ford FE backfiring

I've got a 66 f100 with an FE (***uming 390). Recently, while my dad was driving the truck, it ran out of gas. It backfired extremely loudly, then died. Shortly after getting it home, the starter died. I replaced the starter and now it starts up just fine. Upon test driving it, it died at a stop light after about 5 minutes of driving. I started it right up and then it backfired extremely loudly. It got me back home after that but I have no clue what to do at this point. It does leak oil very slowly but I do not know the point of origin and it also has a bad exhaust leak which I also have yet to find the point of origin. It still has the original intake and 2bbl carb as well as original exhaust manifolds. Could this just be a timing issue and needing a carb rebuild? or could I possibly be looking at a blown head gasket or cracked head? valve issues? Any help would be much appreciated. Cheers.

 

more than likely its a 352 but.. pull your plugs, check and see if any of them are fouled. check your points to see if they are closed or burnt. going through the carb couldnt hurt either.. these engine will burn exhaust valves over time. just did my heads on my 360 for the second time, but then it does have almost 400k. most the time on MY truck when i had this problem it was the carb..

 

Carb running lean or an air/vacuum leak causing it to run lean, dodgy leads/plugs, crack in ditributor cap causing cross firing, faulty rocker, i had a ***** of a time sorting out a back fire one time and it ended up being the condensor, a few suggestions for you, hope it helps.

 

Have you checked your point gap ,that will do it.

 

inspect dist. cap for cracks causing a crossfire

 

Those caps are very susceptible to moisture or condensation too. If it rained lately there may be condensation in the cap causing problems.

Also look for a loose primary wire in the ignition causing the coil not to get power for an instant. Especially if it is backfiring on a rough section of road.

 

Too much slop from a worn timing chain, maybe even jumping teeth when it backfired? Had a 352 that gave me drivability fits until I figured it out and put a new chain in it.

Easy check; pull a battery lead, pop off the dist cap, and slowly bar the eng back and forth using a socket on the front crank/pully bolt while checking for lag between crank and dist shaft movement.

Keep us posted on what you find and the cure.

Ed

 

Not uncommon for a system to **** up the dregs in the tank when it runs out of gas, and water or whatever gets to the carb and plugs a p***age or two. A Holley carb only takes about a single molecule to screw it up! Also a backfire can rupture the power valve in a Holley, but that doesn't usually cause backfiring. I would get a carb kit first and see if a good cleaning fixes the problem.

 

2x. Check the screen where the gas line screws into the carb for junk.

 

To backfire it had to load the exhaust with fuel either poor spark or fat carb.

 

thanks for all the suggestions. i will be checking into these things very soon and will update progress. i'm guessing it will more than likely be a combination of things wrong but we'll see

 

Bent push rod/rods.

 

Regarding the exhaust leak, those FE engines always leak between the manifold and head. The upper bolts also can be really difficult to remove because they rust due to the threaded holes being open . It is common for the exhaust manifold gasket to blow out and cause the manifold to warp or wear. Before installing a new gasket. the manifold should be machined . The head may also need to be machined. You could also not use a gasket and use a high temp sealer like permatex 2.
Even if your manifold is not leaking at this spot, it is good maintenance to regularly inspect it once a year for leaks and turn the bolts on and off and install with anti-sieze.
Regarding siezed bolt removal... that's a whole new topic/thread. Heat with a torch is best, but sometimes they are just stuck.

 

My 390 started backfireing almost same way found to be weak valve springs.Worst part heads were just rebuilt wont go back there again!

 

so we went through the carb and it's clean and functioning perfectly, checked all the wires and everything's fine, checked the distributor, was completely fine, and checked for play in the timing chain and it was fine. i've driven it a couple times since and now it's not backfiring, it's just dying. i'll be putting along and it'll just quit. i'll pull of the road, spend a good 3 minutes trying to start it, it'll start, then 5 minutes of driving and it quits again. it did seem to become more and more frequent. what the hell is my truck doing??

 

One of the problems is the heads are not made to run un-leaded fuel.The valve seats will **** up in the head holding the valve off seat when it stalls the lifter is pumped up and as you sit they will depump enough for you to get it cranked.To make shure what the problem is run the engine till operating temp and do a compression test.If you cant afford to have hard seats installed they make a set of pushrods that are .080 shorter and can buy you a little time.

 

Bad coil messing up when it gets hot?

 

we've been figuring it's the ignition but it very well could be the valves as well

 

Had a SBF do the same thing and it was this^^^^^^^

 

Id check out your entire ignition, check out not replace. Start with timing, then point gap, clean and re gap plugs, then check your coil connections. This is all free and just costs time.

You can then Ohm out ur coil if the problem is still there, change your fuel filter because you ran out of fuel and then report back here. Start doing mechanic things, not parts replacer things.

Also you should have a fuel filter thats on the block, its a cannister type. Id change that out too. So with all this you will be out 2-3 hrs of work and 10 bucks in two fuel filters, thats if you have one in line and the cannister.

 

I,ll second that fuel problem,drain and make sure line in clean and rust in tank best buy new of fix.My gas tank is behind seat on 52 f1 took out and fushed.

 

Long shot but don't forget the ignition switch. I've had a couple go bad over the years, gave me fits, run and quit at odd times.

Ed

 

I had one do that and it was a bad vacuum advance on the distributor.