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.?

had an excavator in the shop the other day. very low power with gobbbs of black smoke. was a restricted fuel system and 1 weak injection pump. strange but it was black smoking because of fuel starvation.

^ That's a very interesting situation! I have to keep that in mind for a possible future reference.

Black only meens fuel if u know its been cranked up ...... also a misadjusted valves would make it run like crap ..... don't take it back to that place ...... wait ..... take it back and demand that they make it right ..... make a stink about it .... especially if the valves are out of adj. This can cause engine damage .....

Like I said it ran great after the valve adjustment and fuel filter change, really great. Lots of power. The shop told me I had air in my injector lines and they bled it for me while they were adjusting the valves. Also said I had a slight injector gasket leak but it "wouldn't hurt nothin" and a slight reuturn line seep that also "wouldn't hurt nothin"

I was easily passing people going 85-95 on high way, getting 30psi no problem. Messing around with my buddy and his honda accord on the freeway. Basically doggin on it here and there (not over doing it).

Up in colorado, I was merging on and off the freeway after the dingus in the back seat misdirected us and there was lots of quick heavy acceleration, this is when the problem arose. Almost felt like lack of torque converter lock up off the line, gobs of black smoke, quck jumping egt's, low idle.

Fast forward, I get the Lift Pump replaced, Power is noticeably better, but not back to what I was used to. (Shop didn't find anything else wrong besides lift pump) EGT's still jump quickly.

Before this whole thing happened I would start it, it would stick no more that 200 on the Pyro warming up. Now it jumps really qiuckley right after start up even at idle to 300.

Cruising around town doing 35-55mph it is around 5-6 easily jumps under light acceleration, up to 7,8,900 if I gun it. If I put it to the floor merging onto the highway boost jumps very quickly, almost quicker than it used to, you can feel the truck "building up steam" then it surges forward after about a second This makes the EGT's briefly jump up to 1100.

If I give her all she's got and wind her up in the fast lane, at peak 2000rpm-2300rpm, for a second or 2 egts hit 13-1400. Normally (before the colorado) I had never seen more than 1200. And they were much slower to climb.

Its almost like its trying to get there but has "nothing to push against" (this became better and not so noticeable after the LP replacement but still not as much power as I am used to) trying to describe the sensation to you guys, but its hard to get the picture across completely.

Smoke is black coming out, no white smoke. Blow by is extremely minimal (268kmi).

Had a shop over the phone tell me it sounded like the p1700 was going out, and I'd have to replace it and the lp all over again, I didn't like the sound of that at all, because the same place that did the LP said my IP souldn't have been damaged.


I just wan't my baby running back the way she used to, I'm a hottrodder and car lover to the bone, and I can't sleep right till she's back the way I remember running. I need to get this figured out once and for all, so All you vetrens out there please help me out.

I'm throwing this out there, but could it possibly be the throttle position sensor? My thinking was that if that was going out it could not build as much pressure in the transmission, in result not building enough load to build boost properly? So that would cause your air/fuel ratio to be richer than normal causing higher EGTs..

I might as well start there. The Trans doesn't seem to shift weird though.

Ok what your describing makes more sence ..... ok your boost sensor line must have a hole in it causing low fuel pressure VIA the afc ...... so from the turbo to the afc housing ... pull the line and install a new one ... just for temp and then run it around for a bit .... if that dosent help re post .... :humm:

That's the first fresh Idea I've heard all month. If that is it I'm going to be pissed about having to pay for a new lift pump. I will definitely do that, my gut told me it was a turbo issue, but no one else seemed to think so. Thanks so much! I hope it works!

---AutoMerged DoublePost---

Ok I can't find a part called that. Is there a more technical name for "boost sensor line" i should be using?

Its the boost sense line or some crap like that ... should be between valve cover 3-4 ish or might even come from the back of the head to the AFC housing ... it tells the AFC when to give fuel based on the level of current boost...... I hope thats what it is too .. and you needed that lift pump anyways .... it did help right ? :tu:

Honestly I think the difference I felt from the LP was Placibo. But if I did need it, I'm glad I got it done. Yeah, I know where it is, just having trouble finding it online to order. Man if that's the problem I owe you big time. I hope to god I don't have a dead piston or pump.

