Is the '98 Z28 LS1 ECU that different?

[Holden_Z28]

It seems like all Programers advertized in the web stores are for 99-02 LS1 Camaros, what's the difference with the 98 Z28 LS1 Camaro ECU? Is it that different from the later years?

[0rion]

the short answer is "yes". I'm not up to speed on all the differences. I do know the 98's ecu is slower and has 1 segment ID vs an 8 segment ID for the 99+. There's also some table differences between the 2 but I'm not sure what all of them are. I know a few of them but not all of them.

[Frost]

The MAF range is a little shorter, the timing table is much easier to bottom out, the idle routines are better in the later OS's (99-up), the later OS's can run HPTuner's real time OS's and 3-bar OS, there are some hokey DTC effects that can mimic physical problems with things like the transmission with large cams, many other internal features and extras as well that are of more interest to tuners.

[N20LT4]

The MAF range is a little shorter, the timing table is much easier to bottom out, the idle routines are better in the later OS's (99-up), the later OS's can run HPTuner's real time OS's and 3-bar OS, there are some hokey DTC effects that can mimic physical problems with things like the transmission with large cams, many other internal features and extras as well that are of more interest to tuners.

I hope this doesn't sound like a stupid question, but what about the '97 LS1 ECU. Is it the same as the '98? Just wondering because I never hardly see much listed for the '97 LS1 (Corvette).

[Frost]

yeah it is...

[Holden_Z28]

From the horse's mouth;

The amount of parameters & the checks the pcm makes against itself the the two main differences, for instance:

Most 98 LS1 pcms have ~395 editable tables Most 99 LS1 pcms have ~455 editable tables

Are 10-15% more tables going to make or break your tune? Probably not, as most tuners will only use 30-40 tables total to tune a vehicle.

Also when switching operating systems on 98's if the end user accidentally hits write calibration only instead of write entire theres a good chance they will fry the pcm since the pcm has no way of checking this against itself until its already too late. So if you can remember to follow directions this will never be an issue and changing operating systems usually only occurs when applying our 2 bar custom operating system and thats mainly for Forced induction applications.

Other than that 98's have near identical functionality & we've seen 700+hp combinations run using the factory 98 pcm so they aren't horribly limited in any way.

William Henn
HP Tuners LLC.
www.hptuners.com

My $$$ goes to HP Tuners!

[N20LT4]

From the horse's mouth;

The amount of parameters & the checks the pcm makes against itself the the two main differences, for instance:

Most 98 LS1 pcms have ~395 editable tables Most 99 LS1 pcms have ~455 editable tables

Are 10-15% more tables going to make or break your tune? Probably not, as most tuners will only use 30-40 tables total to tune a vehicle.

Also when switching operating systems on 98's if the end user accidentally hits write calibration only instead of write entire theres a good chance they will fry the pcm since the pcm has no way of checking this against itself until its already too late. So if you can remember to follow directions this will never be an issue and changing operating systems usually only occurs when applying our 2 bar custom operating system and thats mainly for Forced induction applications.

Other than that 98's have near identical functionality & we've seen 700+hp combinations run using the factory 98 pcm so they aren't horribly limited in any way.

William Henn
HP Tuners LLC.
www.hptuners.com

My $$$ goes to HP Tuners!

Okay, that sounds good. I was just wondering why there are a good number of individuals saying the complete opposite about the '97-98 PCM's. I mean I honestly don't know the difference. I bought my '98 Z28 back in '03 w/ a tune already on it. The only hint that it was probably tuned was the reset fan temp (and there was no ground or switch). Also, I noticed several tuner devices listed online or in the catalogs do not have a unit listed for the '97-98 LS1 - usually just 99-02..

[0rion]

Okay, that sounds good. I was just wondering why there are a good number of individuals saying the complete opposite about the '97-98 PCM's. I mean I honestly don't know the difference. I bought my '98 Z28 back in '03 w/ a tune already on it. The only hint that it was probably tuned was the reset fan temp (and there was no ground or switch). Also, I noticed several tuner devices listed online or in the catalogs do not have a unit listed for the '97-98 LS1 - usually just 99-02..

about the only issue I have with mine is the knock sensors. I upgraded the sensors and harness to the newer stuff but still see a lot of knock all over the place. I'm heading towards disabling them altogether I think. Other than that I've tuned my heads/cam 98 without much of an issue.

