Bad Fuel Pump??
06-01-2011, 06:52 AM
#1
Bad Fuel Pump??
About once a month my car would buck pretty hard when downshifting from 5th to 4th. It only occured when downshifting to step on it and pass someone and not when slowing down. Now it seems to happen more often since I loaded the Bama 93 race tune.
A quick forum search and it looks like it may be a faulty fuel pump, per (TSB 06-9-9. The searches describe hesitation not bucking - could it still be the problem? If so, how difficult is pump replacement.
Thx.
A quick forum search and it looks like it may be a faulty fuel pump, per (TSB 06-9-9. The searches describe hesitation not bucking - could it still be the problem? If so, how difficult is pump replacement.
Thx.
06-01-2011, 07:03 AM
#2
4th Gear Member
Join Date: Apr 2008
Location: North Idaho
Posts: 1,440
My 06 did the same thing...plus after running for awhile then starting out from a stoplight...kinda like a big hiccup..of course didnt really happen until the warranty was up...had the pump changed out and never the problem again...
You might change the fuel filter first..
You might change the fuel filter first..
06-01-2011, 07:18 AM
#3
6th Gear Member
Careful. The fuel pump issue will cause hesitation when accelerating after prolonged steady-speed cruising. A similar sympton of hesitation will also occur when going close to or full throttle with the TCS on which will cut power as soon as you get on it under certain conditions. Try turning TCS off every time you get in the car under dry conditions and see if the issue is resolved.
06-01-2011, 02:55 PM
#4
4th Gear Member
Join Date: Apr 2008
Location: North Idaho
Posts: 1,440
Careful. The fuel pump issue will cause hesitation when accelerating after prolonged steady-speed cruising. A similar sympton of hesitation will also occur when going close to or full throttle with the TCS on which will cut power as soon as you get on it under certain conditions. Try turning TCS off every time you get in the car under dry conditions and see if the issue is resolved.
06-01-2011, 04:53 PM
#5
Was worse today! First day out of the 80's here and it was 98deg. It did the 'bucking on a downshift to accelerate' twice and there may have been some hesistation issues at times. Not sure if the hesitation was for real or me imagining it after reading about it all day at work instead of working. And TCS was on.
So i'm not sure - pump/TSB, filter, or tune? This is the 3rd day i've drove with the new tune. Or a combination. The heat seems to have made it worse and it only occurs on the highway after i've been driving a few miles. Tomorrow i'll go TCS off. Should I try a different tune? I'd think it shouldn't matter.
So i'm not sure - pump/TSB, filter, or tune? This is the 3rd day i've drove with the new tune. Or a combination. The heat seems to have made it worse and it only occurs on the highway after i've been driving a few miles. Tomorrow i'll go TCS off. Should I try a different tune? I'd think it shouldn't matter.
06-01-2011, 05:29 PM
#6
6th Gear Member
Turn TCS "off" and see if it continues. The '06 V6 that I bought for my g/f had the fuel pump issue. I noticed it immediately after buying it used and driving it home and it occurs following prolonged cruising at relatively steady speeds. A buildup of air bubbles forms and when you go WOT it forces these bubbles into the fuel lines to the injectors. My '07 GT, on the other hand, has the issue with the TCS on and going WOT where it'll just sit there and slowly accelerate. Kind of embarassing when you're trying to pick a race from a roll...
06-01-2011, 08:18 PM
#7
4th Gear Member
Join Date: Apr 2008
Location: North Idaho
Posts: 1,440
Was worse today! First day out of the 80's here and it was 98deg. It did the 'bucking on a downshift to accelerate' twice and there may have been some hesistation issues at times. Not sure if the hesitation was for real or me imagining it after reading about it all day at work instead of working. And TCS was on.
So i'm not sure - pump/TSB, filter, or tune? This is the 3rd day i've drove with the new tune. Or a combination. The heat seems to have made it worse and it only occurs on the highway after i've been driving a few miles. Tomorrow i'll go TCS off. Should I try a different tune? I'd think it shouldn't matter.
So i'm not sure - pump/TSB, filter, or tune? This is the 3rd day i've drove with the new tune. Or a combination. The heat seems to have made it worse and it only occurs on the highway after i've been driving a few miles. Tomorrow i'll go TCS off. Should I try a different tune? I'd think it shouldn't matter.
Last edited by Lifter583; 06-01-2011 at 08:22 PM.
06-01-2011, 10:27 PM
#8
1st Gear Member
Join Date: Aug 2006
Location:
Posts: 71
I have the same problem with my 05, highway cruise then downshift and its like the car hits a wall, feels like the engine wants to lock up, then surges back to life. Mine started doing it a while ago, and I thought it was something in the tune.
Right now I'm debating whether to go with the TSB specified 7R3Z-9H307-C replacement sender & pump assy, or take another route.
Right now I'm debating whether to go with the TSB specified 7R3Z-9H307-C replacement sender & pump assy, or take another route.
06-02-2011, 06:23 AM
#9
Hmmm....I'm not the only one then. I had TCS off this am on my work drive - but it was cool outside. Doesn't happen unless its at least upper 80's. Also, on the Bama tunes do they adjust TCS settings? I haven't bounced the needle off TCS yet like it used to since the 93 race tune went on last thurs.
As for the TSB, late July when I'll hit 25k miles i'm gonna change the fuel filter. Whether it needs it or not.
As for the TSB, late July when I'll hit 25k miles i'm gonna change the fuel filter. Whether it needs it or not.
06-02-2011, 08:47 AM
#10
6th Gear Member
Many folks here will tell you that about 30k on the filter is pushing it since a few issues have been linked to plugged filters. As far as not bouncing off the rev limiter since the tune, most tunes have the rev limiitier raised from the factory 6250 to 6500 or even 6800 RPM. Brenspeed raised mine to 6800 but I lowered it to 6500 (and I still bounce off it sometimes).