Six_Shooter

iTrader: (2)

Well, I have in my posession a friend's 1986 Turbo Regal, that I am attempting to tune for him.

So far all I've been able to accomplish is setting open loop.

Adjusting the MAF tables and scalers seems to do nothing, rev limiter and fan scalers seem to do nothing....

Getting pretty frustrating.

He doesn't like driving the car, because it's usually rich at idle, can't get into the loud pedal, and just doesn't perform like he thinks it should.

I've read some stuff on tuning the '7148, but nothing is said to be any different than I'm used to with other ECMs, such as the '7749 using $59, '7730 using SAUJP/$8D/$A1/etc.

I thought I might have been onto something by changing the MAF 1 table scaler to half of the original setting, since it was running rich at idle before that and then was running stoich, so I changed it back to confirm results and it stayed stoich?!

I have fixed a couple of his mechanical changes, such as non vacuum referenced FPR, and no boost reference to his wastegate actuator, which was the likely cause of what he described to me to sounded like a boost cut limiter. I haven't driven it since to verify, that it doesn't cut out anymore.

I am using TP RT V5, ALDU1, Ostrich 2.0 with socket booster.

I have tried a couple different xdfs, and bin files, both downloaded and read from his EPROMs (Stock and Hypertech).

I have search around and read some stuff on here and elsewhere on the intarweebnetz, but nothing has really popped out at me yet.

Any insight into tuning this thing would be grand.

RBob

iTrader: (1)

By the sounds of your post it seems that either the ECM is in limp mode or the Ostrich isn't getting updated. The only time the MAF tables would be ignored is if the ECM thinks the MAF is bad. It will then use n-alpha mode.

The TTA '7148 code is similar to other GM OBD1 code. The www.gnttype.org site has a commented hac of the code along with a spreadsheet listing the calibration parameters.

Be careful with the waste gate solenoid & lines. One port on the solenoid is left open. The other going to the Y connector. The Y connector has a restriction in it that needs to be properly located in the scheme of things. This restricted end goes to the turbo bell port.

The boost limiter your friend mentioned may have been from the vacuum line being disconnected from the FPR. That is a disaster waiting to happen. Without that connected the effective fuel pressure will drop as boost increases. At a setting of 39 psi, at 10 pounds of boost the effective fuel pressure is then 29 psi.

RBob.

Six_Shooter

iTrader: (2)

There was definatly a boost cut limiter activating, It still hit a boost limiter, then discovered he had drilled a second hole in the actuator arm, so I put it back to stock for now and it pulls fine. Go figure..... There seems to be only one vacuum port on this wastegate. The way the boost control is set-up now, there is a connection at the compressor housing, that goes to a "Y" fitting, that splits and with one end going to the wastegate actuator and the other goes to a boost control solenoid located above the passenger rocker cover. This system appears to be conrtolling the boost correctly now.

Also I tried to explain to him long ago, that the FPR needs vacuum reference, I was thinking more to cure his rich idle, since that's what he was mostly complaining about, I meantioned "delta pressure to him" and he was liek a deer caught in the headlights. I completly forgot about the other end of the spectrum while under boost, I should have remembered that, since I've had to make sure of that on all of my cars. LOL

It does seem exactly like the Ostrich is not getting updated, but I haven't had any problems with any of the other cars I've tuned, mine or other frien'ds cars. They have been '7730, '7749 and '7747 ECMs though, this is the first '7148 that I have to tune. I will also be tuning a '7427 later today, once I get back down to my Grandparent's place to tune the '71 Chev truck, but that's a whole 'nother topic.

I don't believe it is going in LHM, the CEL is off, I'm getting data via the ALDL, and it actually runs pretty smooth, where it didn't seem to want to run in LHM, when there were some EPROM issues. There is a stored code 51 though, which is making me wonder.

The ADX I have has a flag for "MAF good" and it flashes the "Good" every few seconds. Is that normal operation? Or is this indicating that the MAF is bad or going bad? If it does need to be replaced, is there a later MAF that will work better, I can't imagine it being easy to find a GN/TR/TTA MAF now-a-days. IIRC, Grumpy used an LS1 MAF on is GN? It's been a while since I searched through the gnttype.org forums.

