Delco probie

[Mamba]

hi all,

i have read various topics within this forum many times and always found it informative and useful. i wont pretend i always comprehend what i am reading but with a some research it makes sense. you certainly know your stuff and i am still getting to know that intricacies of the delco ECU. i have followed the advice of various members, namely delcowizid (mike) as well as dr bob and greenfoam (jason) on sc.

just a quick background, i was born and raised in central africa (hence mamba) lived in aus since 1979, Perth WA, North Qld and Brissie. Married with 2 teenage girls and worked in the federal govt in various depts.

i have owned a vs commodore wagon v6 for the past 12 years, it was a health dept vehicle and have always been impressed with the incredible robustness of the vehicle, genuine holden parts still available and it has never let me or my family down. after all these years, the vehicle is starting to show her age, so i have installed a L67 style OTR CAI and a full lukey exhaust sytem, extractors to end pipe. the original deteriorated and sounded terrible. i am now considering a Kalmaker tune (hornibrook racing geebung) to take advantage of the new hardware but out of my price range at the moment at around $1200.

thankyou for having me as a member and for all the great advice over time.

regards shayne.

[VL400]

Welcome along mamba

With the mods you have getting a kalmaker tune is prob not going to be great value. It is possible to get good results with a quick tune of the factory memcal, you wont gain any power by getting a kalmaker tune over giving the factory tune a tickle. The main difference is the ease of tuning using kalmker in real time on a dyno, but even that is questionable these days with all the info and tools available to DIY'ers.

Have a good read and be sure to ask questions

[Mamba]

Thanks for the advice VL400 and i have to agree, they are mild mods and i am really just trying to get the engine to run as efficiently as possible. any advice is greatly appreciated as i am a complete novice. the mechanic that has fixed the car for the past 10 years uses a generic tuning program called "carmine" or "carmen", not sure of the exact spelling but it does the job. only thing i have noticed is a slight decrease in acceleration since the exhaust was installed. May be a slight lean out with WOT as the exhaust is very free flowing. only a 100 cell metalcat and single lukey sports muffler installed by carline. at this time, I will continue reading the post by Dec_head "delco tuning for dummys", very helpful and I need to crawl before trying to walk.

PS I am from scarborough VL400 and thanks again for the advice. since found out that they change the memcal to a kalamaker??....i thought kalmaker was just the weapon of choice for recalibration....another tuner told me only a "haltech interceptor" would really be able to take advantage of a free breathing engine....obviously never saw either greenfoam or delcowizid on youtube demonstrate what the delco is really capable of!!. If it is permissable with board members and administrators....may I keep any questions confined to this thread so as not to pepper the forum with probably ignorant questions?

regards shayne.

[Mamba]

Still reading....heaps of information to digest...depth of knowledge of members on this board is awesome...

question??... is the delco ECU susceptible to power fluctuation or loss??.....I used to own a Hyundai that was a complete pain if the battery failed or was disconnected, It "lost" memory and had to be driven for some time to reprogram the computer. Others seem to have issues if the battery was disconnected for more than a couple of hours..

also...can a memcal be "flashed" by an automotive tuner accidentally and lose what has been recalibrated??

I noted with interest the posts by Dr Bob and Holden202 concerning memcal chips and how some have security measures to ensure they are not copied and can only be tuned by the manufacturers software...back to base only to retune...including kalmaker!!...just what I don't want.

From what I have read thus far I assume that the delco ECU programs are written in assembly (binary) and recalibration of data is by way of altering the information contained within various tables. Basically, information from various sensors is transmitted to the ECU which continually recalculates the correct ratio air/fuel (stoichiometric mix) for efficient combustion of same. I think the OEM code is written in terms of Lambda which a perfect mix is 1.00...lean higher eg 1.4 and rich less eg 0.8. Is this correct??

I am still struggling with the exact functioning of the various sensors and how the ECU recalculates the information received from each. The tables are also proving challenging. Theory is one thing...practical application is a whole new beast..and I have a whole lot yet to learn...thanks Shayne


TT

[Jayme]

you wont have to worry about being accidentaly reflashed on a VS as its got an Eprom (read only) that you need to take out and reburn to modify the tune. the security is only on the fancy aftermarket binaries, the GM binary is all you need to work with, just edit the calibraiton on it. there are a few VS tunerpro definitions posted on this site that should give you a good start.

[Mamba]

Thankyou for that Jayme....will keep a look out for those vs tunerpro definitions...glad to hear that the memcal cannot be flashed...wouldn't be impressed if a good tune was lost....still reading through posts on Dec_heads thread....my hat off to him, I am confused just reading them without actually performing the functions.....Cheers Shayne.

