Full Power problem
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 2,258
Likes: 96
From: Olive Branch Mississippi
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20-'21-'22-'23-'24
Full Power problem
Ok my Z started a 2.5k-3k rpm stumble in full power the other day I assume it would go through the power band but didnt push it, and is noticably felt on the car. After parking the car and driving it later, it was gone, but came back the next day. Normal power is fine, and out of gear no issue with the full power. I insured the engine was at good operating temp prior to switching to Full Power. Any ideas, bad Injector?????
91 ZR1
Thanks
91 ZR1
Thanks
Le Mans Master
Joined: Jan 2000
Posts: 6,377
Likes: 21
From: Traverse City MI
You could check the resistence on each of your injectors - see if one is falling outside the average range of the others; there is a way to do this without pulling the plenum. Also - put a vacum guage on and check the vacum on the secondaries.
Drifting
Joined: Sep 2001
Posts: 1,251
Likes: 52
From: Niceville
A few questions:
Is the stumble under part throttle/tip in or wide open throttle?
Did it pull all the way to 7000 rpms?
Are any codes (DTCs) set?
Does the secondary vacuum pump run?
Here's the vague answer you didn't want--without any of the above answers:
fuel:
I would pull the primary fuel pump fuse and start the car. It should start, run then die after a few seconds. Both pumps are powered on startup and the secondary cuts off after x time. What is the pressure at the rail? Also, could be a bad filter.
Injectors can be tested on the car--best when hot. Go to Marc Haibeck's www.zr1specialist.com
spark:
I would start by checking the plugs and their gap. It will stumble with the gap too wide-->after time they seem to get this way. You can also measure the resistance across the coil packs. Wires go bad as do the coil packs.
vacuum:
Ground C17 (for a 95 at least) on the back of the ECM and watch the secondary actuators open. Do it with the car not running and running (will set a code-->vacuum present when not commanded). This will tell you the relative health of both banks of secondaries.
Ted
Is the stumble under part throttle/tip in or wide open throttle?
Did it pull all the way to 7000 rpms?
Are any codes (DTCs) set?
Does the secondary vacuum pump run?
Here's the vague answer you didn't want--without any of the above answers:
fuel:
I would pull the primary fuel pump fuse and start the car. It should start, run then die after a few seconds. Both pumps are powered on startup and the secondary cuts off after x time. What is the pressure at the rail? Also, could be a bad filter.
Injectors can be tested on the car--best when hot. Go to Marc Haibeck's www.zr1specialist.com
spark:
I would start by checking the plugs and their gap. It will stumble with the gap too wide-->after time they seem to get this way. You can also measure the resistance across the coil packs. Wires go bad as do the coil packs.
vacuum:
Ground C17 (for a 95 at least) on the back of the ECM and watch the secondary actuators open. Do it with the car not running and running (will set a code-->vacuum present when not commanded). This will tell you the relative health of both banks of secondaries.
Ted
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 2,258
Likes: 96
From: Olive Branch Mississippi
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20-'21-'22-'23-'24
Originally Posted by Demps
A few questions:
Is the stumble under part throttle/tip in or wide open throttle?
Did it pull all the way to 7000 rpms?
Are any codes (DTCs) set?
Does the secondary vacuum pump run?
Here's the vague answer you didn't want--without any of the above answers:
fuel:
I would pull the primary fuel pump fuse and start the car. It should start, run then die after a few seconds. Both pumps are powered on startup and the secondary cuts off after x time. What is the pressure at the rail? Also, could be a bad filter.
Injectors can be tested on the car--best when hot. Go to Marc Haibeck's www.zr1specialist.com
spark:
I would start by checking the plugs and their gap. It will stumble with the gap too wide-->after time they seem to get this way. You can also measure the resistance across the coil packs. Wires go bad as do the coil packs.
vacuum:
Ground C17 (for a 95 at least) on the back of the ECM and watch the secondary actuators open. Do it with the car not running and running (will set a code-->vacuum present when not commanded). This will tell you the relative health of both banks of secondaries.
Ted
Is the stumble under part throttle/tip in or wide open throttle?
Did it pull all the way to 7000 rpms?
Are any codes (DTCs) set?
Does the secondary vacuum pump run?
Here's the vague answer you didn't want--without any of the above answers:
fuel:
I would pull the primary fuel pump fuse and start the car. It should start, run then die after a few seconds. Both pumps are powered on startup and the secondary cuts off after x time. What is the pressure at the rail? Also, could be a bad filter.
Injectors can be tested on the car--best when hot. Go to Marc Haibeck's www.zr1specialist.com
spark:
I would start by checking the plugs and their gap. It will stumble with the gap too wide-->after time they seem to get this way. You can also measure the resistance across the coil packs. Wires go bad as do the coil packs.
vacuum:
Ground C17 (for a 95 at least) on the back of the ECM and watch the secondary actuators open. Do it with the car not running and running (will set a code-->vacuum present when not commanded). This will tell you the relative health of both banks of secondaries.
Ted
Didnt try past 3800 RPM,s for I didnt like the feel.
No codes.
Waiting on my manual I just purchased to do the rest.
Intermittenent though which led me down the Injector side. Will check the next items in the days to come. Thanks again for the info and any other ideas please. Love the motor, just not familiar with it like my L98.