On the MAF subject, I read through some of the MAF Miscelanea last night since it was recomended as being similar between the '165 and the '7148 in another thread. The one thing that kinda popped out at me was that if the MSB is one number, after being calulated, the ECM looks at one table, if it is another number it looks at a different table. Which if I'm understand what was being said there, that the ECM might be using a different table than what I am trying to adjust, though I did try table 1 and 2, and also tried adjust the table 1 scaler.
I'm new to MAF, been tuning SD on everything else, so I'm trying to get to speed quickly here, but when looking at the tables, it would seem to me that table 1 would be low flow through the MAF, table 2 would be at a higher flow rate, etc. Am I wrong in my linear thinking of the MAF code?
BTW, I am getting 4 to 5 GM/sec at idle, which to me sounded low at first until I read some other threads, and it seems to be on the mark. The flow increases with engine speed, so it appears to be working correctly.

The rev limiter, is it only while in drive? I thought about this last night, that it may be ignored in nuetral. If it is ignored in nuetral, that would explain why it seemed to have no effect.

--==EDIT==--

I also wanted to ask about the checksum byte. When I open the bin, in the hex editor, I don't see "31" at 0x04 or 0x08, in fact I don't see it in the first line at all. I see some "00" and a "21" IIRC. I wanted to change the checksum byte to "AA" thinking that that might be part of my problem, but don't know the exact location. I also wasn't getting a quickly flashing CEL, so I don't think that's my problem anyway. This with bins that I have read from EPROMs or downloaded. for the TR/GN/TTA.

Saar

when i made my own $31 XDF, i found the Mask ID to be at $7A2...

Six_Shooter

iTrader: (2)

Interesting, but is that the checksum byte, or just a value in the calibration that is equal to $31?

BTW, the ADS works great, thanks saar.

Saar

that's the mask ID alright...

considering the PROM ID is stored at $79F, that was when i started realizing that the 3.8 and 3800 related masks seemed to be quite different compared to the average GM program..

Six_Shooter

iTrader: (2)

Interesting, according to this page: http://www.gnttype.org/techarea/chips/gmprom.html

The checksum byte is 7A2, verifying what you said Saar.

I will have to adjust that accordingly.

Thanks again.

Six_Shooter

iTrader: (2)

That it seems to be. I'm used to checksum byte being at 0x04 or 0x08.

RBob

iTrader: (1)

The checksum and maskid are two different items. The checksum also being 2 bytes in length.

To use an LT1/LS1 MAF need to use a translator box. For a mostly stock set up it really isn't worth it. Unless the stock MAF goes bad since the aftermarket ones are junk.

The MAF tables are set up in a linear fashion. As the flow increases the ECM moves from one table to the next one up the line.

RPM limiter: no test for park/neutral in the code.

On the Ostrich, is it set up for a 24 pin PROM?

RBob.

Six_Shooter

iTrader: (2)

I guess I'm misunderstanding the relationship, or at least how it seems to work in different codes.

Ahh, ok, I don't think we really want to get into that. So there's no other stock MAFs that are pretty much a direct replacement, electrically speaking?

Ok, so it should be easy enough to adjust, as I thought.

Ok, so I have to test while driving then, makes sense.

I'll have to check that, I think it's still likely set to 28 pin.

The funny thing is, that on the '7747, the switch settings never seemed to make a difference.

the Socket Booster is set to 24 pin.

Thanks RBob.

RBob

iTrader: (1)

No test for park/neutral means that the rev limiter should work in p/n or drive.

RBob.

Six_Shooter

iTrader: (2)

Oh, ok, definatly wasn't working in park/nuetral.

Six_Shooter

iTrader: (2)

Update.

Car won't run if the Ostrich is set to 24 pin mode. Set to 28 pin, car starts and runs fine, just doesn't seem to update to the ECM through emulation.

-=EDIT=-

Another Update...

Seems I have an emulation problem. Saving the bin, then uploading that bin to the Ostrich seems to take effect. I now have TR that will only rev to 1200 RPM. lol

So there's some progress. I wonder if it's bug in TP? I haven't had any emulation issues previously though.

Six_Shooter

iTrader: (2)

*sigh*.......

It seems I had a hardware issue, probably all along.....

