engine running troubles

[bluebronco69]

Been having troubles with my dads bronco lately.
72 with the 302. we converted to a C4, was a 3spd.

he was out driving the other day, it started running worse and worse, got off the hwy into town, would barely idle. AAA tow home.

at home he tried my holley TA 470 from the 69 bronco with 302. same running issues.

here is the scoop on his.

new points, condenser, plug wires, and plugs, cap is newer but no carbon tracks. new fuel pump, and the fuel filter right before the carb was clean and free of debris (plastic in line unit) it has an edelbrock 1460 i think? he did a gasket kit on it. he also tried the coil off of my 69, no change. timing light shows consistent spark for each cylinder.


any ideas out there? was running well previously...

electrical issue? it stumbles and will barely idle, and wont move around. anything to try

 

[broncnaz]

Possible vacuum leak may want to check the intake manifold bolts make sure they are still torqued properly. Have the points gap been double checked? maybe the condensor is bad. check to see how strong the spark is if its a nice big spark then its probably good.

 

[bluebronco69]

checked for vacuum leak at the carb base, but not the manifold bolts, will check those. will check spark too.

 

[66 Bronco Dave]

check vacuum at trany vac line

 

[bluebronco69]

ok some more info from dad

he also tried spraying starting fluid down the carb while it was running to see if there was a low fuel issue, or something like that, it didnt hardly affect the way the engine ran with either carb.

also when he put my TA470 on his bronco (i have a manual transmission) he did not hook up the vacuum line to the transmission, so that is not the cause either.

could the voltage regulator or alternator be suspect? could they cause fluctuations in the charging/ignition system that would greatly affect spark?

 

[broncnaz]

Doubtful its a charging system issue. If you had issues cranking the engine and the battery was pretty much toast then yes but otherwise points dont take much power to run unlike computers.
Any new valvetrain noise's. might have a stuck valve or two.

 

[Justafordguy]

Change the points and condenser. I have had "new" points/condensers leave me stranded several times.

 

[Dannyboy71]

Could he have accidently used a wrong gasket from the kit or installed one the wrong way? I did this on a jeep I had it ran but not well. Took it to a shop they tore it back apart and showed me I had used one wrong gasket from the kit. It all lined up but had an extra hole in it!

 

[blubuckaroo]

Have you checked the supply of fuel to the carb? Maybe plugged tank screen.

 

[bluebronco69]

havent checked fuel pressure, but there appears to be enough volume, the clear filter is full and clean.
the carb rebuild was a while ago (5 months?) but he should have the parts still maybe it had extras in the kit, will check, but this was more of a running fine and now not so much.

i think he had a spare condensor to try also

 

[galen1970b]

check for a loose wire on your ignition system...ballast resistor if you have one.....I had a loose wire and it was heating up the screw super hot making the ignition system not work...would driv ok for a few miles..then after it heated up power would drop off....then it would die....after 20 minutes...would fire right up....then rinse and repeat....

 

[bluebronco69]

turned out to be the condensor! all is well now!
thanks for the tips guys

 

[bluebronco69]

turns out bad voltage regulator was letting the alternator dump 15+ volts into the system and burning up the condensor.
new condensor, new voltage regulator and all is well...

 

[Justafordguy]

Glad to hear you guys found the problem. Be sure to keep spares in the truck from now on.