79 Bronco will not start

[79broncoboi]

my 79 Ford Bronco has been going thru Ignition Coils, replace 3 now, they are overheating engine wont start, can cool off with ice water, engine fires right off, now the problem is engine turns over but wont start, i have replaced coil, spark plug wires, starter solinoid, battery, distributor cap, voltage regulator, took my Electronic Ignition Module to o'rielly's and auto zone and it tested good, any sugesttions? <BR><BR><STRONG><FONT face="Microsoft Sans Serif">Well it turned out that my timing chain jumped, had timing chain set replaced , water pump , harmonic balancer was worn, so replaced that, replaced fan clutch, runs good now.</FONT></STRONG>

 

[Bully Bob]

Hi 79.., welcome...!

1) Pull a plug wire & short to ground.. i.e. see if it sparks.., if so.......

2) Dribble some fuel down the throat of carb.., If it lites up...there's your prob. (fuel pump, float/needle & seat, filters, plugged fuel line, bad fuel switch-over valve, etc.) >< <'>

 

[79broncoboi]

Hi 79.., welcome...!

1) Pull a plug wire & short to ground.. i.e. see if it sparks.., if so.......

2) Dribble some fuel down the throat of carb.., If it lites up...there's your prob. (fuel pump, float/needle & seat, filters, plugged fuel line, bad fuel switch-over valve, etc.) >< <'>

Thanks

I will try the plug wire to ground, i have tried the dribble fuel down the throat of carb, still wont lite up..

 

[Bully Bob]

If you have "go-juice" & spark..., & it still won't fire., it could likely be out of time., or jumped time at the timing chain.

Also., there should be voltage at the + side of coil, with key on.

Do fill-in your info. page so as to rec. more accurate help.... >< <'>

(see at the bottom of my post...it shows ev. post & can be up-dated)

 

[79broncoboi]

If you have "go-juice" & spark..., & it still won't fire., it could likely be out of time., or jumped time at the timing chain.

Also., there should be voltage at the + side of coil, with key on.

Do fill-in your info. page so as to rec. more accurate help.... >< <'>

(see at the bottom of my post...it shows ev. post & can be up-dated)

i checked the spark plug to ground only sparked once out of 6 times

 

[79broncoboi]

i couldnt find the fill info at bottom of post.

my bronco is a 1979 xlt bronco, 351m engine, factory air, power steering, factory a/c, cruise control, only thing i have done is removed the smog pump, evertything is stock

what else do you need?

 

[79broncoboi]

when ignition key is on, i have 12volts at pos side of coil

 

[Elmo]

poss the pickup in the dist not triggering the coil to fire

 

[Bully Bob]

No.., you click on your name at the top right of this sites home

page ..then "profile" or "change profile" then "signature".

When your done...it ends up at the bottom of YOUR posts, every post.

There's also a "help" button that will walk you thru. It's no biggie.., it justs takes out a lot of guess work & ultimately helps YOU.. /

Not sure.., assume that yr. has elect. ignition. If not., there should only be 6v at the coil @ a ballist resistor.

Elect. ign., then 12v is good..!

Un-clear @ how did you count the sparks..? One plug wire pulled & held close to ground...would spark 1 out of 8 times for an 8 cyl. eng. but I wouldn't know how to count that fast with eng. cranking..

Another way, would be to nearly ground the coil wire & crank eng. This way, there would be/should be rapid/consistant sparks.

At the end of the day.., if you're getting spark., & fuel., & still won't light up!....then timing would be suspect.

BTW did you try moving throttle by hand (key off) while looking down carb. throat & observe fuel squirting via the accel. pump..?

Also., check volt. at coil while key is turned to "start" to be sure the voltage isn't going away inside the key-switch. (prob. need a helper)

Elmo just hit on another possibility...the Ford Duraspark is known for that..!!

Does that yr. have the "black-box", for the ignition, under the hood somewhere..? Seems they've been known to fail as well..?

 

[79broncoboi]

ok i nearly grounded the wire from coil to distrubtor, got rapid fire, i replace my rotor and my pickup coil, engine still wont fire, only thing i havent replaced is spark plugs and Electronic Ingition Moduel. The bronco ran fine up until a week ago when the coil overheated, I tested ignition module at orielly's and autozone, they said it was fine. I am at aloss here. think i might replace the ignition module to see if it is the culprit even tho it test good.

 

[79broncoboi]

ok i nearly grounded the wire from coil to distrubtor, got rapid fire, i replaced my rotor and my pickup coil, engine still wont fire, only thing i havent replaced is spark plugs and Electronic Ingition Moduel. The bronco ran fine up until a week ago when the coil overheated, I tested ignition module at orielly's and autozone, they said it was fine. I am at aloss here. think i might replace the ignition module to see if it is the culprit even tho it test good.

Replaced my Electronic Ignition Module, still has not fixed my problem,

 

[Bully Bob]

Curious.,

What lead you to believe the coil overheated...?

Don't see where you checked the timing...

All the plugs wouldn't quit at once, however, you could pull 1 or 2 & have a look. OR, pull them all & clean them.

 

[79broncoboi]

Curious.,

What lead you to believe the coil overheated...?

Don't see where you checked the timing...

All the plugs wouldn't quit at once, however, you could pull 1 or 2 & have a look. OR, pull them all & clean them.

the coil would be so hot you could not touch it, plus the engine would not start or would die, if i cooled the coil with ice water the engine would start .

i have not checked timing, would the timing go out that quick?

 

[Bully Bob]

"i have not checked timing, would the timing go out that quick?""

YEP.... especially if it jumped a tooth or two on the timing chain.

Just do the basics.., put #1 cyl. at top dead ctr. on compression stroke., then look to see if rotor points to #1 on the dizzy.....

You can also, check the chain slop by turning the crank (key off.!) by hand (back & forth) while watching the rotor.

HTH

B