PCM info, help plz! - Tuning Forum

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PCM info, help plz!
Tuesday, March 14, 2006 8:52 AM
Hey guys, i feel bad for posting such lame questions, but here goes:

I was reading the post about HP Tuners coming out with software to edit our PCM's, and I saw mention to several things that I did not understand and was wondering if someone could clear them up for me and possibly others with similar questions, on that note:

I saw mention to both OBDI and OBDII, whats the difference? I have a 1996 sunfire, which would I have? Can you swap from one to the other? Is one easier to tune, or is tuning software more available for one over the other?

Secondly, Whats the difference between a 1 bar, 2 bar and 3 bar fuel map? Whats the application of the different maps?

Whats different between the 96 and 97's pcm that would make HP tuners software not compatible?

thats about it, anything else you guys feel I should know feel free to post it, like I said, im probably not the only one with these questions.

Re: PCM info, help plz!
Tuesday, March 14, 2006 9:00 AM
your 1996 would have the OBD II
Re: PCM info, help plz!
Tuesday, March 14, 2006 11:20 AM
OBD I utilizes a "chip", thus to reprogram it for more power you change the chip. I've used hypertech in the past, good results. Your car should be ODB II, they don't use a replacable chip per se, the program is downloaded into a soldered in memory chip and a "programmer" downloads the software for tuning. By a programmer i mean something like a Hypertech box, or there's software available that lives on a laptop and utilizes a serial (or as of late USB) cable.

The 1,2,3 Bar maps for fuel trim usually are used for forced induction (turbo, supercharger) as they move the atmospheric pressure above normal ranges. Normally aspirated (pardon spelling) engines are within the 1 bar range, some racers utilize 2 bar setups when extreme RPM is used.

I'm not up on the differences between the '96 & '97 PCM configurations, maybe another member could elaborate on that.

Don
Re: PCM info, help plz!
Tuesday, March 14, 2006 8:44 PM
kool, so whatre the reflash options for my 96 as far s speed limiter fuel map etc., like i said above i know nothing about cars PCM's and how they work, so i appologize if these seem like elementary questions.

I know JBP does reflashes, is there software our cars for on laptop so as i learn about it i can do it myself some day?
or would it be better to jus have someone else do it?
Re: PCM info, help plz!
Tuesday, March 14, 2006 8:54 PM
Unfortunately the 96 is a cross between OBD-1 and OBD-2, and the support from HPT will not be available right away. You could do a swap to a 97-98 ECU. HPT will allow you to bypass the speed limiters, completely reprogram the fuel maps, set for different injector sizes, recalibrate what the vehicle thinks stoich (optimum air/fuel ratio is), and much more.

JBP does reflashes, but does not provide the software to do it, so you have to send them the PCM, and they send it back, unfortunately if they don't get it exactly right, you have to take it out and send it back again, and repeat until it works. Its also the same price as HPT basic package.





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Re: PCM info, help plz!
Tuesday, March 14, 2006 9:35 PM
ok, whats involved in a swap from a 96 ECU to 97-98 ecu, and what would i need to do to the 97-98 ecu to make it work on my car as it is now, which is stock,
Re: PCM info, help plz!
Tuesday, March 14, 2006 9:45 PM
First you need to pull the ecu out and figure out if it has 2 plugs, or 3.





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Re: PCM info, help plz!
Thursday, March 16, 2006 1:23 AM
The 96 is a 3 plug ECM..... same with the 95 Automatics. To swap to the 97+ style ECM, you will need a diagram that shows what every wire is.... and match it up to the 97+ connectors...... a trip to a junk yard will be in order (to get the connectors w/ 6" of wire or more, and ECM)

As said before...... bar relates to pressure.......

Major differences between OBD-1 and OBD-2 is the Emissions...... and the way they are programed. OBD-2 is more strict, and harder to work with, while OBD-1 has less sensors, and is easier to manipulate (with the right equipment). Being you have the 96, you can go either way...... but legaly you can only 'Update' a vehicle to newer systems.




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Re: PCM info, help plz!
Thursday, March 16, 2006 6:10 AM
Yep. My tuning experiences lead me to think of what HP is doing as something very similar to what Hondata has been doing for the Honda guys. Except Hondata software tends to require going to OBD I.

I also have a few questions. For someone like myself who has the LN2 with the side feed injectors, and is looking at the top feed conversion, how will that affect the tuning? I've heard that the conversion causes some issues with the stock ECU but I've also heard it doesn't. And if I plan on going the nitrous route, do I need to go to the 2 or 3-bar map system? I did a little searching through the HP Tuners thread but didn't find it. I may have missed it but I dunno. There's a lot of info in there to read.



