My pickup just dies!

[JmanTehan]

Hey guys, so i have a 71 521 with the l16 and a weber dgv 32/36. Runs great, starts right up every time but i will be driving down the road and all of a sudden the truck will start glugging, shoots out a back fire if I touch the gas at all, then dies. When i try to start it it turns over, wants to start, gives a putter then dies. 5 to 10 minutes of waiting and it will start right back up like nothing even happened. On a couple occasions it happened continuously every 4 miles. Replaced the fuel filter, have brand new ignition coil, distributor ignition cables, blew out gas lines in engine bay, checked filter in carb. still no luck! oh and it has been 95 degrees + and very dry but running at regular temp.  Please help 

 

Thanks

[JmanTehan]

Oh and my ignition light has been staying on!

[bilzbobaggins]

Points or ei dizzy?

[kelowg]

Alternator or volt reg is bad. Have them tested. Or maybe loose belt?

[datzenmike]

Hey guys, so i have a 71 521 with the l16 and a weber dgv 32/36. Runs great, starts right up every time but i will be driving down the road and all of a sudden the truck will start glugging, shoots out a back fire if I touch the gas at all, then dies. When i try to start it it turns over, wants to start, gives a putter then dies. 5 to 10 minutes of waiting and it will start right back up like nothing even happened. On a couple occasions it happened continuously every 4 miles. Replaced the fuel filter, have brand new ignition coil, distributor ignition cables, blew out gas lines in engine bay, checked filter in carb. still no luck! oh and it has been 95 degrees + and very dry but running at regular temp.  Please help 

 

Thanks

 

Back firing could be an electrical problem. Why was the coil changed????? If you have an after market coil it's an unknown and may be poorly matched to your ignition system. It should be 1 to 1.5 ohms plus the ballast resistor. If less than one ohm you will draw too much current through your points and fry them. Points and coils can over heat and become intermittent in operation. If you have the old one put it back on and see.

[dat521gatherer]

Generally if you have to wait 5-10 minutes to start back up you have a fuel problem. Check your fuel filter or just buy a new clear one from napa.

[dat521gatherer]

Make sure the hoses are tight on the filter. The bottom hose can suck air in but show no signs of leaking if loose.

[DanielC]

The fuel pickup tube in the tank has no filter, it just stops close to the bottom of the tank.

 

If you have some crud in the tank, like this one, as the engine is running, the crud gets drawn to the pick up tube, and clogs it.  The vacuum from the fuel pump holds it there.   If you wait a few, or several minutes, the vacuum goes away, and the crud falls away from the pick up tube, and the engine runs again.

 

If you suspect this is happening, when the engine dies, disconnect the fuel line from the filter, going back to the tank.  Blow compressed back to the tank, reconnect the fuel line, and see if the engine starts, and runs again, for a while.

[JmanTehan]

Thanks for ideas guys, now i have a list of things to try for the day. 

The coil is not aftermarket or upgraded at all just a new stock coil, same as the old one. should i still try putting the old one back in?

I Did just purchase a new fuel filter however it is not clear cause i didn't look when i bought it but i plan to get a clear one in a day or so!

If there is crud in the tank what is the easiest way to remove thus crud? siphon the full take the tank off?

 

Now the truck won't even start! I can see that the carb is getting fuel when i take the filter off and look in the barrels so I am really stumped. 

Maybe just new alternator?

 

THANKS AGAIN!

[datson4life]

80% of my issues were corrosion in fuse box area

[bilzbobaggins]

I'm on mobile so it's hard to type. If you are getting fuel then you need to check for spark. Are all the connections clean and tight from where you replaced parts? If you pull a distributor wire off from plug and lay it near a screwdriver or other metal and try to start it, do you get a spark? Is it a points or ei distributor? Have a test light?

[Osoi]

I'm with Danial on this one as I just went through symptoms almost exactly like you're describing. The test that proved most helpful for me was replacing the fuel filter, and checking it very shortly after replacing, like the next drive. If it's filled with crud that's almost the sure fire problem. There's lots of DIY tank cleaning solution, but unless you completely replace the tank there's no 100% solution.

[JmanTehan]

Alright Had time today to take out the fuel tank and clean it. I then proceeded to reinstall the tank put some gas in it and try to fire it up but nothin. still same issue, just turns and turns, every once in a while it'll fire once or twice then nothin. I put the original ignition back in to see if that as the issue but nope same thing. I forgot to mention that my battery will not hold a charge, so maybe alternator? will your engine not run if you have a bad alternator?

