Does anyone use a 98 computer and run a sd tune? I know it would be great to upgrade to a 99 up pcm. I am broke and very busy though. My Maf died so now I am looking for options.

Yes, Doc I know I should upgrade.

 

I've done one with efilive, but I really wouldn't want to work with a 98 PCM again. The tune was great, but was RPM limited to 6000 no matter what I tried. There may be some problem that you just can't fix given the capability of the tuners out there for 98's. It did take some time to get it right and that's with using some very good test equipment.
I would try it for a while to see how it goes, but if it gets too frustrating, consider swapping systems to something with better control.

 

slowec,
I never have any trouble tuning w/ my 98 PCM. Although, I run OL/MAF, not "full on SD." It's tuned all the way through 6700 RPM.

white2001s10,
Why do you run into trouble above 6000 RPM?

 

This was a 1998 C5 tuned for OLSD.
ALL RPM limits set to 8000 RPM. Many error codes turned off.
PCM commanded fuel cut at anything over 6000 RPM.

There was just some constant or table that EFIlive didn't show or have access to, or there was an error in the EFIlive definition info for changing the RPM limit tables. I spent a couple of days trying many different approaches, but could never fix it.
I think it comes from the fact that most of the tuners out there barely give you access to 20% of the constants and parameters in the PCM.
There are certain contingency modes and defaults that you never see with your tuner program.
This particular C5 always had problems with the Rev limit even before the OLSD tune, so I see it as more of a 98 PCM problem, and not an OLSD problem.
The first tuner used on this particular car was an old version of LS1edit, so the error in the code may have been generated by Edit, not EFIlive.
Had Edit never been used, this problem may not have occurred, but I'll never know now.

 

Sounds like an issue with your tune, I tuned my 98 without issue shifting at 6800rpms without a problem.

 

I'd agree w/ you that most likely "LS1EDIT" had something to do w/ it. As noted, my V1.2 EFILive software allows me to go to 6700 RPM & above (if needed).

IMO, the biggest gripe tuners have w/the 98 PCM is that the VE back-up table, used w/no MAF, has MAP gaps that require the values to be interpolated by the tuner. Agreed, that the 99 + PCM's are the better choice, but, personally, I'll use the 98's for any of my cars (no licence required between PCM's).

 

Whatever, there is a lot more reason to hate on 97-98s than the secondary VE... I'd like to stop tuning them or at least charge more.

To the guy with the issue at 6K.... if you felt like edit hosed it up, why didn't you put it back to stock programming and THEN tune it. I *NEVER* tune behind other software suites, and only with great exception do I ever tune behind another person. There are other issues that can stop the 97-98 that are unexpected and do not affect the later PCMs.

 

No issues at all here on a '98 pcm. Running OLSD and shift at 7100rpm, making ~500rwhp N/A and close to 700 on the jug. Like said above the 2nd VE table is the only thing I hate about it.

 

Should be no problems tuning a '97/'98 PCM, speed density or otherwise.

LS1Edit should not be his problem either. I tuned 7500+ RPM '98 F bodies SD with LS1Edit when that and hex a editor was all there was. HPTuners and EFILive didn't exist yet.

The '99/'00 box has the secondary VE table also. Somebody is just missing something if it won't rev past 6000. It makes no difference at all what software was used to tune one last, as long as it's not locked.

Like Steve said, I normally just write over what was in the box before anyway. That's quicker than trying to chase down something that may have been done wrong before, and I don't really care how the last guy did things.

 

Same here, I don't even look at the tune, I just flash it back to stock and start over...

 

As everyone said.You can tune it SD but it's more generic than ussing a 99+ computer.I've gone as far as 2 bar(cutting VE in 1/2) and support a 800rwhp Vette for 3 years that way.

I'd also agree that 97/98 Computers just suck.I've had alot of idle problems with them throughout the years.

 

I don't do that, I flash it with a calibration from a car I had already dyno tuned with a similar combo. I have over 1000 calibrations that I did here on my dyno, I just use one of those for a starting place.

 

I use to do the same, I had a list with customers name and mods, find a similar one, up load and start from there. One of my laptops crashed and I lost a lot of info, so now I just start over...

 

Sorry that my statement turned into a thread hijack

If I try hard enough I think I can barely understand why someone would defend the 98's as problem-free if they themselves have had good or great results with their tuning attempts. I wouldn't however, count on smooth sailing given all of the posts documenting odd problems popping up with these older PCMs. I'm not suggesting that the PCM is problematic, but rather that the tuning programs are not fully error-free when it comes to the 98 calibrations.

More to the point, and applicable to my case, is the LACK of access to calibration items, the ability to add, alter or fix calibration items or ability to reference the source code. I know there are good reasons for this LACK, but that doesn't exempt it from being a problem in many cases.

My tuning experience goes back to 1994 with SD tunes and conversions, but this was a one-off combination of both parts and tune. Unfortunately, even as a last resort, I could not have completed the job with a "canned" tune. I spent a LOT of time on this tune for the 1998 C5, and all other aspects of the tune actually worked out better than expected, all but the fuel-cut rev limit function.

When doing a conversion for a different tuning mode, there is obviously need to have access, and adjustability to parameters that are not normally changed for the majority of tunes. It's best to have full access and ability to adjust the code itself at times. No doubt that this is the reason that many people have had to swap electronics to run a different system in order to complete a job correctly. I didn't swap in the case of the C5 because the car was running extremely well, even with the early shift. Being highway geared, it was completely practical to just go with it and take the small hit in quarter-mile performance. I feel it would have only been in the 2-tenth and 2-MPH range, and not worth the expense.

I did post the problem here to get some new ideas to try. I feel that my fuel-cut problem was likely either the result of some fault or error signal (not reported) coming from the transmission control, OR a problem with default parameters for the ETC control and safeties. It didn't appear to be anything that I had access to with the EFIlive version that I was using.

Where were you guys in 2006 ?
link: https://ls1tech.com/forums/pcm-diagn...-fuel-cut.html