realtime monitoring tools for pre-obd2 cars
 

so, i have a 95 integra that is not supported by the scangauge. i'm not prepared (at this moment) to drop $165 into a superMID even if i could get it to work on my car.

so, are there relatively inexpensive tools available that will aid me in knowing how my car is doing as i'm driving?


i've heard of using a vaccum gauge. presumably this indicates the level of load on the engine, higher vaccum=lower load and less fuel consumption.



any suggestions?

I would like to find a cheap fuel rate (GPH) meter and install one in each of my vehicles...the only ones I've seen are appropriate for a boat, not a car, though I don't remember why I didn't think they'd work in a car when I looked them up.

Maybe because a lot of FPRs are integrated into the fuel rail, so you'd have to hack your fuel rail to get it in after the FPR?

On his Honda it has a return-type fuel system so the gph wouldn't really be relevant unless it read how much is returned back to the tank since the electric pump should be pretty much stable on the fuel that's being delivered to the fuel rail.

A had a vacuum gauge on my 95 Integra, and it shows little more than when you push the throttle, you make less vacuum. Be light on the gas pedal and you'll make more vacuum and get more MPG. There is a home-made MPG gauge I saw someone working on (look in the VX lean-burn monitor thread in the tech section on here for a link to it) but it looks quite complicated if you aren't electrically savvy.

I haven't gotten around to doing it yet on my 1991 CRX, so at the moment this is just theory, but...

It occurred to me that you could wire up a LED indicator light (for example "green" for "go") in parallel with the fuel injector (so that the LED is run by the same signals that trigger the FE to use fuel). In theory, this should give you an easy to see (and cheap to install and run) indicator light that gets brighter the more fuel you are using, and cuts out entirely when you get FE cutoff (coasting in gear). Not exactly the same as a real time MPG meter, but it should give you some fuel use feedback on the cheap!

NOTE: Some places will sell you LED indicator lights already combined with a simple regulator, so that you can directly hook them up to a car's electrical system (in this case the FE signals). For example, I've thought about using these LED modules ( https://www.superbrightleds.com/specs/wiredLED.htm ) from https://www.superbrightleds.com ($1.99 to $2.99 each, plus shipping, depending upon LED color) for a few indicator lights (including a FE indicator) added to my dash.

I read about someone who did this, and posted the following question in another thread:
How precise is the current that operates the injector? Could the LED affect the operation of the injector by diverting some of the carefully-measured current from it?

Thinking about it, you could probably rig a voltmeter through a capacitor to give you injector pulse width duration, would probably only be accurate to within a percent or two, but would be a good visual indication.

Nissan injectors seem to have about 15 ohms resistance..

Putting a superbright LED in parallel with the injector circuit with say a 5K ohm current limiting resistor shouldn't hurt the injector performance at all.

Things which move from electrical current, like an injector pintle, generally use a lot more current than a small LED is going to require..

Can you find out what the resistance of the injectors in your car is?

You would have to use a diode to keep current from the capacitor from flowing back into the injector when the capacitor had more charge than the injector drive circuit

Many Cadillacs and Lincolns from the early '80s on have an MPG readout built in. My first one was in my '85 Continental...along with a digital gas gauge which read in gallons (you could watch the gas being sucked right out!). Same with my '84 Town Car, although you got a bar-graph fuel gauge. If you went into diagnostic mode, you could even see the fuel flow rate.

My '83 Eldorado also has one built in. It's been really fun to use it to try out various driving techniques (got behind a truck one day on the freeway for about 20 miles and got my average MPG over 32). It is really nice to have that kind of instantaneous feedback. However, since these work off each car's computer, I don't know if it would be possible to get the appropriate parts from a junkyard and adapt to another car...

Back in the '70s vacuum gauges were sold which were calibrated as green, yellow, red...green meant you were getting good mileage, etc. Some mid-'60s Chevy Impalas came with a similar vacuum gauge installed right in the dashboard.

I just remembered...I used to have a bunch of Hot Rod magazines from the late '40s and early '50s...similar vacuum gauges were marketed even then.

all obd1-obd2b hondas have saturated high-impedance injectors ~12ohms resistance

Would a light emitting diode do the job? :cool:

My 1987 Cadillac Deville had it too. In diagnostic mode you could get all kinds of sweet realtime data, though at the time I had it I didn't care about fuel flow rate. You could also get the trouble codes too. I wish modern vehicles came with that; you still have to pay hundreds of dollars for an OBDII scanner that will give you that amount of data (or at least $160 for a ScanGauge). A cheap one just gives you trouble codes.

