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Even with dyno tune Car starts to run lean after 4800

  • Thread starter Thread starter KenneBell
  • Start date Start date Aug 18, 2005

KenneBell

New Member
Apr 14, 2005
158
0
0
San Jose California
Aug 18, 2005
#1
  • Aug 18, 2005
  • #1
I have kennebell at 8psi, 30# injectors and C&L Maf with 30# calib. tube. I was having my car tuned on the dyno and the guy opened my injectors all the way past 3000 and it ran richer and richer like it should until 4800 when it just starts leaning out from 11:1 at 4800rpm all the way to 14:1 by 5200rpm, the fuel curve is smooth and flat from 2000 all the way to 4800 then starts arcing up. He didn't take it past 5200rpm because it was leaning out. He said my 190lph fuel pump wasn't big enough that I needed a 255 pump and also the C&L using the stock MAF sensor could be the problem and I should get a true aftermarket meter like a granatelli. Has anyone ever had this problem? Is it the MAF, fuel pump, or both? By the way I made 289rwhp at 5200 and 340ft.lb. torque at 3500. I think if I get this lean situation figured out and take it to 6000 I should see around 300rwhp, perhaps? Thanks for all the help.
 
T

The NJ Exile

New Member
Jul 28, 2004
81
0
0
Northern VA, Philly & Northern NJ
Aug 18, 2005
#2
  • Aug 18, 2005
  • #2
With My past KB I had the 42Lbs Injectors, 90mm MAF, and I had a 255 intank pump. @ 12 psi I was good, I leaned out @ 16psi. I would upgrade you pump ASAP.
 

Don 95Vert

Founding Member
Oct 1, 1999
1,091
1
39
Delaware, OH
Aug 18, 2005
#3
  • Aug 18, 2005
  • #3
You need a bigger pump and you probably are also running out of injector - get 42s and a 255 pump.
 
H

HUNTED

New Member
Aug 2, 2005
42
0
0
ENID, OKLAHOMA
Aug 18, 2005
#4
  • Aug 18, 2005
  • #4
do u have a fuel pressure guage my dad had the same problem and he added more fuel to through his pressure regulator and that cured it all and he runs 14 psi. If that doesnt cure it you might need a bigger fuel pump
 

bjl95mustang

Founding Member
Jan 18, 2000
1,495
0
36
Austin,TX
Aug 18, 2005
#5
  • Aug 18, 2005
  • #5
Get a Lightning maf, 42 lb injectors, and a 255 high pressure pump. You can find the lightning mafs for about $100 and you will need a new maf plug. You will also not beable to use it with out a chip/ or tweecer becuase you have to have the maf tables loaded into the comp.
 

MattZ281LE

Founding Member
Feb 6, 2000
345
1
19
Purcellville, Va
Aug 19, 2005
#6
  • Aug 19, 2005
  • #6
Yup I maxed 38# at 5500 on my KB at 8# That was with a 255 intank pump, I pegged the voltage on the Pro-M77 I had at the time. Put down 385 rwhp 420 rwtq at 5400.

New combo I did a complete fuel system with 60# injectors and a lightning MAF.
16# on the KB.
 

CManT1914

New Member
Feb 5, 2004
3,172
2
0
Killeen, Texas
Aug 19, 2005
#7
  • Aug 19, 2005
  • #7
I think those 30's are too small, and so is that fuel pump. The C&L's are known to be pieces of crap, mine was, so I had my Pro-M recalibrated. Bumping the fuel pressure up is only a bandaid cure and I would not recommend it. Try some 42's or something, with a 255 pump, and get a better (Pro-M) maf and see what happens.
 

S/CBlack95GT

New Member
Apr 6, 2003
2,018
0
0
Tampa Palms, FL
Aug 19, 2005
#8
  • Aug 19, 2005
  • #8
Throw a T-Rex pusher pump and an FMU on and it will work perfectly.
 

rustang94

Member
Dec 2, 2003
281
0
16
Milwaukee WI.
Aug 19, 2005
#9
  • Aug 19, 2005
  • #9
The NJ Exile said:
With My past KB I had the 42Lbs Injectors, 90mm MAF, and I had a 255 intank pump. @ 12 psi I was good, I leaned out @ 16psi. I would upgrade you pump ASAP.
Click to expand...
did you have a tune or a chip
 
S

sosstangs

New Member
Aug 12, 2005
6
0
0
Aug 19, 2005
#10
  • Aug 19, 2005
  • #10
well, when you get rid of those 30lb injectors, let me know...i could use a set.

Danny
 

KenneBell

New Member
Apr 14, 2005
158
0
0
San Jose California
Aug 19, 2005
#11
  • Aug 19, 2005
  • #11
S/CBlack95GT said:
Throw a T-Rex pusher pump and an FMU on and it will work perfectly.
Click to expand...

What size FMU calibration?
 
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