Hi all,

Recently finished some motor work putting vortecs on my LO3, I am now making an attempt to get things tuned and running right. I am beginning to understand how it all works but am chasing a problem with no results. I am having trouble getting the tip in right. I cant seem to get the acceleration enrichment right. Generally- when going to WOT it spikes very lean, closed loop compensates up to 50%, and then as the pull continues it transits to going very rich (10:1ish). This is from a stop or very low rpm.

If I roll into the throttle gently at mid rpm then the AFR seems very close all the way to redline and closed loops only compensates less than 10% through the pull. So the base fuel table i believe is at least close to being ok- not perfect but usable. Also- I have had to turn the learn function completely off at WOT because it would keep adding fuel to the learn table even know it was already dead rich- somtimes in the 9.5:1 area. I have been trying different things for a few weeks but have made no progress.

Pictures of the fuel table and a quick log while leaving a red light are attached. Thanks for any help.

 

When you tip in you are in the low MAP area but the RPM is climbing. You likely need more fuel in the midrange low MAP area of your fuel map. Does the Holley software show a run time trace of what cells you moved through? Add fuel in cells that it transients through when you open the throttle.

GD

 

GD, The Holley software effectively does show the trace through the run. I am doing it via Sd card so i just have to click the log and tab back and forth to the fuel table to see it, but it works. ( the cable to do things live is sold separate and on its way soon.)

It looks like the active cell transitions through pretty close to the range where cruise area is, so I will ad some in those areas and just be careful and tedious not to mess up where it lands in cruise. I will hopefully get some more runs in today to play with it.

-J

 

Post the tune and someone may be able to help further.

 

I am brand new to the Holley efi realm, so I joined up on the holley tech forums. Have you thought about doing that at all? those guys know thier stuff!!

I am surprised to see such high numbers on the VE table. my highest numbers are around 119 and thts at 96kpa and 5800 rpm area of cells. I see that yours are much higher and much lower in the rpm and load areas. why is that ?? My table looks very different

 

That is one messed up VE map. Please post your AFR targets table, and pictures of all your Closed Loop & Learn settings.

 

All,

I will get some more screen shots of the current state of things tomorrow. My laptop that i use for tuning is currently in the garage. ( I rent garage space on the other side of town).

After some of the recent replies last week I had found the Holley forums, and since then been doing as much reading and research as I could to try and understand what each thing does to what value.... in the process realizing just how FUBAR the tune really is. It has changed slightly since the last pictures here. It is still largely just as ugly, but the two things that seemed to help were 1. lowering the MAP Roc blanking value a bit, and 2. increasing the throttle position enrichment setting ( forget the actual name of it, not the tps Roc setting) This has the car running better, but still not 100% by any means.

As far as the learning and CL goes- the last couple of times I was driving it I noticed that the learning system seemed to be adding fuel at WOT even know CL was already attempting to pull tons of fuel since it was dipping down to around 10:1 AFR. No matter how low I set the learn limit it would constantly fight the closed loop so I ended up just turning the learning off above 70 Kpa.

 

again, I am a novice at this, but I just dont think your base table looks right at all. that pink area should be where you make peak torque.. as in 5,000 rpm, not 2500 rpm area. and if your base table is WAy off, CL comp and Learn are going to probably do very wacky things. I wouldnt worry about your "modifiers" and enrichments", I would get that base table correct first

 

Your engine should have VE table values less than 100% because it is naturally aspirated engine and I think this is the first thing you should look into. All compensation tables will modifiy your base VE table, which means if VE table is wrong, all other functions will not work. Including closed loop and throttle enrichment.

You should check your fuel pressure. If it is lower than sniper system "knows", you incrase VE table values to compensate that. This was problem with my haltech system when my VE values were off. You also should see that VE values should peak about the rpm were engine makes its peak torque. Also at idle area at the VE table, values hould be around 30..50 %. Depends cam and other engine components.

 

You mean to tell me that my 305 inst a miracle engine that manages 200% efficiency??? well darn it..... But good to know that the VE table is actually referring to the Ve of the engine. ( I guess my mind was stuck on the fact that it may be some other thing that I didn't understand fully). I will definitely check the fuel pressure, assuming there is a read out for it on the Holley. To my knowledge it may very well be the stock original TBI pump as I have never replaced it. we are closing in on the 200K mile marker so it very well may be getting tired.

