348 spitting and sputtering no start,your expert opinion requested

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Hi guys,thanks for checking the post

What I have is a bone stock 59 impala 348 automatic 4bbl daily driver,trying to help a friend diagnose a no start issue

Whats happened so far:my buddy says he was letting the car idle and warm up before he took it out to drive and while idling it just died and wouldnt restart,we got it over to my house (trailered) and it was spinning over but no start,seemed as if there was no fire so these things I checked: plugs-they were wet so I cleaned them up and reinstalled,points condition-not burned,cap,rotor button wires-sanded contacts inside cap,points and tip of rotor button,coil appeared to look ok,but I replaced it with a known good coil just in case,tried to crank,was spitting sputtering for a min or so and then started and ran great for 2-3min-then died and wouldnt restart
Checked dist,was mounted tight,not flopping around,broke out timing light and checked,timing good,checked for vacuum leaks nothing obvious found,had another person spin over while i was under the hood,it barely cranked for 8-10 sec,had my had at the base of the carb,felt air blowing out,base gasket was leaking,replaced with new base gasket,still same no start condition.Checked both fuel filters,not clogged.have a constant stream of fuel at carb when I snap the throttle,so I dont think its fuel related

Its spitting and blowing fire out of the carb like an out of time situation,yet I pulled #1 plug set at TDC and reset the timing from that point,checked intake manifold bolts-none loose,spins over erratically,fast and slow-no coolant in the crankcase oil,no oil in the coolant.If electrical timing is on ,could mechanical timing have jumped out somehow? and if so,why did it run perfectly for 2-3 min?This is a bone stock all orig 348,no power steering/brakes,nothing aftermarket

any suggestions from the experts?? ​

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Did you check for spark; primary and secondary? Should have a strong bluish spark out of coil wire and out of plug wire. Check voltage to coil, could have a bad resistor wire. How much battery voltage is there? Has carburetor ever been rebuilt? What happens if you spray carb cleaner in carb. and try to start? Need 4 things to run: Fuel, spark, timing and compression. Keep checking..you will find the problem. Keep us posted.

 

Try changing the Condenser,

 

Does sound a bit like it might have jumped timing. And it's still jumping and occasionally the timing comes back into phase close enough to start and run, at least temporarily.

I'd try running a cranking manifold vacuum test, explained in this link. Close off any external vacuum hoses and back off the idle speed screws to completely close the throttle plates while doing the test. If the cam timing is OK it should pull at least a couple inches of vacuum while cranking.

http://www.linnbenton.edu/auto/perform/vacuum.html

 

Perhaps the carb float is stuck. Too much gas.

 

Sounds like lots of timing chain slack to me. Try turning the motor by hand back and forth while watching the rotor. Timing chain slack will be obvious.

 

check the wire inside the distributor, that runs out to the coil. if it is shorting to ground, as the plate moves, it will give an erratic spark. could explain why, after you "fooled" with the points/condensor etc, it ran ok for a while.

 

My SBC did the exact same thing. It was a bad points ignition condenser. $5 later it's running like a swiss watch.

 

Did you look down the carb and see if it was drooling fuel down into the intake? Gas fouled plugs suggests that it is flooding, either because the choke is closed or the fuel level is too high in the float bowls.

Oh one other thing, if it is a timming problem it can jump in and out of time either because of a loose timming chain or a bad gear on the distributer.

 

Yeah, check the condenser. This sounds like the problem with my 60 Impala, with a stock 300 hp 327. I went through 3 new condersers in about 100 miles. I suspect that the quality of new condensers is much lower that they used to be. I put a Mallory Unilite in my Impala and haven't had a problem since.

 

Had a 348 do the exact same thing ended up to be a bad rotor!

 

great stuff guys thanks,Ill whittle away at this list and hopefully have good news to report soon

 

Timing chain is jumping back and forth....?

 

update....FYI, checked the play in the timing chain had 1/4-3/8 slack which seem to be within specs,and tried alot of the other suggestions too,I replaced the points and condensor and now runs fine...never heard of that causing one to spit fire back thru the carb,oh well,now onto the next car-thanks guys!

BTW -ClayMart,that link you posted was great thanks for sharing

 

Thanks for checking back in & telling everybody what the fix was. I hate reading troubleshooting threads with no conclusion.

Good work.

 

I've been told by gear heads who have been wrenching longer than me, don't replace the condenser in the dizzy when doing a regular tune up because you could install a new one that is bad from the get go.

 

That is the MOST common part that I come across that is bad brand new right out of the box!

I'm glad you got it sorted, and like Randy said, glad you took the time to let us know what it was.

Thanks

 

I was having the exact same trouble as jalopy junkie. I had recently replaced the dizzy, ran great, then one morning: sputtering, no start. Searched the HAMB, found this thread, replaced the $5 condenser - started right up and runs like new.

 

Beat me to it !!