Hesitation under boost
Posted: Tue Feb 07, 2006 8:57 pm
Ok im stuck hear in a bad one, hopefully i can figure it out on my own but ive tried mostly everything i can think of with no secuess 
of course back ground is a 4 banger 1.8 littler 8:1 CR stock head work bla bla bla turbocharged etc.... running MS2.33 EDIS4 what not...
it seems after makeing sure my VR pickup sensor was sound and brand spanking new, plugs are new etc.... motor is sound (i hope).... i recently swaped in higher boost springs in my wastegate, in my datalogs im seeing 16~18ish boost which is around where i want it for now any how....
on ignition side ive sloped the table so ofcourse in higher boost rangeim seeing 20~18 and 16 degrees at anything higher 20 psi!
another step i took was to adjust my fuel presure so im adding in around 6 psi of more presure nearly 46 psi under boost which before was 40 ish.... this help me lower my duty cycle at full boost before i was seeing over 80% with 42lb injectors ??? dosent add up....
so this is problem, anything after 4000 rpm my engine just runs out of power, it makes a wierd sorta hissing sound and bucks a bit, i never felt a real "knock" from what ive heard its very viloent like "hitting a hammer on top of piston" , i doubt thats whats happening on wideband side of things im in very low 11's AFR its hard to see cleary if its really leaning out but im sure if it was that bad id see it ?....
so with me dumping more fuel in didnt help things much, maybe my wide band is lieing , i doubt it, the inovtative software is perfectly mattched to megatune, i did a free air calibration but no different results...
last, i did a presure test on entire system, i thought maybe my vacume line to megasquirt was blowing air out of it, i hit 20 psi with everhything attached and did not notice any leaks what so ever (with engine fully warmed up) something that came to mind , when this hesitation happens it feels like someone is redline a motor and the valaves cant open and close no more (floating) thats about cose as i can get to describeing the feeling.... this is on a "new" head with all new parts on it...
very wierd situwation, my last dead hope idea is to get a scope on the injectors and hook up a simulator to the EDIS module to fake out the vr sensor and rev it up to 6 grand see what the injectors look like.....
help
in log look at 1249 , thats basicly what im seeing engine just stop reving past that point....
Sean....
http://www.motorsportwerke.com/e30turbo/datalog1.xls
ill attach my log to this post... im just stuck dead right now clueless to whats problem
of course back ground is a 4 banger 1.8 littler 8:1 CR stock head work bla bla bla turbocharged etc.... running MS2.33 EDIS4 what not...
it seems after makeing sure my VR pickup sensor was sound and brand spanking new, plugs are new etc.... motor is sound (i hope).... i recently swaped in higher boost springs in my wastegate, in my datalogs im seeing 16~18ish boost which is around where i want it for now any how....
on ignition side ive sloped the table so ofcourse in higher boost rangeim seeing 20~18 and 16 degrees at anything higher 20 psi!
another step i took was to adjust my fuel presure so im adding in around 6 psi of more presure nearly 46 psi under boost which before was 40 ish.... this help me lower my duty cycle at full boost before i was seeing over 80% with 42lb injectors ??? dosent add up....
so this is problem, anything after 4000 rpm my engine just runs out of power, it makes a wierd sorta hissing sound and bucks a bit, i never felt a real "knock" from what ive heard its very viloent like "hitting a hammer on top of piston" , i doubt thats whats happening on wideband side of things im in very low 11's AFR its hard to see cleary if its really leaning out but im sure if it was that bad id see it ?....
so with me dumping more fuel in didnt help things much, maybe my wide band is lieing , i doubt it, the inovtative software is perfectly mattched to megatune, i did a free air calibration but no different results...
last, i did a presure test on entire system, i thought maybe my vacume line to megasquirt was blowing air out of it, i hit 20 psi with everhything attached and did not notice any leaks what so ever (with engine fully warmed up) something that came to mind , when this hesitation happens it feels like someone is redline a motor and the valaves cant open and close no more (floating) thats about cose as i can get to describeing the feeling.... this is on a "new" head with all new parts on it...
very wierd situwation, my last dead hope idea is to get a scope on the injectors and hook up a simulator to the EDIS module to fake out the vr sensor and rev it up to 6 grand see what the injectors look like.....
help
in log look at 1249 , thats basicly what im seeing engine just stop reving past that point....
Sean....
http://www.motorsportwerke.com/e30turbo/datalog1.xls
ill attach my log to this post... im just stuck dead right now clueless to whats problem