LED's don't like reverse voltages, so the answer is no..

J.C. Whitney still sells one of those... ;)

Good point.

Just wondering if a regular AC voltmeter would work....

"I would like to find a cheap fuel rate (GPH) meter"

Me too, so I got a DMM with a dwell feature.

"It occurred to me that you could wire up a LED indicator light (for example "green" for "go") in parallel with the fuel injector (so that the LED is run by the same signals that trigger the FE to use fuel)"

I don't think this will work, because the injector is controlled by pulse width, not increased/decreased voltage. In other words, I think you will just see a steady glow. The LED is not going to report pulse width.

"you could probably rig a voltmeter through a capacitor to give you injector pulse width duration"

I don't get how that would work. But you can get the info you're looking for if you get a DMM with a dwell feature. Some are expensive, but Harbor Freight has one for $33. For me that was a very good value, because it's a decent DMM, and it's also a tach, which I needed. It will also measure temperature, with a thermocouple (although I haven't tried that). And there's also the dwell feature.

I also bought their timing light for $11. Cheaply made and not very bright, but it worked fine, and is perfect for my occasional use.

I don't work for them. I'm just enjoying these bargains.

I'm using the DMM daily to monitor fuel flow rate (by reading injector duty cycle), and air/fuel mixture (by reading the output of the wideband O2 sensor on my VX). It works great (although I can't read both those values at the same time, of course). I'm learning a lot.

It was easy to set up, and I'd be glad to offer suggestions to anyone who needs tips on how to do it.

Now that I've gotten started doing realtime monitoring on my OBD1 car, I'm thinking about taking it further.

I notice that it's possible to get a PC-based data-acquisition interface for as little as $25 (that's the RS-232 version; USB is $50). See here: https://www.dataq.com/194.htm

With 4 channels, and a laptop sitting in the car, I could do realtime data capture of all sorts of things. The most important data is fuel flow rate and vehicle speed. This would be enough to do all sorts of interesting mpg calculations. But I could also grab throttle angle, air/fuel mix, engine speed and/or engine temp, or other things.

It's hard to mount a laptop next to the speedo, but I could put it on the floor in front of the passenger seat. I could set it up so large numbers appear, so it would easy to glance at it. This is more-or-less how I currently use the DMM. (Or I could rig the kind of support cops use to mount a laptop they can see while driving.)

But the real payoff is that I'm capturing a mountain of data that I could analyze later, in various ways. And if I'm driving the same route every day, I could end up with a spreadsheet or similar program that lets me do careful comparisons of different driving strategies.

It seems to me that an approach like this would beat the pants off a Scangauge, in both features and cost. As far as I know, they still haven't delivered a PC interface. What I'm describing should be able to provide all the measurements provided by an SG, but in a way that captures the data for further analysis, which means you can get a lot more value out of the data the vehicle provides.

Another approach to this is to use a PDA (e.g., a Palm Pilot) instead of a laptop. Then it actually would be easy to mount the device where is can serve as a display while you're driving. While also capturing the data for later analysis and comparison.

As far as I can tell, this hasn't been done yet, because data acquisition systems, and computers to run them, used to be scarce and expensive. But that's not true anymore.

Anyway, I'm wondering if anyone here has tried anything like this, or heard or seen of anyone trying anything like this. And does anyone see reasons why this wouldn't work? I'm trying to think it through.

Wow! Sounds like you know a bunch of stuff I want to know. :thumbup:

What is "dwell", anyway?

Links to HF for the DMM and timing light? I think I found them:
DMM, $33: https://www.harborfreight.com/cpi/cta...emnumber=95670
Basic timing light, $13: https://www.harborfreight.com/cpi/cta...temnumber=3343
Deluxe timing light with advance, $30: https://www.harborfreight.com/cpi/cta...emnumber=40963

I'll be right near a HF store on Friday, and I was already planning to go there and spend money I don't have on stuff I don't need. :D

Anyway, can you provide hookup details for dummies?
- What and where do I probe to read injector duty cycle? What setting do I use on the DMM?
- Where is a good place to probe the o2 sensor? What setting do I use on the DMM?
- Any other suggestions and details?

