I have searched thru many numorus pages trying to find what i was looking for but nothing that would help me, and i couldn't find what i read before about the differences... Before you read on, i know HPT would be my best route but i don't have the money for that at the moment, but i can get an 02 ECU...
Anyways, a while back i read something about 02-04 Ecu's being different on the aspect of going into open loop and closed loops mode. I read somewhere that the 02 Eco Computers, doesn't change the pulsewidth of the injectors making stay at 14.7 Ideal A/F ratio. Unlike that of the 03-04 does change the pulse width of the injectors and what not, keeping it at a 14.7 Ideal. Not being able to get a richer A/F ratio.
The reason im asking this is because im running boost at about 10psi (now) and i was thinking that i might swap out a 04 Eco Ecu for a 02 Ecu... At times i will see my A/F go down to mid 11's 12's While under boost, and sometimes i won't... And i don't want to run it lean where i will damage something.
Im just wondering if this is correct on the 02-04 Ecus for ecos being different... Thanks in advance...
2004 Turbo cavalier 11PSI and blown!
I wasn't sure if i made that make sence or not... I wasn't sure on how to word it. But no i do not want it to stay at 14.7. Why would i want that under boost???
I think what i wanted to ask was, does the 02 Ecu keep 14.7 A/F ratio or allow it to get richer... Unlike the 04 witch like to keep a 14.7?
But like i said before, I don't always see a 14.7... I do see around 11s 12s While under boost....
2004 Turbo cavalier 11PSI and blown!
I don't want to change, i know 11-12s are good, lol... I don't know how to put this...
Somewhere i heard(read) here, that the 2004 Ecotec ECU
Doesn't like to let the car run a richer A/F. Keeping it at 14.7
And i also heard, that the 2002 EcoTec ECUs
will let the car run a richer A/F.
So what im asking is if i run into the problem with my '04' Computer (ECU) not letting the car run a richer A/F. If i switch to an '02' computer will it let me run a richer A/F? while under boost?
Something to do with the open/closed loop the computer goes into, is why im asking this... Or maybe im all confuesd
2004 Turbo cavalier 11PSI and blown!
I'm having the same problem with my 05 sunfire, Sometimes under boost the A/F will drop down to 11.8-12.0 and other times it hovers around 14. I read that same post about the pcm needing to be reflashed, is this really gonna fix my problem? how much would that cost? Can i buy an 03 or 02 sunfire pcm and just bolt it up, those are not to expensive from a salvage yard. Would HPTuners software be able to help with this problem at all?Any help is definatly appreciated. My car is an 05 sunfire and i have the hahn racecraft stage 2 kit (fmu) running 7 psi.
if your not seeing your afr climb up to the 14's , then i wouldnt worry about it
if yours dips then comes up , then i might worry
Under boost it dips down into the 11.8-12.0 range occasionally, but most times it does not... i am worried.
I have a turbo 2005 sunfire too, I do not have that problem... sometimes when I get on it slowly it take a while to drop, but i think its because the throttle isnt open all the way or something, but my friends srt4 does the same thing, so im pretty sure its normal... but everytime i step on it it drops to 11.7-11.4 . . . . i am tuning with HPT... what are you using to fine tune your car?
|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
I use the FMU to tune the car.. Sometimes it will drop down to the 11.8 a/f i want, but most times it does not. maybe hptuners fixes this problem???
does anyone have an 04 or 05 file of a stock eco 5 speed .hpt file, im interested in looking in HP tuners to see if theres any difference or what triggers this searching for 14.7 as the rpms climb
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
one of these days, someone will put it in a sticky or make some use of it but until then I guess I'll just keep repeating myself.
The 2002 ecus (ohv, 2.4 and ecotec) are programmed with open loop, which means under some event (usually wide open throttle), it ignores primary O2 sensor input, and goes to pre calculated "maximum power" air/fuel ratio.
