motor cutout when hitting boost HELP!!
12-01-2008, 11:32 AM
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motor cutout when hitting boost HELP!! Im running a D1 procharger on my mostly stock ls1, other than exhaust, cam and fuel. I cannot make boost. While watching the vacuum/boost gauge and I hit zero vacuum the motor cuts out and falls on its face. This happens everytime. It feels like it's pulling timing or fuel. I had it checked out at a performance shop and they said my rings were too weak to hold the boost with the compression so the boost is going past the rings. I feel this is hard to believe because I dont have oil coming into my PVC. I would think I should be able to see at least a couple pounds of boost. I am running a stock MAF that is ported and polished. Could I be maxing it out when I hit boost and it is freaking out, pulling timing or fuel? I have read by descreening it you could disrupt the airflow causing some problems. Also by rotating it could fix some problems. I dont believe this is the majority of this problem. Any help on this would be great. I spent a lot of money on this setup and I wanna see some boost!!! Thanks
12-02-2008, 10:31 AM
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I went over all of the couplers and retightened them so I dont believe it's a boost leak. I was running NGK TR6's I believe however the shop said they were gapped wrong then they put in some Autolite ones, not sure on the part number. I dont know my fuel pressure cause I dont have a gauge yet; however the fuel system should be sufficient because I am running a Walbro pump and 60lb. injectors. I am currently tuning the car with CraneCams programmer basically only for the larger injectors to trim fuel for startup and idle. The performance shop (Big 3 Performance) didn't tune the car because they said my rings were to weak to even do any tuning. They did a cylinder leakdown test. I havent completed one to verify their results. However if I was leaking that much boost past the rings it would be blowing oil up the PVC.
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12-02-2008, 10:36 AM
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what tuning has anyone done to the MAF? What programmers or programs are people using to tune the MAF? Any that can be bought or are they just the ones shops have (EFI LIVE and such programs)? Is it a good idea to switch to speed density, and if so how do you do it?
12-02-2008, 10:45 AM
#9
for a low boost app. I would stay with a MAF tune. they tend to be less erratic with startups and idling from my experience although my current setup is MAF and runs perfect so maybe I got lucky. You dont have any tuning done for your MAF at all? if not thats my bet for your problem
all that boost is not blowing by the rings 
12-03-2008, 07:26 AM
#15
wow i cant beleive they told you that...always amazes me how incompetent some shops are. first off you will need a better programmer than what you have . those are only good up to a certain point but definitely not for FI. Either get someone to tune it or purchase hp tuners. you have alot more to do to the tune then just injector constant changes. you will also need the timing backed off and the fueling right before your setup will run right and not tear itself up. good luck man...ps spread the word about the idiots at that shop!
......with the tune you are describing and the fact that your car won't build boost it is prably going so lean from the added air that the car can't run