DRLA 45 backfiring out of carb and exhaust (SOLVED)

[evanfrucht]

Ya, I don't know what to do at this point. If my valves seals were not quite sealing perfect would that even be causing major random backfiring like this?

It idles well, but it does not rev up smoothly and makes a lot of popping noises when I pull the throttle. I can feel large strange pulses coming from the exhaust pipes here and there, but no visible flames. popping is the worst from 1500-2500 rpms.

Also with the bigger idle jets I tried now 1&4 speed up with shots or fuel and 3&2 want to die now...
Before it was 1&2 ( on the same carb that increased in idle speed ) but now it's one throat on each of the two different carbs. Makes no sense to me.... the mixture screws don't affect this at all either.
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1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[mark tucker]

a super good ignition curve....Im not sure just what that is, but it may not be so super for your engine, with that said Ive never seen a curve do this... I hope you figure it out before going to the swap meat with it. look down the crabs throat and see if they are pissing...that can cause popping out the xhhaust too, a dead ex lobe can cause pop out the intake...bad/cracked/rong/shit sparking bolts can also cause every bit of what you discribe..as can carbon tracks in the cap..( dist cap not the one on your head)

[evanfrucht]

Ya It's kind of a shit show... I have a hunch it's nothing major but it's still very frustrating. I'm not going to sell or anything. Honestly I like and need this car and have already spent too long on the build so I'm trying to get this figured out and get it installed ASAP.

I may need to try a new distributor and wires/plugs just to eliminate the ignition. The only two distributors I've been trying are:

- My original '67 vaccum only advanced distributor. (Did have new points and condenser + bosch blue coil) With that dist. I can assume it was most definitely not advancing at all. I could get it to idle properly with that one but it still was acting like only some throats had a vaccum a leak...

- At this point I've switched back to the Pertronix III SVDA unit. I can get it idle with this too, but carbs act funny tho in the same way(different throats respond differently to shots of carb cleaner) In addition, my timing light still seems to have a hard time reading this Pertronix unit accurately... and I know the light works fine as it worked with the old vaccum only points dist. and also works on my other vintage car with a electronic ignition and MSD wires.

With both of those distributors I have the same or very similar popping upon acceleration. I have not tried any new plug wires or plugs at this point. I did pull the plugs and check them.
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1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[txoval]

Just let me know, lol

I’d imagine shipping would be $15-20

[67rustavenger]

If your engine is still popping out the exhaust.
You can eliminate the distributors. For the time being.

Sumpin else is going on.

With the care that you put into the build. I'm surprised that you are having trouble getting it sorted.

It's already been mentioned. But every time I have accel. popping issues. It comes down to the carb/linkage sync. Well some jetting issue to. But mostly it's the sync that gets me.

Oh, and you are 100% sure that you have the plug wires on the correct dist lugs/firing order?
This can lead to popping issues as well. In your head, you count it out 1-4-3-2.
In reality your hands and eyes have connected the plug wires, 1-3-4-2.
It happens! That will make funky things happen.

My 2180 with Dell 45's runs,
60 idle
160 main
180 ac
.2 emulsion
38 vents < a little small. But pulls like a freight train.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!

There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!

[evanfrucht]

[txoval]

Is there another VW buddy close where you place the carbs on there engine to see if the problem follows?

Maybe send to Rick to put on his flow machine?

Did you ever connect your alternator/generator to see if it’s a voltage issue?

Cam lobes could easily be checked with a dial indicator, not to mention you valve clearances would be loose

Can you post a pic of the engine on the test stand? We might see something

[Rome]

Have you tried running the engine at night with the lights mostly off, so that you can look carefully if any of the spark plug wires have a break in the insulation so that you can see an arcing? Arcing is when the wires' current travels out from a break in the insulation and grounds to a metal portion of the engine, creating the spark. I've had this happen to a Jetta engine in the early 1990's soon after installing some "hi-po" silicone non-stock wires. You could not see the arcing in daylight. Next day I went to the local VW dealer and bought standard replacement wires, and the arcing went away. Symptom was similar to yours- engine would idle OK but when revved, the arcing started and the engine would not rev cleanly.

