I'm new to the forum but have been lurking, reading, and trying to learn for quite a while now. I have a problem that maybe more experienced folks can shed some light on.

I have a swapped SBC with an early TPI unit (originally MAF, cold start injector removed and now MAP). I'm using a 1227730 ECM. This was supposed to be a fairly mild build, and it is, and a friend burned me a stock chip (supposedly) with the VATS disabled. That was the only request I made for changes.

The engine starts and runs fine, but very, very rich. Eye burning rich. Rich enough it's contaminating the oil with gasoline. I've been approaching this in stages and I'll go through what I've done, starting with mechanical stuff.

The engine has a mild/moderate cam, about 10:1 compression, cast iron heads and the TPI, of course. The cold start injector removed and plugged. All new sensors and the readings on my MT2500 scanner from the various sensors appear reasonable.

Upon startup, the engine is very rich. I've been working with it for several months, off and on, now. To remain running while in open loop the engine has to be held at a very high idle, 2500 rpm or more. Once it goes into closed loop, it's much better, and will idle, but still very rich. I suspected a problem with the calibration on the chip and have been wanting to play with this stuff anyway, so I purchased a chip programmer from Moates, several 27SF512 chips, and the adapters from Moates to use with the memcals.

As for the memcals. The two I have to use (that came with the ECM) have broadcast codes of BCFZ and ASWA. The chip my friend burned was UV erased and left in the memcal with the new programming burned to the chip in it. I copied his program to one of the EEPROMS and using the adapters ran it. The engine ran virtually the same with either the original memcal or the 2nd one with the adapters. I did this to try to rule out differences in the limp home mode and ESC.

The modified bin I've been trying to run is a 16K bin and I believe I loaded the EEPROM properly at the correct starting address 00C000 (because it runs the same as the original copy).

I know you're all going to want more information, but I don't know what information you will want, so if you can tell me what you need I can get it for you to help me figure this out.

Believe it or not, I HAVE been reading the guides and stickies and have learned a tremendous amount, but I obviously have a LOT to learn about all this and any suggestions, ideas, or questions would be appreciated.

John Stricker

 

Welcome to TGO. First off, what size injectors are you using? If you are using a larger injector, and the injector constant, (IC), is not correctly set, will make it rich. What editor are you using to make your changes in the bin?

 

Those two broadcast codes don't ring a bell for me in terms of being a V8 MEMCAL. If they are either V6 or 4-cyl then the fueling mode is wrong and it is going to run way rich. Do a lookup on the broadcast codes. It sounds like that is what the problem is.

EDIT: The BCFZ is for a 4.3 V6.....don't use that one. The ASWA is for a 2.8 V6. There is your rich fuel problem. Get a V8 MEMCAL and you should be much better off. The little black chips control the fuel modes and you are getting two many injector firings of fuel with the V6 chip (yes, even not in Limp Home mode).

 

I read in the FAQ to never use the V6 memcal, that's why I found a second one and I looked and couldn't find what engines those broadcast codes applied to. If you don't mind me asking, where did you look that up at? Is there an online resource somewhere other than the various ftp sites that just list them?

I was afraid this was my problem as I could find neither of them on any of the sites listed as V8 memcals. Well, I shouldn't say that IT is my problem, but it's certainly ONE of my problems, I'm sure.

Thanks for your help, I'll try to find a V8 memcal somewhere. I called local dealers earlier today with the p/n for the AUJP memcal and nobody remotely local had one on the shelf, the Denver distribution center had only one. I should have ordered it but the price has gone from $90 a few years ago to $160 list now. I can get it from MonsterParts for about $80 plus shipping.

I haven't seen this in any of the threads (but I've been reading the FI forums here almost exclusively), but for those of you that haven't heard about them, I've been using MonsterPartsOnline for my GM mail order parts. Their prices are competitive with the other online sources and their freight is just $7.50 per order or 7.5% if it's over $100. That's much more reasonable then GMPartsDirect IME, and I've ordered a lot of parts through both. Monster's customer service is also excellent. They typically ship the next day and when I've been in a hurry, I've called and they've expedited very willingly. Disclaimer: I am in no way affiliated or friends with any of the owners of Monster, just a happy customer

The search is on for a V8 Memcal so that I might be able to get this thing running. Thanks for the help.

