Loss of Vacuum?

[ViperTony]

I've been having fun using my Vec3 logging features and as I have begun doing pulls and gathering logs on my way to tuning my n.a. RT/10, I've come across a strange situation. When I'm doing my pulls which are done in 3rd gear starting at 2K RPM and ending around 5500RPM, I'm getting a sudden drop in Vacuum in the middle of the pull. You can see this in the Vec3 log below. At first, we thought I was letting up on the throttle but this isn't the case. Before I start checking TPS voltage, is there an explanation for this loss of vacuum?

You must be registered for see images

 

[DAMN YANKEE]

Hey Tony,

As you are mapping the "AN1 In" pin position, which is normally an empty... some may ask, "what sensor are we looking at?"

In this case, Tony has added the stock PCM "Manifold Absolute Pressure" (MAP) sensor to "AN1 IN"

Tony is able to look at both the "internal to the VEC3 MAP" sensor output as well as the "Stock PCM MAP's" own output.
They are scaled somewhat differently as the VEC3 MAP has a much wider range (Vacuum accuracy).
Also, Tony has his car's specs at the bottom of his thread so we know he is not S/C or Turboed..
When in "open loop" (WOT), Tony is coming out of Vacuum and moving towards "normal corrected atmosphere"....
Vaccum should exist when the throttle bodies close down and the manifold, starved for additional air, creates a vacuum state..

Interesting questions come up when we start looking for vacuum in WOT...in other words, at WOT the MAP readings should be equal to local barometric pressure...for Tony, thats sea level (plus some temp correction). For those keeping up...if Tony had a S/Cer, when he goes WOT...we would go BOOST!

Tony can you please uncheck the wide band so I can see the scale on AN1 and repost the graph?
In fact Tony, would you please uncheck RPM (now that we know it approx) and check only the "Stock MAP-AN1" and the VECS own MAP?
Lets first look to see if the issue shows up on both...

The scales now? Left hand is his wideband ( a little rich for a normally aspirated Viper..we want 14s), right is RPM (full range on this pull).

Lastly, Tony wants to check his TPS next. Thats "Throttle Position Sensor" to see if there is a problem with the sensor keeping a "fully open" signal constant to the PCM.
A good next place to look...first one would check to be sure both his throttle bodies have

1) right timing to open together
2) acheive FULL OPEN position....No carpets hoding the pedal up, throttle cables properly adjusted, etc.

Thanks!

 

[ViperTony]

Dan,

I'll try to live up to your standards on detailed explanations! A little background on my RT/10 setup: I am running a n.a. engine, Belanger Headers and Catback, RT Cats, Stock Plugs, AB's Wires, K&N Filters, Smooth Tubes. I recently installed a Vec3 and began logging. What you're seeing below is a screen shot (slightly cropped) of the Vec3 Log Window which you cover in your #6 - Let's Go Logging - IA Guide.

I'm using the Vec3 Analog 1 Input to display the Stock MAP Sensor input. All of you SC guys use the Vec's internal MAP sensor and have no need to look at AN1. However, I have both the stock and Vec internal map sensors hooked up. AN1 simply needs to be set to the correct sensor name for AN1 in the sensor settings window:

You must be registered for see images

This log chart shows both the Stock Map Sensor (AN1) and the Vec3 Internal Map Sensor (AN3):

You must be registered for see images

There's a variation between both sensors as it seems the Vec3 MAP sensor has a wider range of operation. Interestingly, if I read this correctly, the internal map sensor shows a bit of boost.

Every pull I've done over the last two weeks shows the same behavior. I will check my throttle bodies and carpet clearance. Hopefully, it's that simple of an explanation.

Thanks,
- Tony

 

[DAMN YANKEE]

Tony,

Great job! Ok, now I got a sense of what I'm looking at. What we have here is the following:

1. At the onset of his WOT (wide-open-throttle) the Viper moves quickly from a vacuum state to "normal corrected atmospheric pressure"..or in other words...all the air the air box, air filters, smooth tubes, throttle bodies, etc. can deliver to the intake manifold. We see both graphs move up from a negative value (Vacuum) to "0" or one atmospheric pressure.
Perfect.

2. At around 4,000 RPM to about 5,200RPM, there is something going on that disallows the required air to be delivered and, according to both MAPs, the same effect as closing down the throttle comes into play. We move from "one atmosphere" to around -5" of vacuum.