I have a Ross Tech Vag-Com for hooking my laptop to my VW, but I won't have it for long, and I'm not entirely satisfied with it anyway. It does a decent amount of logging, and can log at least 4 variables simultaneously. I just got it yesterday and it's broken already, but it seems like it would do what you want. I think they make similar products for non-VW cars too, or maybe it would work on a plain OBDII. Once it's fixed maybe I'll try it on my GMC. The problem is price; it's $250, though that's for the latest one that can do all kinds of cool stuff with a 2006-2008 VW.

The Dataq data acquisition kit doesn't look like something that can be figured out by someone like me, let alone people who are less technically inclined. Could it be done by non-techies with a DIY document?

On your PDA idea, I have a Garmin iQue 3600 PDA/GPS with a dash mount that I've always wanted to interface to OBDII...

"Sounds like you know a bunch of stuff I want to know"

Great. Just ask. I'm also learning some things from you.

"What is 'dwell' "

Before the existence of modern electronic ignition (found on all cars today), ignition systems used to use points (a kind of mechanical switch). They would open and close rapidly, as the distributor spun. They would cause the plugs to fire. It was important to adjust how long the points were closed (as compared with the time they spent being open). Because this had to do with rotation, the name given to this concept was "dwell angle" or "dwell time." It basically means the points are closed a certain percentage of the time, and open the rest of the time.

More stuff about this here: https://www.jetav8r.com/Vision/Ignition/CDI.html

It turns out that this concept (something being in one state a certain percentage of the time, and being in another state the rest of the time) has a general name: duty cycle (see here: https://en.wikipedia.org/wiki/Duty_cycle).

It also turns out that the concept of duty cycle is a very important part of how modern EFI works. Each injector is open a certain percentage of the time, and closed the rest of the time. (This is called either duty cycle or pulse width.)

If you can observe your injectors' duty cycle (or pulse width), you are essentially monitoring instantaneous fuel use.

You can buy a fancy automotive multimeter, which has a special feature called "duty cycle" or "pulse width," that is mostly intended to monitor injectors (although it also has other applications).

But you don't need a fancy automotive multimeter. You just need an automotive multimeter that has a "dwell" feature. Why? Because "dwell" is really just another term for "duty cycle."

So it turns out that a concept (duty cycle) that used to apply with regard to ignition (points and plugs) is now being applied with regard to fuel (EFI injectors).

The term "dwell" is archaic, because cars don't have points anymore. But it's really just another name for "duty cycle," so you can use a dwell meter to monitor your injectors.

If you look around a place like eBay, you'll find lots of dwell meters, cheap. They are often called "tach/dwell meters" because they also do tach. They are typically old and analog, but I think they would probably work sort of OK, for this purpose. But I was happy to find a cheap new DMM with a dwell feature.

Actually, the digital dwell is much better. That's because your injector duty cycle % is often very low (a number less than 10, on a scale of 90). This small value could be hard to read on an analog meter, especially if you want precision. Whereas on a DMM, no problem. Also, the DMM responds much faster than a mechanical needle.

"links to HF for the DMM and timing light? I think I found them"

Yes, you did. I decided I didn't need the fancy timing light.

If someone wants a DMM and doesn't need dwell, HF has them as low as $4! Amazing place.

"I'll be right near a HF store on Friday"

I've never been in one of their stores, but I just found out there's one not too far, so I intend to visit.

"spend money I don't have on stuff I don't need"

I can relate.

"Anyway, can you provide hookup details"

I could be very specific if you had a Honda. You don't, but I think the general principles still apply.

"What and where do I probe to read injector duty cycle?"

My ECU has 4 pins, one for each injector. I just picked one. Positive lead of DMM attaches here. Other lead of DMM attaches to chassis ground.

"What setting do I use on the DMM?"

A dwell meter has choices for number of cylinders (3,4,6,8). It almost doesn't matter what you choose. You should get a precise and meaningful result, at least in relative terms, even if you pick the wrong scale.

I set mine to 4 cylinder. That means full scale is 90 degrees (a quarter of 360). When you're in the world of dwell, you're speaking degrees of rotation.

When my dwell meter indicates 10, let's say, it thinks it's telling me that my points are open 10 degrees out of each 90. But here's what it's really telling me: my injectors are open 10/90th of the time.

90 degrees just happens to be a number that's conveniently close to 100 per cent. So when my meter tells me 10, instead of thinking "10 degrees," I just think "10 per cent." Easy.