John Stricker

 

I had 24#, then 22#, then 19# injectors in the car. None made any difference so I put the 24# injectors back in since they were new. After reading the .bin, I see it is set up for 24# injectors.

I'm using TunerPro and I also purchased, for another project about a year ago, TK's Dos based editing software that had the definition files for the 1227730 and the '90 F body masks.

Thanks for the welcome, you'll probably get sick of my questions. Just thought you might be interested in seeing what this is in so here's a picture of it at the Omaha World of Wheels Show earlier this year.



It's a heavily modified Fiero with a 5 speed and 12" Corvette brakes all around.

Thanks for all the help.

John Stricker

 

I am a believer in freeware infomation. I found the BCFZ using google "BCFZ MEMCAL" and the ASWA using the search engine here. Some guys have the Tunercats BCC lookup program for $20. You could ask here for verification of what I told you.
I tried a 4-cyl MEMCAL once on a V8 with a proper PROM chip back in the day and I had the exact same problem you experienced. That is why I looked up the BCCs you posted. A V6 MEMCAL will squirt the injectors more ofter (33%) with a given PROM duty cycle.
I was getting MEMCALs from gmpartsdirect. I will give the link you posted a look. Thank you.

 

AUJP is a 32k bin, not 16. sounds like you have the wrong bin loaded.
you may want to get the AUJP bin from diy-efi & work with it.

you do need the right MEMCAL for limp home & knock.
i have read that people here have gotten the AUJP MEMCAL from GMPartsDirect for around $40.00 or so.

 

What is the PN needed to order the AUJP memcal from either of those sources, or from the trusty local dealer if they're willing to deal? $40 is about half what I've been expecting to pay, and seems like a good price for a spare.

I'm glad to see an explanation of why NOT to use a 4/6-cyl memcal finally, having just read "don't" in the past.

Clair

 

I don't believe the original basecode in the memcal I have that had the VATS disabled was the AUJP .bin. I did try the AUJP but with the incorrect memcals the engine wouldn't even fire on it.

I don't know WHAT the original BCC was for the modified chip, but at the moment I don't really care, since it doesn't run right. I did notice that the AUJP was 32K when I was loading it and the code I have is 16K, that's why I mentioned it.

The P/N for the AUJP memcal goes like this.

Originally 16134311 superceded to 16134306, then superceded to 16151348, which is the current P/N. This calibration replaces AUJP, ANJA, and ANJF in the 90-92 F Body 5.7-8 (L98). List price is something over $159, GMPD has it for $82.85 and Monster for $80.46. I didn't add to cart to figure the shipping, but my experience with GMPD is that the shipping will be a lot more than that.

I gave the earlier P/N's because there is a SLIGHT chance that a dealer might have an old numbered memcal on the shelf. His inventory system SHOULD catch it, but you know how that goes.

I have the GM Parts CD's through '03, IIRC.

John Stricker

 

You can read about the MEMCAL fuel mode selection here:

PFI/TBI MODE SELECTION
http://www.fortunecity.com/rivendell...ECM/inj_op.htm

You could try the pin to ground that is at 1/3 VRFD on the V6 MEMCAL and see if that fixes your fuel mode problem. It would change from squirting every 3rd DRP to every 4th DRP (less fuel).

