512 BBi ignition problems

Oh, and methodical is my middle name ;) I've spent way to many nights at 2am fixing a downed WAN links in europe not to be LOL

James

>> I agree the results thus far have been less than stellar, <<

It's possible to change that fact by following a few simple rules..{}....

1- do both FD's have adjustment screws in them or not?

2- does the car have Cats or not?

3- are you going to acquire 2 vacum gauges and T them into a convienient manifold vacum source?

4- are you going to post a pic of the exhaust?

{}

Regards, JRV

Patience JRV I'm at work, about 60 miles from the car at the moment LOL. I tried the "I have a sick car to take care of" routine once before, It didn't fly to well hehehe

Coach picked up some vac gages, we'll see what he comes up with. When I'm over there again, I'll get some photos of the exhaust on the lift and post them for you.

James

ok, JRV, I cam home early, after purchasing two vacuum gauges..hooked them up by teeing them to the each manifold, and cranked the car. After minor adjustments to the FD 3 mm screw that I had backed out too far last night, I was able to get a nice smooth idle at 15 lbs of Hg on both banks.

I am not saying the car is running great. I even left the vacuum gauges teed in for the next test. Which brings the next questions.

There are three port on the headers for emissions testing on each side. I now only have one emissions gas tester...in a week or so I'll have another. Do I hook three tubes to each analyzer using a tee? What do I use to hook onto those hot headers? I am sure as I start adjusting the 3 mm screws, the idle screws will have to be readjusted. So I kept them on... Can you answer my questions? I am enjoying this great learning experience.

The vacuum gauges read 15 on each side with no jumping around and that was the smoothest the engine ran...didn't want to press my luck to get 16 to 18.

Coach,

Leave the 3mm screws alone temporarily, they adjust fuel, vacum is air, and the air is adjusted by the large screws on the intake manifolds themselves.


Next step is to test the exhaust gas at the tailpipes. The Left Tailpipeis for readings of the Right Side of the engine. Set Both Sides to 1.5% CO...slowly and carefully, plugging the FD Holes after each turn of the screws. The FD holes must be plugged to get accurate &amp; correct exhaust gas numbers.

Try the above and let us know what you get.

Regards, JRV

how about wrapping the 3 mm allen wrench with electrical tape and pushing the tape all the way down to plug the hole leaving the wrench in place?This way you can make small turn and keep on going?

Probably not the best idea...in that even the slightest air leak, or minute pressure on the adjusting screw will affect the mixture setting.

Dialing in the mixture is a slow, precise process.

Regards,
David

Coach,

I use a plastic ball pen end or a small model paint brussh end cut to fit snuggly and form an air tight seal. As David says even the tinyest pressusre on the screw throws the actual reading far off, as well as any air leaks.


Again, just like the instructions state and David reiterates, getting the settings actually correct is a slow careful process, that has to be repeated side to side over and over until the settings are exact and remain exact, and the same after revving and driving the car.

HTH's

JRV

Coach,

Here are some pics of the adjustment screws.


The vacum gauges should be T'ed in in the small line in the photo. One per side. The Air Balance screw is for Setting Side to Side Air Intake Volume initially as determined by Vacum Gauge readings,, then used to make minor corrections as the balance process is worked thru.



The cover screw for the FD Mixture screw is seen in the photo. This cover screw must be removed for access to the Fuel Mixture Screw underneath, then replaced to prevent Air Leaks after each time a minor adjustment is made.

James and I are here in Anderson, SC, working on the Boxer. We followed your procedure religiously and we had a perfect match on the vacuum gauges, ans then proceeded to get excellent CO readings by adjusting the 3 mm screw slowly, plugging the hole and so on. When we had a near perfect match, we decided to rev the engine. It backfired wildly...which makes us believe we have a more serious problem than a tuneup. We are certain that the exhaust pipes do indeed cross over, and there are not cats...and we are certain that the bank with plugs no.1 thru 6,behind the passenger's seat is the one causing all the trouble. It is misfiring and sometimes flames shoot out of the exhaust pipes.

We checked theat bank for spark...we disconnected the fuel pumps, and we did the paper clip test...and perfect blue spark in each wire.

Where do we go next?

It idles near perfectly, at around 1750 rpm, and runs without any hint of misfiring until it is revved up...then it is scary.

Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!