If I set the meter for six cylinders, then full scale would mean 60, instead of 90. Because on a 6-cylinder engine, a cycle for the points (for one cylinder) is 60 degrees of rotation, instead of 90 degrees.

But understanding this part isn't that important. Even if you picked the wrong dwell scale, you would still see the numbers rise and fall, in a very precise way, as you manipulated the throttle. And you would figure out how to translate those numbers into more meaningful units (like gallons per hour).

"Where is a good place to probe the o2 sensor?"

If you don't have a wideband sensor (I think you don't; do you?), you might find that reading the sensor is not terribly interesting or helpful. Anyway, to find the answer to your question you could consult a shop manual or wiring diagram to understand which ECU pins are attached to the sensor.

"What setting do I use on the DMM?"

With the O2 sensor, it's simple DC voltage. You have several scales to choose from. You probably want something like a 2V scale.

"I have a Ross Tech Vag-Com"

That's interesting. Never saw that before. Thanks for mentioning it.

"I think they make similar products for non-VW cars too"

Their web site says only VW/Audi.

"maybe it would work on a plain OBDII"

My car is OBD1.

"The Dataq data acquisition kit doesn't look like something that can be figured out by someone like me, let alone people who are less technically inclined. Could it be done by non-techies with a DIY document?"

Yes. That would be the concept. You would hopefully just need some simple instructions about how to hook it up.

Did you get the Vag-Com specifically because you liked the idea of getting this kind of data onto your PC?

Hmmmm have to get digging through my old magazines...

https://www.nleindex.com/index.php?pI...dex&tID=E/4157
https://www.4qdtec.com/Automob/TachDwell.html

Slightly off the topic, but...

I was playing with a co-workers 1999 Dodge truck a while back. I knew that with the '80s Mopars you could get the trouble codes by turning the ignition on and off three times. I tried it with the '99...got the trouble codes to read out through the odometer. (She was having issues with the EGR at the time.) Wonder how many other OBD II cars can access the codes in a similar manner?


Regarding the Cad...I love all the realtime data I can get...plus the ability to reset the "Service Soon/Service Now" lights. Most of the sensors have rather dodgy wiring...the car was a home for rodents for a few years, I think (there are still little poops all over the intake manifold!)

:) Thank you for all the data.

They often discount them to $3. Great place, I love it. Many/most of the tools are cheezy chinese knockoffs, but they get the job done and I would have none of them if not for HF. I was ecstatic when they finally put up a store in my state.

A similar company is Cummins Tools. They don't have as many stores, but they have a traveling sale, which comes to my small town once or twice a year.

Cool. I can probably extend this wire to a convenient place on my dash and probe the extension. Then I can buy one $30 meter and use it in both vehicles.

I thought they were common on newer vehicles, but maybe one or both of my vehicles have narrowband. I'm very interested in open/closed loop detection, especially in my VW.

Yeah, I checked and that's what it looks like. However, while using the software it seemed like it would do some of its stuff for standard OBDII. Probably not.

Not at all. In fact, until I had it, the idea hadn't even occured to me as being worthwhile, because I had planned to eventually get a ScanGauge II. I hadn't planned to get a Vag-Com at all due to the expense, but then I realized if I just got someone to commit to buying it from me then I could essentially rent it by buying it and then re-selling it. The only reason I wanted it was to change these programmable behaviors:
- One press of "unlock" on the remote unlocks both doors and the hatch
- Locking it doesn't make the horn go "beep"
- When I shut the car off everything unlocks
- I can open and close the windows using the remote (from long distances, even)
- The rear wiper doesn't come on automatically when I shift into reverse with the front wipers on (at least, I think it won't now)
- The rear wiper won't do the delayed cleanup wipe after I shut it off
- Seatbelt chime partially disabled (sometimes I start the engine first, THEN buckle my seatbelt before driving away)
- Some others that I don't remember
Also I needed it to clear a VW airbag code that my $40 HF standard OBDII scanner wouldn't clear.

The programmability of the 2006+ VW MkV platform is very cool. :cool: You can adjust a lot more things, even mechanical things (like steering effort, for example) but I didn't bother as I don't know how to adjust anything that I care to change.

Anyway, once I had it I decided I'd take it on a few data collection runs, and gather data for my daily commute. I want to know how gas pedal position affects throttle opening with the drive-by-wire system, and how my low RPM / heavy foot strategy affects air/fuel ratio, fuel flow rate, and such. I especially want to know when I'm in DFCO and when I'm not. I'm pretty sure it's all the way down to 990rpm but I think there's some lag in some cases.