Here is an example for one engine revolution (all 8 cyls fire on a V8)
V8 MEMCAL: 8 DRPs -> 8/4 = 2 inj squirts (double fire batch)
V6 MEMCAL: 8 DRPs -> 8/3 = 2.66 inj squirts
2.66 / 2 = 1.33 -> in other words 33% too much fuel for a V8 engine with a V8 PROM/bin in a V6 MEMCAL

This is good info also:

https://www.thirdgen.org/forums/diy-...etres+resistor

This gives which pin on the MEMCAL to short to ground. You could try this before getting the V8 MEMCAL. This will probably get you past the too much fuel problem, but then you will more than likely hit the knock problem (incorrect V6 knock sensor ckt on the MEMCAL). At the least, it will let you know if it is only the MEMCAL giving too much fuel and allow you to start tuning. The V8 MEMCAL will also have the correct knock sensor ckt you need.

VL21P-7730,
Last year gmpartsdirect was selling AUJP memcals (part number listed above) for $60 + $20 for shipping (maybe $10 for shipping). It is worth it to buy a spare now because the price keeps going up and 730 ECM MEMCALs for V8 apps are getting harder to find in the junkyards.


EDIT: I just noticed you are not using the AUJP bin. You want to use it........it was the latest and greatest for the 730 in V8 apps. Once you get it running and tuned a little, you may want to look into the SAUJP_V3 or _V4 bin. It has TGO board user code & data updates.

 

Thanks for the links.

I'm going to try to find a V8 Memcal somewhere today. I think it would be a better solution than the workaround for the V6 memcal. I'm also going to order at least one new one today, but I'd like to have one in my hands so that I can play with it this weekend. If I can't find a V8 one to get NOW, then I'll probably try your suggestion on the workaround.

I'm hoping to use the AUJP but, as I said, when burned to the V6 memcal it wouldn't run at all. I've read about the working up of the s-AUJP. Trax's postings here have been a HUGE help to me and he never even knew it. Assuming I can get the fueling close, I'm really looking forward to playing with this stuff.

John Stricker

 

i was wondering, do you get a good data stream with the 16k bin?
i would say you don't. i think your actually running in limp home.

you say you have an adapter, is it like the G1 from Moates?
i may be wrong, but i think you should be able to at least try AUJP by burning it to one of your EEPROM's & putting the chip in the adapter with one of the MEMCALs for the knock circuit.
before you burn the chip, disable VATS.
i would just stack the bins & then burn the chip instead of worrying if i had it in the right location.

 

Just a quick update since I had some time to play with it today. I looked in my spares box and had no 7.5K resistors. I did have a pack of 3.9K though. I put the Fluke on them and found one that measured 3.82 and another that measured 3.88. Soldered them together in series and when I measured the combination they measured 7.65K ohms. That's well within a 5% tolerance so I decided to try that. Snipped the indicated pin and just stuck the leads in and gave it a try.

The car started instantly and for the first time, idled on it's own when cold. It's still a bit rich, but at least now it's close enough I can put the scanner on it and start tuning.

I used the 4.3L V6 memcal for this thinking it would be the closest to "right" on the ESC and Limp Home circuitry.

Amazing what a few thousand ohms of resistance will do when it's in the right place. I'm sure I'll have lots more questions, but I really want to thank everyone that offered help on my problem.



John Stricker

 

Actually, yes I was getting a data stream to my Snap On MT2500. I didn't pay much attention to the BLM I was mostly just checking to make sure I was getting good sensor data to the ECM, thinking I might have a bad MAP sensor or other mechanical/sensor problem.

The adapter isn't like the G1, it IS the G1. I also have the ZIF socket to make it easier to change chips as I tune and intend to take it out when I have a bin I'm happy with.

With the AUJP bin (stock, not the s-AUJP) in the chip, the engine never fired a shot on either of the V6 memcals. Using the adapter and a copy of the bin I had (the 16K bin) it ran identically bad with either memcal. I don't know enough to even hazard a guess as to why the AUJP didn't work before, but I bet it will now. I'll know tomorrow.

John Stricker
Now that it actually idles and starts correctly, I can start playing with various burns and see what I can do with tuning.

 

i must have missed it, but what did you wire the resistors into?

 

Great to hear you have it running better. Now you know the MEMCAL does more than Limp Home mode. You could drop the AUJP code in now. Good call on using the 4.3 MEMCAL. The 4.3 bore size is the same as the 5.7 so it should operate fine on the PROM. A bad PROM will still be off a little bit in limp home mode.

