86 Bronco

brownbeaver · Feb 26, 2004

put a new long block in my 86 ford bronco (302, 5.0) got it all back together replaced all the necassary stuff. now it will start right up but it won't stay started for more than a few seconds

Gunner · Feb 26, 2004

oh geeze that could be so many things. if it is carberatored like mine than that may need adjusting. you may need to bleed the fuel lines. if it is EFI than you may have your wires crossed so it is misfiring. you may have a bad distributor, bad wires. oh my god i just cant tell you how many things it could be unless i saw it myself. but those are just a few possibilities

brownbeaver · Feb 27, 2004

its EFI, has new wires, plugs, new cap and rotor all tune up stuff has been replaced..... the wires aren't crossed if the timings off i would think it would stay started but run like crap.... i've asked everyone whats wrong with it and still won't stay started for more than a few seconds but yet it cranks right up..... thank you for any help

azrockrat · Feb 27, 2004

check your coil

Stomper4x4 · Feb 27, 2004

Check for a good strong spark and make sure the timing is close. After that, sounds like a fuel delivery problem to me.

Gunner · Feb 27, 2004

yes i agree. and as far as it staying started and running like crap it depends on just how far the timing is off. it could be just a little and run like crap or could even be 180 out and not run for shit. but the battery power and starter will be enough to get it going but when the spark takes over it fails.

shaun94 · Feb 27, 2004

It may sound stupid but check you're mass air flow sensor, It might not be hooked up or it could be broken.

Gunner · Feb 27, 2004

hey shaun please dont take this in a bad way but he probably doesnt have a MAS i am also carberated and that takes away the whole air box concept. my air cleaner sits right on top of the carb. i could be wrong though he may have a different set up. i just know i have virtually no electronics in my truck other than the things i put in.

brownbeaver · Feb 27, 2004

i said i thought it would still run if the timing was off but run like crap.... it's not running for long enough to tell what it's running like....it only runs for a few seconds then cuts right off.... thank you for all the replies even though it's not started yet it still helps

brownbeaver · Feb 27, 2004

has a new coil it wound't start at all until i put in a new coil

Gunner · Feb 27, 2004

damn dude i am out of ideas unless i saw it and listened to what it was doing.

Txquadhunter · Feb 27, 2004

try turning your key on for seconds and off. do this 5 or 6 times to see if your fuel pumps are building good pressure. if it stays running longer by turning key on and off then starting it. it's in your fuel system. the relay on the driver side firewall under the hood, high pressure fuel pump on the driver side frame rail almost right under the drivers seat or the low pressure pump in the tank. also see if your computer is throwing any error codes. this link will show you how.

http://www.therangerstation.com/OBD_I.html

highboy73 · Feb 28, 2004

when it dies leave the ignnition on and check to see if you have power at the coil,module,fuel pump,pump relay,check evrything for voltage after it dies.
there should be a sharder valve on the fuel system somewhere it looks like a tire valve check for pressure there when it cuts off.
are all your grounds hooked up?all of them even the hard to get to ones?
break out the multimeter and start checking it's free,and everybody likes free.
i'm no super mechanic but sometimes a little testing will save you alot of time and MONEY.
if you have to go buy a book from idiotzone,it'll tell you how to test everything.find out and let us all know

amcabbott · Feb 29, 2004

sounds like a bad vacume leak around the intake or carb-throttle body plate try checking by spraying wd40 around everything while it is running if it revs up you found your leak (wd40 will not blow up like starter fluid if you hit a hot spot or an arcing wire). could be timing a tooth off when the chane was put on would do this also. to check take valve cover off,bring #1 to top dead center and check to see if the valves are seated.could use a compresion tester also if ya got one. :-&

copedonn · Mar 8, 2004

i forgot to put the fuel wheel on the front of the cam one time and it stayed running as long i keep pouring gas in the carb.

DanaDRD · Mar 8, 2004

I had a very similar problem on my 89 Mustang 302 EFI. My problem no tachometer signal >>> This is what I learned >>> With KOEO (Key On Engine Off) the computer will run the fuel pump for approximately 5 to 8 seconds to pressurize the fuel injectors then turn off. Your injectors now have about 40 psi of fuel pressure just enough fuel to start the engine but not keep it running. The engine cuts off because the computer is not turning the fuel pump back on-------the computer is looking for at least 200 rpm from the tach signal ( PIP signal) before turning on the fuel pump and keeping it on. Now if you move the key to off then back to KOEO the pump will start again for only 8 seconds pressurize the injectors and run the engine very briefly.

The computer not seeing a tach signal can be caused by several factors including a bad PIP (profile ignition pickup) sensor, faulty wire between PIP and computer or maybe your not using your stock distributor (you need a PIP sensor).

Try this:
You can manually run your fuel pump by jumping the fuel pump power relay (located under the drivers seat on a Mustang). To manually jump the fuel pump relay pull the relay from its socket, locate the two LARGE spade blades on the bottom of the relay and jump the corresponding large spade blade positions on the relay socket using a large piece solid copper wire. This will run your fuel pump until you remove the jumper wire. By jumping your fuel pump relay (continuously running your fuel pump even with the engine off) and the engine starts and runs, then I would suggest your computer is missing a signal from your ignition system. Hope this helps-----Good--Luck

biggnat79 · Mar 8, 2004

I have an EFI 302 and when I pulled off the Air Bypass Valve to clean it, I forgot to reconnect the wire when I put it back on. The engine would crank no problem, but would die unless I kept my foot on the gas. Its the little stuff that always gets me.

Bronco_In_Ny · Mar 13, 2004

well Check Spark and Fuel Pressure, recheck all the connections, its easy to mis something. Will it run if you start it and then give it some gas or does it sound like its trying to run but just slumps out?

Guest · Apr 12, 2004

This might be too simple but , check and see if it has a fuel reset switch,
and reset it.

misti · Apr 17, 2004

brownbeaver said:
put a new long block in my 86 ford bronco (302, 5.0) got it all back together replaced all the necassary stuff. now it will start right up but it won't stay started for more than a few seconds

you should try adjusting the idle or the distributor cap if its all coroded then its not getting enough spark to stay running thats what happened to my car and i had to replace it cuz it was really bad