2-for-1 and possibly related: Bucking and unstable/nonidle

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Mon Mar 09, 2015 11:38 am

Apologies for the prolonged discussion. I don't begrudge anyone who has tuned out.

I'll check the numbers tonight after work and report back what they are so there's something concrete to hang our hats on. I do recollect that the A/F ratios at 4,000 RPM were fairly active, going from bang-on 14.7 to 15.2. But I can't say for sure if I was at full throttle - probably- when that occurred, so I don't know if the enrichment kicked in or not. I'll verify that tonight as well.

I received my bonus at work this last paycheck and ordered a DD CHT to improve upon the lowly VDO CHT I have now. I'm not too worried about the anxiety...quite the opposite, I prefer the extra information. It should arrive any day now.
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Mon Mar 09, 2015 9:29 pm

Something I should've been clear on, my numbers previously were taken with the bus in the garage and running up the RPM there. I've always been uncertain about the tailpipe clamp for the LM-2; it's rattled loose more than a few times when I've thought it was tight. I didn't want to road test it and have it destroyed by coming loose.

On the way home from work, I bit the bullet and attached the clamp for the drive home. The road is mostly flat until I have to climb a big hill (1 mile long and about 500 feet elevation gain). On the level ground portion at 3,000 RPM and light throttle, the A/F ratio was right around 14.5. In fact, anytime I was at light throttle, it was slight on the rich side of stochiometric. The other throttle positions where in the mid- to upper-13s. Wide open throttle dropped it to 13.5. On the hill climb, I was going about 35-40 at WOT; A/F ratio was 13.0. No CHT data yet.
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

luftvagon
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by luftvagon » Tue Mar 10, 2015 5:37 am

That sounds about right.
1981 Volkswagen Vanagon Westfalia - air-cooled Type4 1970cc CV (hydraulic lifters, 42x36 valves, stock cam, microSquirt FI with wasted spark ignition)
1993 Ford F-250 XL LWB Extended Cab 7.3L IDI

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Amskeptic
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Amskeptic » Wed Mar 11, 2015 12:43 pm

luftvagon wrote:That sounds about right.
It will run well, but the CHT readings are going to be the critical data here.
Colin

( Luftwagen, what are your CHTs at various loads/fuel mixtures? Can you ask your computer to give us a real time "seismograph" line chart over twenty miles of mixed driving at 80* ambient? )
ColinGOMegasquirtAreYouMegasquirt?
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

luftvagon
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by luftvagon » Wed Mar 11, 2015 7:20 pm

That will probably have to wait a month or more. We are just now starting to peak to 70F.

I generally cruise at 15.2 AFR - not something you should try with L-Jetronic setup.
3200-3600 RPM with 60-65mph at around 6-4 inHg of vacuum (80-85 kpa engine at 100 kpa ambient).

At full load I'm pushing 12.6 AFR.
1981 Volkswagen Vanagon Westfalia - air-cooled Type4 1970cc CV (hydraulic lifters, 42x36 valves, stock cam, microSquirt FI with wasted spark ignition)
1993 Ford F-250 XL LWB Extended Cab 7.3L IDI

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Amskeptic
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Amskeptic » Fri Mar 13, 2015 11:00 am

luftvagon wrote:15.2 AFR - not something you should try with L-Jetronic setup 3200-3600 RPM 60-65mph full load I'm pushing 12.6 AFR.
Only missing data here is CHT. That is going to be a significant additional factor.

VW was perfectly capable of engineering an:
(I) economical engine that could
(II) move out of its own way and could
(III) stay cool.
Now, pick two.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Fri Mar 13, 2015 11:56 am

Calling Dakota Digital today to find out where the heck my gauge is. It was ordered 2 weeks ago and no shipping update. Will also have a fuel mileage calc available when I gas up after work. Stay tuned.

Update: Still a week out from shipping. *sigh* I'll connect my VDO gauge this weekend and see what that gives me. Intermediate information at least.
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Wed Apr 22, 2015 8:10 am

So Greta has been sitting for almost a month (with only occassional startups in between) since I'm moving this weekend and my free time has evaporated to zero with the selling and buying of homes. Several weeks ago, I had a new battery tray and a bung for my O2 sensor welded in by a local shop. Picked up the bus and drove it home. Ran just like I dropped it off.

Next day I struggle getting to work and barely make it home. Any time I add load to the engine, it falls almost completely on it's face. If I barely finesse the throttle, I can get up to speed with difficulty. This is like the 1st half of a grossly exaggerated buck without the kick of the second half.

So I take a look at the fundamentals, starting with the timing. What I find is that it'll startup fine, the idle is rough (at the best compromise from my previous efforts), but it will idle. When I put the timing light on #1, it'll look fine most of the time, then periodically, #1 will fire when #2 is in firing position. I haven't had assistance to check this at RPM (and obviously can't do it under while driving under load), but I'm guessing that this is what's happening when I'm trying to accelerate during normal driving.

