Fuel 19lbs EV6 fuel injectors, what fuel pressure???

PonyGTrider

PonyGTrider

5 Year Member
Feb 27, 2019
625
110
63
Mexico
#1
Guys I have this setup:
90 Mustang GT 306 flat top pistons, 170 cc Twisted wedge heads,TFS stage 1, 70mm MAF (For 19lbs) cold air intake, 65mm TB, 19lb EV6 injectors, Kirban adjustable fuel regulator, 3.55 gears,T-5, 245-45-17 all around.
My fuel economy is horrendous! 9 miles per gallon... The specs on the injectors I'm running says they flow 20 lbs @ 43.5 psi. I went thru so many things and still can't find anything wrong. No error codes out of the A9L computer, No vacuum leaks, good compression numbers. plugs aren't black as a sign of a rich condition.....
I adjusted my fuel pressure as low as 36 psi vaccum pluged into the regulator but the fuel consumption still high.
I rea the EV6 injectors were more eficient than the stock EV1 but not sure if it is truth.

I have a question to ask:
It seems like my injectors are flowing a bit too much fuel, the biggest problem is that I don't have any dyno or shop near me to go for a tuning.
is there a way to turn the fuel pressure down bit by bit maybe 2-3 psi at a time and do a ride test until the O2 sensors react to a lean condition and from there back up the pressure???? I know this sounds a very rudimentary approach to this issue but at this point I have no choice... And don't laugh at me I'm dead serious.... :rlaugh::rlaugh::rlaugh:

What dou you guys think? Any ideas?
 
#5
My suspicion that one or more cylinders in each bank is not firing.

It's not very often that it happens without 02 sensor switching codes tho. :shrug:

What do your plugs look like?
 
#6
Noobz347 said:
My suspicion that one or more cylinders in each bank is not firing.

It's not very often that it happens without 02 sensor switching codes tho. :shrug:

What do your plugs look like?
Click to expand...
I haven’t seen any misfire at all, and with that much suggested misfire I would expect to see really black plugs but they are not. The ones from the other bank look the same
 

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#8
The test I outlined at the bottom of my posting, is it possible to do it? Reduce the fuel pressure until the O2 sensors react to a lean condition??? Obviously I won’t be red lining it to avoid any damage.
Many people said “For that set up you have to use 24 lbs injectors because you will be running lean with the 19 lbs.
But how come I run as low as 36 psi fuel pressure with no pinging or lean condition error from the O2 sensors???s
I would be willing to take the risk to drop the fuel pressure even further until I get a lean condition. I don’t know, I tried so many things test many others and my fuel economy stays the same crappy way.
 
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#9
Noobz347 said:
Those look pretty good.
Is it the same on the other side?


Maybe take your foot out of the radiator? :O_o:
Click to expand...
Yep they look the same so I they domt show any misfire as far as my concern.

Believe me I trained more than two different driving styles and no improvement whatsoever. And it really demoralizes the hell out of me when people comment “Well I have 347 with 4.10’s a consistently see 20 miles to the gallon” do I trully believe that? Well no but maybe 17 miles per gallon but me doing 9 ridiculous miles per gallon???? Pathetic!!!
 
#10
Another thing, my speedo is as accurately as it can be matching my GPS Speedometer. I was running 18 degrees static timing on regular gas with no pinging, now I dropped it to 14 degrees. So what the heck is going on???
 
#15
First thing I would do is unscrew the o2's and burn the tips pretty much red hot with a torch or just replace them. Not much controls fueling on the eec IV and if its is that bad it thinks its dead ass lean, that would be eye watering rich even for a carb car with that combo unless you drive like its on the track all.the time some things way wrong.. Run a KOER and balance test and see if any rich/ lean codes pop up then go from there they won't all ways be stored in KAM. Fuel pressure isn't going to be the cause of this, its either a shot maf, o2's, electrical wiring /ecu issue or a more serious mechanical issue. I've seen cars run in limp mode with blown sign return not load up that bad with fuel.
 
#19
rednotch said:
First thing I would do is unscrew the o2's and burn the tips pretty much red hot with a torch or just replace them. Not much controls fueling on the eec IV and if its is that bad it thinks its dead ass lean, that would be eye watering rich even for a carb car with that combo unless you drive like its on the track all.the time some things way wrong.. Run a KOER and balance test and see if any rich/ lean codes pop up then go from there they won't all ways be stored in KAM. Fuel pressure isn't going to be the cause of this, its either a shot maf, o2's, electrical wiring /ecu issue or a more serious mechanical issue. I've seen cars run in limp mode with blown sign return not load up that bad with fuel.
Click to expand...
Ok, I already cleaned the O2 sensors with a torch until they were glowing red.
I dont run it under track conditions, I tried two-three driving styles to see if that made any difference... It didn't
I ran all three tests; KOEO-KOER-Balance test no rich condition and no errors whatsoever.
On the MAF issue I'll explain: I had the stock 55mm MAF housing and had bad fuel economy, then I switched to a '95 70mm MAF and sensor which was running with 19lbs injectors and I had better acceleration but as far as fuel economy still the same I'm running 19lbs EV6 injectors.. A friend of mine told me to go back to my stock 55mm MAF which I did and still no MPG improvement at all. So seeing the change was pointless I went back to the 70mm MAF and that's what I'm running right now.
I smell a bit or raw gas but that must be because I removed the secondary Cats and deleted all the anti-smog system except the EGR system.
I can't find any mechanical issues, the motor runs strong, no vacuum leaks, I just re-set up my idle speed and it is sitting nicely at about 750 rpm, my timing is at 14 deg. My vacuum is around 12.5 in which is very normal with the TFS stage 1 cam.
So maybe this set of EV6 injectors are pouring more fuel than the EV1? the specs say they deliver 20lbs @43.5 psi.... Should I get the EV1 injectors or just go to the 24lbs with matching MAF???

I'm absolutely stumped!!! :O
 
#20
Noobz347 said:
That boggles my mind. You don't happen to have some chip installed that [ignores all errors] or something of the like, do you? :O_o:
Click to expand...
No chips just the A9L and I tried the A9P, runs nice but no MPG improvements.
My issue sounds like bad joke but it is not and believe me I tried everything up to different sparkplug gap etc, and no improvements :oops:
 
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