GM 1227165 using $32 Mask tuning questions

**zaut** · 04-03-2012

I am upgrading from a 1226870 ECM using the $1F mask to the 1227165 EMC using the $32 mask. There new terms I don’t understand in $32 as well as some in the $1F. Help with understanding the term and how the ECM uses them would be great.
1. What is the difference between injector flow rate – single fire versus injector flow rate – double fire? I assume one is the static flow rate at 3 bar (43.5 psi). On a related note, does Bosch have a website to get technical data sheets on their injectors? I have never seen a TDS for an injector but I have to imagine they have the data to help you make conscious decisions on things like injector offset vs, battery voltage and low pulse width correction vs pulse width.
2. What is cool comp. Spark spark bias?
3. What is highway mode?
4. What is throttle follower?
5. What is Reference pulses?
6. What is BLM Cell RPM Boundaries?
7. What is BLM Cell MAF Boundaries?
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**1project2many** · 04-03-2012

Once upon a time I could get a *bunch* of injector technical data from Delphi's site. Over the years the amount available has been reduced to nearly none. I have no doubt the information is still available but it's been removed from the publicly accessible areas.

The injector corrections from GM seem to be based on actual injector corrections, i.e. changes in response time due to voltage and reduced PW.

Coolant compensated spark bias can be used to shift the entire spark curve. It's an advance / retard based on engine
temp.

Highway mode is a means to force open loop operation in order to use air:fuel ratios leaner than 14.7:1. It was intended to increase economy without causing problems during emissions testing.

Throttle follower is a means to open and close the IAC valve as the throttle opens and closes.

Reference pulses are generated by the distributor. Four reference pulses are generated every engine revolution. ECM uses reference pulses to determine crank rpm, or to enable specific functions or tests.

BLM is a correction to delivered fuel generated by the ecm based on feedback from the O2 sensor. Block Learn is divided into cells, and the more cells the better the corrections can address deficencies under specific conditions. BLM boundaries define the points where a cell begins or ends.

**EagleMark** · 04-03-2012

Usually the BLM boundries do not need to be messed with. Your looking for mid point of 128 is perfect. Boundries are differant in differant masks but give plenty of room for an engine to correct itself. Like say 84 low and 172 high. lower then 128 (rich) is subrating fuel based of VE Fueling tables and higher then 128 (lean) is adding fuel.

**zaut** · 04-03-2012

Thanks a lot. I now have more questions on spark advance. I understand the main spark advance vs load, and I understand the coolant comp spark advance table. Basically for any one instant, advance will be the based off of rpm, load and coolant temp. It would be the sum of the two tables' points of intersection. i.e. 2000 rpm LV8 is 96 and Temp is 80. You get 29.9 + 4.9 or your spark is at 34.8. Now that is then offset by the Coolant Compensated spark bias constant. The BIN I have that appears to be stock has the bias at 20. So my advance would be 54.8. That seems too high. I have two bins that I got from two different websites that supposed to be a stock $32. I did a compare and everything was zero. So I assume they truly are stock. Is that bias set at 20 correct? The max advance constant is set at 41.8.
.

**EagleMark** · 04-04-2012

The coolant spark bais and warm spark bias are so negitive numbers can be used in final output of spark. Each mask is a little differant but your coming up with 54 which is obviously wrong but if you subtract the warm bias which is probably the case the overall spark would be realistic. Overall spark is put in place so other numbers can not go over max spark and fire wrong cylinder, it has to do with degrees between terminals on distributor cap which is about 45 on a V8 so 41.x is put in place as a safety.

These are just general answers to cover GM ECMs for you. So far everyone is suggesting either 1227730 or if going with th 1227165 to look at $6E. Your starting from scratch so may as well start with what guys are converting to... been a lot of work done to the $8D which is called S_AUJP maybe something to look at for your engine. Keep an open mind to all the experiance being shared with you here.

**dyeager535** · 04-04-2012

Originally Posted by EagleMark

The coolant spark bais and warm spark bias are so negitive numbers can be used in final output of spark. Each mask is a little differant but your coming up with 54 which is obviously wrong but if you subtract the warm bias which is probably the case the overall spark would be realistic. Overall spark is put in place so other numbers can not go over max spark and fire wrong cylinder, it has to do with degrees between terminals on distributor cap which is about 45 on a V8 so 41.x is put in place as a safety.

