Ok, well it's not that bad, but you get the idea. 1986 F150 with FI302 and eecIV. Sometimes when you go to start it will crank and crank for 5 seconds or so before it finally fires, and when it does it sputters to life, not roars to life. Other times it starts normally, no matter hot or cold, morning or night, whatever, basically sometimes it's ok and sometimes its not. The next thing is that sometimes i have a problem with it stalling out if you slow down rapidly, or go around a corner quick, (stick shift) so it's when the cluch is in, like in neutral that it stalls, not in gear, and you can hit the key and it will start right back up. Recent plugs, new wires, cap rotor, put a bottle of gumout in it, cleaned the throttle body with 2+2, nada. any ideas? I was thinking weak coil/spark?

 

check and see if your vacuum advance is clogged up (actually im not sure if it has vacuum advance) did you gap your plugs....and with the startin problem its sound like your fuel pump is about to go out...but im not sure.. but if its carberated then it will sputter till the engine picks up enogh speed to effevctively work the feul pump..if that doesnt help get up with me and ill get you to try somethin else

james



ps make sure yor wires are cross firing or anything ive never had this problem b4 so id have t otrouble shoot it before i could tell you anything

 

sorry dude i dint read your post good. Im guiessin FI 302 means fuel injected..so it could still be the fuel pump or maybe its just a clogged injector or somethin...anyways..sorry bout the screw up

james

 

one more thing...lol fords are notorious for mass air flow sensors our 93 gt did aboutthe same thing (with the corners and the slowin down and stuff) it was meesin the fuel all up i just though about it when i re read my post lol.. see i love modern technology...you never know what in the hell is wrong....



james

 

Hi, thanks for the reply and tips. It is fuel injected. I know what you mean, I love the computer too My 67 'stang's 302 with a dual point ignition and holley starts better hot or cold and runs just as good all the time. I doubt the fuel pump is going out, the truck is old but it's low miles. The plugs were gapped to specs (.045 or so i think) and I don't think there is a vacuum advance, but I'm not sure (it's hard to see the distributor down there under all the crap!) I'm thinking a sensor is clogged or something. I'll have to look into the mass airflow sensor like you said. My buddy had a similar problem with his chebby and it was the O2 sensor, but you never know with 2 different brands of computer controlled vehicles. I was suprised at how much crap I cleaned out of the throttle body, but it didn't help any. I hate to just go and take things apart and clean/replace them for no reason. I'm thinking I'll try another bottle of injector cleaner (it's been a few months, and it helped before) and see where it goes. I didn't bother pulling codes, but I doubt it would give me any anyway. Like I said, it isn't that horrible that the computer probably even knows anything is wrong. Maybe it's something worth checking though.

 

'86 doesn't have a Mass AirFlow sensor (MAF) - it uses the Manifold Absolute Pressure sensor (MAP) mounted to the ventilation box above the R exhaust manifold. Buy a $12 Haynes manual and read the Fuel & Exhaust chapter. It explains how the EEC-IV EFI system works, and how simple it really is. It also tells how to test each sensor with a digital multimeter (DMM) and how to pull codes, but the code list sucks; mine is complete.

The most likely cause is the Idle Air Control valve (IAC) - do a search and you'll find plenty of posts describing it. You can see it in the GP Auto pics album in my signature link. They cost $30-60 and are easy to replace, but you have to pull the throttle body on V-8s.

 

you guys know this stuuf like the back of your hands...i have to have thevehicle sitting in fronmt of me to tell you what its got lol..anyways i guess that just comes with age and experiance..anyways....later


james

 

Hey, thanks to both of you. I think you pointed me in the right direction. Come the weekend (or next weekend, or... well, you know how it is) I'll read up in my manuals and maybe, (with a little luck ) I'll get to take some stuff apart! As long as it dosn't have to come too far apart anyway! My truck likes to fight with me when things have to come off.