3. If that isn't enough to make one go "whaaa?!"...at around 5,250RPM, the restrictive air issue is resolved and...yep, back to one full atmosphere.

So what is going on here?

1. Bad MAP sensor?....its gets interesting now, stay with me...Tony has a stock manifold (no supercharger manifold) and as such he is using the stock MAP sensor (left rear corner of the stock manifold). Tony also has a new VEC3 with its own MAP sensor...so where is that sensor tube attached? Well, Tony is using the front left manifold side NPT fitting right behind the left throttle body. Great place to tap in. So we have two (2) functioning MAPs and they BOTH show a "restriction". So we rule OUT bad sensors.

2. Filter? Nope, they are new.

3. Smooth tube collapsing? Possible as it is hard to check and if they are collapsing they sure wont be getting "better" at 5,250 RPM! Still possible....but I dont think so.

4. Throttle bodies? We start here. Smooth tubes come OFF. Somebody needs to sit in the car and gently press the accelerator to see first if the opening timing on both throttles is correct. Then its carpet out of the drivers side and somebody needs to press the throttle to the floor. Are both throttle bodies all the way open? Grab the connecting bar...can it go more open? Does the bracket on top of the manifold need to be adjusted so that the throttle bodies are WIDE open.

Tony?

Important to note here Folks, no "trouble light" has been thrown here....Logging picked it up.

Recent pull of my 5lber...yep, almost 9lbs....sweet

You must be registered for see images

 

[ViperTony]

DY,

Smooth Tubes: I don't see any signs of collapsing with the smooth tubes. They're a bit stretched over the throttle bodies but don't seem to be collapsing anywhere. I could always put the stock tubes back on and see if that makes a difference.

Filters: I just cleaned and recharged them last week. They appear to be fine. As a side note my RT/10 as 10,200 miles on it.

Throttle bodies: it appears that both throttles are opeining up in sync and there's no play with the throttle bar. While my wife had the throttle through the floor I couldn't move the throttle bar any further and the they were both fully open. I then removed the carpet mat and tried again and it was the same result. With the flaps fully opened I then checked each one to see if there was any play or 'flapping' thinking they could be loose but they're fine.

I will check the TPS sensor voltage in the morning. Sean Roe explained to me how to use one of the analog inputs on the Vec3 to tap into the TPS sensor voltage and log it.

Would oil vapor in the intake cause this? When I had the intake off last week for my thermostat install I found oil in each of the intake ports. That convinced me that my next project will be the catch can install. I'm wondering if I'm getting blow-by which is causing the air intake restriction? In fact, I checked the vent tube that runs into the air box and it had oil in it enough to coat my index finger.

You must be registered for see images

This
As a side note and just in case you're thinking this may have started after the manifold removal...this condition was occurring before I removed the intake. I installed new intake gaskets and torqued the maifold bolts per the torque pattern in my service manual.

I don't think this 'issue' cropped up recently. I always felt a bit of lag in that 4K - 5K RPM range at WOT since I had the car. It wasn't until I started logging and Sean pointed it out that I realized something was 'off'. This condition shows up in every log I've done since I started logging.

- Tony

 

[DAMN YANKEE]

Tony...just you and me still...we continue. Thanks for the promp replies. Good news on the filter, the smooth tubes and the throttle bodies. Interesting news about the oil collection and the resealing of the intake after inspection.

1. Oil in the manifold...in most (every) intake to cylinder...enough to coat your finger on the air box return. It is possible that if that same oil was working its way to the filter (or somehow past it) and back into the throttle bodies that it would have an effect. But...that effect would have more to do with destabilizing the air/fuel mixture (lambda) than creating the conditions that would cause additional vacuum at high rpms. Besides...your Air/Fuel looks stable as all get out right were the problem begins.

However...Look at some of your plugs.

2. The Throttle position Sensor. If the signal sent is WOT, then the PCM goes straight to hard programmed Open Loop. If that same signal begins to deteriorate or waiver, then perhaps the PCM receives a partial closing signal and reads that as the onset of deceleration and therefor vacuum.

Just got Tony's full log, for those that want to tear it apart...go here:

http://www.mediafire.com/?djnfngm0mey

Its late now, so Im going to sleep on this one...be back at ya in the morning.

