Dr Dan's B6 build

[drddan]

I have no EGR (blocked off), and Taylor all silicone 8mm wires.
Dont think the problem is there. They are a couple years old, but are in great shape, and still look brand new, with no cracks or splits.

I used an old disty cap, and old rotor, though. Didnt look bad, but I think i'll get new ones.

There is a way to check the wires. I'll have to look in my subscribed threads.

[KingFish]

My guess would be fuel volume. If you are running on o2 you can put an DVOM w/long jumpers to see if you start to run lean at WOT. Would have to be a decent meter w/ a high sample rate for best results. Watch at idle as it switched back and forth between around 0 (lean) volts and 1 (rich) volt. Anyway the average should be .45 v. Then go for a ride, see if your average drops to the lean side (low voltage) of less than .45 v.

[Christ]

You can check the wires with an ohm meter, even if you dont know the spec, they should all be within 10% of each other or so.

Cap and rotor are old, if it only happens when cruising at lower RPM, check that all grounds are clean and making good contact, also check/clean/replace ignition components and check/set ignition timing.

The fuel volume is a possibility, but out would also choke out on long WOT pulls if that were the case, unless the fuel pump (if mechanical) is leaking internally. Theoretically, the internal lurk would be defeated by pump flow at higher volumes, and almost all pumps can apply much more than the fuel requirement at max volume.

Coil breakdown or internal short is unlikely, but also possible. The idea being that the coil is discharging internally before the circuit collapses at low RPM. Try cruising in a lower gear to see if it changes anything. 3rd and 4th at the cruise speed where you note the issue in 5th.

Also watch for excessive (any) smoke while the stuttering is happening, note color and consistency.

Unless you plan to replace the cap and rotor anyway, clean them with an emery file. The parts are cheap, but so am I. I reuse stuff successfully that most people wouldn't bat a lash over.

If you haven't, pull the plugs and note their condition, then replace them with copper anti seize compound. It is conductive and helps them ground to the head better.

Check that PCV is functioning correctly and there are no vacuum leaks anywhere.

[drddan]

Great advice. I will check on the things mentioned.
This is the new to me swap B6, has ALL new everything, except the coil, wires, cap, rotor. ( Hmmmm....)

All plugs (with anti seize), hoses, seals gaskets, etc... All new.

The coil is original. I have an aftermarket coil, MSD, I think it is, as well.
There are threads here that suggest not using a coil that doesnt have the required 3 ohm's, and why it is not on there now. Something about the incorrect ohm's can burn out the module in the disty, on the carb'd 88-89 models. I have it as a backup. It does work, I used it for a while.

As for the cap/rotor, everything else is new, why not those too?
Maybe i'll vid it, and I can post how it sounds.
It kinda does sound electrical/ignition.

I timed it before the big test drive. Played around with TDC/BTDC.
Ran it at 8* BTDC and 2* BTDC. Pretty much the same with the spitting.
It liked the 2* better.

Think i'll put on new cap/rotor, see how it runs, if ok...well ok!
If not, I might switch the coils and see if that helps.

I will test the wires with my handy-dandy radio shack digital multimeter! :p

A thought: Can the choke on the Weber 32/36 carb cause this?
It is a new choke element and just a dry setting was used when I rebuilt the carb. I'm thinking..nah! But I need to see where it is holding the butterflys at WOTand IDLE and if it is opening/closing right.
Just got it all running friday. Still working out the bugs.

[Movin]

Each segment of throttle opening is tunable on that weber, and in addition the air
correction tubes are tunable to shape the "bathtub" of the lean cruise curve.
Before getting into the complexity of jetting unplug your vacuum advance and
test drive to see if that clears the problem.

[drddan]

Each segment of throttle opening is tunable on that weber, and in addition the air
correction tubes are tunable to shape the "bathtub" of the lean cruise curve.
Before getting into the complexity of jetting unplug your vacuum advance and
test drive to see if that clears the problem.

I am not afraid to get into the Weber. I am getting intimitely familiar with the jets and tubes inside. I have lots of extra jets.
Right now I have the jets set to the factory specs, as it is set, when new from the factory. Which, btw, is different than it was setup on the B3.
The Emulsion Tubes had been switched (used carb) when I got it, and thats how it was until I rebuilt it for the B6. I switched the E. tubes back to the factory setting when I did the rebuild. (Now I am wondering if that could be the problem?)

The tubes are F50 and F66. Factory spec is:

Primary=F66 and Secondary=F50 Which is the way it is now.

On the B3, it was opposite. Primary=F50 and Secondary=F66 before rebuilding and install on the B6.

I will go see if plugging the v. advance lines does anything, first.

Be forewarned, I may PM you! :p

[drddan]

Today I checked the Taylor plug wires with a meter I have and.....


....I couldnt get a reading on the #1 wire :eeeeeek:

2, 3, and 4 checked .585, .597, and .608...zip on #1

Wow, I didnt expect that with the Taylor's.

I checked the 4 plug wires that were on the B6 when I got it and didnt get a reading on any of them either.

Christ you nailed it with the plug wires!

[Christ]

Pretty common thing. Im not sure the composition of the Taylors, but graphite wires (old school, even before my time) used to have that problem. In cold months, the graphite would get brittle and crack, then engine heat and arcing wouldmake gaps in the wires causing misfires. Modern wires are good for the life of the car sometimes because they're spiral wound copper cores. No need to change them at intervals, just as they fail. I sometimes make my own from a cord of wire, replace them as they go out of spec.

[Christ]

Also, when testing wires, there is a change in resistance per the length of the wire. Remember that if you test any other sets.

[drddan]

Okay, I changed out the wire....no luck, still missing

I did notice the diff in length and readings. The new one I put together from a length of Taylor wire I had, read the highest .833

[drddan]

I pulled the plugs wires individually, to see if I had spark on all the wires/cylinders. Good spark on all 4.

I used propane to see if vacuum was an issue. It didnt smooth out like I read it would, if there was a leak, but around the vacuum ports on the rear driver side of the intake, it looked like it blew smoke out around where I had the propane nozzle pointed??? Weird?

[Christ]

New cap and rotor on yet?

Only skips ay cruise load, or at idle too?

[drddan]

Smooth as silk at idle. Only spits when given gas. It appears to be random misfiring. I am thinking elec components...coil, disty, or similar?

I have spare coil, and disty. Swap stuff time.

[Christ]

Yeah, do the easy stuff first... Dont be like me. Lol

[drddan]

Yeah, do the easy stuff first... Dont be like me. Lol

I think I have already been there.... :p

I'll report back, when I swap stuff....one thing at a time...to see if it cures, and what it was. I almost hope it is the disty, because it has a warranty.

Freebie!!!!