Usually its around 13.7:1.. its understood that anywhere from 13.3-13.7 is ideal for n/a maximum power
the 2003+ ecus got a revised set of code that excludes the open loop maximum throttle event. Therefore, even under full power, the ecu is still trimming fuel injector pulsewidth to attain a 14.7:1 air fuel ratio. Optimal for emissions and gas mileage, but not for power and torque(and safety).
typically, people can 'trick' the engine into mechanically delivering more fuel for aftermarket or custom boost set ups three major ways:
1) extra injection - throw extra injectors into the intake stream.. more injectors = more fuel
2) FMU/ AFPR - raise fuel pressure in relation to boost. Pulsewidth being the same, higher fuel pressure means more fuel makes it into the engine. This is limited however by your injectors and fuel pump(too much pressure results in fuel pump suicide, or injector suicide).
3) bigger injectors - can move more fuel than a smaller, stock injector
Most people use at least 2 of any of these methods in tandem to solve their fuelling issues, but this does NOT work on 03+ ecotec ECUs.
why?
I'll explain. Remember how we said that the ecu doesn't have an open loop event for wide open throttle? It constantly monitors air fuel ratio and constantly trims injector pulsewidth to stay at the ideal 14.7:1 air fuel ratio.
Even when throwing in more fuel or raising pressure, the ecu WILL compensate by pulling injector pulsewidth. Its not 'magic', its science. I still don't see why a lot of people are confused about this.
Even your ZEX or NOS or NX wet shot nitrous kit -regardless of the size of shot- the ecu will LEAN YOU OUT TO 14.7:1!!!!!
Then how come so many people get away with it? easy. The genious in the ecotec design is its incredibly efficient combustion chamber. This for the most part keeps you safe from detonation.. and even still, there have been plenty of cases of ecotecs blowing up from this very issue (whether recognized or not).
so to answer the question:
02 ecu for ecotec is conventional programming (allows open loop, responds to familiar mechanical style tuning ie. FMU, AFPR, etc)
03+ ecu is non open loop programming (FMU, AFPR, wet nitrous shots will have little to no effect on air/fuel ratios.. ecu will constantly adapt out to 14.7:1 air fuel)
there's two solutions
1) reflash ecu to 02 spec or
2) control ecu programming via HPtuners or removal of ecu fuel control(MegaSquirt) or full stand alone (electromotive TEC2, 3, MoTeC, F.A.S.T., etc)
I believe that electronic tuning is always superior to mechanical... so if I had to advise someone on what to do, I would say go with the #2 solution.
This is what i thought was happeneing. Just to be completly sure, can hptuners be used to fix this lack of open loop. I want to be sure before i shell out the money to get it. Can a good safe tune be had using the stock 1 bar map sensor, It seems like most of the HPTuners guys are messin around with 2 bar map sensors. Do i need to keep this FMU i currently have... I really want to take it off the car. Thanks for the help fellas.
i have very limited familiarity with HPtuners so maybe someone else can answer that.. but I'd assume it gives you control over injection, which would mean that it would work yes.
If you have electronic control over the injection system, you don't need the FMU. An AFPR is a good idea however so you can adjust fuel pressure to compensate for injector duty cycles and make sure it stays in the safe zone.
Thanks for the info, there was someone else with an 05 sunfire who said that HPTuners worked well for him. So im assuming it will work. Has anyone used this setup with the stock fpr. I have bigger injectors and the fuel pump that comes with the hahn kit. im only at 7 psi right now, i think with the stock FPR i will be ok.
I have the same problem with my 05 cav and i bought the 02 ECU like i was told and i put it in but my car wont start so i put my old one back in can anyone explain to me why it didnt start Thank You in advance.
Short answer the I.D programed into the 02 ecu is not the same as that of the 05 .The BCM reads the I.D and it reads it as not matching. The files it has stored in memory need to match so the to units can work together. You need to get the 02 Pcm reflashed with the same I.D as that of your 05 PCM.
Thats Him Officer The WICKED One.
Thanks man i really appreciate it.
what about the gm reflash though. I would think that even if you had an 02 ecu and got the reflash that it would use alot of the same files as the 03+. Damn i wish we could read the gm reflash
.
and I'm having issues finding an '02 Eco ECU.
I want open loop mode!
gotta save up for a laptop and HPT now.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
you don't need the 02 if you get HPT
you can make the ecu do what you want with HPT, and program open loop just like a normal ecu