Free info. is a great thing......isn't it? That is the way I learned and I hope you do the same.

And welcome to TGO.

 

Thanks to junkcltr for steering me in the correct direction. He gave a good explanation of what was going on and then directed me to

http://www.fortunecity.com/rivendell...ECM/inj_op.htm

For more in-depth explanation. He also pointed me to the thread:

https://www.thirdgen.org/forums/di...etres+resistor (Cylinder select netres values?)

In THAT thread discussion there are excellent pictures of what to do and also direction to the the diy-efi ftp site where there is a .pdf paper on the memcal resistor package at:

ftp.diy-efi.org/uploads/memcal.pdf

If you follow these links and rad the thread carefully, you'll find everything you need to perform the modification. I can tell you not to expect Radio Shack to carry 7.5K resistors.......not in the store stock anymore. (Does anyone else remember when you used to be able to buy parts at Radio Shack??)

I'm going to order some more EEPROMS and some 7.5K ohm resistors from Mouser or Digikey next week.

John Stricker

 

I can't thank you enough for all your help, junkcltr. I really, REALLY appreciate it. I had read that we shouldn't use the V6 memcal package in the V8's but until your explanation, never knew why. Now I do. I've suspected all along that there was something I was just missing and there was. I even at one point put a new distributor in thinking my trigger was not signaling properly. All this time and money fixed by 40 cents worth of resistors out of my junk drawer. Such is life. I'll chalk that up to my education process.

Free info is wonderful. I hope to keep learning as I work to tune it and some other projects (that I won't go into here since they're not F body related). That said, I also don't mind paying people for their efforts. I purchased the Caldata program from CATS and I really don't mind paying them the $20. I wouldn't have for THIS problem alone, but as I said, I have other irons in the fire and I think it's going to be helpful.

Again, I really thank you for your assitance. If we ever get together, I'm buying whatever you're drinking! (sheesh, I hope he doesn't drink Dom exclusively or something.......)

John Stricker

 

DIY-EFI was the start of it all from what I know. I am a relative newbie getting into DIY EFI stuff in 2000.

Atmel dumped the DIP 28 pin packages for the FLASH parts. I think the PLCC would catch on if it wasn't for a cheap ZIF for it. Mouser has the 27S512 in 28 pin DIPs for under $1.50 the last time I ordered. The 27SF512 needs old school 12V erase though. So you need to see if your programmer can handle that.

You did excellent following those threads and getting the job done.

 

I'm actually using 27sf512 chip in my burner I got from Moates. That's also the chip they sell there but they're a little pricey compared to Mouser or Digikey or Allied ($5). Not outrageous though, and Moates service is excellent.

Now on to seeing what I can do to get a more optimal tune on the 1227730 with the TPI.

Once I do that, I have a 3.4L V6 in the race car that needs some serious tuning, but at least there are definition files available for that.

After that, we get into the really interesting things like creating my own definition files for some other projects (Cadillac).

John Stricker

 

ok, i didn't follow any links

glad you got it going

 

Just a quick update since the threa sparked some interest on the "conversion" of the V6 memcals for V8 use.

I modified the 2.8 V6 memcal the same way I did the 4.3 and, using the same chip with a more or less stock AUJP code (VATS deleted, AIR deleted, and EGR deleted) the idle was definitely NOT as smooth. I didn't have the car in the shop so I didn't put the scanner on it, but it almost felt to me like the chip was pulling some knock retard and slowing the timing.

Do you more experienced folks believe that's possible, that the circuitry in the 2.8 chip was that aggressive with KR? It did start and idle, just not as smooth and seemed to be laboring a bit, like an engine will with the timing too slow.

In short, if you're trying to make a V6 memcal work, I'd definitely be looking for one from a 4.3 rather than one of the other variations as it seems, so far, to be an acceptable substitute.

John Stricker