I have a 1987 f150 302 standard transmission i just put the entire wiring back up and i have no spark but heres the catch when i unplug the ECU i get spark but then i lose fuel go figure so what could be telling the computer to send the engine no spark its weird it sparks once then no spark with the ECU in place so something somewhere is telling the engine after the first crank to send no spark any suggestions or help would be great

Tom

 

What does "put the entire wiring back up" mean? Without knowing what that means I'd say test the TFI module. In fact, see what happens when attempting to start w/ the SPOUT (SPark OUT)plug removed. It most likely has to do w/ your "putting the wiring back up".

 

no ok its bin in a accedint .. but started after the accedint drove it 1k miles but then rebuilt the entire truck and i just fount out for some reason its not getting fuel im guessing the ecu relizes and says no spark but when i take the ecu plug out there is a constant spark but then again still no fuel is there a intertia switch besides the one under the dash mounted on the fire wall next to the colum now i know what your saying but i checked all my conections now if this helps the fuel gauge is not moveing from empty i fillled it up but not readin im in a strugle lol the truc starts with the ecu and manualy pouring fuel down the intake but of course dies so some reason ether thers a switch telling the fuel pump to not pump or its broken or something is wrong im going to put the volt meter on it tomarow to see if its gettting power before it wasnt makeing noise wile i cranked it so idk whats teling it to not pump but yeah

thanks Tom

 

Any chance you plugged the PMC relay into the Fuel pump relay connector and visa vera? They're mounted right next to each other. It ran before the rewire?

 

PMC is that the same as the ecu and i cant find the fuel pump relay where is this located

 

yes it ran before the rewire but if posible could you give a diagram of what your saying or a picture

thanks Tom

 

ok i think i got it the ecu relay was missing and i hot wired it useing a diagram but before the rebuild i dont recall it ever haveing one so what would explaine it running before and not now?

 

Good possibility! The relay serves a purpose. You might not have a working ECU anymore. You should have a fuseable link for that circuit too. PCM = ECU. I have the same year,engine & truck. Both of the relays on mine are located, mounted on the backside of the air filter housing, within an inch of each other. The relays are not interchangeable. The one for the ECU has a resister built into it. Although they look similar w/o popping the tops of them. Even then, you would have to know what a resister looks like. You can get them at the bone yard for a couple of bucks a piece.

 

hmmmm but what would explaine why it ran without the relay but now all of a suden it needs it . . . i jumped the relay and it started the reason it wasnt before was because of no fuel now it pumps fuel and continueus spark so posibly it was hot wired originaly and i didnt know it and its a brown plug correct left fender next to the fuel relay now could i just buy a new one instead

 

Yep.