If I pushed on the EMU cable or socket booster just right, Emulation would work perfectly. So I thought it was possibly a problem with the adaptor I made and soldered into the ECM....

Then I lost emu connection again, and it just wasn't coming back, pulled the Socket booster with the EMU cable still attached out of the ECM, look at the pins and pin 1 of the EMU cable (DIP socket actually, thankfully I put that on to protect the EMU cable itself), was bent. So I figure that when I put the right pressure on the EMU cable it was allowing it to make contact with the socket booster and emulate.

*sigh*

Emulation works perfect now..... Go figure. LOL.

Thanks for the help.

Six_Shooter

iTrader: (2)

I'm still having a bit of an Emulator connection issue, where every so often, I will notice that the CEL only turns on at key on and doesn't flash, I seem to need to unplug the socket booster, then plug it back in for the Ostrich to be seen. I'm thinking it might be the type of DIP socket I used on the adaptor in the ECM, to use 28 pin EPROMS.

Six_Shooter

iTrader: (2)

Is there a way to edit the ADS/ADX to show a value that I can then look at (or link) to the MAF tables in the XDF?

I can find with number of "pulses" will adjust fuel at idle, but under load this is more difficult to find. The MAF display only displays values up to 255, whihc makes sense, since this is the Gm/sec limit of the MAF tables, but how can I get a value that I can use to look at the "pulses" in the MAF tables to adjust properly? I've looked through the .ds file for this datastream, and nothing is jumping out at t me there.

In the MAF tables I have "pulses" starting at 0, then 64, then 128, in the MAF 1 table, moving up to 1792 pulses in the MAF 6 table, which I'm sure I won't need to adjust, but I'm just not understanding these MAF tables, and how to adjust them with the info from the ALDL datastream.

RBob

iTrader: (1)

If you want to data log the inputs counts inverse delta, it is ram locations $B0 and $B1.

Using those counts, table 1 is from 0 - 511,
table 2 is from 512 - 767
table 3 is from 768 - 1023
table 4 is from 1024 - 1279
table 5 is from 1280 - 1535
table 6 is from 1536 - 1791 counts

Taking the pulse count value at $B0 and $B1, the upper byte (MSB) defines which of the tables to use (1 - 6). While the lower byte (LSB) is the look up arg into the table.

It is very similar if not the same as the '7165 MAF table code.

RBob.

Saar

and here i just made a histogram that uses the XDF values for grams/sec and records total fuel trim to auto-tune the MAF tables...

Six_Shooter

iTrader: (2)

Alright, I'm going to have to learn how to edit the ALDL stream to get that working.....
I know you tried to help me with injector PW on a '7747 to be used in the ALDL stream, but I could not get it working, and that was a while ago.
Any documentation on how to edit the bin file for this? I'm going to need to find a fully commented hack now.
...And back to reading the Pink Book again..... I think I'll just have to wing it for now and watch datalogs, I don't really have the time to spend to read through it again, or farther than I did last time.

There seems to be a lot of similarity between the '7146 and the '7165, but this MAF stuff is making me feel like a complete n00b again. I can tune SD much quicker than this MAF stuff it seems.

Six_Shooter

iTrader: (2)

Could you share what you did? I haven't fully explored how to use the Histograms yet, but would like to use them more often.

Saar

what i did was copy all of the calculated gram/sec values into a histogram with total fuel trim being the value thats recorded and a "divider" to ignore the BLM/INT that registers while in PE. then setup a spreadsheet that uses the previous gram/sec and total trim numbers, outputs fixed tables(assuming the tables don't pass the maximum vale for the table set by the scaler) that can be pasted into TP. it would probably be wise to go over all of the tables to make sure sensor error doesn't play too much of a part in the calcs though.

it works in theory in $5B.

BTW: there is no 5B7 mask as suggested by tunercat. the code area is IDENTICAL, save one byte, comparing a 94-95 L27 vs 94-95 L67 BIN...

EDIT: you will have to modify the histogram (and spreadsheet if you're **** about it like i am) after every change, but i know of no other simple way of getting the job done.

RBob

iTrader: (1)

There is a hac over on gnttype.org

www.gnttype.org/techarea/ecmsensors/ecmpage.html

ECM Secrets Revealed!

RBob.