[FreeBug]

Swap carbs from side to side.

[evanfrucht]

Maybe I can get a video or something. I was really hoping this wouldn't be so complicated

I've been talking with Rick (carb guy) over the Phone trying to find out what might be going wrong with carbs or whatever. He's been very helpful but we haven't got anywhere really. I'm determined to find the issue and solve it myself basically.

I haven't wired in my generator because that would involved pulling my voltage regulator from the car which would be a whole project. I did check and do have a good 12 or so volts at the coil when batterys charged and car is running. I could attach my trickle charger to the battery while it's running maybe, see what that does... but I'd honestly rather try a new distributor and plug wires before that.

I don't know of anyone close to me who has an engine like this and don't have any local VW buddies either. The valves have been pretty much good whenever I check them.

Today the main things I plan to do are:
Swap carbs side to side.
Go over carbs again inside and out to check for anything odd
Verify jet sizes
Check the mixture screw hole sizes on the carbs.
Spark plugs/wires?
Check fuel pressure

I'm thinking maybe spark issues are allowing unburned fuel to ignite in the headers, causing my loud pops which sometimes puff smoke out the carbs when they ignite at the wrong time with intakes valves open???
BUT, I still need to find out why my carbs are acting weird too... why certain throats are randomly acting lean??? Before 1&2 were, but now 1&4 are. For instance right now if i put my hand over the 1&4 throats the motor wont die, but if I put my hand over 2&3 it will want to die... similarly if I spray carb cleaner into 1&4 it speeds up, but if I spray into 2 or 3 it immediately wants to die.
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[Brian_e]

Did you ever have the valve seats cut after I had the head?

The valve job straight from AA is marginal at best in the sealing department. You did a whole pile of welding on those things, and that heat makes all kinds of thing move around. It doesn't take much tweaking till a valve won't seal.

How about a quick leak-down test?

Brian
_________________
www.type-emotorsports.com

[evanfrucht]

[evanfrucht]

Alright so a semi large update.

I started pulling individual plugs one at a time

When I pull number 1 plug wire from the plug it does not seem to lower idle at all and the backfiring stops completely and it revs up sounding halfway decent. Doesnt seem like I'm getting spark at that plug or maybe that plug isnt firing right.

When I pull plug number 2 wire the idle doesn't drop that much but it does drop a little and I still get backfiring. Maybe that one is similar as number 1?

When I pull plugs wires number 3&4 the idle drops very significantly and it sounds worse all around. Also when I pull those 2 plugs I can see a bunch of arcing when I touch the ends to the intake manifold studs or whatever.

Number 3 and 4 are the shorter wires? Maybe that has something to do with it? To much resistance in the wires for this ignitor 3 or something like that? I used a proper spark plug wire crimper to put these wires together and have made working spark plug wire sets before for other cars, so it's not a bad connection in the wires or anything like that I dont think.
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[evanfrucht]

After further investigation this might explain why I've been having so much trouble with the number 1 cylinder consistantly...

The contact for number one inside the distributor cap is cast over with plastic, and also I saw it arcing for the first time from a crack type casting flaw thing on the exterior (which is also on #1 post) to the cap hold down clamp. This is what to expect from Pertonix quality control I guess.

_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[txoval]

Seems like you’re definitely getting there.

My 009/MSD Coil setup works and I located them last night in the garage. I couldn’t find the dang ballast resistor, but that’s a $5 part and found at Autozone, NAPA, or O’Reillys

Just PM me if you want it

[evanfrucht]

[txoval]

Perhaps #1 is flooding due to issue in idle circuit

[evanfrucht]

[Matthew]

I still think you have a plugged idle circuit on the 1-2 side. Have you tried removing the idle jet and blowing through the passage and jet/jet holder with compressed air?

Popping on acceleration means it’s lean. It could be idle circuit, vac leak, or idle mixture adjustment.
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1965 Beetle sedan
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[evanfrucht]