carb swap/ wont start?

[import convert]

so ive been doing a carb swap on my 90 GM and today i got it to crank over and the motor is getting fuel but it wont start. im using a proform distributer which needs a switched 12v source but doesnt ask for a tach signal.

im begining to think that it may need a tach signal but im not sure till i try.

the other thing right now is my car is getting no power at all. like the interior lights wont even come on. the battery is new so i know its not that but the whole car doesnt get power. so now i need to find out if i blew a fuse/circuit breaker or something.

so im really stumped right now and its bugging the shiz out of me. i want to get the car runnign by the end of hte month but at this rate idk when itll be runnign. thanks guys.

[86VickyLX]

so ive been doing a carb swap on my 90 GM and today i got it to crank over and the motor is getting fuel but it wont start. im using a proform distributer which needs a switched 12v source but doesnt ask for a tach signal.

im begining to think that it may need a tach signal but im not sure till i try.

the other thing right now is my car is getting no power at all. like the interior lights wont even come on. the battery is new so i know its not that but the whole car doesnt get power. so now i need to find out if i blew a fuse/circuit breaker or something.

so im really stumped right now and its bugging the shiz out of me. i want to get the car runnign by the end of hte month but at this rate idk when itll be runnign. thanks guys.

are your battery teminals and cables clean and tight? And is your timing right? Could have it turned 180*. Gotta verify you have spark.

[gadget73]

the tach connection is output to a tachometer. Its not necessary for the motor to run. Do you have spark? Do you have +12v at the connector while the engine is cranking? Fords usually lose +12v while cranking unless you use the I terminal on the starter relay to provide that power.



If you have no power inside the car, you won't have ignition. Check the fuse links at the starter relay.

[import convert]

right now i got one of those fuse jumpers so the +12 source is coming from the fuse box. when i put the motor together i had the dot on the cam gear pointing down and the point on the crank gear pointing up. i hope thats right. i could try and move the power source to the starter relay though.

[1987cp]

So far so good. I'd suggest for testing purposes to run a switched +12V directly from the battery. Some 12-gauge and a toggle switch will do the trick. I often do that when making changes to how the power gets to my ignition system, and it eliminates any other possibilities so you can focus on getting the engine running. Once you know the engine is running OK, then it's a lot easier to focus on wiring the ignition how you want it, whether the alternator is charging, etc.

[import convert]

well my problem is that nothign in the car is getting power. i had to make a new starter wire but the connection was lose at the starter solenoid cause i didnt crimp it enough. so i heard it spark and then it all shut off. now i need to find the fuse links in this POS and see if i blew them. but yea i was thinking bout hooking it to the battey to make sure i get power to the dizzzy.

my other question though is if i could change the fuse links out for an in-line fuse though?

[1987cp]

Quite possibly. I don't know offhand how much current the fusible links are designed to handle, but I imagine it could be quite doable to replace them with even a little aftermarket fuse box on the inner fender, so long as you can buy heavy enough fuses in the size you choose. For my alternator charge wire, I actually bought a big "Mega Fuse" at AutoZone that just attaches inline at the starter solenoid and is rated at something like 125 Amps.

[import convert]

well the weird thing now is while trying to find all the links, or at least try to find what i thought were the links, the interior lights came back on and shit. i tried to crank it over and it just lost power again to the whole car. now im wondering if the car has a circuit breaker somewhere to save the computer or somethign. but now im back to where i started and i dotn want to go buy new links and change them if i dont have to. im so lost right now.

[gadget73]

the fuse links are right at the starter relay. no need to look for them.

if you have intermittent lights, you have a bad connection. Its not a breaker. Fix the electrical problem instead of trying to rig wiring around it.

[1987cp]

Fix the electrical problem instead of trying to rig wiring around it.

Sorry, my idea was to try to isolate the no-run problem first and then investigate the no-electrical problem.

Wait ... Barry, did I just read something about a computer? Oh wait, I think I read that wrong ... you were talking about a theoretical vestigial remnant of the EFI system.

I assume you've removed and cleaned all the connectors at the starter solenoid?

[import convert]

no, no no. i still have most of my wiring harness in tact. the collant temp sensor is gone, the fuel injector harness is gone. all the rest of hte stuff is still there and hooked up.

my problem was that i had a loose connection going from the stater solenoid tot he starter itself. the motor was cranking over but not starting. i tried it again and i heard "zap" like when you connect hte negative connector to a battery and hten nothing worked. after like 2 hours of trying to figureout what heppened the lgihts came back on so i tried to crank it over again and it all died again.

so now i have no idea what could be wrong. i dont know if its a loose wire somewhere or if i actually damaged something. the only thing im using the ecu for is to run the fuel pump and the gauges and stuff. but yea im just confused right now and im gonna shoot myself in the but if all it is is a loose wire.

[gadget73]

I say put the fuel rail back on and leave the EFI alone, or completely remove it and the wiring and make it a proper carb car. the ecm will not run the fuel pump without signal from the stock distributor, and you should not be using that distributor with a carb because it won't have any sort of advance curve.

[1987cp]

x10,000 on ditching every last remnant of EFI wiring. BTW, how did you decide to provide power to your electric fuel pump?

[import convert]

well idk but im still getting fuel from the pump. the distributer has vacume advance on it and builds its own tach signal and whatnot. now if i ditch it all then i need to put in a carb sending unit and wire in an external electric fuel pump or i use the stock pump and put it on its won circuit with a toggle switch like they do in nascar and shit

now if i take out all the wiring am i still gonna have the interior lights? im guessing ill have to cut out some wires and save others

[1987cp]

You'll keep your interior lights as long as you keep a way to power them. If you haven't already, this might be a good time to start cutting apart wiring harnesses and running about with a test light or multimeter to see where stuff goes.

I'd forgotten you're still trying to use a factory EFI fuel pump with an aftermarket pressure regulator. One reason I like having a mechanical pump is because it's more simpler to get the engine running.