Re: PCM info, help plz!
Thursday, March 16, 2006 7:20 AM
ln2johnny wrote:

Yep. My tuning experiences lead me to think of what HP is doing as something very similar to what Hondata has been doing for the Honda guys. Except Hondata software tends to require going to OBD I.


Brew-san posts here with an RSX-S and has a Hondata system. I believe they added a daughterboard to the ECU or something. It's certainly not OBD I.





Re: PCM info, help plz!
Thursday, March 16, 2006 7:36 AM
Hondata has made a ton of changes as of late from what I hear. A lot of their earlier systems required going to OBD I. I'm not sure what they use now but I only remember that from working on Hondas that a lot of my friends owned. Those tuning programs worked wonders if you ask me. And I was just reading an article about Hondata not too long ago and they were discussing how they had been switching to OBD I because it's so much easier to work with. I think the article was in SCC or Turbo n High Tech but I can't remember. I probably still have it in my stack of magazines if I look hard enough. It was a pretty interesting article.




Re: PCM info, help plz!
Thursday, March 16, 2006 10:26 AM
All the ealier Hondata systems (the stuff for B-series engines) did require you to go to ODBI.. when they started working on the K-series engines though that all changed.

For mine (Hondata K-pro) they added a daughter board with a USB port on it and a few pins for things like Nitrous control. I then just use Hondata's software (Kmanager) to make the changes I want (fuel, cam angles, etc, etc) and then write them to the ECU using the USB port.



Re: PCM info, help plz!
Thursday, March 16, 2006 10:40 AM
Nice. But I think we thread jacked. So back to the topic at hand, any thoughts on the injector issue I was wondering about? How about nitrous?



Re: PCM info, help plz!
Thursday, March 16, 2006 11:55 AM
Someone correct me if I'm wrong but I don't think a 2 bar sensor will help you with nitrous. Nitrous isn't really like other forms of boost where you got more air instead you've got something that burns better (has more oxygen) than air. I dunno if the HP supports it but if it supports nitrous then it should have either another fuel table for nitrous or some way of altering the fuel tables (ie. bump them up by 5%, in my case I can also retard the timing when nitrous is engaged) when the nitrous is engaged.

Don't really know anything about the LN2 so I can't really help you there..



Re: PCM info, help plz!
Thursday, March 16, 2006 12:24 PM
Yeah, I've been searchin the web for a while now and nothing. I was just trying to find something about 2-bar map systems with nitrous but I found more questions than answers. I'm at that point where I'm ready to start putting together a motor but I still haven't decided if I want the bottle or boost. I know I want to get the HP software though.



Re: PCM info, help plz!
Thursday, March 16, 2006 3:26 PM
2 and 3 bar map sensors work by measuring the air pressure in the intake manifold. Nitrous does not increase the pressure in the intake manifold, so a 2 bar (or 3 bar) system would not work.

HPT is different from Hondata in that Hondata requires you to wire in a board on the PCM (I believe between the engine harness and the ecu connector). HPT does not require you to do any wiring at all, plug and play.

And, adding to all that, I don't believe HPT plans on supporting 2 or 3 bar systems on the LN2 unfortunately. They will only support 2 and 3 bar systems on the 2k+ LD9 and Eco because an existing 2 bar OS exists from the factory.





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Re: PCM info, help plz!
Thursday, March 16, 2006 4:33 PM
Shifted wrote:

Unfortunately the 96 is a cross between OBD-1 and OBD-2, and the support from HPT will not be available right away.


His car is fully OBD2, As are all cars sold in the United States from the 1996 model year and up.

Dave Eichorn wrote:

Whats different between the 96 and 97's pcm that would make HP tuners software not compatible?

Simple. Your 96 PCM is a different computer than a 97up PCM. HP has to decode the program for each different PCM before they can support it. They haven't done it for a 96...yet. They may never do it. Depends if they think there will be a market for it.

Don Austin wrote:

OBD I utilizes a "chip", thus to reprogram it for more power you change the chip.

No OBD1 does not use a chip. OBD1 only refers to the reguirement that the names of various Fuel Injection components that are for the same use must be the same no matter who (which automaker) makes them. It only applies to 94 and 95 cars. Before 93 GM called a PCM an ECU and Ford called it an EEC. In 94 all companies were required to call them PCMs (and the same goes for all other components).
Pre- 95 Ford and Chrysler PCMs were never chippable. If they made a calibration change from the factory, The dealers would have to replace the whole PCM. GM did it with chips.

ln2johnny wrote:

I also have a few questions. For someone like myself who has the LN2 with the side feed injectors, and is looking at the top feed conversion, how will that affect the tuning? I've heard that the conversion causes some issues with the stock ECU but I've also heard it doesn't. And if I plan on going the nitrous route, do I need to go to the 2 or 3-bar map system?