-J

 

I think you have an issue with the wideband, maybe an exhaust leak. The learn capability on these works really well. If it was adding fuel when it was dead rich either the wideband is pooched, or your fuel was just soo far off that it was an artificial lean on the wideband.

-- Joe

 

Here is a google drive link to the actual GCF if anyone wants to look at it that way. https://drive.google.com/drive/folde...-5?usp=sharing Should let you download it to view.

I will attach some screen shots as well.

Target AFR table

Closed loop limits page

Learning Limits page.

General EFI params. This is all from the wizard, I made no changes here.

Base VE table. (also transferred most recent learning to base so the learn table is zeroed)

 

Ok, again, I am very very new to this holley efi tuning stuff, but I am willing to learn, and in looking at your problems, I am putting my limited knowledge to use (I think)

I think you need to start fresh. save what you have, but put it in a GCF and start a new one from scrtatch. reason being, is now your VE table is getting stranger. I think the learn and modifiers are stepping in so much because your VE table is so far off. When I switched to graph-view of your VE table, it had two huge mountains in it. the VE table's graph should be smooth and nicely shaped

here is what I saw in yours:



also, I noticed the Acceleration Enrichment curve is pretty drastic change too:




and your spark/timing table has some issues too:






and your AFR for "Cruise" should be much higher too




for comparison, here is my current VE table:


and my VE table in graph view:



and here is my AFR table


and my AE graph:

 

Right now the Learn settings are working against you. The first thing I'd do is give the system a fighting chance to correct the VE map on it's own. Then follow the data to see where to go next. Here's a quick little experiment you can run in the driveway:

1. Turn up the Learn Compensation Limits to 100% across the entire table. This will enable the entire fuel map to be adjusted.

2. Turn down the Learn Gain from 100% to 50%. A Learn Gain of 100% is so sensitive that it reacts to EVERYTHING and will produce ever-changing, bizarre fuel maps. A gain of 50% is still super fast and will make adjustments in seconds.

3. Idle in the driveway and wait for both Closed Loop and Learn to activate. Let the engine warm up and watch the Learn table change at idle. Wait for the Learn table to stabilize and see if you're starting to get some reasonable numbers. If idle starts to look "normal", then proceed with tuning elsewhere. If the numbers don't look right, then there is something else throwing off the fuel flow calculations (maybe fuel pressure and injector data).

I'm kind of expecting you to come back and say it didn't work, but we'll see. Also, pull a spark plug and see what it looks like. If you're really throwing too much fuel at the engine, then I'd expect the spark plug to be really fouled already.

 

Also observe if injector pulse width hits the minimum 1.2 ms. Your injectors are waaaaaaay over sized for your engine. Not sure why you bought such a large system.

 

I can't open your files (don't have the software and not loading it on my laptop), but I'm thinking there just has to be something wrong with your basic system settings. Either wrong injector specs, wrong engine displacement, or something else effecting fuel flow calculations. Or else you fumble fingered the keyboard and accidentally scaled up the VE curve without knowing it.

 

That's a good point. The minimum hp sizing for that system is 250hp.

I wonder what that l03 makes with the vortec heads and stock cam.

-- Joe

 

With VE table values that high, something about the fuel model is completely spanked. This usually happens on most systems when the correct data for the engine wasn't input properly - like displacement, injector sizing (fuel pressure effects this), type of fuel, or other critical system settings.

The fuel map should (very generally) climb with higher RPM and climb with higher MAP. See the comparison map with IROCZman15..... but note that yours is nearly the inverse of his because when he graphed yours he failed to rotate it so the axes align with his map. So your's starts out high and drops off with climbing RPM and also drops off with climbing MAP. That's entirely, and completely F'd. But also the numbers in the VE table are so incredibly whack that if it runs at all there is some critical issue with the fuel model as I mentioned above.

Check everything - fuel pressure, and all the scalar settings. Just flatten the entirely map down to like 35 in the idle area and taper it up to like 85 up top. Then figure out what settings you need to give it that will make it idle around 35 VE and start the learning process from there.

Again - I would start completely over with a fresh slate. Your settings or the fuel pressure or something fundamental is entirely wrong.

GD

 

Soooooooooooooo I may have possibly bricked the ECU.... I checked to see if the firmware was up to date. It was not. So i figured I would update the firmware and really start fresh like mentioned above. Got the new files on the SD card, got them flashed and updated, went to power cylce- and now the handheld only says searching for ECU. I cant seem to reach it on the handheld or the USB link. I traced power and fuses- everything was good there unfortunately. I am going to take my nice laptop over tomorrow and see if I can at least find any drivers or ports on the CAN bus before making a call to Holley

Either way- Here is a plug I guess.



Seems Like one side of the ceramic is noticeably cleaner than the other.

 

So an update to fill in the gaps in case someone has a similar issue in the future.
1. I didnt brick the ECU thank god. There was a glitch trying to update the firmware- flashing an older version of the firmware on, and then re-updating it seemed to be the fix.
2. I got a fuel pressure gauge installed, and it turns out I only had about 20 Psi constant. dropping to below 15 when you crack the throttle. So in the Holley software I set the "actual system pressure to 15 psi and started the tune from scratch through the wizard. This seemed to help alot, it was obviously still a little wonky with such low pressure but I think that is enough proof to isolate the problem to the fuel system. Does the tbi pump really only make 20? yes it is old and high mileage but It primes up to that point and then clicks off even with the holley relay powering the pump so maybe the pump has a switch internal?

3. I will be putting a new pump in regardless since I unfortunately blew 3rd gear (RIP t-5) and will have the car taken apart and in the garage again for a while.

-J

 

Fuel pressure should be lowest at idle and should climb when you open the throttle. It needs to be vacuum referenced. When vacuum is high fuel pressure will be low, and when vacuum drops (open throttle) fuel pressure must rise. If you open the throttle and the fuel pressure drops that's entirely wrong and is not going to yield a consistent pressure across the injector which is what the Holley is expecting and what traditional fuel map shapes are targeting.

GD

 

On a lot of newer OEM stuff it's not vac referenced. The fuel pressure regulator is integrated in the fuel module (inside the tank). I'm not sure if the OE calibrations take that into account in the VE calculation or not, but I guess it doesn't really matter.

Where it becomes a problem is when people want to retrofit forced induction, and now the injector is fighting to spray against intake pressure. Some of the LSx guys are disabling the fuel module regulator and running one at the rails when going forced induction.

The Holley sniper regulator is NOT vacuum referenced. For forced induction applications, it says to cap off the integrated regulator and use an external boost referenced regulator.


-- Joe

 

Yeah we have noticed that all the newer stuff is return-less now. You can overcome it in the fuel map, it just looks funny compared to a conventional. Pardon my recommendation I wasn't aware the Sniper was built that way.

GD

 

Yup. It's kinda stupid but they do it.

On my blown formula I actually ran into a situation where the LT1 style regulator couldn't return enough volume to the tank at idle with the 500lph pump, so I had to go with a big boy external regulator. Like anything, if they sell it in a box it will probably give you a headache.

-- Joe

 

Oh yeah - the return port on the TPI rails is really tiny. I can see that. For a short time I gutted the regulator on my TPI and installed my external regulator using the stock rails. But on the TPI you might have to drill out the regulator hole in addition to gutting it.

GD

 

I'm using a miniram which uses a stock LT1 regulator. The return orifice was very very small. I ended up making new fuel rails and welding -6 in and out on each rail so it's parallel fed, parallel return into a big regulator. I think I drilled the return orifice to 3/16 or something.
The only down side to the aftermarket regulator is the fuel pressure bounces around a lot. Both the digital and analog gauge show a fluctuation of a few psi at idle even though the map is rock steady.

https://documents.holley.com/199r11489.pdf

Pages 5 onward cover the fuel routing on the Sniper.

Either way, Jspink38 needs to get rid of his low pressure TBI pump and get a high pressure pump sized to his combo.


-- Joe