91z with LS1 stumbling when you give it gas?
Thread Starter
Junior Member
Joined: Feb 2002
Posts: 95
Likes: 3
From: Lexington, Ky
Car: 91 Camaro Z28
Engine: LS1
Transmission: 4L60E
Axle/Gears: 3.42 Posi Disc
91z with LS1 stumbling when you give it gas?
I have a 91Z28 with a Ls1 and 4l60e tranny. The problem I am trying to figure out is when I give it gas in first gear. The car stumbles for a few seconds then takes off like a bat out of hell. If I try to acelerate slow it stumbles worse. But if I lay into it slightly it stumbles then takesoff. Fuel pressure is at 58 psi. Dont have any codes showing on the scanne.
Does anyone have any ideas to try or thoughts?
Thanks,
Chris
Does anyone have any ideas to try or thoughts?
Thanks,
Chris
Senior Member
iTrader: (-1)
Joined: Oct 2008
Posts: 809
Likes: 1
From: Siloam Springs AR.
Car: 1998 Trans/Am, 1989 RS Camaro
Engine: LS1, LQ9 6.0
Transmission: 4L60E, 4L60E
Axle/Gears: 2.73, 2.73
Re: 91z with LS1 stumbling when you give it gas?
TPS might have a bad spot on it.
Joined: Sep 2005
Posts: 6,258
Likes: 6
From: O'Fallon, MO
Car: 1991 Z28 convertible built 3/1/1990
Engine: Cammed 6.0L LSX
Transmission: T56
Axle/Gears: custom Ford 8.8", 4.10 gears
Re: 91z with LS1 stumbling when you give it gas?
Misfire?
Pleaaaaase change your profile. An LS1 is a 346 not a 350.
Pleaaaaase change your profile. An LS1 is a 346 not a 350.
Thread Starter
Junior Member
Joined: Feb 2002
Posts: 95
Likes: 3
From: Lexington, Ky
Car: 91 Camaro Z28
Engine: LS1
Transmission: 4L60E
Axle/Gears: 3.42 Posi Disc
Re: 91z with LS1 stumbling when you give it gas?
Changed the TPS last night. Didnt help the prolem any. Oh well, one less thing to think about. Lol!
Senior Member
iTrader: (8)
Joined: Mar 2008
Posts: 655
Likes: 2
From: NH
Car: 1967 Firebird P.T.
Engine: LS3 4" Strkr 422ci
Transmission: MN12 6 speed
Axle/Gears: 3.73 8.5" 10 Bolt Eaton
Re: 91z with LS1 stumbling when you give it gas?
is it running rich? i havent hooked my 02's up yet and it does the same thing when idling and leaving from a stop from being overly rich from lack of the sensors.
Thread Starter
Junior Member
Joined: Feb 2002
Posts: 95
Likes: 3
From: Lexington, Ky
Car: 91 Camaro Z28
Engine: LS1
Transmission: 4L60E
Axle/Gears: 3.42 Posi Disc
Re: 91z with LS1 stumbling when you give it gas?
Tried the Throttle position sensor. No difference. Hooked a scanner up to the PCM (ECM) and it gave me a code PO134 O2 sensor no activity. I did a scan while idling and found this information.
O2 sensor Bank 1 sensor 1
Rich lean threshhold
Max-----V ?
Meas 0.365V
Min-----V
Mod $10
_________________________
Lean Rich Threshold (Same as above)
_________________________
Lo V for switch
Max----V?
Meas 0.300
Min ----V
Mod $10
_________________________
Hi V for switch
Max----V
Meas .600V
Min----V
Mod $10
_________________________
Rich Lean Switch Time
Max .24s
Oxygen Sens Mon - Inc
Oxygen Sensor Heater - Inc
O2 S11 V .570-.595
O2 S12 V .440-.445
O2 S21 V .585-.730
O2 S22 V .440-.450
Fuel Rail Pressure 55-56 PSI
_________________________
Is any of this information helpful to diagdose this problem? Hate to spend money just swapping out O2 sensors if its something else!
Thanks for your help!
O2 sensor Bank 1 sensor 1
Rich lean threshhold
Max-----V ?
Meas 0.365V
Min-----V
Mod $10
_________________________
Lean Rich Threshold (Same as above)
_________________________
Lo V for switch
Max----V?
Meas 0.300
Min ----V
Mod $10
_________________________
Hi V for switch
Max----V
Meas .600V
Min----V
Mod $10
_________________________
Rich Lean Switch Time
Max .24s
Oxygen Sens Mon - Inc
Oxygen Sensor Heater - Inc
O2 S11 V .570-.595
O2 S12 V .440-.445
O2 S21 V .585-.730
O2 S22 V .440-.450
Fuel Rail Pressure 55-56 PSI
_________________________
Is any of this information helpful to diagdose this problem? Hate to spend money just swapping out O2 sensors if its something else!
Thanks for your help!
Joined: Jul 2008
Posts: 266
Likes: 2
From: Long Island NY
Car: 84 Z28......99 TA
Engine: Lq9 6.0... Ls1
Transmission: 4L60E X's 2
Axle/Gears: 3.73 on both
Re: 91z with LS1 stumbling when you give it gas?
Which injectors do you have? Stock 28 or ford. I had a set of ford 39 lb injectors and I had shitty idle and the same problem as you have. I changed it out to stock vette injectors and now she is fine.
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Thread Starter
Junior Member
Joined: Feb 2002
Posts: 95
Likes: 3
From: Lexington, Ky
Car: 91 Camaro Z28
Engine: LS1
Transmission: 4L60E
Axle/Gears: 3.42 Posi Disc
Re: 91z with LS1 stumbling when you give it gas?
I dont know which I have? I will have to check and see. Thanks for the advice!
Supreme Member
iTrader: (1)
Joined: Feb 2005
Posts: 2,642
Likes: 2
From: Pleasant Grove, Utah
Car: 1993 GMC Typhoon
Engine: 4.3 Turbo
Transmission: 4L60
Axle/Gears: 3.42
Re: 91z with LS1 stumbling when you give it gas?
Sounds like a fuel pressure problem under load to me. Do you have a manual gauge you can hook up to view the pressure while driving?
Joined: Jul 2008
Posts: 266
Likes: 2
From: Long Island NY
Car: 84 Z28......99 TA
Engine: Lq9 6.0... Ls1
Transmission: 4L60E X's 2
Axle/Gears: 3.73 on both
Re: 91z with LS1 stumbling when you give it gas?
http://www.youtube.com/watch?v=BdQeA...5&feature=plcp
its the spray pattern for the ford injectors. hopefully you dont have these try to pull one out and take a pic of it or take a video of the car at idle and driving. good luck bro
its the spray pattern for the ford injectors. hopefully you dont have these try to pull one out and take a pic of it or take a video of the car at idle and driving. good luck bro
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