The PCM doesn't know how the injectors are fed. If the replacement Injectors are very close to the same flow rate of the OEM ones, they will run fine. If not, the PCM will need to be retuned.
Nitrous means nothing to the MAP sensor, so you wan't need to change to a different range (2 or 3 BAR) sensor.

Shifted wrote:

And, adding to all that, I don't believe HPT plans on supporting 2 or 3 bar systems on the LN2 unfortunately. They will only support 2 and 3 bar systems on the 2k+ LD9 and Eco because an existing 2 bar OS exists from the factory.

How could a speed density based PCM not support a 1, 2, or 3 BAR MAP.
HP sells Operating Systems (im my OEM world we call these 'strategies') for cars that run on Air Mass systems and are unable to undestand or even read a MAP sensor. HP rewrite the code so that a MAP can be wired in, read, and then used in the calibration for calculations.

So, how hard do you think it could be for a PCM and OS that already can read and refer to a MAP sensor input for calibration to do so? Ummmmm, it can't not do it!
All Map sensors are 0-5v no matter what the pressure range is. The PCM doesn't know which sensor is plugged in. All you have to do is plug in the new sensor and then shift your fuel and spark tables down to the where they will shift to because of the sensor change , then tune the values above that point yourself.






sig not found
Re: PCM info, help plz!
Thursday, March 16, 2006 4:37 PM
Dave Eichorn wrote:

kool, so whatre the reflash options for my 96 as far s speed limiter fuel map etc., like i said above i know nothing about cars PCM's and how they work, so i appologize if these seem like elementary questions.

Ooooh. A thinly disguised "How do I remove the speed limiter question"!!


sig not found
Re: PCM info, help plz!
Thursday, March 16, 2006 5:39 PM
woot!!! I'm not half retarded after all

Looks like I was paying attention in 'Engine Controls' class




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
RACER X - '78 Opel Kadett W41 Swap

Re: PCM info, help plz!
Thursday, March 16, 2006 6:16 PM
protomec wrote:



Shifted wrote:

And, adding to all that, I don't believe HPT plans on supporting 2 or 3 bar systems on the LN2 unfortunately. They will only support 2 and 3 bar systems on the 2k+ LD9 and Eco because an existing 2 bar OS exists from the factory.


How could a speed density based PCM not support a 1, 2, or 3 BAR MAP.
HP sells Operating Systems (im my OEM world we call these 'strategies') for cars that run on Air Mass systems and are unable to undestand or even read a MAP sensor. HP rewrite the code so that a MAP can be wired in, read, and then used in the calibration for calculations.

So, how hard do you think it could be for a PCM and OS that already can read and refer to a MAP sensor input for calibration to do so? Ummmmm, it can't not do it!
All Map sensors are 0-5v no matter what the pressure range is. The PCM doesn't know which sensor is plugged in. All you have to do is plug in the new sensor and then shift your fuel and spark tables down to the where they will shift to because of the sensor change , then tune the values above that point yourself.


Actually, it is a bit on the difficult side. Its not just a simple matter of voltage, the tables are actually larger. In a 1 bar setup, the ECU reads from 0 to 105 KPA in 5 KPA increments. The 2 bar tune has from 0 to 210 KPA in 5 KPA increments. It also has additional tables like boost enrich.

I'm also wondering, that if you did without the boost enrich table, and could settle for 10kpa resolution, if you could tune your VE table like it was 0 to 210 in 10 KPA increments (pretty much multiplying the position in the table by 2), and that may give you a usable boost tune. I believe this is what you are getting at, the first paragraph is what I was getting at.





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Re: PCM info, help plz!
Thursday, March 16, 2006 6:48 PM
Whether the table is to 105 kpa or 210kpa is only a function of the software you are looking at. The PCM sees sensor inputs in a binary representation of the voltage no matter what the software translates it into on the screen your looking at.
You just have to translate in your mind instead.


sig not found

Re: PCM info, help plz!
Friday, March 17, 2006 8:03 AM
Hmm, kinda makes sense, except, do I or do I not need to go to a 97+ PCM?
Re: PCM info, help plz!
Friday, March 17, 2006 5:41 PM
Wow, in hindsight I couldnt have been more ambiguous with my last post, I am planning on building a turbo motor at some point, and Im just wondering if in the process I'm going to need to swap my PCM.

I know I'm going to need it reflashed, but is my 96 PCM capable of being flashed?
Re: PCM info, help plz!
Saturday, March 18, 2006 4:06 PM
You aren't changning most of the code. The OS just needs to realise there are more positions in the table.

Even if I define a bigger table where I keep my variables in memory the OS will never get a call for those cells if I don't program them into the code.

It would be considered a 'minor revision' but it is a lot of work.


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Yea, ummmm. I used to have a J-body...
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