Delco probie

[delcowizzid]

worth a read not specific to the car but lots of good info http://www.diy-efi.org/gmecm/papers/tunetip.html

[VL400]

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...

The NVRAM replaces the memcal, its an aftermarket addition. So instead of an EPROM that you must remove, erase, reprogram then re-install, you use NVRAM that can be reprogrammed using the vehicle data bus even with the engine running. The memcal contains the entire operating system including the calibration - the bits you adjust to tune the engine.

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??

The closed loop process uses a PID (proportional integral derivative) algorithm. The INTegrator is the integral function of that proces, its commonly reffered to as the INT or short term fuel trim (STFT). There is plenty of info on PID control on the internet, its a common process control method. The BLM is the long term fuel trim (LTFT) and uses a table in RAM.

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

The tables are exactly as they appear, nothing tricky going on. They just use one or two inputs (2D or 3D table) and do a simple lookup then apply the data. The axis values can be pretty much anything, a value from a sensor or a calculated value. Download the 12P package and have a look at the binary using the suplied XDF and TunerPro. Its simpler than the VS Ecotec, its MAP based and not MAF though, so should get you started on learning what types of items are available to tune.

[Mamba]

Thanks heaps guys.....sorry I was offline due to end of semester functions.....great to hear from you delcowizd, the site is very helpful and I'll go through it slowly...maybe something will sink in LOL....love your vids, cars and advice, anything you can't do???....NZ beautiful country, only seen north island specifically Auckland and surrounds..I digress...thankyou for the helpful reply,

Hi VL400, your advice is always invaluable & I appreciate your time and assistance, thankyou for replying so qiuckly.
I can see why the SVRAM would be so popular, certainly a lot easier and more efficient to just alter values while connected to the ALDL. Knowing this helps me understand the threads...Why don't OEM use it?? or do the ADR's prohibit it...they prohibit just about everything else!!...I found heaps of information on PID, STFT and LTFT...somewhat embarassing that I had never heard of a process (PID) that is used in so many devices used almost daily..do you have to know the actual algorithm or just its function within the ECU?? and it is only used in closed loop not open loop....I found a training document used by Toyota technicians that explained the whole process in detail and included an assignment at the end to test your knowledge...will keep on reading

Had a look at TunerPro....impressive program!!....hard to believe tuners provide software of this quality for free dowload or donation....just to clarify MAP is manifold absolute pressure and uses a diaphragm connected to a vacuum line...unit of measure in bars of atmosphere..MAF is mass air flow and uses a heated wire that sits directly in the airflow, the cooling of which is directly proportional to the movement of air over it..after going over the tables again with the information you supplied..the penny finally dropped..the values are exactky that...values used by the ECU in its calculations which is why there is no unit of measurement..doesn't reqiure it. Once again your advice has helped me heaps..your blood is worth bottling!!!..my sincere thanks cheers Shayne

[Holden202T]

manufactures don't need nvrams in the cars because once they role off the production line they don't want know about them, so the cheapest option is the eproms they come with.

[Mamba]

Makes sense....anything for the all important profit margin..thanks holden 202...just an quick update....11.50am local brissie time and my car has shot itself completely (thats not a spelling error..I could use a far harsher word but will restrain myself)....remember the acceleration problem I was having????...well...it just got a whole lot worse..and suddenly...doing a few things at lunch time and returning when at the car failed at around 1500rpm, 40-50 kmshr....after that it settles down again and runs fine. I know when I am out of my depth and have to seek professional assistance...sooo..its currently sitting outside the mechanics workshop...just as well the guy is also a good friend and will fit me in when things go wrong at a moments notice..this one has got me...
no check engine light
no loose connections
backfiring at 40-50 kmshr only...before and after no problem
no oil or or leaks
exhaust still attached!!

Frustrating but it happens....theory is good ...but nothing can replace practical application and experience...my hat off to all of you!! Cheers Shayne

[Holden202T]

sounds like its too lean in that area ?

whats the engine setup ?

[VL400]

Could be many things so hopefully the mechanic can sort it out pretty quickly for you. It could possibly be a failing crank angle sensor (CAS), they tend to play up when the engine heats up rather than when cold. Fuel pump, dont ask holden202 about fuel pumps

[Holden202T]

[Dec_head]

I have had similar issues and it was coil pack failure was intermittent at first then i went around a round about and 1 died altogether.
Easy way to check was take 1 lead of each pole at a time on the coils and start the car and look for a spark from each pole individually.
It was funny because i got a second hand coil pack of a mate and only ended up with 3 good coils out of 6 and then a few weeks later another 1 failed i then picked up 3 aftermarket replacements and never had another problem with them.
A mate had a vt he thought had transmission issues because of shuddering when changing gears etc funny thing was it turned out to be a spark lead he left off.
After he spent a few dollars at different mechanics having them plug in and try to diagnose the problem and not fix it.
I tried telling him that computer diagnosis has limited capabilities and quite often gives the wrong faults if any but do you think he listened.
Whats funny is I have found it more useful using info relating to car faults through a google search and forums and doing it myself rather then paying someone.
What a ramble i best shhhhhhhhhut the f up i am going

[Mamba]

Right on the money Dec_head!! coil failure!!...the 2-5 coil was failing intermitently and as I went around a corner it packed up completely. Well I guess I failed the pratical assessment..sunday afternoon, tighten every bolt, check leads, plugs, vacuum pipes etc...monday morning, watch car self destruct!! self confidence took a hammering..thought I had touched something I shouldn't have or not re-attached a pipe..they are not easy things to diagnose are they??...thanks guys ....you advice is always welcome. I am glad it wasn't a Crank angle sensor..sounds expensive to correct...as for engine setuup...stock ecotec v6, only mods are a replacement exhaust (Lukey fitted by carline) and cold air intake...minimal in the scheme of things unless the police see it then you swear you have a jet engine running on moonshine under the hood..they do not like aftermarket anythiing!! What I don't understand is...

firstly..why did the ECM not return an error by way of engine light ont the dash when 2 cylinders weren't firing but using dianostic equipment show a misfire??
secondly..the amount of vibration I thought would have set off the knock sensors and put the car in limp home mode?? I could still travel above 50kmhr..
finally..always under the assumption that electrical items had only two modes..working fine or paperweight. The coil must have been slowly deteriorating over the last couple of months...occasionally packing up completely but still kind of working??

Is it advisable to now replace the other two coils or just leave them..they are the original ones and have taken the car over 300,000kms..

Thanks for the advice and rants welcome on this thread...its all good!! and I can not tell you the number of times I have not taken good advice and lived to regret it...and I am not allowed to ask about fuel pumps LOL..thanks again..cheers Shayne