choppy accelleration... - ZR-1 Net Registry Forums

pig_iron · 09-09-2005

What started out as a little hesitation after shifting gears has become a full onslaught of choppy, jerky accellerating. Stepping on the gas displays a very rough ride and I can even feel a little wobble under the gas pedal. I ran a fuel system cleaner through it and it only seems to have gotten worse. Could this be a bad injector(s)?

tomtom72 · 09-09-2005

Do you know where the MAP sensor is? Did you check the vacuum hose on it to make sure it is still attached? At the middle of the plenum at the fire wall you see the round black thing = Fuel pressure regulator, look more to the center, just along side the regulator and you see a brushed alunimium bracket & cover plate. That's the MAP bracket & cover. It's tight over there. The hose is under that and it goes to a port on the plenum, the port is more to the passenger side of the plenum. If it falls off the motor runs bad.

Do you have any codes? Do you have the Helm manual? If you have the manual do the fuel system pressure test. I have a 90 so in my Helm the "driveability & Emissions" section is 6E. The charts and the text describes various compliants. Yours sounds like it could be "cuts out & misses" or "rough, unstable, or incorrect idle, stalling".

Did you pull the plugs? Did you check for spark? Check the MAP hose first.
Listen I'm a rookie Z owner & don't know much but the MAP thing comes up the most with your symptoms from the members that really know these cars.

Tom

09-09-2005	#1
pig_iron Join Date: Jan 2005 Posts: 22	choppy accelleration... What started out as a little hesitation after shifting gears has become a full onslaught of choppy, jerky accellerating. Stepping on the gas displays a very rough ride and I can even feel a little wobble under the gas pedal. I ran a fuel system cleaner through it and it only seems to have gotten worse. Could this be a bad injector(s)?

09-09-2005	#2
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Do you know where the MAP sensor is? Did you check the vacuum hose on it to make sure it is still attached? At the middle of the plenum at the fire wall you see the round black thing = Fuel pressure regulator, look more to the center, just along side the regulator and you see a brushed alunimium bracket & cover plate. That's the MAP bracket & cover. It's tight over there. The hose is under that and it goes to a port on the plenum, the port is more to the passenger side of the plenum. If it falls off the motor runs bad. Do you have any codes? Do you have the Helm manual? If you have the manual do the fuel system pressure test. I have a 90 so in my Helm the "driveability & Emissions" section is 6E. The charts and the text describes various compliants. Yours sounds like it could be "cuts out & misses" or "rough, unstable, or incorrect idle, stalling". Did you pull the plugs? Did you check for spark? Check the MAP hose first. Listen I'm a rookie Z owner & don't know much but the MAP thing comes up the most with your symptoms from the members that really know these cars. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member Last edited by tomtom72; 09-09-2005 at 08:44 AM.