 

[DAMN YANKEE]

Had a revelation last night....

Check this out...

You must be registered for see images

Duty Cycle shows a cut-back on the injectors, just where the vacuum comes back....it also shows duty cycle going to 100% as it corrects itself at 5,250 rpm.

This vacuum effect is directly effecting fuel flow to the cylinders. In other words, the PCM is cutting back on the injectors at the onset of the vacuum... as it should when confronted with vacuum.

Shows up perfectly on the "milliseconds added fuel" as well, injectors are having their fuel add cut way back...and then BANGO! adding fel like crazy....again..as it should when confronted with vacuum.

You must be registered for see images

Also, the timing map is changes as well at exactly the same time.

You must be registered for see images

I'm thinking...

1. TPS electrical signal is deteriorating and causing the PCM to respond to a less than WOT throttle. Since RPMs continue to build throughout the failure period, ignition is working and firing but with deteriorating timing conditions. A/F is good troughout so its not the "mix" of your fuel (though it is rich..and that along with a warm engine in hot temperatures can make for some pretty rich burning). Tony, lets see what the TPS reading look like. Im hoping they do not stay "WOT" throughout.

The key for me is that you said this condition has existed for as long as youhave owned the car (a sense that at 4k to low 5k, there is a loss of power). Lets hope it is TPS.

 

[GR8_ASP]

How do you explain the f/a being steady while the manifold pressure drops? To me that indicates the pressure drop is real and the MAP reading is directing the change in injector pulse width.

Do you have a dyno graph as well? I would expect it to show the power leveled off during that period. If the peak power was during that period then you know that you have a flow limitation somewhere.

I would work to isolate the potential causes of a flow restriction (the real pressure drop indicates a near constant flow during that period, which should be the highest flow region). It could be intake, valvetrain or exhaust.

 

[ViperTony]

GR8 ASP,

Here's the same log with HP and Torque curves. Both decline at about the point we see the drop in vacuum but both rebound when the condition corrects itself:

You must be registered for see images

Here's a Dyno chart from January (larger version http://members.cox.net/aperugini99/images/dyno.jpg):

You must be registered for see images

In January, I had a different exhaust setup: Borla Headers, B&B cats/catback. I don't see power and torque dropping off in the dyno chart. I'm wondering if an exhaust leak can contribute to this condition? I swapped out my exhaust in April. I'm going to check the TPS voltage this afternoon.

- Tony

 

[DAMN YANKEE]

GR8,

I would agree with you. I DO believe that the pressure drop is real in as much as the PCM/VEC believes it is real and IS calling for the changes in both injector modulation and timing. However the continued climb of the RPM and the constant A/F can only (to my mind) be tested against the Throttle Position Sensor.

Do I understand you correctly that when the MAP is at constant pressure...that a vacuum state is created? This sentence...."the real pressure drop indicates a near constant flow during that period, which should be the highest flow region"...I don't follow completely here.

I also agree with you about your top three....intake has to the most extent been checked by Tony...of those left (and after a faulty TPS).... I spoke to Tony and asked him when he last had his valves checked earlier this morning.

 

[GR8_ASP]

What I meant is a constant a/f ratio with a decrease in pressure can only mean one thing. Lower air flow. And lower air flow is completely in synch with everything mentioned. The question to me is why lower air flow. The power graph shown above now discounts some causes as the peak power does indeed occur later, meaning the intake and exhaust system can flow more air than demonstrated in the 4000-5000 region. For that conclusion I equate air flow with power. More power means airflow. Now finding the cause is another matter and very difficult to do from a far. Things like a resonance in the valvetrain or inlet/exhaust system could be the culprit.

As to the statement about pressure and pressure drop I talk in engineering lingo. Sorry. A MAP sensor is stating the pressure in absolute terms, thus no vacuum. Just lower pressure. The maximum pressure here is when the throttle is fully open and approaches zero, or 14.7 absolute. A pressure drop from 14.7 is in effect a vacuum.

 

[DAMN YANKEE]

Agreed on all points with one exception, MAP attaining "0" reflects one normal atmosphere of air desity (plus air temp correction), zero in this case does not relate to Lambda's 14.7 (14.7 pounds air to one pound fuel.. though that is the target a/f). That is why, as we loose one full normal atmosphere (non positive induction engine, so all we have is the air pressure we get from the atmosphere) the MAP reads a drop in air flow at the "zero" (one normal atmosphere) level, it does reflect vacuum and it does signal that the a/f needs to reflect the lessening air by reducing milliseconds to the injectors and/or timing changes.

