New motor - bogs terribly off idle, undriveable
#1
Staging Lane
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New motor - bogs terribly off idle, undriveable
So I had a place locally build me an LS7 and set me up with a base SD tune to get me going until they can get me in for a full tune. It idles pretty decently, but give it any gas and it bogs. No throttle response at all and the car is totally undriveable. Here are the specs:
LS7 - 12:1 CR
245 Trick flow heads
Comp 243/251 .653/.660 110 LSA
Fast 102mm intake, NW 102 Cable TB
42.5# injectors
Not running a MAF. I verified I have 58psi at the rail at idle. I also verified my TPS is at 0% when it should be. My IAC count is 50-60 or so when its warmed up, but they are up there when its cold. The IAC is wide open when its cold and it sounds like the thing could suck up a small volkswagen.
I have HPTuners, but I am pretty clueless with most of it. Ive tried going through some idle tuning procedures online, but the ones ive found assume you are running a MAF.
Any ideas on where to start with this? Thanks in advance.
LS7 - 12:1 CR
245 Trick flow heads
Comp 243/251 .653/.660 110 LSA
Fast 102mm intake, NW 102 Cable TB
42.5# injectors
Not running a MAF. I verified I have 58psi at the rail at idle. I also verified my TPS is at 0% when it should be. My IAC count is 50-60 or so when its warmed up, but they are up there when its cold. The IAC is wide open when its cold and it sounds like the thing could suck up a small volkswagen.
I have HPTuners, but I am pretty clueless with most of it. Ive tried going through some idle tuning procedures online, but the ones ive found assume you are running a MAF.
Any ideas on where to start with this? Thanks in advance.
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Do you have a WB hooked up?
Sounds like the V table either needs fuel added or taken away. When I started tuning my car it would idle GREAT, but when you would go to pull out it would bog and just die. The AFR was taking a dive down to 15-16:1.
Tuned the VE and now she is nice and smooth.
Sounds like the V table either needs fuel added or taken away. When I started tuning my car it would idle GREAT, but when you would go to pull out it would bog and just die. The AFR was taking a dive down to 15-16:1.
Tuned the VE and now she is nice and smooth.
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Gotta get a wideband on there... only way to know whats going on. Sounds kinda like an LS7 I tuned recently, except the customer had a Vic Jr and 4 bbl TB. If you were using EFILive, I could help you out, but I don't have HPTuners to even look at it...
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Staging Lane
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Awesome man, I really appreciate any help you can provide. Here is a scan that I just ran.
Basically I took the base tune my builder gave me and added 40% fuel across the whole range to the VE table. This was basically the only way I could make the car half driveable. Crazy amount of fuel, I know. Oh and also, I disabled CL completely because that seems to help.
Ive attached the tune I used in case that helps as well.
Thanks again!
Basically I took the base tune my builder gave me and added 40% fuel across the whole range to the VE table. This was basically the only way I could make the car half driveable. Crazy amount of fuel, I know. Oh and also, I disabled CL completely because that seems to help.
Ive attached the tune I used in case that helps as well.
Thanks again!
#7
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VE was kinda ugly. Displacement was not adjusted. Try this one out.
Use your histograms VE/STFT to dial in the VE further, but this should get you pretty close.
Base LS7 tune.EH1.hpt
Use your histograms VE/STFT to dial in the VE further, but this should get you pretty close.
Base LS7 tune.EH1.hpt
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#8
Staging Lane
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Awesome! Thanks so much! I will give this a shot as soon as I can.
Yeah, I noticed displacement wasnt right, but I just assumed it really didnt come into play anywhere.
Yeah, I noticed displacement wasnt right, but I just assumed it really didnt come into play anywhere.
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Just thought id mention that the car is probably running its best so far! You definitely helped a lot. Again, cant thank you enough for helping me out here.
I just need to sit down and analyze the logs a bit, but it seems like its leaning out past say 10% throttle. Ill likely just buy a WB and tune from that.
One thing I noticed is that the idle wont really come down very well now. Any thoughts on that?
I just need to sit down and analyze the logs a bit, but it seems like its leaning out past say 10% throttle. Ill likely just buy a WB and tune from that.
One thing I noticed is that the idle wont really come down very well now. Any thoughts on that?