Reading a 1227730 chip

[EagleMark]

I'm having problems reading a chip in a memcal from a 1227730 ECM. I am using my AutoProm
http://www.moates.net/apu1-autoprom-pac ... l?cPath=64 (http://www.moates.net/apu1-autoprom-package-usb-version-p-54.html?cPath=64)
and a HDR1 Memcal Header from Moates.
http://www.moates.net/hdr1-memcal-heade ... l?cPath=64 (http://www.moates.net/hdr1-memcal-header-p-52.html?cPath=64)

The car has a 5.7L TPI engine and a 1227730 ECM. It came with 2 Memcals from an unknown aftermarket source?

My problem is when I read the chip and save the file I end up with a 4kb file? Should be 32kb... Right?

The car runs and drives well although does not have much power. Specs should see close to 350 HP but it drives well but my stock TBI car would blow it away. I used my AutoXray Scantool on the car when I went to pick it up and I got no codes but but the data was half correct and half just plain wrong? Like voltage reading was 25 volts with key on and when started goes to 6.4 volts? Other odd readings as well... I do not have a vin code to set the scan tool too and the only setting I could get data from was a 1990 corvette. I tried earlier years and it was complete failure. I did not try later years...

Are both these chips just no good? Am I doing something wrong?

I think I am going to put one back in the car and see if the check engine light works correctly. This is a transplanted engine and I did not watch for CEL blink when turned on.

[EagleMark]

OK got the chip problem figured out. When I was reading the chip I did not set the chip type correctly. I still only end up with a 4kb file, then looked at some of my TBI files and some are only 4kb as well and have burned and worked fine. So I guess I have some learning to do there as well?

I looked up the chip and found 2 listed for the ECM which I don't understand... but it's either 27C128 or 27C256 as listed here:
http://wiki.3400z24.com/1227730

Why are there two differant chips for one ECM?

Biggest problem I can see in the aftermarket chip is Injector Flow Rate is off by almost 4 pounds. Comparing the aftermarket chip to a stock AUJP there is a lot of work done and looks good. But there seems to be a mistake in spark advance at idle causing knock retard which is set at 30 degrees? Wow taking out 30 degrees would explain low power... maybe he meant 3 degrees?

Anyway I can record data tomorrow and see what it's doing.

[EagleMark]

This is probably to simple a subject for this week so I will just ask for information on Checksum? I have never looked into it and just used what was always on a stock chip. But this new project I have that has an aftermarket chip has a checksum of 53255.00 and the stock chip has a checksum of 55865.00 If this is not set properly what are the consequences?

I have read some on it because of emulating with the AutoProm but really have no understanding of it?

:confused1:

[RobertISaar]

sounds like you're playing with a 8D car, read the BINs out as 27C256 chips. read it out and check location 0008, should be 8D.

the checksum will normally be updated by tunerpro when saving the file, so if it's different it's not a problem since there have been changes to the chip.

checksums are a fast and efficient way of determining if the ECM can read all of the bytes of a PROM correctly. it starts adding up all of the bytes after a certain location (8007 in the case of 8D) and goes until the end of the PROM at FFFF. then it compares the sum against the value found in the checksum location, 8006-8007 for 8D, if it matches, the ECM figures the PROM is good, if not it goes into limp-home mode. if the mask ID is changed to AA, the checksum is ignored, generally this is done during GM's engineering phase or while emulating.

[EagleMark]

Thanks for the explaination! :happy:

Well I had played with this for hours and can't find anything wrong mechanically or in the chip. So Dave gave me a bin file and Viola! Car runs great to start. So I think the aftermarket chip had a hex error maybe. It was something wrong I could not find with any mask.

But now I have a cylender Select error and have no idea what it is or how to address it?

[RobertISaar]

cylinder select DTC comes up when the value stored in the PROM for cylinder count doesn't match the value it sees on one of the NETRES chips in the MEMCAL.

[Six_Shooter]

You should have tried the later years on your Auto X-ray. ;) 1227730 was used in the '90 to '93 F-bodies and used $8D. This is also the change over from MAF, that used the the 1227163 ECM, to SD.

The '90 'Vette used $8D but had extra information on the datastream as I understand it to work with the HUD/DIC.

$8D is a 32kb bin, so if you're only saving a 4kb file then you still need to change some settings there while reading to get the proper bin.

Robert has said all the same (and more) than I would have said for the rest of it.

[EagleMark]

You should have tried the later years on your Auto X-ray. ;) 1227730 was used in the '90 to '93 F-bodies and used $8D. This is also the change over from MAF, that used the the 1227163 ECM, to SD.

The '90 'Vette used $8D but had extra information on the datastream as I understand it to work with the HUD/DIC.

$8D is a 32kb bin, so if you're only saving a 4kb file then you still need to change some settings there while reading to get the proper bin.

Robert has said all the same (and more) than I would have said for the rest of it.
Where were you a few days ago? :tounge: When I got home I researched it and did find that to be the case.

The problem with only getting 4kb was when downloading the bins in my AutoProm I did not have the offsets set correctly. Once I did that I got the entire file. You'd think I would learn from my mistakes as I did the same thing when I started playing with the 427 as most of my time has been a 1227747 thing.

What's a HUD/DIC ?

[RobertISaar]

HUD = heads up display, displays important stuff on your windshield, like MPH, sometimes RPM, warning lights, etc... none of the OBD1 units i know of use the ALDL circuit though.

DIC = driver information center, also known as a trip computer, shows fuel economy, bunch of other stuff. these DO use the datastream.

[EagleMark]

cylinder select DTC comes up when the value stored in the PROM for cylinder count doesn't match the value it sees on one of the NETRES chips in the MEMCAL.
Ahhh! So this aftermarket chip/Memcal this guy bought was not a V8. But today it went limphome when my emulater cable came loose? Idled at 1500, data stream went blank, I have it recorded when it happened and it ran OK.

So other than getting a V8 Memcal is there anything else I can do? Will it cause a check engine light? Will it cause any other issues?

I do have cylinder count set correctly in chip at "0" for 8 cylinders.

[RobertISaar]

the cable coming loose may have triggered it, there used to be a way to check the NETRES to see if it was a V6 or V8 MEMCAL, somewhere on TGO, can't think of the search terms necessary though.

[Six_Shooter]

I was away at the cottage for a few days.

You can modify the MEMCAL to have the 8 cylinder count, by shorting a couple pins. There is info on TGO about which pins. I plan to port that info over here soon.