I agree completely on all your other observations. I think Tony is bringing it into Tator a.s.a.p. for a scan and the Master's touch.

 

[DAMN YANKEE]

Update?

Well, Tony has spoken now to Chuck Tator, Sean and a whole host of kind members.
He is going in to a Dyno Shop in a short while and then a trip to Tators.
He is also finished hooking up the signal to TPS and we can expect to hear about that soon.
Thanks to all for the help.

 

[GR8_ASP]

14.7 psi is approximately 1 bar or 1 atmosphere. I was not talking about f/a ratio at that point. 0 vacuum is actually 14.7 psi on an absolute scale.

Good luck!

 

[GR8_ASP]

I have seen very strange causes for similar results. Even as strange as broken rings (serious ring flutter at higher speeds), or a camshaft with substantial wear. Lots of things can cause unusual flow effects. Keep us posted as to this mystery's cause.

 

[DAMN YANKEE]

GR8, now that IS remarkable, I did not know that! I just took it for granted you were refering to Lambda.

"Commonly used in the U.S., but not elsewhere. Normal atmospheric pressure is 14.7 psi, which means that a column of air one square inch in area rising from the Earth's atmosphere to space weighs 14.7 pounds."

" In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location. Similarly, as elevation increases there is less overlying atmospheric mass, so that pressure decreases with increasing elevation. A column of air 1 square inch in cross section, measured from sea level to the top of the atmosphere, would weigh approximately 14.7 lbf. A 1 m² column of air would weigh about 100 kilonewtons (equivalent to a mass of 10.2 tonnes at the surface)."

Thanks for the info...

Is it just a coincidence that Lambda is also 14.7:1 for a gasoline engine? Or is a pound of gas formulated to essentially support the "one atmosphere" equation?

 

[ViperTony]

Well, I was finally able to get a couple of runs in today and I captured my TPS voltage through the Vec3 log interface. Sean Roe gave me some instruction on how to use one of the Analog inputs on the Vec3 to capture the TPS voltage. The TPS voltage is not one of the sensors captured in the Vec3 log out of the box. I had to splice into the TPS output wire and into the Vec3. I'll post a write up on how to do that soon. Took about 10 minutes.

Why? The goal in capturing the TPS voltage was to see what the TPS is sending to the PCM during WOT. The TPS is one of many sensors the PCM relies on to control the engine. Is the TPS sending the correct voltage? Does the voltage represent WOT? Let's see...

According to my 2001 RT/10 Service Manual..."The TPS output voltage (input signal to the PCM) represents throttle blade position. The TPS output voltage to the PCM varies from approximately 0.5 volts at minimum throttle opening (idle) to 3.5 volts at wide open throttle."

I decided to the disconnect and reset the PCM and let the PCM learn the TPS voltage before I started my logs today. After reconnecting the PCM, I turned my ignition key to the "ON" position (engine not running) and slowly pressed the throttle to the floor representing the WOT position. This procedure let's the PCM learn the voltage range for the TPS, particularly the WOT voltage. I also logged this event in the Vec3. Here's the what the Vec3 log recorded:

You must be registered for see images

I did WOT three times. As you can see in the graph The TPS voltage varies from .8 volts in the Idle position to 4.0 volts in the WOT. In fact, if you look at the first curve, there's a bit of variance between 3.98 and 4.00 while holding the throttle in the WOT position. Odd. I saw the same idle voltage when the engine was actually running/idling.

I then proceeded to record two pulls. I'm maintaining WOT during the entire pull which is between 2100 and 5400RPM. I never let off of the gas pedal until my pull was complete at about 5400RPM. The results from both pulls were similar. This log shows the TPS voltage throughout the RPM range during the pull:

You must be registered for see images

Despite the fact that I have my pedal firmly planted on the floor, the TPS is telling the PCM otherwise...Could this be causing the condition we're seeing in the graphs below? Well, the TPS is definitely NOT representing reality. Could this be the culprit? We'll find out when I swap out the TPS tomorrow afternoon (assuming Chuck has them in stock).

