Bringing this one back from the dead...
I'm after the same answers about the proportional gains settings for surging problems. Which PRP settings do you want to adjust? I'm guessing the ones that concern airflow.
BTW, saw the Caddy at the GoodGuys autocross, looked like a lot of fun!
Hey There Blue68deville,
Nice to see another Caddy guy going EFI, the 2 fields that I played with to reduce the surging were indeed: "O2 Prop Gain Mult as fuct of Flow" & "Prop Error Vs. Slow Filt. O2 error"... Incressing those fields and testing and tweaking did help with the surging while driving, but never fully fixed the "pulling at the Leash" at a stop that I also was having (also smoothing the main spark table helped a bit as well). In the end (about a week before goodguys) I threw in the towel and bought the Holley Terminator TB-EFI system. Let me tell you... That system out tuned my 2 years of work in 2 days. I had the idle 90% dialed in, in 3 turn on/off's and about 45 seconds of running time. Throttle response is better, even with 100 more CFM that the TB flows. The only thing that is a little sad now is she just doesn't lope quite as hard at idle as with the GM system and how I had it setup, but, as this is my daily driver, that was a do-able trade off for me (and you heard her at the show, she's still pretty nasty at idle). Also WOT is fully under CPU control, so no more strange inconsistent AFR when doing back to back WOT test pulls. I also added a CPT (real Art Carr) 200-4R stage II+ with a 3000 stall 10" TC the week before the Holley install that really pissed off the idle/low throttle characteristics (wanted to stall under braking at low RPM and while sitting at the light) and that was not an issue for the new system either (no more left foot braking and feathering throttle at the light). In the end, when thinking about the 200+ bin files, the God knows how many gallons of gas, the hours I spent trying and never getting it exactly right, the # of samples per second the new system takes compaired to the 1989 GM CPU, the WOT full control, the little handheld controller that gives you real time data without the laptop plugged in, the on the fly while driving updating, and not losing any of the options I had with the old system, (after the free upgrade to the HP setup) having every table full detailed in the software (not floating over and having blank or ?'s); I can say it was worth every cent of the 2K I spent. Also, as I already had a EFI fuel system, install was less then 4 hours. And with all the sensors in the TB my firewall looks so much cleaner. All of that said, I'm still happy I did the GM system first, it truly help me learn and understand the basics of EFI tuning and made the further tweaks on the holley system i've made stupid simple for me. But in the end, if you think about CPU's from 1989 vs. what we have today, there really is no way the "Pac Man" era system can compete, all things considered. If my cam had not been so radical, and if I wasn't always trying to out perform my co-worker's turbo, E-85 sipping subaru (we have a bit of an "arms race" going here at work) the GM TBI system could be workable. But the ease, added features, and control at all times really made the difference for me. I hope that those 2 fields and a little spark advance tuning will get your caddy where you want it... And if you can't get that to work, just know there is always another option out there! Also, seeing you're local, if you want, we could meet up, have a drink, and pick eachother's brains on how to get your system where you want it. Plus I'd love to see your caddy, being such a huge caddy freak myself. Maybe even have a little showdown big block vs. small block/50's vs 60's caddy's. ;) Just let me know!
Maybe you can convert this over to TunerCat title but the two you want to lower for larger cam issues are:
1. PRP - Gain vs. O2 Error
2. PRP - Gain vs. Air Flow
That issue with inconsistent AFR at WOT... as long as you have the pressure and supply of fuel needed the issue starts from the VE table. If BLMs are 128 or below, then the ECM will just use the PE AFR. But if the BLM are higher then 128, it adds fuel to 128 then PE fuel. So has a lot to do with VE fueling being in order first. This is why I tend to tune BLMs a little rich, all under 128. It's not really rich as the O2 sensor is making the correction, just that people use the term rich and lean for over and under 128.
HTH! :rockon:
Sounds like your having fun with the Holley Terminator! Some of those systems now are really working well on big built engines.
51caddyman; If I wasn't on a dumpster-diving budget for this I would have went high-dollar, but I'm ok with the constraints of TBI. It's a pretty mild motor so no high rpm antics for the tuna boat. That said, I'd like to cram a roller cammed 500 into a 60's short bed truck...
Maybe we could meet up at Golden Cruise.
EagleMark; I've played with some of the PRP settings, but wasn't sure how far to go. I found a post of yours from a while back, I copied your settings into my bin and will see how it drives this afternoon. It's hard getting the VE table dialed in where the surging happens, and it seems to be affecting my idle VE as well.
Here's the settings screen shot from your post, thanks
http://www.gearhead-efi.com/Fuel-Inj...9&d=1372122540
Every bin is different so can't necessarily use the numbers I did from that bin. I can tell you that cutting them in half is a good start and may be all you need. The PRP is meant to be a means to adjust fueling as fast a possible for emissions, so an over shoot is not going to hurt, but if you had none? Then it would not help at all. The closer the VE is the less PRP is needed at all.
During surging there's hardly anything about data that is accurate in a way that it would help. So in TBI getting the throttle blades open as far as possible and still have a little IAC control for idle is a key. Not necessarily the first thing to do though. Adding spark advance to idle, taking away VE, lowering the prop gains, raising idle, IAC position Vs temp, Idle AFR bias, throttle plate adjustment and if tuning for CL or OL... it's all got to be done and a balancing act as you go.
Then your dealing with a wet intake! So if I'm Idleing enough to drive then I drive and get some BLM numbers for my VE... after a little driving as soon as you start to idle is the best time to use the data, the intake should be warm and dry at that time. If your sitting there trying to adjust idle for 15 minutes? Forget it! May have to rev motor to 1500+ RPM for a minute to clean it out so data from NB or WB O2 sensor is not lying to you!
Mark,
I figured your settings would give me a start point to see how much adjustment makes a difference. It did change the surge slightly, seems to oscillate more rapidly but not as strong. I may be chasing the wrong adjustment, but it's something to play with. I've changed PRP more, used the compare and graphs to get it about 50% like you recommended. I left the INT and rich/lean O2 settings alone. I'll see how that does.
My idle is actually nice and steady, 5-10 IAC counts in gear at 700, P/N is around 900. The surge is present on light/no throttle decell, 20-30 MAP <2k RPM. My BLMs still need adjustment there, so I'm sure that's not helping.
I had a pretty dialed in Async bin (ANTY) that barely surged, but the idle was just choppy feeling, accel didn't feel smooth either, so I made it Sync by copying the ASDU settings. Now I get the surge, but everything else is smoother.
Either way, the car runs so much better than when it was carbureted. Even the Async bin was a big improvement.
Now to burn version 40+ and see how the morning drive goes!!
Thanks for the suggestions:happy: