Cylinder select error

[RobertISaar]

knock filter is created based mainly on bore size, so try and match up the bore of the 4.0 with the closest GM application.

cylinder select code is based on a couple of pins on the MEMCAL and what's stored in the PROM as the correct combination of pins either high(5 volts) or low(0 volts). it's only 2 pins in every application i've come across that uses them, so 4 possible combinations. 00, 01, 10, 11.

[JeepsAndGuns]

Is there a way to test the specific two pins with a ohm meter?
Any chance a A1 V6 memcal, and a 8D V8 memcal use the same setting?
When you change cylinder count in a bin, does it also change what its expecting to see from the memcal?

[RobertISaar]

there is a way to test, but i forget how at this point. if i had to guess, i'd say take a multimeter and test resistance of the pin that sets it and see if it's connected via a resistor to the ground or to the 5V pin.

no, PFI V6 and PFI V8 have different pin combinations.

$18=TBI
$10=4 CYL PFI
$08=6 CYL PFI
$00=8 CYL PFI

the way to read that is that with TBI, both pins are tied to 5V via a resistor(or directly, i forget at this point), 8 cyl PFI, both pins are tied to ground, 4 and 6 cyl PFI both have 1 pin going in each direction, but it's the opposite pin depending on 4 vs 6 cylinders.

i don't think it makes an actual difference unless you get into limp-home mode, or at least that's what my currently MEMCAL-less testbench is implying, since i have it setup for 6 cylinders in the BIN and it seems to be firing them in the correct sequence.

there MAY be more than one location that needs changed, in A1, it's done in the diagnostics section.

[JeepsAndGuns]

Well the 4.3 is probably gonna be the closest to the 4.0 as I can get. So I got wondering, could I use a 7427 CPI 4.3 memcal with the 7727? Is the CPI memcal set up the same since its CPI?

I have a 7427 TBI 4.3 memcal, but not a CPI one. Could the MPFI jumper wire be put in the TBI memcal to make it work?

[dave w]

I've noticed the '7427 PCM's use different knock sensor part numbers, auto vs. manual transmission.

dave w

[RobertISaar]

i ASSUME that CPI would be setup like PFI, since it is 1 injector per cylinder, but it would be good to confirm this first.

did some digging, bits 3 and 4 of the FMD byte 2(?) response. that's chip U13 on the board. it performs a LOT of functions, unfortunately, Ludis didn't specifically identify those pins in his diagrams, so some digging on TGO would probably turn up an answer.

[1project2many]

I've noticed the '7427 PCM's use different knock sensor part numbers, auto vs. manual transmission.

dave w

Check the number of sensors used... dual vs single may play a part. Also, sensors used in lower part of block have 1/4" pipe thread while sensors installed in back of block or head may use 3/8"-16 thread.

[JeepsAndGuns]

OK, had what I think is a productive day.
Started out remembering once when looking through the s-aujp xdf seeing a bunch of error qalifiers. So I pulled up that xdf and found the one for cylinder select error, and the comments gave what to type in for what your using.
00=8cyl
18=tbi
10=4cyl
08=6cyl

So I checked the hack and found it was the same address as the stock bin (0x293) So I copy and pasted that to my xdf. I then opened my test bench bin, changed it to 08, burnt it to the chip and gave it a go. Success! No more cylinder select error!
Also, I looked at my harness, and noticed I had forgot to hook up the ground wire from the distributor , fixed that and no more EST failure error!

So since I was on a roll, I decided to try one more thing. I took the 7427 4.3 TBI memcal I had, added the jumper wire for PFI, and decided to give that a go. I found out the moates G1 will not fit in a 7730...lol. But fits fine in a 7727. Popped it in and gave it a go. Everything seemed to work just fine. No cylinder select errors or any other error codes. I even ran the distributor a little longer than I had just to make sure. All the data on the log looked the same as it did with the 7727 A1 V6 memcal.
Now I cant say everything would function like it should with the jumpered tbi memcal if it went into limp home. Mabey yall might know?


OK, I did lie a bit, I said no error codes, when actually I do have one, but its for the esc, and thats because I dont have a knock sensor hooked up. But that ones expected, I just forgot to turn that code off...lol

[Six_Shooter]

G1 definitely fits in a '7730, that's what I'm using in mine.

[JeepsAndGuns]

Strange. For some reason I could not get it to fit for anything. The memcal kept hitting the main body and wouldnt let me even get it close to plugging in. Maybe I didnt try hard enough..lol

[RobertISaar]

i seem to remember 7730s having issues with the access door closing with a G1/G3 with a ZIF installed, but would otherwise fit.

i ASSUME it will work correctly in limp-home mode, but you'll never really know until it happens. good to hear it's all functioning now though.

[Six_Shooter]

i seem to remember 7730s having issues with the access door closing with a G1/G3 with a ZIF installed, but would otherwise fit.

i ASSUME it will work correctly in limp-home mode, but you'll never really know until it happens. good to hear it's all functioning now though.

