Boxer tuneup

JRV: I am following your tech section on the balance, etc, for the Boxer.

I wanted to do this, because, when one stands behind the car, one can just smell the "rich" exhaust.

The car had a major service in '01, with new wires, plugs, injectors, and cleaned fuel distributors. The car now has about 2K miles more on it, since then.

Using the vacuum gauges, I was able to balance the manifolds evenly, to 15 in Hg.........they where only slightly off.

Using the gas analyzer, I came up with the following figures:
Right; CO = 0.48-0.55........HC = 300, with spikes to 500.
Left; CO = 0.48..............HC = 340, with spikes to 500.

The manual calls for CO to be around 0.9%.

Since it already smells "rich", if I increase the CO to 0.9%, won't the HCs go up as well?.....and the smell will even be more obvious?

Did the previous tuner compensate for something, by leaning it out to 0.4%?.....thus, trying to keep the HCs down?

Could the plugs be fouled due to driving the car 2K miles, thus the present readings?

I am unsure where to go next.

BTW: The car runs very well.

Thanks

Henry,

the HC's should go down when you richn to 1%..low CO high HC's is lean missing...once the CO is at 1% the HC's should come down to 150-200ppm...the smell is probably HC not CO you are smelling.

Try that.

Do your FP Regulators have the crossover pipe?

Interesting. I will try this tomorrow.....setting the CO to 1%, and "watching" the HCs go down.

I agree that the smell is HCs.

I am not sure of the FP regulators.......will check that tomorrow.

Thanks.

Hank,
I couldn't agree more with JR...

Years ago when I had my shop, we would adjust for the lowest possible HC. HC reflects combustion inefficiency, so a lower number is better. If all other engine factors are in order, the CO...which can be calculated to the A/F ratio, will fall within factory specs. You'll find as you adjust the mixture richer, the HC will fall as the CO rises...and then the HC will start to rise again. You'll know at that point, that you've gone too rich...

I don't mean to second guess the master at this...just providing my observations from past experieces.

When I had my Euro 328, she typically would measure 160-180ppm HC and 1.1-1.2% CO...

Regards,
David

>>I don't mean to second guess the master at this...just providing my observations from past experieces. >>

David..with all due respect I still consider myself a student of the craft, and plan on being able to use this forum to learn as well as share my learnings. I truly hope everyone will feel free to contribute & share their knowledge & experiences without feeling any reason to hold back. Truy what I would like to see "is a whole group" of guys "that can & will share with others"...maybe something like the Rand Corp. of the Ferrari world, an awesome think tank where we can all come and solve problems. {}


>>When I had my Euro 328, she typically would measure 160-180ppm HC and 1.1-1.2% CO... <<

which raises another question...I thought BBi CO specs were 1.1%-1.2% as well, rather than 0.9%?

>> Years ago when I had my shop, we would adjust for the lowest possible HC. HC reflects combustion inefficiency, so a lower number is better. <<

absolutely...once one gets the engine running right...HC is used to find the 'sweet spot' , where, given the conditions (compression, timing, cam timing, etc) the engine is tweeked to find where it is firing as perfectly as it will as reflected by the lowest possible HC numbers one can obtain. Additionaly if the HC won't come into range it tells the tuner other anomollies exist somewhere that may be unknown, and need to be found...bad timing, dirty injectors, incorrect FP..air leaks, etc.

Well, the results are in. Using the CO meter I obtained the following:

Both banks; CO = 1.1-1.2.......HC = 136-140

After doing this the Hg went to 17 in, and the idle went to 1200. I used the bypass screws to adjust.....Hg went to 16, with idle at 1000.

While the HC was at about 140, I noticed frequent spikes up to 300.......I assume that this tell me of some sort of miss, as in plugs or wires. Since the wires are new, I will assume that some plugs may have to be replaced, due to driving for the last year with the originally high HC figures.

I will drive the car for a while and re-check.....maybe things will settle in.

Thanks JRV, and David.

Oh, I forgot........after I set the Hg to read even, I have to go back and "re-adjust" the CO. Is that correct? I just took a break.

I didn't realize how everthing affcts the HC/CO readings.......does this mean that when I replace the air filters, I will have to do this again?

BTW: When doing the adjustments, I had the air cleaners off. It would seem that the final adjustment should be done with the air cleaners on.....is this correct? The vapors from the crankcase enter here, and the air filter could restrict "some" air.

Henry,

Yes in all truthfullness once you turn a screw it has an effect on something else, and also yes when you put the AC's back on the mixture normally richens up a bit.

The situation is that as you get closer to exact the smaller and more careful you need to be with adjustments and the more often you need to check opposite sides..in the end one or two very Slow and steady sets &amp; checks will bring you to just about absolute. You can check the CO AC on &amp; off
and compensate pre-install if you find it neccesary.

Regards, JRV

A couple of thoughts/experiences...

The spikes in HC...Hmm. Although I would certainly check the plugs for abnormality, I wouldn't discount a faulty injector spray pattern and/or drip.

HC/CO and idle speed will all react with one another. Now that you've got the base idle back to where it should be, a re-check of the HC and CO levels would be prudent. Re-installing of the (clean) air filter(s) should have little effect.

A good drive and a re-test makes perfect sense...I always felt, either real or imagined, that with low HC numbers, the car always felt snapier...

Hank..I really admire your dedication and persistance to dial this baby in!

JRV: Thanks........well back to the car, for the final dial-in.

David: This is a fun hobby for me.......I would NOT want to do it for a living!!!!! Besides, finding out how lean the car was running, and correcting it, can only help in the longevity of the engine........the gas analyzer already paid for itsef........see how I justify these toys? I can't wait to get the injector testor..HAHA.

Those monster size vacuum gauges you recommended worked great.......I wouldn't have wanted them any smaller.

Thanks.