problem with 87 running
Thread Starter
Instructor
Joined: Nov 2003
Posts: 129
Likes: 0
From: Ringgold GA
problem with 87 running
I am having problems with my 87. It idles very rough and will not take any throttle, if you unplug the alternator it idles perfect and the throttle resonse it great.
I replaced the module, distributor cap, rotor, coil, spark plugs, egr valve, and computer and also checked fuel pressure which sets steady at 45 psi with the vacuum line unhooked then checked all the fuses in the fuse block and checked the fuseable links near the battery before finding that if I unplug the alternator it ran perfect so I replaced the alternator thinking that would be it and it does the exact same thing.
Any ideas what to check or try
Please help
I replaced the module, distributor cap, rotor, coil, spark plugs, egr valve, and computer and also checked fuel pressure which sets steady at 45 psi with the vacuum line unhooked then checked all the fuses in the fuse block and checked the fuseable links near the battery before finding that if I unplug the alternator it ran perfect so I replaced the alternator thinking that would be it and it does the exact same thing.
Any ideas what to check or try
Please help
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
Stop just throwing parts at it, get a FSM do the tests for your running condition. Do you have any codes? Try cleaning your IAC, TB and MAF that costs about $10.00 for a couples cans of cleaner. Also check the volts on your TPI should be .54 at idle and increase smoothly as you open the TB.
Thread Starter
Instructor
Joined: Nov 2003
Posts: 129
Likes: 0
From: Ringgold GA
Thanks for the input guys, I found the problem. It was the Mass Air Flow sensor, it had shorted out somehow and was backfeeding through the electrical system, You could unplug the alternator and it would run fine or unplug the Mass Air Flow sensor and it would run fine in the driveway.
Hope this helps someone else...
Hope this helps someone else...