[antus]

with regards to the questions about battery power loss.. being rom based the pcms maintain a lower resolution table of differences between programmed VE, and real world measurement. It stats at 100% of the calculated value, but if it sees that at a particular rpm/load the mixture is rich or lean (and several other factors, such as engine is at run temperature are also met) then it starts 'learning' the tune is out. This would be due to physical faults, such as perished & leaking air pipes, or degraded sensors, but provided the o2 sensor is still accurate gives the car a way to get the mixtures right. If the ecm looses power for a couple of minutes this information is lost and the car needs to re-learn. If performance is right out you should still go over the air pipes and check for leaks, and/or test sensors. Logged data from the ecu would usually point you in the right direction.

[Mamba]

Thanks antus...I was wondering about the learning aspect of the ECU. So being ROM based, it has a set of fixed values that are constanlty compared to actual values by way of sensors in order to maintain stoich. By the sounds of it, the o2 sensor plays an essential role in these calculations. This would mean that the ECU would be in closed loop if stoich is being maintained changing to open loop as the A/F ratio increases or decreases past a certain point.
NVRAM is mentioned on the board which is non-volatile and not usually susceptble to power fluctuations....what is its role within the ECU? I had no idea that the ECU could lose its calculations after such a short time but it does continue to recalculate and apply new values until stoich is achieved once power is restored?
Performance is still lacking, idle fine, cruise fine, economy fine but acceleration is still restricted....usual suspects are being checked but nothing to report so far and unfortunately I am unable to perform data logging at this time. What software would you recommend to perform this function?

I personally think that the ecotec is a very capable engine and can be fairly powerful if it is running at its full potential. Few engines leave the factory at optimum efficiency due to tolerances and constraints placed upon them to ensure reliabilty in a range of conditions and drivers. I wish to draw on the knowledge and experience of members on this board in an attempt to find the vehicles full potential.......long way to go yet!!!...cheers Shayne.

[VL400]

The PCM has some RAM where it can store the fuel trims and other items that get learnt over time, but like antus said disconnecting power you lose it all. Once reset it will start using the default values with no trims, it does not take too long to re learn everything. The NVRAM serves a different purpose and in our case will allow you to make tuning changes over ALDL. Rather than the code running off an EPROM you can run it from an NVRAM, this means that you can read and write instead of just reading like in the case of an EPROM. The NVRAM will retain its memory with no power, it does not however take the place of the RAM so disconnecting power still means the RAM gets reset.

You are also correct regarding the closed and open loop fueling - anytime stoich is commanded (14.7:1) and all the closed loop qualifiers are met then it will use the O2 sensor, anything other than stoich its going to be open loop. The PCM looks at the O2 sensor reading and determines if its rich or lean and trims the INTegrator and BLM (Block learn multiplier) accordingly. You can access the BLM values if you get a ALDL cable and can help in tuning the fuel requirements. TunerPro V5 and an ALDL cable will get you logging.

[Mamba]

Thanks VL400...plenty of great information flowing my way....NVRAM is still confusing me.....is it part of the OEM ECU or an aftermarket addition??. My understanding was that the memcal could not be programmed unless removed from the ECU. I am making the assumtption that editable values are only available on the memcal as most performance shops are usually in a hurry to change it. With regard to the memcal, can single table edits be made to it or does the entire memcal get erased and reprogrammed with the addition of new values? I apologise for all the questions, the more I learn, the more I realise just how little I know...

I glad to hear that I got something right...I think I,ve got a handle on open and closed loop operation, but have no knowledge of the INtegrator or BLM, I'll have to research those...reading your response, am I right in thinking that in acceleration, open loop mode is employed and the o2 sensor information isn't used by the ECU or does it communicate with all sensors including the o2 under all conditions??

Thankyou for suggesting Tunerpro V5 to commence datalogging. I'll get on to that as soon as I can. Actually sighting the values and operation may assist. Also the tables used by the ECU. Antus advised that the ECU compares set (and presumably theoretical) values with actual values as supplied by the various sensors and determines what acions to take to maintain VE...I've seen ECU tables for a different vehicle and noticed that the values appear fixed..ie if x then y...the information sent by the sensor, compared to fixed values then a set value within the table applied...is that correct?? I am still unable to read a table as I do not understand the values contained within them say MAF vs RPM...what do the values relate to??...the cylinder mass vs RPM is three dimensional and completely threw me....what would you suggest to get up to speed with the tables and understand what I am seeing...internet sites...a VERY patient board member to dumb it down for me....I have many other questions and more developing all the time, but I'll stop there and re-visit a few threads...Cheers Shayne