The procedure was similar for lots of 80s vehicles, which usually reported codes by flashing the dash backlight IIRC. However, for some such vehicles, a proprietary scan tool is now $25 at the nearest chain auto store.

A basic OBDII scanner is $30-40 at Harbor Freight now, worth it considering how many vehicles it will work on.

I have a major rodent problem with anything outdoors where I live, backed up to a state forest. The damned things have been destroying everything and I'm tired of it. I recently put out poison...

AH Finally! someone who thinks like us...
https://www.ggimages.com/rx7/pwm.html

I can send you some cats....

lol I've got two of 'em, don't let them outside.

Plus, the Buick has a cat that I'll be removing...

Keep it up, love the links you're coming up with! That one may be too difficult (especially when you can get that DMM from HF for $33 to do the job) but this one from the same site, I like:
https://www.ggimages.com/rx7/afmon.html

He's got a few cool links, actually...take a look at the list at
https://www.ggimages.com/rx7/rx7.html

It's hard to say, I might hook up my DMM across one of my injectors and take a look when I get a little time to play.. I don't think I have an analog voltmeter any more.. I'll have to take a look in my junk box..

FWIW, an LED does indeed respond to pulse width as long as the current is kept quite low, a 5K ohm series current limiting resistor and a schottky diode would do the trick.

The circuit would look like this...

Injector positive---->LED--->5K resistor--->schottky diode--->injector ground.

A regular diode would probably work just fine but a schottky diode is high speed and might respond to narrow pulse widths better.

You could pick up everything at Rat Shack for less than $5..

I would get 2K, 5K, 10K and 20K resistors and see which one gives the best brightness variation.. Or just use a variable resistor and play with the settings ..

I know this thread is more about the cheap DIY solution, but I think it's worth pointing out that for a little more than a Scanguage, one could have an OBD-1&2 compatible scan tool with real time display and logging. E.g.

road: "have to get digging through my old magazines"

Great stuff! I had a bunch of those old magazines. I knew I never should have thrown them out.

"AH Finally! someone who thinks like us..."

Another nice find. I like the chrome plate.

I think it's interesting when the hot-rod car culture starts bumping into the green-miser-cheapskate car culture. They are seemingly contradictory, but I think a lot of us (like me) have a foot in both worlds.
-------------------
holy: "A similar company is Cummins Tools"

Good tip, thanks. I didn't know. I think they are found at toolsnow.com.

"I can probably extend this wire to a convenient place on my dash and probe the extension."

Exactly, yes. I think this would work just fine.

"I thought they [wideband O2 sensors] were common on newer vehicles"

No, I don't think so. New vehicles have a bunch of O2 sensors, but I think they're the simple kind (i.e., not wideband).

"I'm very interested in open/closed loop detection, especially in my VW."

I think there are various approaches to accomplishing that. But since you intend to use dwell to monitor your injectors, it could be that the simplest thing is just to watch what they do at large throttle settings. If they suddenly open up a lot, this could be a nice direct indication of open-loop.

I haven't tried this, so I'm not sure. It's a hunch. Maybe someone else who knows more about this aspect will chime in.

"while using the software it seemed like it would do some of its stuff for standard OBDII"

Maybe so. But I don't even have OBDII. No VW, no OBDII. So Vag-Com can't do anything for me.

"I can open and close the windows using the remote (from long distances, even)"

Oh, so that's you. Now I know why my windows go up and down at night. jk.

"I especially want to know when I'm in DFCO and when I'm not."

I find that my DMM/dwell device gives me great info on that. I see it happening very clearly and consistently (850 rpm, just like the shop manual says). Then again, I still much prefer coasting in neutral.
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fume: "I might hook up my DMM across one of my injectors and take a look when I get a little time to play [Just wondering if a regular AC voltmeter would work]"

I tried a DC voltmeter. Didn't work. It didn't occur to me to try AC, but I don't think that would work either.

"an LED does indeed respond to pulse width as long as the current is kept quite low"

Interesting. I didn't realize that. Sounds like it might be a very simple way to get some useful info.
-------------------
snax: "one could have an OBD-1&2 compatible scan tool"

The beauty of watching the injectors is not just that it can be done simply and cheaply. It's also more accurate.