[N20LT4]

about the only issue I have with mine is the knock sensors. I upgraded the sensors and harness to the newer stuff but still see a lot of knock all over the place. I'm heading towards disabling them altogether I think. Other than that I've tuned my heads/cam 98 without much of an issue.

Gotcha! Just a few knock issues - that's it. That's nothing to be too worried about.

[Frost]

Gotcha! Just a few knock issues - that's it. That's nothing to be too worried about.

There's a lot more to it than that, and more than Bill let on in his email. I have had more than one 98 that the knock sensors were totally useless on even after tuning and tuning. They show knock at cruise where there is none, and I *HEAR* it at WOT and they show nothing.

That's not to say that I'd ever turn down tuning a setup because it was a 98. The table differences he quoted are on-point, but the control algorithms work much differently. I am much more prone to use SD or OLSD on a 98 with a rad setup than I am a later year car. Driveability and general operation will be better in many cases. The fuel trimming control routines work differently in 98s too. There is also that annoying tendency for the IAC to fall out of closed loop and you lose idle control down around 10VDC @ the PCM. In later years the threshold for OL IAC comes at a lower voltage, so it's only ever shown it's head to me in 98s.

Just trying to give a fair overview for anyone reading.

[N20LT4]

There's a lot more to it than that, and more than Bill let on in his email. I have had more than one 98 that the knock sensors were totally useless on even after tuning and tuning. They show knock at cruise where there is none, and I *HEAR* it at WOT and they show nothing.

That's not to say that I'd ever turn down tuning a setup because it was a 98. The table differences he quoted are on-point, but the control algorithms work much differently. I am much more prone to use SD or OLSD on a 98 with a rad setup than I am a later year car. Driveability and general operation will be better in many cases. The fuel trimming control routines work differently in 98s too. There is also that annoying tendency for the IAC to fall out of closed loop and you lose idle control down around 10VDC @ the PCM. In later years the threshold for OL IAC comes at a lower voltage, so it's only ever shown it's head to me in 98s.

Just trying to give a fair overview for anyone reading.

It's starting to be a bit confusing, but I pretty much grasp what you are saying. Basically, if I were to ever get another '98 LS1 I would seriously consider swapping ECM's...which wouldn't be that expensive. Thanks for the info.

[Frost]

Well they aren't that bad once you learn to work with them. I would swap if it were my car or fiancee's car, but I would never tell a customer he needs to. A race car is different too though.

[foff667]

There's a lot more to it than that, and more than Bill let on in his email. I have had more than one 98 that the knock sensors were totally useless on even after tuning and tuning. They show knock at cruise where there is none, and I *HEAR* it at WOT and they show nothing.

That's not to say that I'd ever turn down tuning a setup because it was a 98. The table differences he quoted are on-point, but the control algorithms work much differently. I am much more prone to use SD or OLSD on a 98 with a rad setup than I am a later year car. Driveability and general operation will be better in many cases. The fuel trimming control routines work differently in 98s too. There is also that annoying tendency for the IAC to fall out of closed loop and you lose idle control down around 10VDC @ the PCM. In later years the threshold for OL IAC comes at a lower voltage, so it's only ever shown it's head to me in 98s.

Just trying to give a fair overview for anyone reading.

The 98 Knock sensor issue really isn't related to the pcm from what I can tell, they just happen to read 4* of knock retard on many vehicles for no obvious reason sometimes, you can pull as much timing as you want & it'll still pull 4* in those same cells lol.

Coding wise there are some things different but compare a 98 to a 99 pcm & then compare a 99 to an 02 pcm and you'll see there are differences between them all. I simply pointed out the major points that everyone goes over which are fewer parameters & the lack of custom operating systems.

Personally my 98 Never hit any limits ie maf or spark etc. but then again I was only an A4 with heads/cam. Boosted applications will obviously hit these limits much sooner.

Anyway I hope this clears things up further.

