Need help with a troubleshoot (fuel? Ignition?)

[GraficO]

OK... couple weeks ago drove the Bronco and picked up some gas. I usually put premium in but topped it off with 2.4 gal. of regular. Leaving the gas station the bronco was dogging out, trying to stall, backfiring but I got it home.

After assessing that the only thing that changed was the addition of a different fuel, I drained a couple gallons out, changed the fuel filters, removed the carb and drained the bowls (Holley 650), replaced the power valve, blew out the plates, checked the jets and the fuel screen where the fuel line attaches to the carb... no luck. It would run but would try to die when you gave it gas. Continued backfiring and running very rough.

Well... fuel system seems good... so let's look at ignition.

Took off the distributor cap and it looked like the contacts had a couple of chunks taken out of them and were worn due to the rotor screws being a little loose (Flamethrower II billet distributor). Replaced the cap and rotor, pulled all the plugs and checked/re-gapped them.

Put a timing light on the distrib/coil wire... constant steady lights from the timing gun. Put the timing light on each plug wire and all were inconsistently firing...

Thinking is that the Ignitor II module in the distributor is fragged... or the coil is toast (Flamethrower II)... or both and have a new Iginitor III module and a new coil on order from Wild Horses.

Any other thoughts or avenues to try?%)

 

[Broncmeister]

OK... couple weeks ago drove the Bronco and picked up some gas. I usually put premium in but topped it off with 2.4 gal. of regular. Leaving the gas station the bronco was dogging out, trying to stall, backfiring but I got it home.

After assessing that the only thing that changed was the addition of a different fuel, I drained a couple gallons out, changed the fuel filters, removed the carb and drained the bowls (Holley 650), replaced the power valve, blew out the plates, checked the jets and the fuel screen where the fuel line attaches to the carb... no luck. It would run but would try to die when you gave it gas. Continued backfiring and running very rough.

Well... fuel system seems good... so let's look at ignition.

Took off the distributor cap and it looked like the contacts had a couple of chunks taken out of them and were worn due to the rotor screws being a little loose (Flamethrower II billet distributor). Replaced the cap and rotor, pulled all the plus and checked/re-gapped them.

Put a timing light on the distrib/coil wire... constant steady lights from the timing gun. Put the timing light on each plug wire and all were inconsistently firing...

Thinking is that the ignitor II module in the distributor is fragged... or the coil is toast (Flamethrower II)... or both and have a new Iginito II module and a new coil on order from Wild Horses.

Any other thoughts or avenues to try?%)

I'm not trying to be a smartass here, because what I'm about to say I have actually mistakenly done. Are you sure you put reg unleaded in? Because honestly that sounds a lot like you may have inadvertently put in diesel instead of reg unleaded (aside from the inconsistent plug sparks). When I did it, the bronco behaved exactly as you are describing. After burning ALL of the diesel out of the tank, she ran better again. If that is the case, all is OK, that amount of diesel won't hurt your horse. However, throwing reg gas into a diesel will be devastating.

 

[GraficO]

90% sure it was just regular unleaded... I could prolly find the receipt to be sure...

 

[dave67fd]

Put a timing light on the distrib/coil wire... constant steady lights from the timing gun. Put the timing light on each plug wire and all were inconsistently firing

First off, The timing light only goes on the #1 spark plug.

Did you do the required checks to confirm if the Pertronix or coil is bad?

 

[GraficO]

called Pertronix and they said there really wasn't any checks other than changing out parts from another system.

I know the timing light goes on the #1 wire... but I wanted to see if everyone was off in addition to #1

 

[broncnaz]

Most likely its just the ignitor that is going wacky coils usually work or they dont. Since your getting the timing light to flash I'd say the coil is probably ok.
Unless you have to run premium fuel in your engine because of pinging I'd just run regular

 

[GraficO]

Most likely its just the ignitor that is going wacky coils usually work or they dont. Since your getting the timing light to flash I'd say the coil is probably ok.
Unless you have to run premium fuel in your engine because of pinging I'd just run regular

It had hardened seats put in so I could run anything...