I would check the overflow valve on the Injection pump. a bad overflow valve will make the same symptoms of a bad lift pump.

also check the intercooler boots as they have a tendency to expand under boost and rub on the inner fender, as there is a seam right where they are, and it rubs a hole in them. this causes a boost leak, causes higher EGT's, slower spoolup, excess smoke.... all the conditions you describe.

there is a thread somewhere telling how to build a pressure tester setup to check the intake tract for boost leaks using an air compressor and off the shelf parts from Lowes / home Depot.

Not a bad idea as well, I need to fab one up too ..... mosly for work.... like 60 series and such

I ordered the AFC hose and a 50hp Injection pump over flow valve. I thought I should also add one more detail. When going 45mph - 55mph or so, if I accelerate moderately to heavily, rpm's and boost rise, egt's rise, but the truck doesn't really go anywhere, it will "rev up" but not "catch" is the only way I can describe it untechnically. At higher speeds however it will do the "hesitate, blow smoke, accelerate." I know this isn't the transmission tech section, but could it also be a tranny problem? Still woldn't explain quick rising and high egt's at idle or light acceleration. I still don't understand why the egt's jump so quickly right after start up to 300 almost instantly, then idle's at 400 when warm. Used to idle at 0-200 about a min after start up, and 400 cruising around.

Yeah sounds like ur converter istaking a dump on ya , the lock up clutch is most likley toasted

That's what I was afraid of and it's a triple disk, but that wouldn't explain the high egt's at idle?

You posted this in post #14
( I didn't like the sound of that at all, because the same place that did the LP said my IP souldn't have been damaged.)

First off, that's wrong. If your lift pump fails, it can burn up your fuel pump. Because your lift pump feeds fuel to your fuel pump. So if the fuel pump doesn't get fuel it will go out, and injectors are fed fuel from the fuel pump.

I knew that was a huge issue with the 24 valves the LP failing and starving the VP 44. When I asked the same question, "could I have damaged my IP by starving it with a bad LP?" their response was "nah those pumps are pretty tough, you're fine." I've been told if I have to replace my IP, that the shop will still replace my LP any way otherwise the warrenty wont cover it. I did a TC test. She still spins the tires at 1800 pretty well with a break stand. I'm going to order a new FP guage next I guess. I hope to god it's not the IP, that's going to cost me what $2k? installed. This is a 12v for god's sake I'm not supposed to have to throw this much money at it!! Alright well. One step at a time.

---AutoMerged DoublePost---

THE NEXT QUESTON I should ask is, will I see problems with a 50hp Overflow valve and a stock LP. I got in a hurry to order a new one and just saw 50hp and bought it. Didn't bother to read that it is for use with a FASS or AIRDOG electric LP.

Sounds like you bought a Tork Tek overflow valve? Yes I would get the adjustable that is safe with factory lift pumps. Reason I think that overflow valve is only reccomended for Fass and Airdog users is because the factory lift pump cant come up with the pressures those pumps provide, so it won't be enough to flow through the valve. Fuel flow through the overflow valve is what helps keep the injection pump cool. with constant fuel flowing through even if it isn't all being used. Think of a pool compared to a river.

the fuel pump shouldn't be damaged, as it is lubricated by engine oil and unless you know 100% that the lift pump was dead, and more than likely it wasn't because it did run and drive, it wouldn't contribute damage. the P pump will not pull fuel like the VP or CP3 trucks will to limp home.

that over flow valve should be fine. when using a FASS or Airdog you completely bypass the factory lift pump. with the factory pump being a high pressure, low volume pump the stock overflow valve works OK up to a certain point. the overflow valve acts more like a pressure regulator than anything with the stock pump.

adding a FASS or Airdog will put a lot more volume through the pump and overwork the factory overflow valve causing it to bypass more fuel than normal, therefore causing low pressure at high RPM due to the excess volume it is bypassing it will not allow the pressure needed at high RPMs to build, since pressure is only a measurement of resistance. that is why the Tork Tek valve has a smaller orfice than the stock one. it flows less volume, therefore keeping a more consistent pressure at high RPMs

Allright guys so Here's the breakdown so far.

I replaced the Overflow valve with an adjustable one and left it at the stock setting.
I'm still waiting on the AFC boost reference hose in the mail.

