Idle has dropped from 800 out of gear to 720, and 620 in gear.

Boost climbs quickly when floored on highway, but still a slight loss from what I am used to in power.

Truck also occasionally vibrates at stop, mostly when the wheel is cocked to the left.

Took the truck to West Texas Diesel, they "checked it out" and decided it was the lift pump (which didn't really make sense to me, I suggested a possible timing slip) They put in a new fuel lift pump, but the problem for the most part is still there.

Truck has a "little" more power, still high quick climbing egt's, sluggish off of line, low idle.

Truck has the following modifications
#0 plate, 4 clicks on pump, boost elbow at 35psi wot, 4kgs, exhaust, cone filter (new).

Need a compression test ...... sounds like u have two cylinders swapping compression. ..... any other symptoms like stumbling , low power, ..... what's ur idle warm fuel pressure ? Wot pressure also ..... loaded if u can ...:humm:

Thanks for the reply,
Like I said slight loss in power. From what I can tell, no stumbling. Cold it idles at 620 in gear, 710-20 in park. Warm not much change. 650 - 680 in gear, 720 in park. What confuses me though is that there are only 3 hashes between 0-500 rpms. So I don't know exactly what I'm reading. Logically I feel like there should be 4, because that actually puts the 1000rpm mark at 900 if you count from 0. My FP gauge is not functioning right now (glow shift vibrated loose) so I'll have to get a new gauge or sending unit to test that.

Sharing Compression? Sounds pretty major how would that happen? I just had a valve adjustment recenlty. Does that occur when the valves/pushrods/rockers are so loose? Timing problem?

Besides vibrating at a stop.. all those symptoms are similar to a large altitude inclincation. Like if you tune your truck at sea level, and then are driving around at an altitude of 10k feet you get similar symptoms. So it makes me think it is an air problem.. Somewhere between your air filter to your intake valves something it different... but I wouldn't think idle would be effected that much.. I don't know if a really bad valve adjustment would cause this either..

Or maybe something has siezed on the engine itself to cause a load making it harder to rotate?

was told by a mechanic my throttle cable assembly was pretty worn. Truck was tuned in central Texas. Drove to Colorado Denver, but im back in tecas now. so that would make a little sense, I don't know what could have seized. It honestly feels like a clog between the turbo and intake like it has to try to spool really hard, but idk how or why or what could do that.

You could pop each valve cover off and check the clearances to make sure they adjusted them correctly. Intake 0.010, Exhaust 0.020. This link shows you in what order to check and adjust them. Maybe pull the intake tube off and spin the compressor wheel on the turbo to see if it still spins freely?

..Of course doing both with the engine off.

It ran the best it ever had for about a month after the valve adjustment you think the lock screw on top of one of the rockers may have come loose? Also yes, turbo wheel spins freely no back and forth play.

It could have come loose, you never know until you check. I haven't heard of that happening before, but it doesn't hurt to check. Just to rule that out.

any smoke? colors of smoke?
possible air in fuel line?

crack injector lines with the truck running see if you find a dead cylinder or one not contributing as much. (this will help us rule a few things out)

and engine blow by?

recheck the new lift pump. i hate other peoples grubby hands on my stuff, they always seem to not tighten or leave something out. i wanna lean towards air in the system for right now. is your pre heater still on the truck or has that been deleted? also a clear fuel line from the fuel heater to the IP is oh so helpful if you are utilizing the factory lift pump. you can see air leaks.

My question is did this begin to occur after then valve lash was performed? could be that the person who did it did not set the correct lash. When you say vibration is it engine vibration or vibration from something else? If you blowing alot black smoke, and have high EGTS its either an indicator of over fueling which I doubt because of your power loss, or you are lacking air supply.?