-Bill

[Frost]

It wouldn't stop me getting a 98, and they are certainly quite tuneable. I didn't mean to sound all dramatic in my previous posts, but many of the things that annoy me about 98s are transparent to the owners. The fact that the trims are nutty and I have to keep separate config files for the scanner for 98s, and if I forgot to pick a proper config from my 98 list, I get 101948^10 for LT trims, and the crazy random knock that isn't real. I don't know why I fuss about the configs, I obviously have tons for Gen IV and later, but the GenIII pot is dipped into daily. Heck half or more of the H/C 98s I have tuned all show KR AT STARTUP! And I like I mentioned, in more than one car as well, with OEM KR settings except for decay, no event detection at WOT but I could hear it. Obviously these aren't big deals, they are just annoying. They aren't something for an owner to sweat unless he tunes his own ride, otherwise let the tuner sweat the stuff.

[0rion]

It wouldn't stop me getting a 98, and they are certainly quite tuneable. I didn't mean to sound all dramatic in my previous posts, but many of the things that annoy me about 98s are transparent to the owners. The fact that the trims are nutty and I have to keep separate config files for the scanner for 98s, and if I forgot to pick a proper config from my 98 list, I get 101948^10 for LT trims, and the crazy random knock that isn't real. I don't know why I fuss about the configs, I obviously have tons for Gen IV and later, but the GenIII pot is dipped into daily. Heck half or more of the H/C 98s I have tuned all show KR AT STARTUP! And I like I mentioned, in more than one car as well, with OEM KR settings except for decay, no event detection at WOT but I could hear it. Obviously these aren't big deals, they are just annoying. They aren't something for an owner to sweat unless he tunes his own ride, otherwise let the tuner sweat the stuff.

my car is guilty of that.
The funny thing is my buddies cammed 98 vette shows almost no KR. I'm also leaning strongly towards just keeping mine OLSD for good. It runs really good right now minus the KR issue and I kinda hate messing with a good thing. Idle is perfect under all situations. I get no surge...nothing. AFR looks good across the RPM range minus being a little rich at WOT which I plan to work on but hate doing that on public roads if I can help it. I'm just not seeing a huge reason to go back to CLMAF.

[slpcamaro]

good read guys question how much am i looking at paying to switch my 98 out and is it pretty easy or do i need someone to do it. A how to link or some instrucetions and a place to get the ecu at would be nice.

[foff667]

good read guys question how much am i looking at paying to switch my 98 out and is it pretty easy or do i need someone to do it. A how to link or some instrucetions and a place to get the ecu at would be nice.

I would expect to pay no less than $300 to have this swap done at a bare minimum and more realistically about $500

Figure:
New pcm-$100-150
1 hour of labor minimum if the shop has done the swap before-$85
Perform the proper segment swaps for the fuel system-$100-200

The entire pcm needs to be repinned so someone who has not done this before would probably take several hours of labor longer.

-Bill

[0rion]

I would expect to pay no less than $300 to have this swap done at a bare minimum and more realistically about $500

Figure:
New pcm-$100-150
1 hour of labor minimum if the shop has done the swap before-$85
Perform the proper segment swaps for the fuel system-$100-200

The entire pcm needs to be repinned so someone who has not done this before would probably take several hours of labor longer.

-Bill

I agree. I saw the write up on doing this a while back. Nothing hard....just labor intensive.

[9t8z28]

There's a lot more to it than that, and more than Bill let on in his email. I have had more than one 98 that the knock sensors were totally useless on even after tuning and tuning. They show knock at cruise where there is none, and I *HEAR* it at WOT and they show nothing.

That's not to say that I'd ever turn down tuning a setup because it was a 98. The table differences he quoted are on-point, but the control algorithms work much differently. I am much more prone to use SD or OLSD on a 98 with a rad setup than I am a later year car. Driveability and general operation will be better in many cases. The fuel trimming control routines work differently in 98s too. There is also that annoying tendency for the IAC to fall out of closed loop and you lose idle control down around 10VDC @ the PCM. In later years the threshold for OL IAC comes at a lower voltage, so it's only ever shown it's head to me in 98s.

Just trying to give a fair overview for anyone reading.

Hmm, I had a trouble code that come from the IAC after I installed my Procharger, but I can't remember what it was. I do have a poor idle quality. It is inconsistent and goes up and down. But, I also have a Po103 code pop up that states MAF high voltage and my A/F is at 16:1 As soon as i disconnect the MAF, the idle is perfect and the car goes to 14.7:1

I can't figure it out.

Sorry to jack your thread.

[9t8z28]

SD stands for Speed Density right? But what does OLSD stand for?