I have a 1990 Corvette, which has the 1227727 running $8D. I'm looking at tuning it for boost, but I can't find an option that preserves the ECM-CCM communications required in '90-'91 vettes for some...
Type: Posts; User: 90Vette
I have a 1990 Corvette, which has the 1227727 running $8D. I'm looking at tuning it for boost, but I can't find an option that preserves the ECM-CCM communications required in '90-'91 vettes for some...
As promised, here's a TunerPro log. It was taken with ALDLDroid, but it should be identical to one taken with TP.
Hey Elky,
Sorry for the delay - haven't forgotten about this, my datalogging is just on the fritz. Once I get datalogging and a few other issues sorted out I can get a TP log of startup. In case...
Yeah, referring to the section "OL NOT in PE AFR" starting at the bottom of page 30. If I understand the logic correctly, the startup enrichment and the open loop enrichment terms (like 0x41F, OL %...
That's very helpful, thanks! I've read and re-read your post several times over the past couple of weeks as I've been working through this. I've also revisited various parts of that doc a few times....
Over on Thirdgen, RBob explained that it's circular - the calculated airflow from one loop is used in the inverse MAT lookup table in the next loop.
My current best guess is that the inverse MAT g/s column is calculated using VE, RPM, ideal gas law, and the raw MAT value (not the weighted MAT-CTS value).
If this is the case, my workaround for...
Okay, looks like there are two relevant tables: MAT Inverse Term Lookup Delta Mult. vs. Airflow and MAT Compensation Counts vs. MAT.
I'm trying to wade through all the math on how each plays a...
I stumbled back across the Thirdgen Prom Tuning Guide Book - what a resource! I need to not forget about it again.
And what do you know, in chapter 5, under the 7730 ECM, there's a topic titled...
I've gone back and taken a slightly more rigorous look at the data. In addition to my comparison at 5250 RPM, I've compared at ~3600 where PE AFR is slightly different. Rather than relying on the...
$8D, 1227727 (basically 1227730) ECM.
I'm tuning WOT VE using my wideband, and I noticed that my AFRs are pretty inconsistent. For example, in one evening I had three WOT pulls, and in three...
Thanks. I'm still based on the stock bin (ARFP but with the 3.33 rear end), and I was just trying to get a better feel for what's in that. I suppose there's not gonna be much support around here for...
Alright, found the hack for $8D, and it lists the missing parameters. L8301 (0x301 in TunerPro) is reset speed, L8302 (0x302) is enable speed, L8303 (0x303... you get the pattern) is disable speed,...
FINALLY found it. "$8D" here is the only of ~8 XDFs I reviewed that had it ("C.A.G.S. Enable Coolant Temp" at 0x300).
I recall seeing a lot more parameters, and I see in the XDF that the next...
I drive a 1990 Corvette running $8D on a 1227727 ECM. I did most of the tuning for a new engine ~3-4 years ago, and I'm revisiting the subject to dial things in finally. The Corvette has CAGS...
That's what I'm wondering. When I'm driving with the windows down, if I pass something that reflects my car's sound back to me it sounds like I can hear an exhaust tick coming from the left side.
...
I was able to take a few more logs, and on the first two I'm certain I captured the problem. I haven't been able to log with someone in the passenger seat watching my phone, but I'm almost certain it...
Here's a new datalog. For some reason I didn't see it running super rough like usual, although right after startup it was wanting to buck a bit when cruising in first/second gear.
The only change...
Lately it's been happening pretty bad, and I've been paying close attention to what it feels like.
It seems that when I add throttle, I get a momentary surge of acceleration, but then it...
I've noticed the coolant temperature needle is always in the exact same spot when it starts running rough. Does this just point to a bad spot in my closed loop AFR table?
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What would be...
I tried leaning out startup, and that didn't help. It wasn't any better when it was cold, and it was a lot worse hot. Is it possible this is moisture related? I realized I kept it in the garage in...
I've driven it the past couple days with the tune with more AE, and it's definitely worse. I just made a new tune with less AE, and hopefully that will take me in the right direction. If that helps,...
I increased the AE table like so:
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and hooooly crap that was bad. Whenever I touched the gas, the engine just about died. After about 30s to a minute though, it ran great. Check out the...
I've smoothed my VE tables pretty extensively, although there are a few little areas that are a little jagged. Here's the graph of my lower VE table:
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Whoops, found the right table. Here it...
Thanks for looking at my logs. I tried checking the fuel pressure before I drove out to VA, but the gauge I got from O'Reilly was leaking like crazy. I don't have time (or tools) to pull a spark plug...