Fuel pressure and regulator type.
Fuel pressure and regulator type.
Fuel Pressure is consistent 57.9 psi per VCM Scanner.Originally Posted by blindsquirrel
I'm embarrassed to say I'm not quite sure what you mean by fuel pressure regulator type. Car has the OEM in-tank regulators with Primary in the driver-side tank & the Secondary in the passenger-side tank. Car had been fitted with a A&A Boost-a-pump for the supercharger which I removed while removing the supercharger kit.
I attached my latest tune & log since I had changed a few things. My injectors & o-rings are incoming.
Thanks for your help!
No. Mechanical gauge. The sensor is not a real reading on these early non-variable-speed cars/trucks.
The stock system is non-referenced, the fuel pressure does not change with manifold vacuum, like it would with an aftermarket regulator. Not knowing what all was still left over from the previous mods, I didn't want to guess. I'll post up your file with all the injector data in it in a bit, all you'll have to do is flash it in.
StartOver - 12613412 data.hpt
(this is assuming 58psi)
If he had a referenced setup,(vacuum line from the regulator to the manifold?) then the table would be a single number all across? If so, how do you know which number to put in the table?
58 PSI (gauge) is 400 kPa Delta. So the number for 400 would be used for the whole table. And the 400 kPa column in the offset table would be used for all columns. Because the referenced reg always adjusts rail pressure so that the Delta is always the same, therefore the flow rate & offset is always the same.
If it was 43 PSI, then Delta would be 300 kPa...
If the table doesn't have a 400kPa column; do you just take the column before and after to figure what it would be for 400?
400 vs 408 kPa is a difference of 1.16 PSI... how much do you think your tune would change if you changed rail pressure by 1.16 PSI?
Honestly, I am not sure how much it would change. Is that a trick question? I'm going to try to spare myself from sounding dumb here. lol
Last edited by LS ROB; 05-30-2023 at 10:41 PM.
You would not notice it. Day-to-day weather changes would have more of an effect.
Hmm.. Nice, Good to know. Appreciate you sharing information!
I mean, the service manual for non-variable versions gives a fuel pressure spec of "55-62psi".
Pressure at rail is just over 61.5 psi (taken with Actron analog fuel pressure gauge)
Does that mean I am good to go with flashing your attachment once I install the new injectors? All data added & calculations done?
Thanks!
Open it in 'Compare' with your previous file, it'll show what was changed.
Yeah, I saw the Fuel Injector Flow Rate vs Pressure, Min Injector Pulse Limits, Offset vs Pressure vs Ignition voltage & Short Pulse Adder Corrections table changes that were redone bigtime. I can't Thank you enough. Got my o-rings today, injectors due tomorrow, can't wait to dig in. I appreciate your time & help.
Got new injectors in and have been MAF tuning using LTFTs. Fuel trims were lean initially but have somewhat stabilized. Wondering if O2 sensors are OK given the differences in LTFTs between Bank1 & Bank2.
Seeing knock retard and want to know how I need to deal with it.
Attached files,
Thanks
The knock could simply be timing a little too high or tip in, but cant say for sure. Log Cylinder Airmass in your channels and it will help give you a better picture.
Will add Cylinder Airmass, Thanks!
After installing the new injectors & logging and flashing 7 MAF calibrations with LTFTs I'm at a stalemate with reuslts. I attached my latest flash (MAF Flash7) using Special paste from log (MAFlog7). I also attached my latest flash with SD Reactivated (MAF Flash8), wanting to know if I am properly disabling SD for the MAF logging.
Knock Retard seems to be getting worse as I continue to log. I'm new to computer tuning but have enough experience with old street & race cars to know that knock ain't good. How do I address that? LS Rob suggested I add Cylinder Mass to my Scanner channels & I did.
I know, it's a mess, so where do I go from here?? Should I move on to trying to disable MAF & tune SD??
I attached (MAFlog9) just to show the latest with SD Reactivated. Thanks All!!
Last edited by Les10; 06-04-2023 at 09:35 PM.
Hey Les, I Looked at the MAFlog7 and the knock is from the tune not being dialed in. From my observation, timing is a little high in the lighter load area, that mixed with a lean conditions is where you are getting knock. The MAF curve from what you have done so far is looking better! Just going to have to put more fuel to it. If it were me, id highlight the MAF table from 3900Hz on up and multiply it by 1.03 then hit smooth a few times and start from there. Remember though, once you make a change to the tune, drive around for about 15-20 min BEFORE you start logging data.
I noticed that you had a few random instances where your spark dropped like it cut timing. It may also be helpful to log FUEL CUT TORQUE MANAGEMENT TYPE, SPARK TORQUE MANAGEMENT TYPE, ETC TORQUE MANAGEMENT TYPE in your channels. As for going back and forth between MAF & VVE, I'd continue with the MAF tuning until it gets a bit more better. Then I would switch over to VVE.
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