These are just general answers to cover GM ECMs for you. So far everyone is suggesting either 1227730 or if going with th 1227165 to look at $6E. Your starting from scratch so may as well start with what guys are converting to... been a lot of work done to the $8D which is called S_AUJP maybe something to look at for your engine. Keep an open mind to all the experiance being shared with you here.

And as someone who is currently running '165/6E, I can tell you to not wait, go straight to a '730, '727, etc. if you plan on doing your own tuning.

'165 has a serious problem for tuners in that it "clams up" (technical term from Moates or Mangus lol) on the data side...you will be tuning, all of a sudden your data freezes, and the only solution is to shut the vehicle down and restart. Kind of a hassle on the freeway, or anywhere, when you are trying to get something done. May take 15 minutes to happen, may take 1 minute.

If you are skeptical of my statements (which I wouldn't blame you for), do some searching on the thirdgen.org diy-prom forum from Craig Moates and Mangus about the problems with the '165 and data. If you trust anyone, it should be the guy who designed Tunerpro and the guy who runs moates.net.

Just my tip for you. While I have made progress with my '165 setup, I've had it with the data problem. Last straw was finally having someone to drive for me while I was tuning...just after getting on the freeway, the ECM clammed up.

**zaut** · 04-05-2012

Thanks for the tip. I wish I would have asked the questions before I sunk a $175 in a ECM, PROM and Memcal adapter. Are you using 160 baud or 8192 Baud?

**EagleMark** · 04-05-2012

That stuff is in short supply and I'm sure you can resell to get your money back. May as well start with an upgraded ECM. If that one was perfect then GM wouldn't have made better and guys wouldn't be swapping.

**dyeager535** · 04-05-2012

I use strictly 8192. 160 sucks.

**EagleMark** · 04-05-2012

Hey, my 1990 Suburban is 160 baud and runs fine every 1.2 seconds...

**zaut** · 04-06-2012

Ok, I went to the junkyard today and got a 1227730 ECM with a couple feet of harness attached. The Memcal is a AZTY from a V6. Can I use that memcal for my V8 or do I need to find another memcal? The good news I only spent $15. I hope it works!

**zaut** · 04-06-2012

I ask the question about the memcal working or not becasue I don't know what the other 1/2 of the chip contains. I know my memcal adapter wires around the eprom on the chip so I can add the new tuning information. What does the portion of the chip that stays connected with the memcal adapter do? Does it contain the limp home inforation or does it configure the EMC for the mask it runs?

I reviewed the wiring diagram for the 870 t0 730 EMC swap. It looks straight forward. I have some very important questions:

1: Aside from adding a MAP sensor, are all my existing sensors going to give the proper signals to the new EMC. Did GM change any of the calibations or pin outs etc that would mean I need a different sensor?
2: Is the vehicle speed signal from my 85 cluster ok? Or do I need another vehicle speed sensor?

**dyeager535** · 04-07-2012

If I understand the MEMCAL right, it's the limp home stuff...so therefore need a V8 one for a V8.

I can't answer the 870 to 730 exactly, but most of what GM did was interchangeable. Just pay attention to things like the TPS, MAP, etc., where there are multiple wires. If anything what wire goes to what terminal on what connector might have changed, but the sensors themselves are pretty basic.

A good for-instance is the oil pressure switch and sending units. Early on they were two separate pieces, sending unit one wire, switch two wires. Later on GM went with a three wire single piece. Wires did the same things, just went to a different piece.

When doing wiring, it never pays to assume GM kept them the same. If re-pinning a harness, ensure EVERY pin matches up correctly via the pinout charts. It's the one you think is right, that will get you.

VSS. If no one answers you here, check over on thirdgen.org, search the diy-prom forum. I know I've seen the '730 VSS swap talked about, I believe it's a setting within the bin that selects what type of VSS the ECM expects.

**EagleMark** · 04-07-2012

The memcal has the chip of course and the other side is limp home chip which should match engine but V6 can be jumpered for V8, then on top of that is the knock module which must match knock sensor.

Your VSS and all other sensors should be fine, I can't think of any glitches.