Common sense says that would be true on the coil... I figure I'd change everything as I'm tired of fooling with it.

Any ideas on what would make the module crap out or is it a "luck of the draw" type thing?

 

[bax]

First off you do have hardened seats so your good there however you have a nice set of 289 small chamber heads. So It will ping with regular gas. However I dont think this is the problem. It sounds like ignition to me too. Check for a loose wire and grounds. Do you have a resister wire on the the ignition? How many volts to the coil?

 

[dave67fd]

The Petronix rarely go bad. One of the only things that can damage it are leaving the key in the "on" position (without vehicle running) which can overheat the module.

Once you get your new set-up. Send me your old system. I'll pay shipping;D

 

[72_EB]

What are you running for a fuel pump? Is it electric and running through a relay? Make sure it is getting a full 12V if electric. Just another thought.

 

[swampu]

If you set the timing using premium I think you would have to advance it a little for regular.

 

[robinsoncc]

Did you find the problem?

 

[GraficO]

it sits for now until I get the new module Friday. volts to the coil were 11.7. It's a Centech harness and the usual pieces are on the ignition.

Found the receipt and it was just regular gas not diesel.

Just bugs me that it was running perfectly until I stopped for gas.... as we have been trying to find the problem the issue seemed to get worst initially.

The timing hasn't been changed and the hold down for the distributor is tight and hasn't moved... in theory.

Honestly I was hoping is was the cap and the rotor... but no.

 

[broncnaz]

Yeah pertronix rarely go "bad" take that with a grain of salt they've had a lot of failures compared to the number that are out there. But I will say that a lot seem to be due to hooking them up wrong. but they do go bad and if Im not mistaken they usually tell you in the instructions to put your points in the glove box in case of failure. but anyhow
The failure could be due to the bad cap and rotor if pieces were floating around in side the dizzy then they may have damaged the internals might also check the advance mechanisms maybe a piece of the cap /rotor is hanging them up.
What plug wires are you using? also how old are the spark plugs? old plugs can causes issues I had issues with plugs that were to cold even though they were the standard plug that was called for in that year.
Also did you verify that the timing didnt change? normal wear in the engine can causes changes although since it happened in a short time frame that may not be the case. but I would inspect the dist drive gear make sure the roll pin that holds it on hasnt sheared off. that can cause big issues as well.

 

[broncobilly72]

Drove my Bronco to a job...ran fine. Came out to start and it ran like crap! Got it home checked fuel, timing, everything, no luck. After a lot of reasearch and tests found out the timing chain had jumped. Was lucky that no valves were messed up. Changed timing chain and all was good.....could be the problem if everything else is ok.

 

[bax]

It's not the timing chain. That was a new double roller timing set.

 

[72_EB]

Bax, you mentioned it earlier, but I'm curious how the ballast resistor is hooked up to the Centech and also what type of coil is being run.

 

[GraficO]

as it turns out... after getting the wrong ignitor... it was the coil. So now there's a Flamethrower III ignition and a Flamethrower III under the hood along with a new rotor and distributor cap... at least it got figured out

 

[mac77]

pertronix

just chiming in to say flamethrowers can go bad. installed one,as well as a few other things at same time, on my 72 and it wouldnt fire. i was told that they are checked before they leave the factory so i thought i did something wrong, played with everything for a few days and took to a mechanic he worked a few more. i told him everything was new so we dug in. long story short bad module. i was glad because i KNEW i put everything on right and was really questioning myself.

 

[nrramse]

as it turns out... after getting the wrong ignitor... it was the coil. So now there's a Flamethrower III ignition and a Flamethrower III under the hood along with a new rotor and distributor cap... at least it got figured out

Dang! I guess checking the coil with an ohmmeter isn't definitive. I'll have to remember that.

Double-dang! I had a spare coil with me the other day that we could've tried:-[.

I've got a Flamethrower coil too - I think I'll continue carrying that spare coil!