hi guys i just picked up a 87 gt convertable, in a trade. only problem is it was sitting for 7 years, and runs a little rough. well actually its skipping lol. i checked the spark plugs, and they were very black. i changed them, and it ran great for 5 mins. then started to skip again. i pulled the plugs and they were black again. that means it running too rich right? i dont know too much about working on cars, but i would really love to learn. does anyone have any clues to what could be causing the problem? any help would be great thanks
Since the car has been sitting for 7 years, I would drain the fuel system if you haven't already and replace the fuel filter, distributor cap & rotor and plug wires.
Check fuel pressure at the fuel rail. Fuel pressure should be 32# at idle and if you remove the vacuum line to the fuel pressure regulator it should increase to 40#.
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"Ignore that whistle, it's just a vacuum leak."
2000 Mustang GT:
Saleen Series IV Twin Screw, Chicane I/C, AFCO Extreme H/E, 2.8" pulley, FMS 42# injectors, Dual Catted 2 1/2" UPR X Pipe, UPR LCAs/UCAs, 2 1/2" Flowmaster American Thunder kit, 90mm LMAF, 112" Goodyear Gatorback, Kenne Bell BAP, Mosaleen idler, T-56, Detroit TrueTrac w/ 373s, Demolet 100mm CAI, SCT XCal2 with JDM Engineering 93 Octane "Race" tune.
Since the car has been sitting for 7 years, I would drain the fuel system if you haven't already and replace the fuel filter, distributor cap & rotor and plug wires.
Check fuel pressure at the fuel rail. Fuel pressure should be 32# at idle and if you remove the vacuum line to the fuel pressure regulator it should increase to 40#.
yes i already changed all that before i changed the plugs. how do i test fuel pressure?
It has been a while since I had my 89 LX 5.0, but if I remember correctly there was a schrader valve (like the tire stem valve) on the fuel rail with a cap over it. You have to get a special gauge to screw to it. Autozone or advanced will probably have this gauge to let you use at the store or rent if you don't want to buy one.
Where in NH? I used to live in Tuftonboro real close to where the movie On Golden Pond was filmed.
__________________
"Ignore that whistle, it's just a vacuum leak."
2000 Mustang GT:
Saleen Series IV Twin Screw, Chicane I/C, AFCO Extreme H/E, 2.8" pulley, FMS 42# injectors, Dual Catted 2 1/2" UPR X Pipe, UPR LCAs/UCAs, 2 1/2" Flowmaster American Thunder kit, 90mm LMAF, 112" Goodyear Gatorback, Kenne Bell BAP, Mosaleen idler, T-56, Detroit TrueTrac w/ 373s, Demolet 100mm CAI, SCT XCal2 with JDM Engineering 93 Octane "Race" tune.
It has been a while since I had my 89 LX 5.0, but if I remember correctly there was a schrader valve (like the tire stem valve) on the fuel rail with a cap over it. You have to get a special gauge to screw to it. Autozone or advanced will probably have this gauge to let you use at the store or rent if you don't want to buy one.
Where in NH? I used to live in Tuftonboro real close to where the movie On Golden Pond was filmed.
ok tomorrow ill go and get the guage. i live in Salem. its south on the MA border. thx for the help
You're welcome, it has been a while since I worked on the 5.0, a buddy just bought one that we have been working over, so that might help me remember better.
__________________
"Ignore that whistle, it's just a vacuum leak."
2000 Mustang GT:
Saleen Series IV Twin Screw, Chicane I/C, AFCO Extreme H/E, 2.8" pulley, FMS 42# injectors, Dual Catted 2 1/2" UPR X Pipe, UPR LCAs/UCAs, 2 1/2" Flowmaster American Thunder kit, 90mm LMAF, 112" Goodyear Gatorback, Kenne Bell BAP, Mosaleen idler, T-56, Detroit TrueTrac w/ 373s, Demolet 100mm CAI, SCT XCal2 with JDM Engineering 93 Octane "Race" tune.
That could be caused by a bad regulator, injectors in need of cleaning, or lots of carbon buildup. I'd suggest having the fuel system flushed and this means taking the injectors off the car to have them cleaned. Running a bottle of cleaner through the tank won't get the job done.
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