[Tristin]

Have you looked at timing at all? I had extremely similar issues as you describe. It was actually the nut on the bottom side of the distributor. It had fallen off so on large bumps it would advance/retard the engine all of a sudden which would flood the carb and kill it. Huge backfires and wouldnt start up. After the gas evaporated in a few minutes it would start right up and go. 

 

Everything looked great and narrowing it down to that nut was quite the hunt. 

[thisismatt]

If your engine will turn over then you have plenty of electrical power to run, so the starting problem is not an alternator problem.

[banzai510(hainz)]

If your engine will turn over then you have plenty of electrical power to run, so the starting problem is not an alternator problem.

True!!!!!!!!

 

look for fuel(pour tiny abount in carb and see if fires off then spark.

maybe the condensor is bad. this would be backfiring. but it should still start.

Look at Points if burnt badly ,dist shaft loose will also cause backfiring.

 

reck the valve lash will be hard to start.

 

 

fuel finlter cut up the old one. even with junk in carb with gas poured in it should fire off for a few seconds.

 

 

look at sprk plugs

re ck the coil wireing.

 

 

this is a SIMPLE fix

 

 

tighten carb intake manifold

 

 

carb could be BAD .truck will fire off if gas poured in

[JmanTehan]

I have poured gas in and still nothing. However every once in a while it try to start and wants to gives a nice put put then nothing again. I did recently replace the cables from spark plugs to distributor if that could be an issue? But they are set up on 1342

[kelowg]

Sounds like points or timing issue. Try using timing light while someone cranks it over. 

[banzai510(hainz)]

I did recently replace the cables from spark plugs to distributor

 

 

if it ran fine after you did this then you have the correct fire order.

 

I think I would look at the points if still stock ignition

But did you even read what I wrote to you and ck it all out ???????????????

[denmarkboy]

Where you at on central Oregon ?

 

Depending on where your located I can probably find a datslocos member that is close to you that could lend you a hand .

 

I pm'd you my number,

 

I agree with Whats already been pointed out.

 

Sounds like points and timing to me. I would put new plugs in , reset the timing , replace the points .

 

And yeah it will run without the alternator working . But a low battery won't give much spark when its trying to crank over the engine. And combined with fuel soaked plugs and ill set points ,it's not helping

[dat521gatherer]

your valves are not closing. Even if you have not played with them this will happen over time and one day it wont start. Happened to me and if I turned my engine over long enough like a half hour it would heat up a little and then the valves would seal and it would start. Crazy but true.

[Chiquidrac]

Something similar happened to me 2 weeks ago with my son's 1970 521 with a weber carb, we spend a couple of days troubleshooting everything that has been described here and found that there were 2 problems preventing the truck from starting.

1.- the truck started running because the weber carb had the bolts on the bottom plates got loose so the carb was sucking more and more air as the bolts where getting loose.

2.- the second problem was the tensioner on the timing chain somehow ( don't ask me why because I'm not an expert) lost the tension and the chain was "loose". The way I found this was by taking the valve cover out and press the to sides of the chain and sure enough it had some play, my logic told me that was the reason I was getting the backfire sometimes.

 

So we tighten the bolts on the 2 bottom plates (I think they are the adapters) and we bought a new chain and tensioner, installed (of course following the instructions on one of the threads here) and iit now starts and runs like new.

 

Just my 2 cents, now as I said before I'm not a mechanic nor an expert, it was just my own experience.

 

Hope this helps.

[Chiquidrac]

Sorry, on bullet #1

 

"1- the truck started running because the weber carb had the bolts on the bottom plates got loose so the carb was sucking more and more air as the bolts where getting loose."

 

I should have say "stopped" instead of "started "

[JmanTehan]

Alright, today i stated checking off different things on the list of things to check. Took valve cover off and timing is good, TDC showed distibutor at 11:28 position. Tightened all Carb to manifold bolts and adapter bolts as well as checked the intake manifold to block bolts. all good. Points were slightly corroded so i took a small rasp to them and cleaned them up. Brand new fuel filter, cut up the old one had slight amount of stuff in it but was still relatively new. new spark plugs.  Still nothing. So i decided to put in the old spark plug cables just for shits and giggles. BOOM starts right up, maybe i got the wrong spark plug cables? I don't know. But after driving the truck about 10 miles down a dirt road It dies on me again. Now there is no fuel in the carb float bowl at all, but if i put fuel in the float bowl the truck will fire right up.

 

Is this a fuel pump issue? I did just get a new mechanical not electric fuel pump and this was the first time driving with it in. I just cleaned out the fuel tank and blew out the gas lines. 

 

Very confused as to what is going on

 

Thanks guys

[Elkie]

Pull the fuel line to carb off, point it into can and crank the motor. Does it pump gas?