If anyone is interested in dissecting these VEC3 logs, they can be found here:
http://www.mediafire.com/?9jdctcftl7y (Pull2)
http://www.mediafire.com/?d3h2rjyg2c1 (Pull1)
http://www.mediafire.com/?d3h2rjyg2c1 (Reset)

- Tony

 

[DAMN YANKEE]

Well, Tony...how telling is that! A perfect example of the Power of the Pull in giving the owner the info they need.

Great job on the whole process. Seems to me that you have found your answer! Its either the sensor or a grounding issue.
I know you are also looking into GR8's recommendations as well and are going to check out your header gaskets.
Best to Tator today, let us know what happens with a new TPS (Throttle Position Sensor).

Once the Viper is running without incident, lets work on the Air / Fuel.

For the reader...the oil found in the manifold was thought to be normal and not part of this issue.

 

[Purdue_Boiler_Viper]

Interesting. I'm curious on the root cause. A couple of hundredths of a volt variance at WOT or idle should be expected. When measuring voltage, you will see at least that much variance with any real world measurement device.

I am curious why you would record 0.8V to 4.0V vs. the manual's spec of 0.5 and 3.5V. I don't know if this is significant, but if you engineer a system for 0 to 3.5, 4.0V might be a problem.

I'd also think that your A/F would get screwed up if the PCM thought that you were at ~3/4 of WOT when you were really at WOT.

I'm just getting started on all of this on my 01. Thanks for the write up guys.

 

[dansauto]

Interesting. I'm curious on the root cause. A couple of hundredths of a volt variance at WOT or idle should be expected. When measuring voltage, you will see at least that much variance with any real world measurement device.

I am curious why you would record 0.8V to 4.0V vs. the manual's spec of 0.5 and 3.5V. I don't know if this is significant, but if you engineer a system for 0 to 3.5, 4.0V might be a problem.

I'd also think that your A/F would get screwed up if the PCM thought that you were at ~3/4 of WOT when you were really at WOT.

I'm just getting started on all of this on my 01. Thanks for the write up guys.

I think a couple hundredths will make a differance. I always thought the TPS read .5-5 volts? Good info, I think the 4 volts is correct the the manual is wrong. The TPS will not adjust for A/F that would be the o2 sensors, they would correct the condition caused the the TPS. I think he found his problem, Put a new TPS (make sure to listen to Chuck about the connectors as well-they sometimes dont "fit" right with a new TPS)

 

[DAMN YANKEE]

dansauto,

"O2 sensors, they would correct the condition caused by the TPS"...only if we reverted back to closed loop. And that may be the BIG NEWS here! In Open Loop we would be on hard maps. With the throttle bodies wide open and the air/fuel still "in line"...well that may explain it..closed loop has kicked in.

 

[ViperTony]

I think he found his problem, Put a new TPS (make sure to listen to Chuck about the connectors as well-they sometimes dont "fit" right with a new TPS)

Thanks for the advice. If the new TPS doesn't solve it...then I hope its not a grounding issue. I may check the PCM output voltage to the TPS sensor to see if it holds steady except I'm running out of Analog inputs on the Vec. Anyway, this has turned into quite the adventure. While my wife thinks I'm nuts I'm actually having fun with this. I'm still going to have Chuck check out the valve train at my next appointment, maybe install a set of rockers. I have to say the Vec3 has turned out to be quite the diagnostic tool. I'll keep everyone posted on the TPS sensor.

- Tony

 

[KenH]

Good work on this guys. The normal maximum TPS is anything over 3.5 if I remember correctly. I had a low reading TPS and my car would not go into open loop which caused all kinds of problems.

I think you are completely correct that the TPS voltage is dropping under 3V and the PCM sees it as lifting off the throttle and goes into closed loop operation and starts to try to drive the lambda to 14.7 instead of running off the VEC3 maps and starts pulling the gas.

 

[Steve 00RT/10]

I hooked up my TPS to the VEC 2 last year at install. My WOT voltage is always around 3.89-3.91........ give or take a few tenths. My idle voltage is around .84. A quick rev at idle runs it between 1 and 2. This would be closed loop.

Good luck. I'll a little smarter when you get this figured out.

Steve

 

[ViperTony]

Good work on this guys. The normal maximum TPS is anything over 3.5 if I remember correctly. I had a low reading TPS and my car would not go into open loop which caused all kinds of problems.