OBD2 does not report what the injectors are doing. (I think some makers, like GM, might have that info in their OBD2 protocol, but it's not part of the general OBD2 protocol. And I think this is also true about OBD1.) Therefore, OBD2 is a fundamentally flawed way of monitoring fuel consumption.

Devices like the Scangauge are a good example. It relies completely on OBD2. Therefore it can have a hard time calculating fuel use. It accomplishes this by making calculations involving air flow. This usually works pretty well, but there are all sorts of circumstances where the scheme falls apart, and the result is inaccurate results. A lot of the time, the user is probably not aware that they are accepting numbers that are wrong.

The methods being discussed in this thread aren't just cheaper. They're more accurate. And also more universal, because they apply to any EFI car, OBD or not.

More details on this issue can be found in various places, like here:

https://forum.ecomodder.com/showthrea...ight-1949.html

The thing is, they are both about getting the most out of a vehicle, which requires a scientific/technical mindset.

I'm coming at it from the same perspective, old hot rodder, sports car/motorcycle enthusiast suddenly forced to look at it from the opposite point of view.

Being obsessive helps. :D

I think everything you said probably applies to a bunch of us. Well said.

Good idea. What kind of data does it provide and log? Sites describing it are a bit short on info...

Anyway, the biggest problem with it is the form factor. It can't easily be used as a gauge. The ScanGauge can be mounted on the steering column and you can look at 4 simultaneous pieces of data while driving. That DMM from HF won't fit there, but with its big display it can be mounted somewhere less direct, such as off to the right of the car's gauge cluster. Of course, unlike those two, the Equus unit can log data, which can be useful in different ways.

I guess they changed their name. It looks like they're not as good as they used to be. I bet their traveling sale is still good though.

Which shop manual provides that info? I'm almost 100% sure it goes down to 990rpm in my VW, but in my GMC I can't even begin to guess except by someone's report here that their Cavalier only does it down to 1800.

Trying to keep an automatic above 2000 rpm when approaching a red light / going downhill / etc makes for a bit of a jerky ride, which makes my wife sick. Generally if I'm driving the GMC my wife is in the passenger seat...

Thank you. I've been trying to find out if it measures fuel flow or if it calculates it, but nobody's been able to answer. You may have just saved me $160, though the SG is probably still convenient.

This thread is great. :thumbup:

I spent some time yesterday working on a couple of rattles, so I guess I also one of those obsessive types. My wife and pop (now 87) think so.

One of the real annoying rattles turned out to be what I think was one of those dealer sabotage jokes that stupid mechanics play on each other at the customers expense.

Someone had popped out the access plug to the back end of the rocker panel and dropped in an old Proto 5/16-1/4 drive socket, which would roll around in the cavity in the rocker panel when you went around a turn. The second was the glove box. Honda had installed a shock absorber on the box which had a loose pivot on one end. The glove box rattled when you drove at low rpm. Now I have no more annoying rattles when I use low engine speeds.

I learned clutches a long time ago, but when I first drove a Z car with the old SU carbs the throttle response was so instant I learned to keep my heel on the floor when working the clutch. I can engage the clutch completely at 200 rpm above idle.

All this may seem irrelevant but be patient, I'll get there.

I bought my VX in March this year, did the second oil change yesterday.
Filled the tank, also another local tank at 55 MPG. I have driven this car long enough to be able to closely estimate the mileage based on the fuel guage itself. Not precise or instantaneous but it doesn't cost me a dime.

Basically my mileage is 55 in local traffic, 60 in low speed highway (55MPH) and 65 at 65 drafting big trucks at three stripes distance (I believe that is legal everywhere, as well as fairly safe).

In my previous 84 Del Sol the best mileage I ever got was 47, the average was 42-43. Thats over 10,000 miles. Worst was 36 at 75-80 MPH, about 39 at 70.

I dont do engine off coast, the amount of attention it requires in the sometimes very heavy traffic here is detrimental to my situational awareness.
In 42 years of driving no person has been injured while riding in a car with me. I would like to think that is priority number 1 for every driver.

The VX required a change in driving tactic to achieve the mileage I currently manage. The first two tanks were 50 MPG. I was actually somewhat disappointed compared to the difference in the EPA ratings of the two cars.
Reading this forum especially the links to VX info by Tom O with the article by one of the Eco marathon hypermilers (probably some of the best anywhere) I learned that the VX is difficult to hypermile. Lean burn does not work for 30 seconds after engine off coasting. Lean burn is difficult to maintain on acceleration, not possible at greater throttle opening positions.

