Fuel injectors/Pressure ? - ZR-1 Net Registry Forums

LGAFF · 09-07-2008

Last year I installed 2 new fuel pumps and new injectors, one set from SAP and the other Accels. I pressurized the fuel system and it jumps to 57lbs of pressure then drops to 41 and within 5 minutes pressure is down to 30 or less. I know Dominic had this issue earleir, wondering if the SAPs are crap and are leaking.

Times at the track are down fromlast year, MPH was down 2-3mph from last year. I was running 113-114.5 vs 115-117 last year.

LGAFF
92 ZR1
#234

LGAFF · 09-07-2008

Tested the Inj for resistence results as follows:

2ndry= 1)12.5 2)12.4 3)12.4 4)12.9 5)12.8 6)12.6 7)6.9

8)12.4

Primary= 1)15 2)15 3)15 4)15 5)14.8 6)15 7)15 8)15

Hmmmmmmmmm

LGAFF
92 ZR1
#234

09-07-2008

Sucks, so which injector brand failed?

Pete · 09-07-2008

Change the damn injector,LOL
Did you go to Byron?

What as your 1/8 MPH
Was your 60ft the same as last time.

Did you make any changes to the car,chip tune, plugs,etc.

Pete

LGAFF · 09-07-2008

SAPs.... only 1 year old.......bought these off the bay. As I was nice enough to test these for the forum members please send your check or money order to Lee Gaffigan

Guess I know what I am buying next week.

LGAFF
92 ZR1
#234

LGAFF · 09-07-2008

Byron sucked.......

Started running 12.8s at 113, even realed off a 12.64. Speed was slow but that might be the injector. I think they worked out the timing issue both sides consistently sucked for me and 1/8ths seem consistent in MPH and times.

I was going to try one more run then a motorcyle engine blew just past the 1/8th....guy launched parts over the friggin fences on both sides. That was worth $25 right there. I got 8 runs in, could have done 12-15 but spent time trying to figure out what was wrong.

I might as well change the coils also. I wonder if SAP makes those

LGAFF
92 ZR-1
#234

LGAFF · 09-07-2008

I was running 8.3-8.4@ 89MPH on both sides fairly consistently. I was not getting the second half pull I am used to out of the car. I had the same issue when I went in early May. This also means my 391hp Dyno run was with a crap injector.

LGAFF
92 ZR1
#234

LGAFF · 09-07-2008

Accel 150121 (8) "Only $259.88" #150821 21# High Impedence Fuel Injectors. Ford 86-95 5.0L, 96-98 4.6L, GM 86-92 TPI, 93-97 LT-1, ZR1 ZR-1 Ford
Price $259.88
ACCEL 21#* High Impedance FUEL INJECTORS #150121 (Set of 8) Applications: GM V8 1986 to 1992 TPI GM V8 1993 to 1997 LT-1 FORD V8 5.0L 1986 to 1995 Ford V8 4.6L 1996 to 1998.

Are these the ones I need??

LGAFF
92 ZR1
#234

Ccmano · 09-07-2008

Line pressure down to 30 psi in 5 minutes? The spec. in the Shop manual is only to hold pressure for 10 seconds once the fuel pumps are shut off. Per the manual, the system should show 48-55 psi while the pumps are running with the engine off. When the engine is started pressure should drop 3-10 psi.

I don't think 5 minutes is relavent here. Sounds to me like your system is just fine.

Didn't you change your tune from last year? Change it back and see how it preforms.

Hans

LGAFF · 09-07-2008

Hans,

My manual says system should drop some once pumps stop but pressure should be maintained, however look at the test on the injectors, one at 6.8 and thats cold I would imagine once heated that one is toast.

LGAFF
92 ZR1
#234

09-07-2008	#3
Jeffvette Guest Posts: n/a	Re: Fuel injectors/Pressure ? Sucks, so which injector brand failed?

