Matt's Tune Thread

No worries, I've been busy too.

Just posting here to keep a log as to what's been changed.

-Deleted P0140 CEL codes
-Messed with shift points - did not raise WOT shift points above what they were, only for 80%-99% TP

Matt, are you still running any of the tune we flashed when you visited? If so, your part throttle shift values should have been raised, I think.

It's similar to it, pretty sure they're the same shift points that we set. Just changed it so that 80% and up shifted near/at WOT points

96v7 - MAF tables are pretty well down, just have to mess with WOT a bit. Bumped up the in gear idle a bit because it was having trouble idling without giving a bit of gas to keep it at ~1k RPM.

If it's having trouble idling at factory spec, there's something wrong.....
Without a cam, it should idle perfectly at ~750rpms. Is it running too rich at idle?

matt270avian wrote:

Bumped up the in gear idle a bit because it was having trouble idling without giving a bit of gas to keep it at ~1k RPM.

what does it idle at once it reaches operating temperature? You have to give it gas when you first start the car cold?

Does it choke or anything?

Haven't looked at the fuel trims for idle, but it's only when it's at cold start. It didn't do it when it was warm out (~60*), it only started when it dropped down to ~30*. When it's all warmed up it idles alright.

Well it still doesn't like to idle even after I bumped up the idle RPM. I'll upload the bin and scans when I get home for you all to review. I think abaddon is right about the idle fueling being weird.

https://www.dropbox.com/sh/mbldmi92dyzzwcn/AADhpt6f2FCOTSeNSwT1EjH6a?dl=0

Current tune and today's scans. Car will not idle without giving it some gas when cold. When fully warmed up it will idle, but a little roughly.

So wait now it doesn't want to idle? What's been changed that it's not idling? It was idling ok since you installed the northstar setup? Those LTFT's on your latest scan there are quite rich. The PCM is commanding a pretty pig rich AFR during a cold start in the first place so if it's got a very rich tendency and those compound, it'll be drowning in gas until warmed up. It just doesn't want to idle even after warmup though? I thought I saw you installed the new O2 and the signal does look spunkier than before so what all went wrong that it doesn't idle? You wouldn't wanna just add some big multiplier to the maf table without having evidence to say it needs it. Need stock maf table and reset FT's and read what the fresh o2 says.
Btw my fuel trims are almost as rich as yours are there right now. I'm suspecting my gas station snuck in a winter blend of e85 that has more gas but the car starts, idles, and drives like before without any of my intervention so I just have a suspicion you still have something going on besides an AFR issue.

So you just want me to go back to the tune I had before the N* install and see what everything says? I did install a new O2 in the manifold the other day.

Went back to old tune as Codith recommended. Already idles much better even after a fresh fuel trim reset. Did 2 long drives with 2 restarts, so I'll go get a scan tomorrow or Monday.

Computer crashed while flashing a tune. Car won't start. DHP can't read pretty much anything from the PCM. Should I just go out and buy a new PCM?

Ouch! Did you just try to re-flash the cal? Or DHP can't even connect to the PCM? If that's the case, it's toast.

It can connect, but it won't read any of the information on it.

Yep. If it won't let you upload a cal to it, I'm afraid you're going top need a new PCM. I don't see why it won't let you just re-flash it though. We have programming errors all the time in the shop. 9 times out of 10 we can just start the program over again. It's that 1 other time where the module actually has to be replaced...

bricked. If the computer goes down mid-write you basically need a new PCM. What year is your car?

It's a '96. I got SUUPER lucky and the local JY had one out of a '96 Riviera supercharged. Only difference is the OSID. Mine is 16238447 while the new one is 16211539. Will this cause any issues? I'm also assuming I'll have to do a security relearn by turning the ignition to accessory for 10 minutes, off for 5 seconds, and repeat 2 more times. Do I have to do a CASE learn, and if so how do I do it?

I also have another one coming from eBay with the same OSID as the "new" one.

There's a separate Theft Deterrent Module that controls the Security functions, so you should be ok there. Normally, we have to upload the PCM file via GM's database to a TechII, then load the file to the new PCM. Now, we can do it wireless via an MDI and GM software.

I think that in your case, you might be able to just flash the new PCM with your .bin from DHP. It should be the same thing, as you'll be burning the VIN and everything right to it. I'm not exactly sure though. I've never had to deal with it outside of work.

If/when it works, the only thing you'll have to do is a Crank Variation Learn, which is an option on DHP every time you flash.

New on top (just realized it's a reman), old on bottom.

It's in and readable/writeable. Yaaaaaayyyy.

Do not try to write your old OSID onto the replacement PCM. It will instabrick

turtleman wrote:

Do not try to write your old OSID onto the replacement PCM. It will instabrick

I didn't do anything more than write the my bin and update the VIN.

Abaddon - I didn't see the option to do a crank learn, so I haven't tried starting/cranking it yet. Can you guide me a little more to where it is?

The Crank Relearn should be under "Scan". Hook up to the PCM/DHP via "scanner"....the same place you go to start a Log. There should be an option for "Crankshaft Variation Relearn". At least I think I recall that's where it is. If you can't find it, post back (obviously) and I'll go hook up to my Riv and find it.

Yep that's it. It's under real time controls. Thanks everybody for helping me and not letting me freak out too much. Car started right up and is purring like usual.