launching issues

dipapadakis

dipapadakis

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Joined
Jan 20, 2011
Messages
151
so i went out to the track last night, and when i went to stage i could not build more than 3-4lbs of boost on the line rpms were right at 1500 no matter how long i power braked no matter on position of pedal i could not get it to move its got a 2000 stall converter from goerend that was rebuilt about a year ago, driving on the streets i still achieve full boost and normal spool up, this one has kinda stumped me. i ran a 14.9 1/4 with a 2.7 60ft at 98 this same morning with no modifcations my truck dynoed 496 & 1072 on a 248x dynojet driveablilty seems pretty much the same just on the line it wont build boost any ideas?
 
Sounds more like you've got a 1500 rpm stall. When it was rebuilt did they restall the converter?
 
yea they put the new stall in it when they rebuilt it, it was a way lower stall before and itll usually revs up to 1900-2k this just happened withtin the past couple days i launched it about 3 days ago and it built up 20lbs on the line like nothing and launched hard, only thing ive done to it since then was beat it on the dyno a little
 
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Same thing just happened to me, major problem was the wastegate arm overheating and bending back at a 45degree angle, thus leaving the gate open.
 
ill have to check the turbo it is only 2 months old but that doesnt mean it cant fail, would sure hope not though, i just noticed while brake boosting there is an exhaust leak pre turbo seems like its coming from bottom of the exhaust manifold, i wouldnt think that would be bad enough to cause it not to spool ill have to look at it with a mirror couldnt notice any cracks but the truck is still hot, you can see there are slight leaks around the manifold where it bolts to the head, which makes me think drive pressure maybe that turbo is ****ed, checked wastegate it still opens and closes when applying regulated shop air to it and fuel pressure isnt dropping under 40.
 
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Any chance your pre boost screw loosened and now you dont have as much pre boost fuel so you cannot get it to spool? Maybe try loosening the AFC spring a few clicks
 
okay guess its time for a new exhaust manifold, i checked the afc and diaphragm couldnt find anything there
 
Did you pull the cover off the wastegate and confirm that all is OK inside?
 
no havent had time to pull the cover and check it just put air to it to confirm it was still getting full travel, exhaust manifold is slightly cracked on the bottom, ill have to check that when i put the new manifold on. The other day it did spool up took longer than it use to but did still build up 20lbs then a few days later it was back to not building more than a few lbs i wonder if afc or gate is intermittenly sticking or binding
 
Sounds just like mine, really slow to spool, but will if you try long enough, wastegate arm still has full travel, even the exhaust pressure test was good. The pucks just weren't covering the ports competely, had to pull the cover and use a mirror to find it.
 
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