To allow the vehicle to obtain max mileage averaging better than 56, required different driving tactics from those I have used for several years. It takes a while (about 3000 miles) to reprogram my old brain.

When they build the right engine powertrain combination hypermiling will be ineffective. which is the basis of my powertrain and engine designs. When that is done (whether its my idea or someone elses) hypermiling will fade into history because the worst driver will have a hard time driving stupid enough to be uneconomical. At present it takes the smartest driver to accomplish maximum mileage (not necessarily the smartest person-just one who drives smart ;) ).

The specific changes in driving my VX for max mileage (remember no engine off) are:

Pulses are much more gradual, with significantly lower throttle openings specifically to try to stay in lean burn. If lean vurn didn't exist I would use much larger throttle openings, but the much higher AF ratio cancels out the advantage of larger throttle openings (just my opinion)

P&G cycles are therefore much less perceptible to other drivers, probably unnoticeable to many.

P&G full cycle times are shorter with a speed variation of only 5 to 7 MPH in traffic. Call it stealth P&G, most of the drivers around me are probably unaware that my minor speed variations are intentional (or they just think I am a jerk who can't maintain a constant speed LOL). It does discourage tailgaters.

Deceleration is accomplished with transmission downshifting to maximize fuel shutoff time, Since almost every red light ahead of me has cars waiting for it to change I try to downshift to keep engine speed above 1100 rpm for as long as possible. Ideally I match the speed of the traffic as it accelerates away from the light in the correct gear at just above 1100 rpm (eliminating all idle losses).

I have to loose some efficiency to accelerate enough to keep the lights timed properly due to the way they are timed here. In most cases if you go the speed limit you will catch every one, three miles over the limit and you catch almost none of them. It works against efficiency to a degree but thats just the way it is, and if you get caught at every light you loose a lot.

I draft whenever its possible. The traffic here can be very heavy and I use that fact to my advantage, instead of allowing it to aggravate me. Every time a SUV pulls over one car lenght in front of me it's a drafting oportunity. It used to be a source of aggravation.

I strategically plan my routes (40 years local knowledge) to minimize thraffic lights and left turns. In one instance a left turn can result in waiting 1 minute 45 seconds for the light to change. When that happens I take an alternate route. My average speed in local driving is about 38 MPH, which is exceptional when you consider that route has 56 lights in 40 miles, with speed limits in the 45 mph range, except for a 4 mile stretch at 55 mph. Maintaining the highest possible average speed (to a reasonable point) minimizes idle wastage, especially combined with in gear deceleration which is the same as engine off without killing lean burn potential.

Sorry about hijacking the thread. It would be nice to be able to have an instant fuel economy reading to further improve my technique. Instead I have used the knowledge available here to accomplish the same.

My driving technique also has another advantage in that it is prioritized to preserve my vehicle without creating situations that would accelerate wear and tear on components. My goal is to drive this car another 8 years (I will be eligible for Medicaid) until the manufacturers have resolved their design issues to the point where it will no longer be necessary to hypermile, because the vehicle itself will do the hypermiling and the driver will not have to be the real brains of the system.

regards
gary

Palm Pilot datalogger for OBD-1... mitsubishi specific, but may work for some functions on other vehicles that use similar protocol...
https://mmcdlogger.sourceforge.net/

MiniDash for chrysler SMEC/SBEC
https://www.squirrelpf.com/shelgame/M...niDashUser.pdf

More reading...
https://www.getglitched.com/pgmfiwiki...taLogging.html

HAlo OBD1 datalogger demo...
https://downloads.zdnet.co.uk/0,10000...297387s,00.htm

Most of those you'll be needing a RS-232 to TTL serial (5V) adapter, hackable with a MAX232 chip.

I think we have to be in the 10s of Mhz range before we need to worry about needing schottky for speed, and is it gonna make any difference if the rise time in the LED is slower anyway. I guess it does mean less forward bias voltage drop though.

I looked through Ebscohost for the articles listed in there. I've found only this one:
Build a duty-cycle monitor. By: Campisi, Skip, Popular Electronics, 1042170X, May97, Vol. 14, Issue 5 (in Ebsco's "MasterFILE Premier" database)

It's got the full text, parts list, and photos of the finished product but the circuit diagrams are missing. :( I think there's enough info in this thread that it's no loss anyway.

I *said* I was obsessive. :D