running lean, weak fuel pump?
07-12-2005, 01:10 PM
#1
TECH Resident
Thread Starter
iTrader: (4)
Join Date: Nov 2004
Location: Nashville, TN
Posts: 879
Likes: 0
Received 0 Likes
on
0 Posts
running lean, weak fuel pump? I've had my car on the dyno 3 different times now with 2 retunes, and it's still running a bit lean. The first run it was around 14.5-15/1, the second run with the 1st retuned PCM was consistent 14/1, 13.9/1, and the 3rd run with the 2nd retuned PCM was around 13.6/1 the whole time. But what I can't understand is that on the last retune, the tuner said he added alot more fuel than the stock tables, and I'm still a little lean. Does this sound like a weak fuel pump? The car always starts fast even with less than 1/8 tank and has 86k miles. thanks
Jason
Jason
07-13-2005, 06:19 PM
#3
TECH Resident
Thread Starter
iTrader: (4)
Join Date: Nov 2004
Location: Nashville, TN
Posts: 879
Likes: 0
Received 0 Likes
on
0 Posts
Yeah I know. I'm gonna borrow a buddy's guage when I get back home later this week. Just wanted to see if there may be something else besides the fuel pump that could cause this.
Jason
Jason
07-14-2005, 01:58 PM
#5
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes
on
6 Posts
Pump or filter will manifest as an AFR that climbs with
RPM using a flat fuel curve. If it's off, but flat AFR w/
RPM, look to regulator pressure setpoint or air side
errors. Might check that somebody in the past didn't
go mess around injector tables from stock, or like that
(at one time this was the common advice for fixing
mixture, although it involves lying to the computer).
RPM using a flat fuel curve. If it's off, but flat AFR w/
RPM, look to regulator pressure setpoint or air side
errors. Might check that somebody in the past didn't
go mess around injector tables from stock, or like that
(at one time this was the common advice for fixing
mixture, although it involves lying to the computer).
