30065 on 6-71 tuning help!
Hi everyone. So, I have a 383 with a 6-71 on it, ~5-8lb of boost. Put on Fitech (30065 power adder system) about 1 year ago now and it's driving me nuts, I have not been able to really drive my car for a year. It starts, idles, and cruises fine. However, when the rpm comes up and boost kicks in, it goes lean. It's not tip in, meaning i can hold the pedal steady but have the rpm's at say nearly 3k and it goes lean, but the power oscillates like it's coming on and off, jerking the car back and forth. I know it's the Fitech because right before that I had everything dialed with carbs and it ran like a bat out of 43ll.
I've been back and forth with Fitech and they keep telling me either check fuel pressure, or just let it learn. Well, I put a fuel pressure gauge (under left side of scoop in video linked below) and it reads a steady 60psi, bounces a bit when I get on it but still between 58-60psi so doesn't seem to be it. My system is newer and does not have PWM, they changed it to a relay that's on all the time with 12V (which is what my pump requires, 350lph, 58psi pump). It's learned for a year, if it has to learn in that rpm range, it can't this way because it would be dangerous to my engine!
Only thing I've witnessed a change with is acell pump, but as I said it's not a tip in thing and hasn't fixed it. Could even be placebo, but here's that: It used to do this but not as severely if I leave it in drive, the issue is exacerbated if I manually shift letting the rpm's come up. When I increased the acell pump settings about +20, it feels like the issue is nearly gone in Automatic but just as bad if not worse when I manually shift. So, I could keep increasing these settings but I love manually shifting it around town and it doesn't add up with the constant rpm/pedal described above.
PLEASE can anyone help, I'm ready to sell this system and lose money to go back to Carbs or Sniper! Here is a video, hopefully you can hear and see the issue. Pressure gauge under left side of blower scoop. I let off at the beginning because of the backfire, you can hear the oscillation though towards the end when I bring rpm's up again. I have a log too but forum will not let me attach.
I would say fuel as well. However send the data log to austin@fitechefituning.com
Thanks Austin, log sent. Also, if anyone knows a shop that would touch these in the Sacramento valley of CA I would happily pay at this point to get it dialed in and done. I've called a few and nobody seems to want to touch it.
I looked at the log. It looks like a fuel supply issue, however you say the fuel pressure never drops.
The system is adding fuel to compensate for the lean condition. However it isn’t adding enough.
I keep thinking the fuel table may need to be modified, but that shouldn’t be the case for a 383.
Is this a brand new system? Curious which version of software you have. Go to display setup and the top line will give a version number.
Bought straight from Fitech new, T210 software.
It's only a 2 psi drop when the needle fluctuates, 58-60. It's a Marshall gauge, maybe not fully accurate? Could it be 56-58 or something in reality? The needles bounces more rapidly too than the power oscillations in the engine.
I'm not sure then what the steps would be to diagnose and fix, so here's what I have and maybe I can get a suggestion what to try next.
I will confirm that today if I can, I know that's what I ordered, but maybe they sent me the lower LPH (2xx) on accident?
All new 3/8 efi line front to back: https://www.amazon.com/dp/B081W79ZC1?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1
This filter, about 3-4 feet before it goes into the Fitech units (I'm reading some filters flow lower, searching for spec on this but maybe it's the issue? I think I need the full 350 lph for this dual setup?): https://www.amazon.com/dp/B0CFV475C3?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_3
And as I said, SHOULD be 12V straight to pump. I was looking for the PWM settings I read about and they were non-existent. When I asked Fitech about it they said they are gone, my unit has the little box with 4 fuses which they said they removed PWM on and it's now just a relay pushing 12V to pump.
Oh and forgot to mention, the Holley pump is a returnless so I am not running a return line.
All sounds correct. And yes, PWM was removed in the newer relay box ECU that you have.
There are a few versions of T210. Will be a version number in the display setup menu. 1.49, 1.53, etc
Found it!!!!!!! Lines 720-730, watch your RPM. It starts to break up. I would be looking at your ignition system. The Fitech is not getting a consistent rpm reading under boost. Right before the ignition break up, you are at 4.9 boost. The data looks good there. Then the rpm signal drops and all goes wrong.
GD_V1.53 in display setup.
Ok, but that's what the problem is too, it's dropping in rpm like no power then coming back on, so how would I know it's rpm signal if it's really dropping (chicken and the egg)? Ignition system should be good, it worked perfectly fine just before the swap from carbs to the EFI. I had a tach gauge before too but I admit I didn't pay much attention to it while driving because the car ran great. But, maybe a wire went bad in tapping into it for the EFI. Or could it be the signal interference thing with EFI?
I will look into the wiring again, what's the recommended distance for the EFI wiring from the ignition system? I did put the master unit at the back, but with the wiring coming out the front of it between the 2 units, but then ran the wiring around the back.
Ah! I see a code 36 in fault1 near those same lines! Says rpm noise. What should I look for to solve?
Also interesting, seems to start at 3k rpm like this guy: https://www.chevelles.com/threads/fitech-shutting-off-during-mild-to-hard-acceleration-at-3500-rpm.1005577/
The Fitech cannot create its own interference. Yes, your engine is cutting out, however the rpm is not actually dropping to 500rpm. Your ignition system is cutting out almost like your rotor is phased wrong. Are you running timing control?
No timing control (although I want it, have wrong distributor for it right now). I have this ready to run:
https://www.holley.com/products/ignition/distributors/chevrolet/parts/8360
custom 10 degree stop so initial 18d max 28d, like I said though, ran fine before the carb to carb swap, no changes to distributor other than the new fitech tach wire to positive coil. I will double check wiring and move it away if I can tomorrow.