got the car dyno'd, had a weird problem though...check it out..
06-11-2011, 01:58 PM
#1
got the car dyno'd, had a weird problem though...check it out.. Sry this is a repost from the "internal engine section" but was told to post here. Hope you guys can help..
First of all, some of you ahve seen my recent posts about my cam and intake swap. Well i finally took it to a tuner, mike norris @ norris motorsports to be exact here in indiana. Id like to start off by saying thank you to mike, awesome guy to work with and he knows his ****! Now the thing that scared me though, hes been doing this a long long time, and he couldnt figure out what was up with my car. ok heres what was going on..
When i got there, he puts it up on the dyno, hooks evrything up and does a base line ll...the car put down like 236 hp......The reason being...the car was waaaaaaaaaaayyy waaaaayy lean... He kept messing with it and messing with....he finally got it to a safe AFR...and did the final dyno pull that scored me 383/360...not too shabby, but, with this cam, i had the impression i should b more in the 400/380 area. He said he had to force the car to put fuel to the motor. So much in fact, that he said he had the AFR set for like 10.1, cuz it would only do 13.xx. Hes like "in the 10 years ive been doing this, ive never had to do this to a car to adjust the fuel trims.." and he couldnt really figure out what was up. He said the fuel pressure checked out, and the o2's were working. He did say though the injectors are maxed out. He told me to go ahead and replace the MAF and pick up some 30lb svo injectors and if it runs really rich, that was the problem...he said it could also be the PCM not calculating the tune right? or someting like that...do you guys have any ideas? it kinda stumps me
Mods are in sig!
heres the graph..
First of all, some of you ahve seen my recent posts about my cam and intake swap. Well i finally took it to a tuner, mike norris @ norris motorsports to be exact here in indiana. Id like to start off by saying thank you to mike, awesome guy to work with and he knows his ****! Now the thing that scared me though, hes been doing this a long long time, and he couldnt figure out what was up with my car. ok heres what was going on..
When i got there, he puts it up on the dyno, hooks evrything up and does a base line ll...the car put down like 236 hp......The reason being...the car was waaaaaaaaaaayyy waaaaayy lean... He kept messing with it and messing with....he finally got it to a safe AFR...and did the final dyno pull that scored me 383/360...not too shabby, but, with this cam, i had the impression i should b more in the 400/380 area. He said he had to force the car to put fuel to the motor. So much in fact, that he said he had the AFR set for like 10.1, cuz it would only do 13.xx. Hes like "in the 10 years ive been doing this, ive never had to do this to a car to adjust the fuel trims.." and he couldnt really figure out what was up. He said the fuel pressure checked out, and the o2's were working. He did say though the injectors are maxed out. He told me to go ahead and replace the MAF and pick up some 30lb svo injectors and if it runs really rich, that was the problem...he said it could also be the PCM not calculating the tune right? or someting like that...do you guys have any ideas? it kinda stumps me
Mods are in sig!
heres the graph..
06-11-2011, 02:55 PM
#3
he said he had to force 25-30% fuel to the motor to get it to run in a safer AFR. he said he was forcing 10.1 in the tune, but it was actually only reading 13.xx AFR. The car was running so lean he had to tell the PCM to dump that much fuel (10.1 AFR), but in real time was only getting 13.xx AFR after forcing the fuel increase. He said fuel pressure was at 55PSI also at WOT. and injectors were 100% duty cycle.
06-11-2011, 03:05 PM
#5
Meaning it probably has a fuel issue. Possibly injectors, plugged fuel filter, weak pump, restricted line, ect.
06-11-2011, 04:35 PM
#7
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He doesn't have a fuel delivery problem (other than maxed injectors) if he has 55psi WOT
1. I would NEVER attempt top tune a car with injectors maxed at 100%. Stop, get the right injectors, and start again. Why waste time and risk a motor when it's going to have to be done again anyway
2. You don't fix the WOT lean issue by raping the PE table to command 10-1. Adjust the MAF and VE tables to get it correct.
1. I would NEVER attempt top tune a car with injectors maxed at 100%. Stop, get the right injectors, and start again. Why waste time and risk a motor when it's going to have to be done again anyway
2. You don't fix the WOT lean issue by raping the PE table to command 10-1. Adjust the MAF and VE tables to get it correct.
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06-11-2011, 06:55 PM
#8
So it's my injectors holding me bak?? He said he doesn't like doing maxing them out but he really didn't have a choice. I couldn't drive it home at 15+ AFR :-/. I'll find some
Injectors soon and get em in....he's gonna b on vacation for a month soni can't get retuned till then
Injectors soon and get em in....he's gonna b on vacation for a month soni can't get retuned till then
06-12-2011, 04:47 AM
#10
You need to do some logging with a wideband and see whats happening, while you're driving. Also you could have the correct fuel pressure, but if your fuel is getting heated somewhere along its travels, it could be vaporizing, in the line and not supplying enough fuel. Are you sure your fuel line isn't near your long tubes or any of your exhaust?
06-12-2011, 07:32 AM
#12
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Unless I miss-read the post, and maybe I did, he is only refering to the dyno session. I don't think he was doing a street tune and having injector/AFR issues, so the fueling issue is at WOT. He said he was had "set" the afr at xxx to get xxx, which you do for PE, not stoich
The injectors are find for just driving around, but you don't want to go WOT until they're swapped out
He either has 26s or 28s in the car, and if he's cam and bolt on, he will close to maxed out. My wife's set up was at 87%, and when we added the heads (and still lean) she was at 97% (I stopped and got bigger injectors) so he's getting close to maxed out at 380+
The injectors are find for just driving around, but you don't want to go WOT until they're swapped out
He either has 26s or 28s in the car, and if he's cam and bolt on, he will close to maxed out. My wife's set up was at 87%, and when we added the heads (and still lean) she was at 97% (I stopped and got bigger injectors) so he's getting close to maxed out at 380+
06-12-2011, 08:15 AM
#13
55lbs of fuel pressure / 100% Duty Cycle says stop and replace injectors and or fuel pump..Or as slowhawk says MAF is off or bad..I did a Vette last weekend, (Runs high 11's) and on the dyno she was a little lean on top, I started to add fuel and noticed if I tried to increase values more than usual the A/F remained the same or barely showed any improvement, and the duty cycle was going up. He had plenty of injector and so we stop, checked the Fuel pump, and it was going out...
06-12-2011, 03:35 PM
#14
Good info guy guys. He also said replace the MAF. I think I'll just replace all of it. Imma do a nitrous setup in a couple months anyway so I'm going to need the fuel pump anyway and this one has 109k on it so u guys are probably right. It's probably on it's last leg. A board member suggested 30lb FIC injectors. My tuner said SVO red tops. Id like not to spend more than $250 on injectors. He also said injectors out of an 02 supercharged bonneville would work. He said they are white and are 38lbers.