09-07-2008	#4
Pete Join Date: Dec 2003 Location: Chicagoland,IL Posts: 2,679	Re: Fuel injectors/Pressure ? Change the damn injector,LOL Did you go to Byron? What as your 1/8 MPH Was your 60ft the same as last time. Did you make any changes to the car,chip tune, plugs,etc. Pete __________________ '91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage

09-07-2008	#5
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Fuel injectors/Pressure ? SAPs.... only 1 year old.......bought these off the bay. As I was nice enough to test these for the forum members please send your check or money order to Lee Gaffigan Guess I know what I am buying next week. LGAFF 92 ZR1 #234

09-07-2008	#6
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Fuel injectors/Pressure ? Byron sucked....... Started running 12.8s at 113, even realed off a 12.64. Speed was slow but that might be the injector. I think they worked out the timing issue both sides consistently sucked for me and 1/8ths seem consistent in MPH and times. I was going to try one more run then a motorcyle engine blew just past the 1/8th....guy launched parts over the friggin fences on both sides. That was worth $25 right there. I got 8 runs in, could have done 12-15 but spent time trying to figure out what was wrong. I might as well change the coils also. I wonder if SAP makes those LGAFF 92 ZR-1 #234

09-07-2008	#7
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Fuel injectors/Pressure ? I was running 8.3-8.4@ 89MPH on both sides fairly consistently. I was not getting the second half pull I am used to out of the car. I had the same issue when I went in early May. This also means my 391hp Dyno run was with a crap injector. LGAFF 92 ZR1 #234

09-07-2008	#1
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Fuel injectors/Pressure ? Last year I installed 2 new fuel pumps and new injectors, one set from SAP and the other Accels. I pressurized the fuel system and it jumps to 57lbs of pressure then drops to 41 and within 5 minutes pressure is down to 30 or less. I know Dominic had this issue earleir, wondering if the SAPs are crap and are leaking. Times at the track are down fromlast year, MPH was down 2-3mph from last year. I was running 113-114.5 vs 115-117 last year. LGAFF 92 ZR1 #234

09-07-2008	#2
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Fuel injectors/Pressure ? Tested the Inj for resistence results as follows: 2ndry= 1)12.5 2)12.4 3)12.4 4)12.9 5)12.8 6)12.6 7)6.9 8)12.4 Primary= 1)15 2)15 3)15 4)15 5)14.8 6)15 7)15 8)15 Hmmmmmmmmm LGAFF 92 ZR1 #234

09-07-2008	#8
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Fuel injectors/Pressure ? Accel 150121 (8) "Only $259.88" #150821 21# High Impedence Fuel Injectors. Ford 86-95 5.0L, 96-98 4.6L, GM 86-92 TPI, 93-97 LT-1, ZR1 ZR-1 Ford Price $259.88 ACCEL 21#* High Impedance FUEL INJECTORS #150121 (Set of 8) Applications: GM V8 1986 to 1992 TPI GM V8 1993 to 1997 LT-1 FORD V8 5.0L 1986 to 1995 Ford V8 4.6L 1996 to 1998. Are these the ones I need?? LGAFF 92 ZR1 #234

09-07-2008	#9
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Fuel injectors/Pressure ? Line pressure down to 30 psi in 5 minutes? The spec. in the Shop manual is only to hold pressure for 10 seconds once the fuel pumps are shut off. Per the manual, the system should show 48-55 psi while the pumps are running with the engine off. When the engine is started pressure should drop 3-10 psi. I don't think 5 minutes is relavent here. Sounds to me like your system is just fine. Didn't you change your tune from last year? Change it back and see how it preforms. Hans __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

09-07-2008	#10
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Fuel injectors/Pressure ? Hans, My manual says system should drop some once pumps stop but pressure should be maintained, however look at the test on the injectors, one at 6.8 and thats cold I would imagine once heated that one is toast. LGAFF 92 ZR1 #234 Last edited by LGAFF; 09-07-2008 at 11:18 PM.

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