1992 Geo Metro 1992 Geo Metro Lurching/Stalling

Tiny
DICERMAN95
  • MEMBER
  • 1992 GEO METRO
Engine Performance problem
1992 Geo Metro Front Wheel Drive Manual 90000 miles

I recently bought a 1992 Geo Metro. It has a 3 cyl motor. The fuel pump is brand new as well as the fuel filter. It also has a new timing belt! When the car idles sometimes it will idle fine then other times it will try to die. The main problem is when you get it driving at about 20 mph or right around there it will stall or lurch. Then it will pick back up again the do it again. Seems that for some reason it is cutting either power or fuel to the motor! I have removed the battery and it made no difference. But when I went to plug the battery back in it puts the motor under a load at idle. Im stumped.
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Saturday, May 31st, 2008 AT 4:41 PM

9 Replies

Tiny
MASTERTECHTIM
  • MEMBER
Disconnecting the battery on a running vehicle will damage vehicle. Under no circumstances should the battery be disconnected. It sounds like your losing fuel pressure. Do you have access to a fuel pressure gauge that you can install and drive vehicle? Id start there. Are you sure its not misfiring, like losing a spark plug intermittently? These cars need spark plugs changed alot more frequently than other cars.
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Saturday, May 31st, 2008 AT 7:17 PM
Tiny
DICERMAN95
  • MEMBER
I could try that! But I am totally sure that it is not misfiring. I took the plugs out yesterday and they are new plugs gapped right and everything! It acts as if there may be something cutting off feul or electricity to the car! It will stall then pickup and then stall almost as if it were running out of gas!
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Sunday, June 1st, 2008 AT 9:32 AM
Tiny
DICERMAN95
  • MEMBER
I checked the pressure and it holds between 20 and 23 psi constantly at idle or driving. It also maintains the pressure during its stalling! It will spike up a little if you accelerate hard!
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Sunday, June 1st, 2008 AT 1:09 PM
Tiny
MASTERTECHTIM
  • MEMBER
Does the check engine light come on? this is a odd duck vehicle but i worked for chevrolet when they were new and im trying to remember any odd problems. one thing i remember is the map sensor and the vacuum line going to it was usually the only problem i ever found with this car. check it out and get back to me


http://www.2carpros.com/forum/automotive_pictures/139033_ac_4.jpg

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Monday, June 2nd, 2008 AT 10:47 AM
Tiny
DICERMAN95
  • MEMBER
The check engine light does not come on! I checked and cleaned the egr valve and it it working now! I also checked the map sensor and it is functioning also! I have noticed while driving it it will do the stalling when you hold the accelerator steady. If you accelerate or slow down it does not stall. Seems to be at around 2000 rpm. I wonder about the throttle position sensor? Upon futher investigation I see that the injector is cutting off fuel when the stall occurs. It also wants to stumble when you first start it!
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Tuesday, June 3rd, 2008 AT 1:03 PM
Tiny
DICERMAN95
  • MEMBER
Im still patiently waiting!
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Thursday, June 5th, 2008 AT 5:13 PM
Tiny
MASTERTECHTIM
  • MEMBER
Sorry I missed your repost. Tps is a possibility, you caan check the voltage of the tps and see if it drops out at the steady throttle, also how did you check the map sensor and did you check the vacuum supply and volume? And its losing injector pulse not fuel pressure correct?
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Friday, June 6th, 2008 AT 6:28 AM
Tiny
DICERMAN95
  • MEMBER
I checked the map sensor by first taking it off and inspecting the vaccum line itself it was fine! I then pluged it back in to make sure there was vaccum and there is. Then I unpluged the sensor while the car was operating and it made a significant difference! I also checked the tps and it was not the problem! The fuel presure is remaining at about 20 psi but the injector stops the pulse.
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Monday, June 9th, 2008 AT 12:15 PM
Tiny
MASTERTECHTIM
  • MEMBER
I have looked through all my data and there is nothing else thats pops out. What needs to happen now is to drive vehicle with a scan tool and watch data to make sure the o2 sensor is functioning properly. For instance if the o2 sensor gives a rich reading to the computer, the computer will lean out the injectors trying to make the o2 sensor switch to lean and if the o2 is bad it will make system run full lean. Also spark output voltage needs to be checked. Making sure not weak spark
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Tuesday, June 10th, 2008 AT 9:08 AM

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