I Finally Did It.....EFI
- Thread starter threewood
- Start date
You will never get the car back!You can come over and borrow the car whenever you like to do some testing.
andyf
Well-Known Member
First thing to do is to see if the engine is in closed loop when the spikes happen. Click over to a screen that shows you CL and Learn status so you know what is going on. If the engine isn't in CL then it just means that your base fuel table isn't correct. If the engine is in CL when the spikes occur then double check your TPS to see if it is changing. If the TPS is changing then that means your AE (accelerator pump) table might be wrong. It TPS is stable and the engine is in CL and you still have AFR spikes then you most likely have a mechanical problem. A misfire will show as a lean spike and so will a weak valve spring or some other problems like that.
With a data logger the problems are much easier to find. You still have to have some debug skills but if you understand engines and tuning theory then the log really helps a bunch.
With the gas mileage you won't get far!
andyf
Well-Known Member
Closed loop comp of 50% means your base fuel table is way too lean. The ECU is maxed out at 50% added fuel. Basically that means you've hit the guardrail. You need to add fuel to the base table. Or you can raise your limits on the CL comp table to 100% and let it tune itself.
Do I need to do that on the Holley app or can it be done on the handheld monitor?
andyf
Well-Known Member
Did you dyno test this engine? Fuel flow of 375 lbs/hour is enough to support 750 hp. You are close to maxing out the Sniper's fuel flow. Do you have a fuel pressure gauge that you can watch while you're driving? Your fuel pressure might be low which is causing the Sniper to overdrive the injectors to try and keep up. If it isn't a 750 hp engine then my bet is that you have a fuel delivery issue. Could be a fuel pump problem or a restriction in the line or something else. If this is a brand new install then you need to rig up a fuel pressure gauge so you know what is going on.
andyf
Well-Known Member
Do you have the Sniper software loaded on your PC? If so then pop the SD card out of the hand held and do it on your computer. I don't think you can change the base fuel table on the hand held. You might be able to change the CL limits to 100% on the hand held.
I never use the handheld, I do everything on the laptop or the desktop. The handheld is very clumsy to use for tuning.
rmchrgr
Well-Known Member
I have considered getting rid of the handheld though having it in the console at least keeps it out of the way. Had to order a replacement screen for my PC based laptop which should be here any day, looking forward to finally having the software in the car, I'm sure there will be a lot to look at. Too bad it snowed 8" here yesterday and the roads were salted like crazy - perfect timing.
750hp is very optimistic. Never dynoed to tune. The in tank pump is the Walbro 255lph pump that came with the Sniper tank. It is 2 years old.
I'd need to buy a gauge and fittings to hook up to the fuel system in order to see pressure. My current gauge only goes to 12 psi (when I was tuning for the AVS).
I'll get under the car and check for kinked lines. Both are 3/8".
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rmchrgr
Well-Known Member
Did you put the recommended filters in the supply and return lines? Make sure they flow in the right direction.
I have a filter before the Sniper unit. None on the return.
I've been looking at specs for the pump and I am not sure the 255lph pump is big enough. It looks to max out at 500hp and I am probably above that at the crank.
andyf
Well-Known Member
You are right at the limit. Your data log shows 375 lbs/hour. Do the math and convert that into liters/per hour. You'll be close. But, I'm not so sure your numbers are correct. You need a fuel pressure gauge before you do anything else. The picture of the data log that you posted makes me think your fuel pressure is low. If your fuel pressure isn't low then you have a different fuel delivery issue. Maybe one injector isn't firing for example.
So low fuel pressure would be pump? Or kinked line?
And pump is 2 years old. My how time flies!
That_Tall_Dude
Well-Known Member
Yeah no kidding; particularly this weird *** year...
Dumb question; has the filter been changed?
Filter is about 2 months old.
That_Tall_Dude
Well-Known Member
Hey so do people usually pick up a few mpg going from carb to EFI and computer controlled timing with equivalent performance; have seen claims about 30% increase, but dunno if they are just hype
Getting like 50 miles more per tank and not having to stop as much for gas seem like a big deal to most; is to me...
If that is true; I have some ideas that might be cool... to some (won’t put that blasphemy on this sweet thread though)
Getting like 50 miles more per tank and not having to stop as much for gas seem like a big deal to most; is to me...
If that is true; I have some ideas that might be cool... to some (won’t put that blasphemy on this sweet thread though)
rmchrgr
Well-Known Member
I don't know about 30%... one would have to think gas mileage depends on the combo and what type of driving you are doing. It's self learning based on your driving habits so it either adds or trims fuel depending on the demands. Drive with your foot in the radiator all the time? It's going to add fuel more than not. You can tweak the fuel curves and timing in the software to create a tune that optimizes mileage.
I would say a marginal increase. Heck, when you get 10 mpg and increase it to 12 mpg that's a 20% increase in mpg. With a 19 gallon tank that would be an extra 38 miles to a tank.
EFI is going to be more efficient.
EFI is going to be more efficient.
And because the current fuel pump is now going to bother me if I keep it, I ordered a Walbro 450 pump. And a fuel pressure gauge and fittings to see where the current one is at.
This project keeps getting bigger.
This project keeps getting bigger.
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