Horribly Bad MPG less than 150 miles per tank
 

Hey Guys,

So my megasquirt V3.0 is given me problems. I havent had time to check it out yet due to finals, but my gas mileage is horrible. I dont think I am running rich because I am using the PNP basemap and I don't smell un-burnt gas. I have posted my log posted can you guys please check it out. It might be obvious what is wrong but I have to take care of finals first.

Some info: Running no MAF (IAT in its place), Timing is set, everything seems to be working correct.

http://www.mediafire.com/?mxmzty1mptx

thanks guys

you don't think you are rich? did you tune the map? it will run out-of-the-box, it certainly wont be perfect out-of-the-box...

Do you have a wideband O2 gauge? If so, then take some datalogs and start tuning in megalogviewer to some target AF ratios. I am doing that myself now. If you do not then maybe someone with a similar setup can help you out. You need to include your configuration in your sig so we will know what you have.

my nose is calibrated to itch at 12:1 AFR.

Post your entire setup, every single piece of your system... better yet, ad it to your signature.

sorry if I have been leaving things out... I have been super stressed with 4 finals in a two day period.

My setup is a stock 1.6 miata with a stand alone megasquirt. The wideband is on the way but not here yet. The only thing I have modified is I have removed the MAF and uploaded the PNP basemap. I have not changed any of those settings because I havent had time, but this gas mileage is horrible for school so I really need to figure it out.

Other issues (might be related):
My idle was surging high to about 1300-1500 constantly even after warmup.
The "warmup" box in the realtime display is constantly red regardless of it the car is warm.

if it makes you feel better I have a WBO2, tuned the car right, and I get about 14 mpg city. Granted I'm making at least twice as much power.... but it's still hitting my wallet just as hard.

really? i got my WBO2 in and the pnp all set up and after yesterdays tune im doing about 30mpg city and highway mix on my last tank of gas

Hmmm, so I'm not the only one.

Haven't been to the dyno yet, but I seem to be getting ~ 19-20 MPG lately, even on the highway! My cruising AFR appears to be right around 14.7, but of course EGO is still doing a lot of the work.

Thinking of leaning it just a tad in the lower cells, and of course I need to get off my ass and do some steady-state work. MLV is nice, but there's no substitute for a nice fine-tuning on the rollers.

i just changed to this afr target map on my 1.8... havent finished tuning because im broke and have been driving long distances lately, so the OEM 30mpg ecu is runnin shit for now.

Attachment 214060

I'm running mine much leaner than that in the cruise areas, more like 15-17:1 AFR. However when I get into the throttle, even just a little, it gets much richer very quickly, more like 12:1. I have been told by some in the know that this is an acceptable strategy.

I have been playing with this lean cruise a lot this week since my mileage dropped from 27 to 20 after the addition of the MS and the turbo. Of course a lot of the mileage decrease could be due to appreciating my new levels of power AKA heavy foot :) I'm logging my commute and tuning it in megalogviewer based on the 8X8 AFR target map which I am tweaking.

IMO life will be a lot easier once you get your WB02 in and start logging.

Dude, so you haven't tuned anything at all, yet your bitchin' that it's not tuned? For fuck's sake.

The worst I've been seeing is 24mpg. 27 is easy with mixed driving, and I've seen ~30 a couple of times. Pretty sure it would break into low 30s on extended highway trips. Cruise at like 15.7 or so. Rich down low. Rich up top. Gets rich under any load like gentle acceleration or a low grade hill.

This is with my factory odometer and 4.30 speedo drive, and 4.10 gears. So it's not an optimistic reading.

That is why I asking for help. I am running the PNP map as a base, that shouldnt cut my MPG in half. If I were to buy the PNP and run that I know for a fact that I wouldnt get 17 mpg.

If you dont feel like contributing then dont put me down, I am new to this megasquirt and there is a ton to learn. :) obviously you have been around a while since you are a mod, so I would really appreciate any help I can get.

Thanks

I used the PNP map as a base on a base miata. i used about 1/4 tank in about 20 miles. gotta tune!

