well the other day I swapped out a full B1 turbo & a #100 plate in my truck & went back to a stock turbo w/a 14cm wastgated housing & a TST #10 (wanted to tune it down a bit as I'll be doing alot more pulling during the summer months) & first impressions were great, lots of bottom end, very little smoke, & just all around ran good, not as peppy as w/the #100, but just good smooth power, then all the sudden a few days l8er I noticed it sounded a little different through the exhaust & then it started to miss & blow blue smoke at certain rpm's so I figure timing needs to be reset, checked it today & it was sitting at 11 degrees, woo hoo found the problem??? reset the timing to 16.5 degrees & took it for a drive, & I really can't tell that much difference, motor runs alot smoother, but still doesn't spool as quick & runs hotter than it used to, it seems to have that weird thump through the exhaust that you hear when an intercooler hose blows off, & it kinda acts like it may have a boost leak someplace, but I can't find one anywhere????? all the boots look good, no soot anywhere around them that I can find?? this is really bothering me, but i'm about out of places to look????? I'm gonna stick a new overflow valve in it & see if maybe I've lost some fuel pressure?? I can hardly get this thing to smoke now in the lower rpm's, but with it loaded it won't hardly clean up a good haze of smoke, before when in a pull as long as I didn't have the pedal on the floor it would clean up almost all the smoke, only spit out a slight haze that you had to look to see?????? I'm not sure what to do now????? any ideas??????? thanks, Dusty

 

Did you remember to slide the afc housing forward after you changed plates?

 

yep it's full forward & the starwheel is maxed out, like I said it ran great for a couple days, then just seemed weak all of the sudden, it feels like a boost leak, I drove it a little more this evening, & I can only make about 32 psi. of boost, as opposed to the usual 40+??????? & if I stand on the throttle in neutral the needle on the boost gauge doesn't even move, I got a little smoke out of her by tweaking on the starwheel, but still runs horrible & hotter than usual, the turbo seems to spin free, & I still see no signs of any boost leaks????? I'm thinkin about swappin AFC housings with a buddy of mine & see'n if the diaghram in the AFC might be messed up???? any other ideas???? Dusty

 

how about presure testing the system for boost leaks,some times a leak will only show up under pressure.

 

After swapping out plates

did you actually make sure and tighten the 7/16 nuts that clamp the boost lines to the air intake hat? i forgot to do those once and it was causing me to lose power.. What about the afc line to the wastegate? is that slit or pulled out of place? if so that can cause a power loss as well... Fuel filter? is that ok? when was the last time it was changed? What about the intercooler boots, if you have a leak in any of those then that might cause ur power loss...

Another shot in the dark, what about your lift pump? hope this helps...

Rick

 

well the clamps are good & tight, & as far as I can tell the line going to the AFC looks good, fuel filter is gonna get changed today, & the lift pump seems to be doing ok, I'm getting fuel, I just have lost alot of boost, I can still get plenty of smoke it just doesn't run like it should, I'm thinking it's either an AFC problem or maybe even a stuck wastegate, thought it could possibly be stuck open???? I'm gonna go check the AFC & lines & see if I can find anything wrong there, keep the ideas coming & thanks again, Dusty

 

Could it be valve related, could you have bent or floated a valve or pushrod?

 

??? don't think so, but at this point???? the motor runs smooth as silk that's the main reason I didn't really think it was anything internal, but like I said at this point I don't really know??? I changed out my injectors this morning & put a set of 180hp sticks out of a 94' in it & it still runs about the same, low power/boost, & won't clear up smoke like it should, the thing still seems like it has a boost leak somewhere, drives like it & runs like it, I might add that after it starts to build some boost between 15-20 lb's it takes off & runs pretty decent, my big power loss is in the low rpm's where I can't get the thing to make any boost????? thanks again & keep it comin', Dusty

 

Have you removed the furthest to rear portion of the AFC to see if the diaphragm has a split in it?
Usually when this happens power is really low but perhaps the hole is very small.

 

got it fixed, my wastegate actuator rod had came off, took some air & blew it back out & hooked it back up & now all is well!!!! dang thing had me all torn up over something so ridiculous, thanks a bunch for the help, Dusty

 

Did this cure the thump in the exhaust?

 

most of it, my truck has always had that sound???? no matter which injectors, turbo, plate, or where it's timed, or before & after adjusting the valves, it's always had a bit of a lope at idle, course my 96' was the same way, but the majority of it is gone after fixing the wastegate, it's back to it's usual lope now, thanks again for all the replies, Dusty