Here's what has been done to the ignition system within the last 2-3 months (recapping earlier parts of this thread):
  • * wires, cap, rotor, coil, and pertronix swapped out in A to B testing with no difference found.
    * distributor rebuilt and recurved
    * plugs gapped and wire separators added between #1 and #2 to avoid cross firing
I also think I may have a short somewhere in the vehicle, if this seems relevant, but other than the driver's side brake light repeatedly going out and the battery drained from sitting, I have no other indication of an electrical issue.

I think I can manage to limp the vehicle over to my new house, but unless I improve things, it'll be a late night trip to avoid traffic as much as possible.

Looking for suggestions of what to investigate. Thanks in advance!
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

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Amskeptic
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Amskeptic » Fri Apr 24, 2015 9:27 am

Ronin10 wrote:periodically, #1 will fire when #2 is in firing position.

I also think I may have a short somewhere in the vehicle,
Does the engine speed drop when see this cross-fire?

Do you have 13 + volts when engine is running?

Have you experimented with running the engine without the O2 sensor plugged in?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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SlowLane
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by SlowLane » Sat Apr 25, 2015 1:52 am

Hey, um, what spark plugs are you running? Sure you have the right heat range?

In this entire adventure I note that you've pulled and re-gapped your plugs several times, but haven't tried a new set. Everything else in the ignition system seems to have been swapped out. Why not try the plugs too? Who knows, you could have one bad player.

FWIW, I'm not a fan of Pertronix, for a variety of reason. For the brief time I had a Pertronix on my Vanagon it didn't seem very happy until I swapped it back to the Crane XR700 which then gave me sterling service for years. Presently I have a modified CA-spec VW electronic ignition using the springs, weights and vacuum can from my original points distributor. That, plus a set of Magnacor wires give me about as good a spark as I can hope to achieve, short of going to a direct-fire system,

Good luck. Keep plugging
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Thu Apr 30, 2015 10:39 am

Sorry for the delay guys, I'm now settled into the new house. Still have to close on the old house in about a week, but other than a little basic cleaning, we're completely out.

Here's my status at the moment:
Image

I'll have this sorted by the weekend and get you the answers to your questions then. I do know that I did not have the O2 sensor AFM connected after I picked it up from the shop. And I'm using NGK plugs, but not sure of the model. I do remember taking the heat range into consideration when purchasing them way back when

Stay tuned.

Edit: Air Fuel Ratio meter not AFM. Doh!
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Sat May 09, 2015 12:08 pm

Amskeptic wrote:
Ronin10 wrote:periodically, #1 will fire when #2 is in firing position.

I also think I may have a short somewhere in the vehicle,
Does the engine speed drop when see this cross-fire?

Do you have 13 + volts when engine is running?

Have you experimented with running the engine without the O2 sensor plugged in?
Colin
Finally getting going in the new place. I have a dead battery after sitting a week without running. Second time it's happened in the last month so definitely suggestive of a short. Furthermore, in an effort to test the 13V+ while running, I measured the nonrunning voltage at the + coil terminal (should be zero) and found a nonzero voltage (0.01 after ramping down and settling).

Just to confirm. When I was testing previously, the A/F meter was not plugged into the vehicle. The port in the tail pipe was open however as the shop lost my plug. That shouldn't matter though.

Once the battery is charged, I'll report in again on the above queries.
SlowLane wrote:Hey, um, what spark plugs are you running? Sure you have the right heat range?
Plugs are NGK B6ES. I do have another set of B6ES's to install if need be, but I think I need to eliminate the alleged short first.
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Sat May 09, 2015 3:23 pm

Amskeptic wrote:Does the engine speed drop when see this cross-fire?
No, it doesn't. It does occur more frequently now, though. Instead of occasionally popping up, it's pretty regular.
Amskeptic wrote:Do you have 13 + volts when engine is running?
Never quite achieve 13 volts. When the engine is at it's rough idle, it's running about 11.6 - 12.0 volts. When the RPM is up, it's more like 12.5 - 12.9 volts.
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

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Amskeptic
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Amskeptic » Sun May 10, 2015 8:11 am

Ronin10 wrote:
Amskeptic wrote:Does the engine speed drop when see this cross-fire?
No, it doesn't. It does occur more frequently now, though. Instead of occasionally popping up, it's pretty regular.
Amskeptic wrote:Do you have 13 + volts when engine is running?
Never quite achieve 13 volts. When the engine is at it's rough idle, it's running about 11.6 - 12.0 volts. When the RPM is up, it's more like 12.5 - 12.9 volts.
I surmise that you have a blown diode in the alternator that is draining the battery when the car sits, and it drops the alternator output by a third . . .
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Ronin10
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Re: 2-for-1 and possibly related: Bucking and unstable/nonid

Post by Ronin10 » Mon May 11, 2015 7:15 am

Amskeptic wrote:I surmise that you have a blown diode in the alternator that is draining the battery when the car sits, and it drops the alternator output by a third . . .
If the diode in the alternator has gone bad, how does that relate to this cross firing issue?
Oscar: 1976 Sage Green Bus, Stock Motor, Solid Lifters, Manual Transaxle

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