Six_Shooter

iTrader: (2)

Ok, I think I'm just not understanding this MAF thing....

I was out tonight trying to get this [explitive deleted] car running right....

It seemed no matter what change I made to the MAF tables nothing worked, or at least nothing improved much.....

I know that the changes I was making had an effect, just didn't seem to be the desired effect.

I've done some more reading on here, and it seems that the '7148/$31 MAF fueling is NOTHING like the '7168, or at least $6E. $31 doesn't seem to have a PW table like I have seen mentioned for $6E. $32 and $32B sounded like they were closer at first, but then not the same either, or I'm just not understanding.

The part I guess I really don't understand is the way the MAF tables are adjusted....

The Grams/sec gets adjusted, but how does this correlate to the MAF Grams/sec that is spit out the ALDL?

The way I would think it would work is that the MAF would have counts or "pulses", that would match the set parts of the MAF table, that would then look at the Grams/sec and use that for fueling calculations.
In reading some $32/B posts, it almost sounds like it is backwards, adjust the Grams/sec setting in the MAF table that you find it in, which would then move the pulses or counts that would correspond with that Grams/sec. If the latter is the case, then this would mean thet the corresponding "pulses" gets slid along the MAF tables in relation to the Grams/sec, as they are changed.

Lay-man's terms, pretend I'm dumb and please explain it, since I am feeling frustrated and dumb trying to figure out this MAF tuning thing.

Give me SD anyday. If the car wouldn't require such a drastic change to the ignition system, it would already have a '7730 or '7749 with $59.

--==EDIT==--

After doing some more looking around, it looks as though swapping in '7749 might not be so difficult...

I don't want to do that just yet, I would like to understand the '7148, but it's getting frustrating.

RBob

iTrader: (1)

Just go with an EBL flash. Kills many birds with one stone. No waste gate control, but it will handle a 2 or 3 bar MAP sensor. And the data logging, doc's and features, it'll knock your socks off. You won't ever go back to another stock ECM. It will also run with the LC2 DIS set up.

As for the '7148, it uses true conversion from airflow to injector PW. Not like the $32/$32B PW tables. GM did away with the PW tables from there on out. $6E does not have them.

The '7148 $31 code is like the MAF tables and scalars and calculations as I described for the '7165 ECM. This is always that way with the $6E code, and option selected for the $32/B code.

So if you are looking at the PW table tuning for the '7165, it doesn't work that way in the '7148.

Another thing about the '7148 ECM is that the data logging rate is 160 baud. That is about 20 bytes of data every 1.6 seconds. And in those 1.6 seconds many internal variables will be in a state of flux. So one variable in the beginning won't correspond to a variable in the middle or end of the stream.

To be honest, this is why the EBL/Lockers set up was created.

There is another item to consider: fuel pump pressure/delivery. For the most part whenever I've gone in circles on tuning. It was always that the fuel pump/delivery system was not up to the task. Without a solid fuel delivery the tune will run you up a wall, across the ceiling and then back down the other wall.

RBob.

Six_Shooter

iTrader: (2)

Sorry RBob, the EBL is just not in the cards. It's either the '7148 or a '7730/'7749 with either $58 or more likely $59.

The 160 baud datalogging is making me want to poke my eye out with a dull spatula.
That was one of the main reasons I swapped from a '7747 to a '7730 in a friends truck, and didn't even consider the '7747 for the '71 pick up. Went with a '7427 for that one. I do feel I am missing a lot of vital information that could be used to tune this thing quicker, but I'm only trying to work with what I have.

Oh, I must have had a lot going through my mind when I read the thread posted by funstick, linked in the sticky, it is $32/B, that has the BPW table.

I don't see any explaination of the MAF tables. Just that the ECM moves from one MAF table to the next as the flow increases. This makes sense, but just doesn't seem to be working that way in this car. I mean I can change the tables all I want and I don't seem to get any real results from that.
I would have to assume the scalers are changing what I see in the MAF tables, but not effecting what is displayed by TP RT. Since I can seem to have the same Grams/sec displayed in a couple different tables. This is why I would think that having pulse count in the ALDL would help with tuning much easier, then you could see at what point in which MAF table the ECM is looking at.

My biggest problem right now is I have no clue where or what MAF table the ECM is looking at, at any given time. If I had that information, this would be a lot easier to do.