I am contributing. You're not. If you don't feel like reading the manual, or the FAQ, or searching the board, don't come here asking for help. :bang:

I have done all that, which is why I was asking. Apparently from what I read I got the wrong answers, so I guess I gotta read more.

One thing I havent found from reading... why does the warmup tab on the bottom for the Realtime Tuning Display always stay red?

That means it is staying on. Check your settings in the warm up wizard. Also check your calibration for your coolant sensor. If it is off and reading cold, then your warmup enrichment might be staying on all of the time which would explain the crappy mileage.

OK on a whim I looked at your log file from your link above. Look at your coolant temps! Unless you have that set to celsius somehow, does a max coolant temp of 87 deg F seem correct to you? That would explain why your warmup enrichment is always on. Always check your data to see if it seems reasonable.

Hey 150 miles per tank is crappy but at least it runs. Get through your finals and fix it afterwards.

when you say standalone MS do you mean the MSPNP by DIY or did you have one custom built?

when I am running MS, the gauges show about 195-200 so I thought nothing of it. When i am in warmup wizard it has the cell at like 160 highlighted which corresponds to enrichment of 100% so theoretically it shouldnt be enriching, however that red light stays on.


and paul, the MS standalone is one i built following DIYautotunes site, this site and the megamanual

so what easytherm values did you use when burning the firmware?

did you copy the 3 .inc files for coolant and air temps to your working folder so MT shows the correct values?

I am positive I did, but ill try it again. If I copy them over again do I have to update the ECU or are they just for megatune?

those target afr's are a little lean at high load if you're concerned with longevity.

when you built the MS you should have had to burn the firmware to the ECU. Did you burn the parallel firmware which would have the wrong easytherm values?

what happened at 233 seconds in your log? Your CLT jumps up over 27 degress instantly at the same time your throttle position drops to 2 for the rest of the log yet your RPMs and MAP are all over the place. Bad connections?

91... check and check again. i forgot a zero twice when i was doing the easy therm and therefor i had a wacky function that wasnt linear so the car would be fine at some temps and other ones would just throw it into 300% enrichments

Definetly check your values, and as for the gas millage TUNE IT!!!


hustler, were you refering to my AFR table?

My fuel economy has been pretty bad lately, because of this I changed my AFR targets just before refueling. So far I have done 100km on 1/4 of a tank with the new settings which seems to be better than before.

Here is my revised AFR target table:

http://tim.kent.googlepages.com/2008...fr-targets.png

wat ru guys using for ego control settings?

I have:
Ign Events per step: 72
controller step size: 1
Controller authority % : 6

sometimes it seems too slow acting

Ahh OK I don't know what is going on there. Did you load the corresponding MSQ into megalogviewer when you looked at the log file?

Check the req_fuel value too. Should be around 13 for stock injectors IIRC.

At any rate as said above you will need to tune to improve your mileage. I'll bet the PNP maps are really conservative (tuned rich) to keep people from damaging their motors from being too lean. That is my experience anyway. It's better to have crappy gas mileage than a burnt exhaust valve.

What I just did was recreated the easy therm values and rewrote the .s19 and .inc files. I know I have updated the .s19 on the chip before but looking at the old .inc files they are different. So I just re-update the firmware on the chip, or would i be fine just copying the new .inc files. I dont know what will be lost if I update the chip. Will it just be the .msq that is on there?

Sounds like you need to change the output setting for the LED in megatune. It's probably set to some other feature instead of warm up enrichment.

its not the actual LED. It is the "button" labeled warmup in megatune when you are looking at the realtime display. It is red upon cold start up and does not change even at operating temperature

I've got the same settings as you, but my controller authority is only 5%. My main use of the AFR target table is within MegaLogViewer. Have you done a fair bit of datalogging and fed the data into MLV?

Cheers

Poor economy here too, although I've got a few other issues I'm trying to sort out. My target AFRs are similar to saboteur's, but I'm yet to do even half a tank on those settings to bother posting them yet.

I don't know what you guys are talking about I get great gas mileage. :giggle::giggle:

With my parallel install on my 97, on the highway I get about 29MPG, and could probably do better with better tuning. In town if I drive normally without a heavy foot, I get about 23-25, but with a heavy foot <20mpg. On track I get <11mpg, lol