I think you are completely correct that the TPS voltage is dropping under 3V and the PCM sees it as lifting off the throttle and goes into closed loop operation and starts to try to drive the lambda to 14.7 instead of running off the VEC3 maps and starts pulling the gas.

I paid Chuck a visit today but he didn't have the TPS in stock. I picked up one at my local NAPA store. It was a quick change. I won't be able to do any runs until the morning but I was able to log the new TPS output voltage. This new TPS seems to output a little higher range than the old one. From 0.92 volts at idle to 4.06 volts at WOT as compared to 0.8 volts and 3.98 volts from the old TPS.

One thing that concerns me is that if the PCM is trying to drive the lambda to 14.7 when it sees this condition then my A/F readings don't reflect this...I would expect the A/F to rise above 11.2 to the 14 range but the logs don't show it. In fact, the A/F readings remain constant when this condition arises. I'll have results posted in the a.m.

 

[GR8_ASP]

Interesting. But one thing is a mystery. That is the real drop in pressure (increase in vacuum) measured by 2 separate MAP sensors. A TPS signal may impact power by adjusting fuel or spark, especially if it invokes closed loop. But it cannot cause a drop in intake manifold pressure. That requires a real restriction or dynamic condition.

Is it possible that the throttle is indeed closing some during that portion of the test? Maybe engine roll due to motor mounts or something.

 

[ViperTony]

OK. Finally got some runs in today with the new TPS installed. First, I wired in the PCM output voltage to the Vec3. Since both the MAP and TPS sensors are supplied with the same voltage source from the PCM I figured that if the PCM wasn't feeding the sensors a constant voltage then that might be an issue. I wired the input into the LCM-1 analog input so I wasn't logging A/F during today's runs.

Good news...throughout all of my pulls the PCM's output was a constant 4.98 - 5.00 volts. So we can rule out that the PCM voltage supply is an issue.

Here's one of my better pulls which is the last pull I did:

You must be registered for see images

In this pull the TPS voltage is stable from 4.0-4.02 but then drops off a bit to 3.89 before I pull off the throttle. At this point, I may have been hitting a rough patch of highway and my foot may have been vibrating around on the pedal. Even so, these TPS readings are much better than what we saw with the older TPS. The stock MAP sensor signal looks better but is still showing a slight dip. In this pull the worst dip was about - .90 to - 1.02.

Power and Torque numbers rose as well and the car felt a lot better. I picked up a little over 30TQ and 55HP. However, I hesitate to post Vec3 HP/TQ numbers and that may be a whole other discussion at some point. Suffice it to say, the car ran stronger with this TPS. The RPM line looks much better.

The chart below is the same pull as above but I added the Vec3 Internal Map sensor.

You must be registered for see images

The MAP sensor readings still bother me, especially the Vec3 Internal Map sensor. It's all over the place as compared to the stock map sensor. Which one do I trust? Does it matter?

Here's the same log again but showing Fuel DC% and Ignition:

You must be registered for see images

I don't think I'm out of the woods completely but this is definitely much better. My next task is to check the exhaust. When I go WOT during these pulls, I smell exhaust fumes for a brief moment. I have a theory that my crappy Belanger fiber manifold gaskets are leaking. I'm going to replace those with the OEM metal ones this evening and look over the exhaust for leaks and do a few more runs tomorrow morning.

GR8: You may be on to something with with engine roll and mounts. I noticed more vibration than I'm accustomed to seeing on my engine amongst other signs. I'll save this detail for later on. I'll get to this after I rule out the exhaust.

The logfile can be found here: http://www.mediafire.com/?8leobgsdym2

- Tony

 

[Joseph Dell]

I'm late on this thread... I did want to confirm for everyone that if you put a voltmeter on the TPS sensor, it won't go much beyond 4v at WOT. So this is normal.

My question to you Tony - what does your fuel curve look like? too much fuel or taking out too much timing (it does appear that you pull timing at the point where the bog happens) could cause the symptoms you are seeing. consider this: zero out the VEC2 and do a pul with data logging. does the case of the missing vacuum still exist?

JD

 

[DAMN YANKEE]

Just back from Flagstaff, I serve on the board at the Lowell Observatory and we are putting in a huge new scope with the Discovery Channel, really interesting. Looks like I missed alot of good work and great progress.