Engine issue has me stumped

[TyWebb]

1974 Thing we have just recently put back on the road.
1600 DP (may be original)
New EMPI 34Pict3 carb
tried several distributors while I was trying to figure out a workable solution and ended up with a 009 with retrofit Pertronix unit.

I know that is generally considered a bad carb/dist. combination with a flat spot, but after many days of experimenting I got it running really well. Started and idled great. Ran great and little to no discernable flat spot. Had it running like a champ. And it was running cooler than it had been while trying to get everything straight.

Was DD it for a week or so and decided one day last week to run up the road to get food. Decided to take the highway for 1 mile to the next exit (may not be relevant). Got it up to something like 65mph and was sooooo happy with how it was driving....then it started cutting out. Like a firing miss. Kept getting worse. Made it to get food and got home mostly by over reving on starts.

Anyway tried driving it 20 minutes to my shop the other day and first 8-10 minutes it drove perfectly then the same thing started happening again until I ended up on the side of the road. Towed it to my shop.

Decided since it seemed like an electrical problem it may be the pertronix. So, I swapped in a new Pertronix SVDA I had laying around. Re-tuned everything and got that running great. Would start and idle fine. Ran great while running it in the shop for 10-15 minutes. Was running hotter than I liked, but other than that seemed fine.

Took it for a test drive and everything was great - for about 10 minutes. Then the same thing started happening. Sat at the side of the road for 10 minutes and then was able to re-start it and drive back to shop.

It has a new gas tank and changed the fuel lines recently. Tested the fuel flow before swapping to the SVDA distributor and fuel flow was great.

I'm stumped. Thoughts? TIA. Patrick.
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Patrick.
76 Westy Deluxe, Original engine (2.0L, FI, solid), Sage Green

"Don't sell yourself short judge, you're a tremendous slouch."

[kpf]

Might be fuel starvation.

- Fuel filter clogged?
- Junk in the fuel tank, pickup sock clogged?
- Small leak in fuel line allowing pump to suck in air?
- Fuel tank vent clogged?
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1971 Super Beetle

[TyWebb]

[heimlich]

Check your coil.
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[TyWebb]

[TyWebb]

[74 Thing]

If you take off the gas cap and hear a swoosh sound then it is not venting and actually sucking.

If it does this and you stop and remove the cap and start it with no problem then the venting is blocked.

I agree with checking the coil too-what coil are you using and is it compatible with the distributor you are running since pertronix requires a certain resistance in the coil.

[TyWebb]

[TyWebb]

First pic is with the 009. It was running beautifully at this point.

And this was yesterday after I installed the SVDA and got it running:

Pics just for info. The chrome coil is a Pertronix model. I normally avoid anything chrome, but that's how it is and it's supposed to be matched to the CDI.
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Patrick.
76 Westy Deluxe, Original engine (2.0L, FI, solid), Sage Green

"Don't sell yourself short judge, you're a tremendous slouch."

[74 Thing]

Pertronix makes different resistance level coils. Some are compatible with certain Pertronix modules and others are not. Get your ohm meter out and check the resistance on your coil between the pos and neg posts on the coil.

Are you running a CDI ignition as well? If that is the case then it does not matter what coil you are running, but the CDI may be causing the problem. You may want to bypass the CDI, but then coil to module compatibility comes into play.

[Heiferman]

Many years ago I had a similar issue. My first thought was a coil overheating and then some sort of fuel/vapor lock.
It turned out I had a tiny piece of debris in the accelerator pump dump tube of the Solex 34 pict 3 carb. We actually were able to see the fuel squirt was restricted. Pulled the tube and forced out a tiny piece of debris. Looked like a small stone.
Weird right? But your description of events and my trouble shooting was/is similar. G/L
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- 1973 Thing, some LandCruisers and an old Ambulance

[heimlich]

I had a carburetor once that if I drove it over 50 it would run it out of gas. It's a simple adjustment to fix it but I played with it a little. I'd be driving down the freeway and decide I would go 55 for a little while. The car would shut off after a little bit it would start back up again. It's common with aftermarket carburetors.

Check your coil. Grab a multimeter and put it on ohms. Put the leads across the two terminals. Then put the leads across one terminal and the middle. One should show you 3 ohms and the other 10,000. If yours doesn't come up with that it might be ok but check the specs from the manufacturer. Post them here as well.

Did you use the same distributor cap and rotor? Pop the top of the cap and look for any black lines. Then take your multimeter and check the end of the rotor to the middle.
_________________
www.vwnos.com [email protected]
Classic Brands. Classic Quality.
Not all parts are made the same. NOS OE/OEM parts made mainly in West Germany, Early Germany, and Early Brazil are where VW produced the best quality parts and best fitting products.
5% Off your order with coupon code: 5%OFF
Restored Distributors Available (<--Click here)

[TyWebb]

Appreciate all the responses. Lots of work on the Thing today, but no final solution.
Replaced the fuel lines and fuel filter. The filter looked terrible.
Cleaned out the solid fuel line running through the tunnel. When first cleaned the liquid came out terribly dirty. Kept cleaning until fluid came out clean. Also checked the fuel coming out of the tank was clean and running freely.

Pulled the idle valve out of the carb and cleaned, however, I did not pull the carb and fully clean it today. I will do that tomorrow or later in the week, including pulling the accelerator pump and valve apart and clean.

I then put it all back together to see if that solved it. Ran great until it got really warm, then it started running poorly when revved (idled fine). Re-tuned the carb and re-timed the dizzy. Did not help.

Checked the Pertronix Ignitor module in the distributor and it's the D-57-22 module, however, I could not find specs anywhere on what resistance coil is correct for this module. I will keep looking.
Felt the ignition coil and it was very warm, bordering on hot. So, I took the ignition coil out to measure everything. When I first tried measuring the resistance I got no measurement across the + to - at the terminals. So I took it all apart to clean it all up and was then able to measure 3.9 ohms, but it had cooled down considerably by then. I then measured 11,500 ohms from the center to either + or -. From what I have read that is too high so I'm going to replace it.
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Patrick.
76 Westy Deluxe, Original engine (2.0L, FI, solid), Sage Green

"Don't sell yourself short judge, you're a tremendous slouch."

[TyWebb]

Should have said D186504 Pertronix Flame Thrower distributor. Looks like it should use a 3.0 Ohm coil, which is what the one I have is rated for. Have already ordered a new one and will report back results.

Patrick
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Patrick.
76 Westy Deluxe, Original engine (2.0L, FI, solid), Sage Green

"Don't sell yourself short judge, you're a tremendous slouch."

[TyWebb]

[doublecanister]

You may have checked the gas tank screen inside the tank but my engine started bucking one day under load in the mountains of all places.
At Idle was fine, start trying to drive and the engine bucked horribly, was starving for fuel.

Before I figured that out I ended up bypassing the gas tank with a 5gal and long hose and the problem cleared.

Also I've heard some fuel pump (mechanical) rods can get hot and get stuck and cause issues.

My gas tank had been previously sealed with a non ethanol compatible tank sealer, it melted and looked like a big purple buggar in the tank.
I noticed the fuel was turning purple in the engine bay filter I had at the time as well as small rust pellets.
Ended up with new gas tank and new tank filter to fix.
Hope you find the issue and it's a cheap fix
T
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2020 - Mustang Eco Boost [High Performance]
1973 - Thing
1966 - Mustang GT- Fastback
1951 - Ford F1 pickup Flathead V8

[joosty_chin]

Mine had a similar problem, and it was the distributor condensor.

[Heiferman]

[TyWebb]

So, this problem seems to be resolved at this point, but it was a long road to get here and I broke the 1st rule of troubleshooting - I changed more than 1 thing at a time. I'm posting this 'resolution' post just to maybe help people in the future with this problem.

I made a lot of assumptions based on the fact that since I purchased the Thing as a father son project in 2018, did a lot to it, including new fuel tank, lines, filter, etc. that that was all still good. It wasn't. Even though it had like 10 miles on it. So, to begin with, never assume.

Yes, the tank was 'new'; but in the years since I purchased it, sitting there with gas in it, it got really gunked up. It was stupid of me to believe otherwise. When we eventually got around to pulling and draining the tank (and the nasty fuel that was in it), and pulling the filter sock out of it, it was nasty. If you believe you might have a fuel delivery problem, pull the damn tank and ensure it's clean. It's got to be the easiest tank to pull on any vehicle ever made. I don't believe I had a fuel delivery issue, but I feel a lot better about the system now that we have thoroughly cleaned the tank, replaced the outlet elbow (old 'new' one leaked), new fuel lines (again), cleaned central line, and replaced the fuel filter (that had 10 miles on it).

Then I replaced the ignition coil with a new Petronix unit that measured the right resistance. At this point the problem was probably solved, however, when I tried to test drive it, it had no brakes. This is the reason the this 'resolution' post is soo late. I spent the last 2 months going down a brake issue rabbit hole. Ended up replacing reservoir (original was cracked), then the wheel cylinders, then flex lines, then the master cylinder, then the brake light switch. It was a mess. It was probably the leaky switch the whole time, but now we have a pretty much new brake system, which I guess is the bright spot.

So, the down side is I cannot definitively say it was the ignition coil that was 'the solution' in this case, but it probably was.

The up side is that we are now really confident of the:
1: fuel system (cleaned tank, new outlet elbow, new fuel lines and good hose clamps, thoroughly cleaned carb (including fuel pump on carb which I skipped cleaning prior to a suggestion in this thread)
2: brake system with new reservoir, MC, brake light switch (only replaced 1), flex lines, wheel cylinders, proper adjustment and brake bleed
3: ignition coil which is new and measures out correctly

And my son is now REALLY comfortable with bleeding brakes, adjusting brakes, adjusting axle nuts, bearings, setting timing, etc. All the things I had hoped to get him used to in 2018 when we first started working on this father son project. It's 6 years later than I had hoped, but he's really taken ownership, and that makes it all worth it.

Moral of the story, I guess, is don't give up if you find yourself in a similar situation. If the problems seem to multiply, keep working through them. And don't assume. Start at the beginning and work from there. You will find the solution. It's just a car, and a simple one at that. And when you eventually get the end it will be satisfying and you will both have learned things and be more confident in your skills when the next problem pops up.

Thanks again to all the helpful posters.
Best,
Patrick
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Patrick.
76 Westy Deluxe, Original engine (2.0L, FI, solid), Sage Green

"Don't sell yourself short judge, you're a tremendous slouch."

[Heiferman]

Glad you got it going. It can be a confusing battle at times. I am in the middle of advance v rich v retard v advance right now on a big engine I know nothing about.. congrats
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- 1973 Thing, some LandCruisers and an old Ambulance