An ECM swap is looking so much more appealing right now.

RBob

iTrader: (1)

Don't discount the EBL Flash so quickly. It has a lot to offer, and you did mention SD. With that I'm done talking/posting about it in this thread.

See this link:

https://www.thirdgen.org/forums/diy-...scellanea.html

Post #3 explains how the MAF tables work. As noted the $6E code converts the analog input to a VCO input. Then continues on with the code.

The basics are:

Read input (VCO or voltage from MAF)

Figure out which MAF table to use

Do look up

Result of look up is the gms/sec airflow

Check/set minimum/maximum airflow

Use the gms/sec airflow and the injector flow rate to calculate the injector PW

That is all there is to it.

Although the $31 code does do a temperature compensation. Which IIRC, $6E does not.

The other thing here is to remember that different injectors require different compensations.

RBob.

Six_Shooter

iTrader: (2)

No, EBL isn't an option due to cost/time. I'm sure it can do a lot, it's just not for this particular application. Also this is basically a tune once, and maybe tweak every 6 months or so type of thing, if the owner was going to be tuning it or tuning more frequently than the EBL would be a good choice.

I'll have a read through that thread, probably in the morning, I'm kinda burnt out right now, after reading a bunch earlier today, and just pulling the engine out of my Datsun in the past couple of hours.

Six_Shooter

iTrader: (2)

Al right, I have pretty much given up on getting this thing tuned using the stock '7148 ECM in any reasonable amount of time, so I am looking at other ECM options. "Options" being the '7749 or '7730 using $58 or $59.

The only thing that I have a concern with is the DIS. From diagrams it looks to have pretty much the same signals to and from the ECM as I would expect with any other GM ECM. If that can be confirmed I will make an adaptor harness and start tuning it very shortly.
Also what is the timing offset? I know the 60 degree V6 DIS needs an additional 60 degrees of timing added to the base to have proper crank timing. Is the TR/GN/TTA DIS the same offset (60*) or is it like I have read with the later 3800, that uses 30 or 33* offset?

liquidh8

six shooter, I have a turbo buick my self I started tuning, I have to get it on the road to do anymore. playing with the EBL all these years on my chevy, and using HP tuners on friends cars, I feel your pain with trying to tune the 7148.

I'll be following your thread. I have a turbo tweak chip that the car runs pretty good on, but idle is WAY rich, so I started on my own tune with it. wasn't using tp5 though.

RBob, maybe I can PM you and discuss the differences from the EBL flash versus the 7148, other than maf and SD of course?

RBob

iTrader: (1)

The main differences between the '7148 and an EBL w/Port Mod is: SFI vs batch fire, loss of wastegate control, MAF vs speed density, 160 baud vs 57.6K baud data logging. The EBL Flash has single fire mode to handle short PWs.

RBob.

liquidh8

I think I would like to keep the SFI, since this will be a DD I would think mileage would be better with the SFI? The wastgeate control is niether here nor there, I would just run a boost controller. hmm, I'll have to ponder my options for a minute, lol. TY

Saar

if you don't mind, i'll throw in my 2 cents about SFI vs MPFI: no mileage difference.

at least that's been my experience with a 3100SFI that i'm running on a 16149396.

liquidh8

Well thats cool. I was looking at the powerlogger for the 7148, for 270. just a logging tool, but way faster then an ADLD stream. Six shooter, don't want to jack your thread. There isn't much on here for turbo cars, few thread here and there. I have a few, but this place is the best for DIY stuff. RBob, should I start a new thread?

RBob

iTrader: (1)

It would be best if it isn't relative to Six_Shooter's topic.

RBob.

Six_Shooter

iTrader: (2)

There won't really be much to follow, I am swapping to a '7730 or '7749 and running $59 on the car. I just have to continue with making the adaptor, then a tune.

liquidh8

cool, lemme know how it turns out.

I have been doing some researce thats suggest the SFI fires in batch mode for the 7148 after 3000 rpm.

So if I one were to use the EBL in batch fire, it may make little difference. You would have to lower the BPC for the same injectors.

I have a lead on the powerlogger for the stock ECM, would give me the same logging abilities as the EBL, but would still have to use tunerpro.

RBob, what do you thing?