Easy way to test LHM, pull the EEPROM, and have only the LHM NETRES and RDF chips connected. ;) This is how I know that my car will run on the TGP MEMCAL, after finding out the hard way that it wouldn't run on a Cavalier MEMCAL.

[dave w]

OK, had what I think is a productive day.
Started out remembering once when looking through the s-aujp xdf seeing a bunch of error qalifiers. So I pulled up that xdf and found the one for cylinder select error, and the comments gave what to type in for what your using.
00=8cyl
18=tbi
10=4cyl
08=6cyl

So I checked the hack and found it was the same address as the stock bin (0x293) So I copy and pasted that to my xdf. I then opened my test bench bin, changed it to 08, burnt it to the chip and gave it a go. Success! No more cylinder select error!

So since I was on a roll, I decided to try one more thing. I took the 7427 4.3 TBI memcal I had, added the jumper wire for PFI, and decided to give that a go. I found out the moates G1 will not fit in a 7730...lol. But fits fine in a 7727. Popped it in and gave it a go. Everything seemed to work just fine. No cylinder select errors or any other error codes. I even ran the distributor a little longer than I had just to make sure. All the data on the log looked the same as it did with the 7727 A1 V6 memcal.
Now I cant say everything would function like it should with the jumpered tbi memcal if it went into limp home.

You have me re-thinking about my not so successful experiment to use a '7727 for TBI using 8D.
http://www.gearhead-efi.com/Fuel-Inj...7-ECM)-for-TBI

I ended up not being able to resolve the cylinder select error. Basically I used an unmodified '427 V8 TBI Memcal to get the correct DRP's, which appears to work according to the O'scope. Thanks for posting your results!

dave w

[EagleMark]

Also, I looked at my harness, and noticed I had forgot to hook up the ground wire from the distributor , fixed that and no more EST failure error!

Sweet! That's how I found the error code when I did a bench, but it took a lot longer...

OK, had what I think is a productive day.
Started out remembering once when looking through the s-aujp xdf seeing a bunch of error qalifiers. So I pulled up that xdf and found the one for cylinder select error, and the comments gave what to type in for what your using.
00=8cyl
18=tbi
10=4cyl
08=6cyl

So I checked the hack and found it was the same address as the stock bin (0x293) So I copy and pasted that to my xdf. I then opened my test bench bin, changed it to 08, burnt it to the chip and gave it a go. Success! No more cylinder select error!

So since I was on a roll, I decided to try one more thing. I took the 7427 4.3 TBI memcal I had, added the jumper wire for PFI, and decided to give that a go. I found out the moates G1 will not fit in a 7730...lol. But fits fine in a 7727. Popped it in and gave it a go. Everything seemed to work just fine. No cylinder select errors or any other error codes. I even ran the distributor a little longer than I had just to make sure. All the data on the log looked the same as it did with the 7727 A1 V6 memcal.
Now I cant say everything would function like it should with the jumpered tbi memcal if it went into limp home. Mabey yall might know?


OK, I did lie a bit, I said no error codes, when actually I do have one, but its for the esc, and thats because I dont have a knock sensor hooked up. But that ones expected, I just forgot to turn that code off...lol

Those are hex vaules and the way the XDF is commented is wrong. You just found a major flaw in the $8D XDF. Since most of the work has been done for V8 I suppose is why no one ever noticed.

The comments "Use 0 for 8 Cylinders Use 128 for 4 Cylinders Use 192 for 6 Cylinders " are wrong. I went into the XDF paremeter and tried all the options and could not find one that would show proper hex for any of the entries, entered like that?

If you open Edit XDF Paremeter and change Significant to 0. Then use comment:
Use 0 for 8 Cylinders.
Use 16 for 4 Cylinders.
Use 8 for 6 Cylinders.
Use 24 for TBI.
It all comes out properly in hex.

I commented my XDF to say:
"Use 0 for 8 Cylinders.
Use 16 for 4 Cylinders.
Use 8 for 6 Cylinders.
Use 24 for TBI.

Hex values are
00=8cyl
18=tbi
10=4cyl
08=6cyl
"

[JeepsAndGuns]

Just read that whole thread. My head is spinning just a bit. But by the end, it looks like yall found the same value that I did at 0x293. So using the 7427 tbi memcal, and changing that value to 18, you still got the cylinder select error? I have my test harness all laid out and ready to test, also have a few 7427 V8 tbi memcals. I have a couple of tbi injectors, but I do not have any of the resistors yall mention using to put between the injectors and the ecm. If you do not have a test harness set up at the moment, can give me instructions on what to do/change, I would be willing to help out out with testing. What did you end up using? If I am reading post number 120 correctly, you used $A1? it also looked like you were changing the cylinder number to 18, the 8D xdf I have says use 0 for 8cyl, 128 for 4cyl, and 192 for 6cyl. I'm thinking changing that value (0x09) to something other than those 3 values may not work right. Did you have sucess running a tbi engine with the 7727?
I would like to try some testing myself, if you can tell me what to do about resistors and the injectors, so I don't fry something.
I agree with yall that being able to run tbi with the 7727 would be handy for conversions.