Truck Still has same issues

1. Sluggish right off line with less black smoke than before the LP replacement but still more than normal.
2. EGt's climb rapidly. 300-400 at idle. 600-700 cruising around town at 45-55mph. 8-9 under light to moderate acceleration. 1000-1300 under moderate to heavy highway acceleration. Easily bumps 1350 at WOT, or 1400 If I really stay on it.

3. Took the truck to the tans shop had the guy drive it, he said he couldn't feel any slip with the TC. Truck still "winds up" while cruising but doesn't really go anywhere until it downshifts and drops rpms significantly. Then it begrudgingly billows smoke spikes EGT's and and finally takes off.

4. Idle is still low. 660-700 in gear. 760-770 in neutral (warmed up).

5. Bad vibration at idle with wheels turned left and while making slow left turns.

6. Boost reads reads 0 while in od crusing 50 or so, but I think thats just a cheap gauge.

Turbo wheel probably has about 1mm of play back and on the push and pull.

My gut tells me this could be a pump timing issue, but what do you guys think now?

im gonna agree with timing, I would have it verified and set to around stock till u get the other issues resolved. then play with only 1 thing at a time ..... easy to diag that way:tu:

If I'm alrighty going to dig in the pump for timing, could I just set it to 15 to get a little extra power. Stock is 13.5 I believe, and you don't want to go to 16 without head studs.

did you check for boost leaks?

i revised my reply... i will sleep better with this one.

!!!!!!!!!!!!!!!!!!!!! the thrust in the charger you describe is most likely your problem. in and out play is thrust side to side is just the space for the oil to go when the truck is running. if your charger has thrusted over and over again due to high drive pressures. (exhaust side has more PSI than the compressor side) it has wore the thrust bearing. chances are friction is much higher @ the bearing and thus slowing the shafts rotation. it will be slower to come to boost and make lower boost numbers which will make engine temps run hotter especially when you want to go fast, and you will see a power loss like you describe because of the loss of air. IF.... your turbo goes in and out, take it off and have it rebuilt. it WILL fail and when it does you risk more than just a turbo. IDK what clicks are on the pump? (turns of the gov spring nuts?) did the idle problem come right after you messed with them. to tight and you screw with idle quality. and a big rpm drop when you put the truck into gear. dont F with timing right now if it were lack of fuel it wouldnt be running so warm. so i instantly stray away from fuel OTHER than a possible nozzle but if this were the case you would have white smoke too. so ide mark that off the list. get your trusty heat lazer out and check each cylinder @ idle. see if you have 1 that is way off. I dont think you will but you can check.

check into your turbo.:c:

I can say that Turbo her does have a good point and a valid idea, pull the exhaust off the turbo and get to checking things out on that end...
and I wouldnt do anything more that stock timing until you have the heat issue and the studs done ... remember , houses are built from the foundation up ... dont try to start at the roof ... :td:

I've started from the roof before, on a sbc, never a good idea. Ok, so when I wiggle the wheel it really seems nearly noticeable, just enough to detect that it moves at all, should there be any play at all?

Just to recap: It has 4kgs (I believe 6.5 turns on both springs) right after I installed them it wouldn't idle without being on the peddle, but I took it to a diesel shop in my area who said it just needed the idle adjusted to compensate for the springs and it ran great after that, no problems. Boost elbow at 35psi, 0# plate, and 4 clicks on the pump.

The problem started occuring after heavy on and off acceleration and I did notice the turbo "whipple" increased in frequency after the problem. On the highway when it upshifts it didn't used to but now it will "whup-whup-whupwhupwhupa" before it accelerates, I probably should have mentioned that :w2:. And the problem started like I said after "merging and exiting" the highway a lot because of a wrong turn so heavy on and off acceleration. The thing is, there isn't necessarily more black smoke as the egt's rise when the truck is moving alrady. As soon as the TC locks up, or from a rolling start, IT accelerates and the egt's rise w/ out having excessive black smoke necessarily.

..

sounds more like your gate is stuck ..... need to verify its moving ...

Some wise advice here for you to be ignoring it.....

Alll he needs to do is verify the wastegate movement ... a lot easier if thats whats wrong rather than spending a bunch of money and wasting time ... his latest post is indicitive of a stuck or non-actuating wastegate......

And yes you are giving great advise no doubt there my friend :tu: ... no toe stompin here :td::nope: