Bus - Rough Running Engine

ruckman101 · Post by **ruckman101** » Mon Jul 09, 2007 9:45 am

Finally my schedule allows a day to address Bertha's running issues still unresolved after our road trip out of Maupin.

Won't idle, runs at higher rpms. Compression good, spark plugs look good, timing was on, dwell at 50, valves fine, new points, cap, rotor, generator light glowing slightly always.

I'm down to the dash, turn signals still out, spark plug wires and the distributor.

I've never had my dash out. Here we go!

neal

ruckman101 · Post by **ruckman101** » Mon Jul 09, 2007 10:54 am

Bertha is a 1970 pop-top camper with a stock engine but for 87 mm cylinder/pistons and easier breathing exhaust.

My distributor would appear to be the culprit. Again no gap. The springy metal cup with the ball bearing riding under it wasn't holding the plate the points mount to down. Thus, instead of my points opening, the plate would flex up. So dismantling so as to give the cup springy thing a bend back to stiffness needed to hold the plate down, I discover the copper grounding braid is loose, no longer attached to the same plate. Bugger.

Rather than paw through the distributor carcasses I have (because they were pawed through to assemble this distributor), I'm going to try a new Aircooled SVDA.

neal

ruckman101 · Post by **ruckman101** » Mon Jul 09, 2007 12:34 pm

Better, but still rough, so here's to spark plug wires being the final misfit in the equation.

neal

ruckman101 · Post by **ruckman101** » Mon Jul 09, 2007 1:15 pm

Curses! Still no joy. I'm flummoxed.

neal

ruckman101 · Post by **ruckman101** » Tue Jul 10, 2007 1:16 pm

Okey dokey, my distributor will not seat turned 180 degrees. I thought about rearranging the spark plug wires, but I'm pretty confident that isn't the issue.

I got excited when I noticed a vacuum fitting on the intake manifold wasn't plugged, but that wasn't it either. So I pulled spark plug wires from the cap and have good spark at each cylinder, and a noticeable change in the way the engine was running, except #2. No change, but sparking away. Not getting black smoke, and the compression was fine, I don't get it. Maybe a different spark plug?

neal

RSorak 71Westy · Post by **RSorak 71Westy** » Tue Jul 10, 2007 1:49 pm

If pulling the plug wire on #2 made no difference, that's your problem. It's not firing. Check the plug and the valve adjust on that cylinder pronto.

ruckman101 · Post by **ruckman101** » Tue Jul 10, 2007 5:18 pm

RSorak 71Westy wrote: If pulling the plug wire on #2 made no difference, that's your problem. It's not firing. Check the plug and the valve adjust on that cylinder pronto.

Already checked, valves are spot on, spark plug looks fine, healthy spark at the distributor cap, I have one more thing to check, brb.

neal

ruckman101 · Post by **ruckman101** » Tue Jul 10, 2007 6:13 pm

Nope, the intake manifold and boot aren't loose at all.

neal

Post by **Amskeptic** » Tue Jul 10, 2007 7:29 pm

Neal, I am not following what the issue is here.
Does it not idle, period?
Does it run well at higher rpm?
You MUST guarantee that the idle solenoid is actually retracting when installed in the carb. We had that little issue last summer. A click is not good enough. If necessary, turn the solenoid still plugged in while you are futzing with the throttle lever to keep it running. See if it suddenly clicks or behaves and then idles properly. Is the solenoid unusually hot?
Colin

ruckman101 · Post by **ruckman101** » Tue Jul 10, 2007 10:44 pm

Amskeptic wrote:Neal, I am not following what the issue is here.
Does it not idle, period?
Does it run well at higher rpm?
You MUST guarantee that the idle solenoid is actually retracting when installed in the carb. We had that little issue last summer. A click is not good enough. If necessary, turn the solenoid still plugged in while you are futzing with the throttle lever to keep it running. See if it suddenly clicks or behaves and then idles properly. Is the solenoid unusually hot?
Colin

It idles, but rough, shaking, doesn't accelerate up without stumbling, seems to smooth out at higher speeds but I'm leery it's just the higher rpms smoothing out the shake. Cylinder #2 doesn't seem to be contributing to anything at idle. No change in how the engine runs when the spark plug wire is pulled, unlike the other three cylinders. The spark is there and looks fine, the spark plug isn't goobered up or an odd color, a different spark plug did nothing, otherwise, new ignition components, timing is on, dwell is on, compression is there, I just don't get it. Intake manifold is tight, boot is tight,...vacuum leak? Issues at the dash?

Disheartening to say the least. VW wrenching and video are the same, the moment I start feeling accomplished, the rug is yanked out and I again am intimate with humility.

neal

RSorak 71Westy · Post by **RSorak 71Westy** » Wed Jul 11, 2007 9:25 am

When was the last time compression was checked on #2?

ruckman101 · Post by **ruckman101** » Wed Jul 11, 2007 10:34 am

RSorak 71Westy wrote:When was the last time compression was checked on #2?

I checked compression last week. If I don't have an all-staff meeting tomorrow, I'll futz with my idle solenoid. I haven't given that a look at all.

neal

Post by **Amskeptic** » Wed Jul 11, 2007 11:18 am

ruckman101 wrote:
RSorak 71Westy wrote:When was the last time compression was checked on #2?
I checked compression last week. If I don't have an all-staff meeting tomorrow, I'll futz with my idle solenoid. I haven't given that a look at all.

neal

Swap the entire wires between #1 and #2 from the cap to the plugs. If #1 is dead now, the connector's resistor might have gone south on you.
If you have spark, compression, fuel/air, #2 HAS TO WORK DAMMIT.
Colin
(I will be out in your area. . . . forthwith)

ruckman101 · Post by **ruckman101** » Thu Jul 12, 2007 12:40 am

Amskeptic wrote:
ruckman101 wrote:
RSorak 71Westy wrote:When was the last time compression was checked on #2?
I checked compression last week. If I don't have an all-staff meeting tomorrow, I'll futz with my idle solenoid. I haven't given that a look at all.

neal
Swap the entire wires between #1 and #2 from the cap to the plugs. If #1 is dead now, the connector's resistor might have gone south on you.
If you have spark, compression, fuel/air, #2 HAS TO WORK DAMMIT.
Colin
(I will be out in your area. . . . forthwith)

I had a brand new set of wires I put on. The only change was that it would at least idle and not die, roughly on three cylinders.

I'm with #2.

Now when you say idle solenoid, your talking about that device that also serves as my choke, yes?

Regardless, I'm going to be looking at my carb for possible massive dust contamination. Spark, fuel, air. Do I have to pull a spark plug, ground it still wired and make sure the spark is getting to the cylinder? Spark looks plenty healthy at the cap, and clips right along. Actually that sounds kinda dangerous.

Oh, wait, what do you mean my "connector's resistor"?

neal

Post by **Amskeptic** » Thu Jul 12, 2007 7:09 am

ruckman101 wrote:
[Now when you say idle solenoid, your talking about that device that also serves as my choke, yes?

???? The choke is the choke and the cut-off solenoid is the cut-off solenoid. The choke is on the upper right of the carb with a wire leading to its heater element, the cut-off solenoid is that little can on the left side with the wire attached to it.

ruckman101 wrote:
Do I have to pull a spark plug, ground it still wired and make sure the spark is getting to the cylinder? Oh, wait, what do you mean my "connector's resistor"?

The connector must have 1,000-5,000 ohms resistance measured from the wire end to the sparkplug clip inside the other end. You have to "unscrew" the wire from the connector to perform this test. If they are new Bosch wires with connectors, I doubt the connector resistance is off, unless they are making them in China these days.

If everything checks out, yes, you can test plug fully connected to wire. Ground it at the engine latch well away from the fuel and air spraying out the spark plug hole while the engine is cranked. Make sure you are in the shade so you can see the spark more easily.

I am getting curiouser and curiouser.
Colin

Itinerant Air-Cooled

Itinerant Air-Cooled

Bus - Rough Running Engine

Bus - Rough Running Engine