79 bronco runs for 15 min then dies volts drop 10

[my bronco dont get stuck]

after driving my79 bronco 351m for 15 minute engine starts to sputter, volts dropped to 10 goes back up 13 14, stalls @ stop but refires wont stall on throttle runs rough. new distributor, coil, optima battery, had alternator boosted to 90 amps, stock ignition box, all electical works lights etc. had truck dynoed no vaccuum leaks.

has any one had this problem? could it be fuseable link? voltage reg.? ready to give up & rewire truck

does anyone know ? or give me idea

 

[muddrivermike]

sounds like either a misfire or a coil going bad

 

[J&SBroncolvrs]

check your connection to your voltage regulator, see if it's corroded at all. That plug connection can cause alot of greif if it's bad. If you have never looked at it, it's bad lol.

 

[my bronco dont get stuck]

check your connection to your voltage regulator, see if it's corroded at all. That plug connection can cause alot of greif if it's bad. If you have never looked at it, it's bad lol.

thank you i will check it

 

[BLADE262US]

Might check the stock box your using for excessive heat and maybe swap it out I have had that happen run good till it got hot then quit . /emoticons/[email protected] 2x" width="20" height="20" />

 

[my bronco dont get stuck]

Might check the stock box your using for excessive heat and maybe swap it out I have had that happen run good till it got hot then quit .

thank you we tryed swapin out the dura spark box the coil still the same thing i think we wave a bad wire going to try a jumper wire to the coil next duncan

 

[79RAGTOP]

CHECK GROUNDS FIRST THEN COIL CONNECTIONS GOOD LUCK SOUNDS LIKE A P.I.T.A.

 

[Seabronc]

I do believe that you have a Duraspark II system in that truck, correct? If so, the pickup inside the coil has a reputation for shorting out as the engine warms up. It is sort of like someone turned the key off for you. When the engine cools off, it starts again and runs for a while and then as the engine warms up it quits again.

I don't believe that it is your alternator since the engine should be able to run off a good charged battery for quite a while before draining it down to the point where the engine would quit. Ground for the ignition system is through the surface contact with the block and the hold down bolt.

If you replace the pick up, be careful, there is a roll pin that holds the armature in place on the shaft, don't loose it. Also there is a small E-clip holding the vacuum advance diaphragm rod to the pick up (stator assembly).

Good luck,

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