351 back fire/stall
- Thread starter fordgt
- Start date
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BroncoJoe19
Active member
when you say spark do you mean spark on time or spark at all. it is getting gas when you are under the hood you can smell it.
Shadow_D
Active member
to the Zone!A little more info about your motor, setup and what you were doing when she backfired would help...
i was doing about 60k/h in third (4 speed manual) and it went bang. it felt like it was running out of gas, i kept pumping the gas to try and keep it running(there is lots of gas in the truck) and then it semd to rev up for me and act normal for about 3 or 4 seconds then bang and stall. i did try to put it in to second and pop the clutch but it only stopped the truck faster. i took one of the wires off the plug held it to the fram and had nothing for a sprak. it is a 351m in a 1979 bronco ranger XLT.to the Zone!A little more info about your motor, setup and what you were doing when she backfired would help...
dirtrider883
New member
my 78' with 351m first ran great cold, but not at all warm, so new carb. then great warm for 2 weeks, new distributer and coil. then ok at best, then new ignition module, been fine since. Do a real tune up, if nothing still, then about $200 for dist., coil, and ecm. do like me and replace one at a time, or just buy all at once, and not know what it was, for future reference. may have bad spot in cam and broke dist. shaft off. if it cranks over slow may have jumped timing. not real descriptive, not much info, but hope it helps. oh yea, forgot to mention, backfired through all these problems. knew it was ignition system through all this, but listened to to many others (including a mechanic) cost to much but it's all new now. guess it'll be another 30 tears till it does it again.
Last edited by a moderator:
BroncoJoe19
Active member
You have no spark to a plug wire, so see if you have one from the coil.
IF yes, pull the dist cap, and crank the engine to see if the rotor turns.
If yes, check to make sure you have 12 volts to the bat side of the coil.
This is what I would do.
pull the cap and crank the engine to see if the rotor is turning.
pull the coil wire and check for spark at the coil
if none. check that the small wires to the coil are clean and tight.
check to make sure there is 12 v to the bat side of the coil with the key turned on.
check continuity of the wire that goes from the tach (-) side of the coil to the ignition control module it is a tan-yel wire and the resistance should be less than 5 ohms.
Assuming all that checks out, I would
pull the ignition control module and have it checked (if possible, I think that a parts store may be able to check it)
IF they can't check it, I would replace it and just kick myself in the a$$ if it didn't fix the problem and continue troubleshooting.
Another possibility is the pick up coil inside the distributor assuming that you have an early Duraspark ignition.
A portion of this thread shows one how to test the coil.
http://broncozone.com/forums/index.php?s=&...ost&p=72467
