won't start back fires every few seconds.

[Eddy1973Transporter]

It was running fine just the day before. Always had a cold start issue. starts good but doesn't idle. after struggling for a few minutes runs fine. Suddenly while running it backfired a puff of white smoke and stalled. Now it won't start at all. turns over, won't start and backfires every few seconds.

Is there anything simple I can do to resolve this issue?

[Abscate]

Start by filling us in on when the last time the rotor , cap, points, and spark plugs were replaced. These are annual service items
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.ssS!

[TDCTDI]

Carbureted or fuel injected?


If fuel injected, it’s possible that the backfire popped an intake hose off.
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Do something, anything, to your project every day, and you will eventually complete it.

[andrewtf]

Long shot if its fuel injected ('73 so doubtful?)

We had almost the exact thing happen on Big Emma.
And it was really difficult to find......

We had a fairly substantial backfire and the same situation occurred afterword.
After LOTS of diagnosis, the issue was the backfire propelled the wider needle on the AFM HARD past the pin to limit its range..... effectively eliminating the AFM from the system. It took us maybe a week of trying everything we could think of before finding this issue.

While I would do it almost as a last resort (or maybe a first since its easy).... but remove the AFM cap and see what's going on inside there.
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'77 Riviera - Murphy' (being reborn.... slowly)
'63 Austin Healey

[airschooled]

Post two pictures of your engine, one from behind and one from above.

Robbie
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[aeromech]

Replace your points
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[mikedjames]

If your distributor has some wear on the drive dog, you can put it in 180 degrees out and then set it up and time it.

It will sometimes stay put for a while then suddenly jump out, leaving you with timing that is all over the place.

Spent a while trying to get an engine running a few weeks back, and we got it sort of running (despite having a head bolted on with an extra spacer ring on top of No3 barrel) , then suddenly it stopped.
We took the cap off the distributor and it was pointing somewhere random instead of at No1 when we had just set the timing.
That was another assembly mistake by the owner. ..
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[SGKent]

I would suspect that the points rubbing block broke.
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[ImAddicted]

It sounds like you have two (possibly unrelated, but maybe not) issues.

1) won’t idle when cold. Makes the TS2 likely suspect. Can be compounded by a vacuum leak (btdt) at the AAR.
2) Backfire\no start. Sounds like timing\ignition - see SGKents comment - also could be compounded by vacuum leak.

Start with the basics:
Check ignition components - points, condenser, cap, rotor, static timing (since won’t start). Make sure the distributor hasn’t moved because of a loose clamp (btdt). Make sure distributer is firmly seated. Might not be a bad idea to pull it and make sure the drive dog isn’t AFU. Multimeter and test light are your friends. Buy or borrow if you don’t own one. Get a helper, some things are just easier with two people.
Look for disconnected hoses, cracks in hoses, loose hoses. AAR is a BITCH to get to, find a helper with small hands if possible.

WHAT NOT TO DO:
Throw parts at it.
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1979 Transporter (sold)
KC1MUR

[Eddy1973Transporter]

Thanks for all the help so far. I'm not a mechanical expert by any means. I understand the basic principles. Fuel and air mix in the carb and it gets burned up in the head. The coil feeds elect via the points and dist cap to each head. That's about it lol. The references to TS2 & AAR and @#$ I have no clue, could you please spell it out for me, pretty please?

I've only owned it for about 8 months and haven't done anything to it. Took it to 1 mechanic who made it worse. It has 1 carb that looks exactly like the weber carb that's on my jeep. pics of engine from top & rear uploaded.

Thanks very much for your help.

[cmonSTART]

Definitely look inside the distributor and check to see if you have points. Easy and quick, and is consistent with what you're experiencing.
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'78 Bus 2.0FI
de K1IGS

[ImAddicted]

Yup, skip the TS2 and AAR stuff, you have a progressive, those are FI parts and don’t apply.
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1979 Transporter (sold)
KC1MUR

[ImAddicted]

So to help with this, let’s circle back to the beginning. It ran great one day, you touched nothing, next day it’s FUBAR? If so, there’s places I would look first, things that can easily fail\change without intervention. Yes, your basic understanding is correct, the missing piece is TIME. The ignition n the head has to happen at the right time as well.

Check all vacuum (small and big rubber hoses) for splits, cracks, looseness.
Check your points. Burnt? Broken rubbing block? Frayed wire? Closed up?
Do you have a multimeter? Timing light? A Bentley manual? Even the Muir guide would help get you in the ballpark as well as some simple automotive theory. Leave the wires on the distributor cap, remove the cap, look inside. If not sure what you are looking for, post up a pic. You can tackle this, be methodical, check thing at a time. Side question: when was the last time the valves were adjusted?
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1979 Transporter (sold)
KC1MUR

[Whaanga]

You might consider flipping the carb 180* so that the the adjusting screws are much easier to access. Yours is reversed. It's quite doable, remove the four 13mm nuts that connect the throttle body to the manifold, and reverse its orientation. You'll have to deal with the fuel line but that should be easy to remove it and then reattach. And most folks suggest that you simply cut the line rather then try to pull it off the brass nipple; you only need to cut about 1" off the end (just enough to clear the nipple) and then re-attach the hose.

The photo below shows carb set up as suggested with the fuel intake nipple on the left (as you look from the rear of the car).

_________________
Late 1973 Bay w/a transplanted 914 Engine

[Eddy1973Transporter]

removed the distributor cap and this is what it looks like. I guess it looks ok. what do you think?
Silly question should I be able to reach in to the distributor and rotate that red piece? I'm thinking no because it should be connected to the engine somehow. but it does move, is it broken?

engine still doesn't start but now it doesn't backfire at all.

[timvw7476]

perfect place to start. yes, it should wiggle just a bit, but not rotate around like a top, also check the carbon brush under that distributor cap, it's spring loaded & gently rubs/rides on the rotor.
Next thing wires to the coil, all tight enough so they don't walk/wiggle off & cause this nonsense. Next the battery cables, no green-(ish) mold like growths, those will shut you down quick.
Do not forget the wire from coil to the center of the distributor cap, check all the 'wells' where the ignition wires go, I've had carbon wrap wires disintegrate & leave their carbon in those contact points. Excellent way to break up voltage flow.
I usually use a multimeter to check rotor, cap contacts, wires themselves. If you have any ultra high Ohm/resistance values, that bears investigation.

[vwmaniaman]

Did you just buy gas? You may have got some watery gas or some with diesel. Got a load of bad gas in my 86 VW vanagon. It acted that way.
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[cmonSTART]

[Eddy1973Transporter]

It spins freely in one direction and with some resistance in the opposite direction. If I mark the location and then try to start it I can clearly see that it is in a different spot.

Nothing wrong with the gas, or battery connections.
Just wish it was easier to get at lol.

[ImAddicted]