hesitation problem
Thread Starter
Advanced
Joined: Feb 2001
Posts: 98
Likes: 0
From: Houston, Tx, USA
Cruise-In III Veteran
hesitation problem
The 90 Z is hesitating when I get on the gas after shifting gears or when letting off the gas and getting back on it at cruise speeds. There is no check engine light on. After warming up it will die if I just tap the gas. It is almost like the engine looses all spark if you just barely hold the gas down at any speed. What the heck??? :confused: :confused: :confused:
Burning Brakes
Joined: Jul 2002
Posts: 1,050
Likes: 59
From: McLean Va
Re: hesitation problem (RatRacer)
Hi, I am having a simillar problem but motor does'nt die like yours. Your mention of dieing after warm up sounds like your primary fuel pump may be dead (ZR-1s have 2 pumps in the tank). Go to corvetteactioncenter.com ZR-1 section forum. There are a few threads that deals with fuel pump issues including how to replace fuel pump instead of spending $1400 for the entire assembly at the chevy parts counter.
Racer
Joined: May 2000
Posts: 300
Likes: 1
From: Syracuse, NY
Re: hesitation problem (HwyStar)
Have you pulled all the plugs? I would pull the codes from the computer. I had a similiar hesitation problem on my '92 ZR-1 and it turned out to be the left O2 sensor.
Racer
Joined: May 2000
Posts: 300
Likes: 1
From: Syracuse, NY
Re: hesitation problem (HwyStar)
Have you pulled all the spark plugs? I would pull the codes from the computer. I had a similiar hesitation problem on my '92 ZR-1 and it turned out to be the left O2 sensor.
Thread Starter
Advanced
Joined: Feb 2001
Posts: 98
Likes: 0
From: Houston, Tx, USA
Cruise-In III Veteran
Re: hesitation problem (Illiad)
The scan tool says (code 61 throttle secondary error) The car runs great wide open. I have had fuel pumps fail and I know that this is not the problem. The car simply runs great when getting on it and runs like butt when driving it normaly. Here is what it does. You crank it, it runs and idles fine. You just barely hit the gas and it dies no matter what the temp. It is almost like there is a dead point in the throttle. If you angle the throttle in at a certain percentage, it looses all spark or fuel (I checked psi and it looks normal at 45psi idle and almost 55-60 at 3500 rpm) I repalced the tps and the AIS (I think that is what they call the sensor on the other side of the tps) When getting on the throttle, it sometimes feels as if the power key is off and all of a sudden it kicks on. Help. Can not afford Corvettes of Houston to tinker with it at $60 to $70 an hour for a couple of days untill they find the BS problem. Thanks guys.
Pro
Joined: Jan 2000
Posts: 682
Likes: 0
From: DesPlaines IL
Re: hesitation problem (Daine Deaver)
Hi Diane
Check the scanner and look if you get a lot of knock retard.
Mine was doing same thing, it was picking up a lot of engine noise cause i had tightened the knock sensor too much and was taking out 20 degrees of timing and the car would die just driving it exactly the same way you say.
Let me know what you find.
Check the scanner and look if you get a lot of knock retard.
Mine was doing same thing, it was picking up a lot of engine noise cause i had tightened the knock sensor too much and was taking out 20 degrees of timing and the car would die just driving it exactly the same way you say.
Let me know what you find.
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Joined: Dec 1999
Posts: 10,230
Likes: 885
From: Alexandria, Virginia, USA VA
Re: hesitation problem (ZR1Pete)
check that the TPS voltage is working. a dead TPS will do this. also check the MAP. sounds like one of these two may be bad. a TPS with a "dead" spot is common. the computer doesn't know you are opening the throttle.
a bad vacuum leak could also cause a bit of stumble. good luck!!! :yesnod:
a bad vacuum leak could also cause a bit of stumble. good luck!!! :yesnod:
