Need help fuel pressure dropping
Thread Starter
Racer
Joined: Feb 2011
Posts: 310
Likes: 9
From: Miami Florida
Need help fuel pressure dropping
Hey guys I have an 01 c5 with an mp112 last week I changed the pulley to a 3.0 and as we were tuning we noticed the afr at 4300 or so begin to go leaner after that I payed attention to the fuel gauge and I'm seeing the fuel pressure drop even without getting into boost. I have the stock fuel system with a boost a pump. I changed to Fuel filter I also had the injectors cleaned and still nothing. I was thinking the pump but wanna be sure of it. Thanks in advance!
Melting Slicks
Joined: May 2008
Posts: 2,606
Likes: 355
From: Rochester New York
Whats the pressure reading from peak to lowest point when it drops? What is the AFR reading during drop? With forced induction you should be running >12:1 AFR at WOT. What injectors are you running? If your injectors are too small they may be maxed out/static causing this issue.
Thread Starter
Racer
Joined: Feb 2011
Posts: 310
Likes: 9
From: Miami Florida
I have 60lb injectors and when I put the key on she only goes up to 51 then when I turn her on she slowly goes up to 56 or 57 but as soon as I start driving she drop and if I sort of punch she'll drop to like 51
Melting Slicks
Joined: May 2008
Posts: 2,606
Likes: 355
From: Rochester New York
Are you getting this reading from a wideband 02 sensor? Narrowband sensors and those cheap sensors that come with gauges can be quite inaccurate at WOT. But even still, it shouldn't be that far off. Do you know what the injector duty cycle % is? If you have EFI live, data log and upload so I can view. Are you running closed loop or speed density? Did it run spot on before?
I forgot to ask, did you get the car retuned after changing the pulley? You would need to considering you're pumping more air into the engine. You could always try changing the pulley back and see where your AFR is.
I forgot to ask, did you get the car retuned after changing the pulley? You would need to considering you're pumping more air into the engine. You could always try changing the pulley back and see where your AFR is.
Last edited by n8dogg; Dec 7, 2012 at 05:29 PM.
