1993 Mustang Cobra Fuel Pump Issues

hostilian

Member
Sep 21, 2016
5
4
13
35
First I want to thank jrichker for his in depth post about the fuel system and electrical diagnosis which has got me almost to beat this issue.

http://www.stangnet.com/mustang-for...uously-with-key-on-but-car-wont-start.754221/

Now to what I have. My dad owns a 1993 cobra and bought it brand new in 93. He has an issue where the fuel pump stopped working. I read the above post and tested all the above. relay is good, inertia switch is good, and fues links are good. My problem is that when I turn the key to run, the fuel pump does not turn on and the relay does not click. I hook up a jumper from the ecc test connector pin to ground and the relay clicks and the pump turns on and does not turn off, just keeps running. Even if i remove the jumper wire from ground, it just continues to run. So I test this section of jrichkers post ("The light blue/orange wire provides a ground path for the relay power. With the test connector jumpered according to the previous instructions, there should be less than .75 volts.") When I do this, I get around 8 volts instead of .75 volts. Which tells me that maybe I have two wires that have maybe been ate up by mice and got crossed with each other. So I cut the light blue/orange wire, solder on a long wire that I run right to a chassis ground. Now I turn the key to run and the fuel pump turns right on but does not shut off. So im then led to believe that maybe no wires are crossed but instead the ecc computer has gone bad.

I get the part number off the computer and it is the X3Z computer. I look around and they are about 400 bucks for a new one. But I can find used ones on ebay that are the A9L and A9P. And they are a dime a dozen. Im curious if I can change out the x3z computer with one of the others and even if I have a slight drop in car performance, that is fine, dad just putts around in it anyhow and doesnt have hardly any money to throw at it (kind of why im the one trying to fix it) Any help or suggestions would be awesome and Thanks again to jrichker and this forum for the awesome help so far..
 
  • Sponsors(?)


90sickfox

I didn't really have an issue with the stink...
SN Certified Technician
Mar 2, 2015
5,302
4,351
203
42
You can send the computer out to be repaired. Is it stick or auto ?
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,059
9,204
224
Massachusetts
If you change to the A9L computer, you will need to change the injectors to 19# and change the MAF to a standard 5.0 Mustang MAF to get it running correctly.

To retain the stock 24# injectors and MAF, you'll need a tune.

Might be cheaper/easier to repair the X3Z
 

hostilian

Member
Sep 21, 2016
5
4
13
35
I see. Anyone have a guy who they trust to work on these and any idea what the cost is. Or if someone has one laying around that they want to sell?
 

a91what

SendMeUrDataLog
Mod Dude
Apr 6, 2011
10,128
6,022
204
31
Hillsborough county
I believe in the MAF uses the stock curve all the extra fueling is done in the ECU. Have you check to see if the computer pulls it to ground when you turn on the key maybe try grabbing the wire for the fuel pump off the ECU and tying it directly to the relay you may have a break somewhere in The Wire just a thought. If you do get a9l you will need to get the matching 19 pound orange top injectors from a Mustang or Explorer
 

hostilian

Member
Sep 21, 2016
5
4
13
35
I wanted to give an up date on the situation with the car. I hate when people figure out what was wrong but never update the thread with the answer. So just to recap. I Turn the key on and the fuel pump does not prime. I use the jumper wire at the test port and the fuel pump kicks on but does not turn off. I run through all the test as described in the above thread by jrichker. I pull the ECM (COMPUTER) and once I get down to the board (which is the first picture) I see that two of the blue barrel looking things (capacitors) are burned up. (second picture has a close up of one of the capacitors) I buy three of them off ebay (two of them are 47uF 16V capacitors and one is a 10 uF 35V capacitor) I solder them on to the board and now my dads 93 runs again. Just want to say thanks again to everyone who continues to contribute to these forums.
 

Attachments

Thread starter Similar threads Forum Replies Date
B SOLD For Sale - 1993 Mustang Cobra - Black on Black 75254 Miles Fox Body Mustangs For Sale (1979-93) 2
B SOLD 1993 Mustang cobra 48k original miles owned and built by Johnny Lightning JLP Performance. $28,000 Fox Body Mustangs For Sale (1979-93) 4
M WTB/Trade WTB 1993 Ford Mustang Cobra Black, Teal, or Red on Black Fox Body Mustangs For Sale (1979-93) 3
H WTB/Trade WTB 1993 Mustang Cobra Black on Black Fox Body Mustangs For Sale (1979-93) 0
ZephyrEFI WTB/Trade 1993 Mustang Cobra X3Z ECU Engine and Power Adder 0
M 1993 Mustang Cobra - need to replace rack and pinion. Need suggestions where to buy. 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 12
S For Sale 1993 Mustang Cobra - black/gray - 57k miles - Newton, NJ Fox Body Mustangs For Sale (1979-93) 0
C For Sale 1993 black on black mustang cobra 74xxx miles in De, Delaware Fox Body Mustangs For Sale (1979-93) 8
J Expired 1993 Ford Mustang Cobra Fox Body Mustangs For Sale (1979-93) 0
1993cobra5.0 1993 Cobra Mustang Hates Me .....sos .. Help ..sos ..help 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 109
D SOLD 1990 Mustang 1993 Cobra Clone Very Nice Car! Fox Body Mustangs For Sale (1979-93) 4
S SOLD 1989 Mustang Gt 5.0 -"1993 Cobra Clone" Fox Body Mustangs For Sale (1979-93) 5
J Expired 1993 Mustang Cobra Wheels In Md $400 Wheels Tires Brakes 0
des89stang Expired Oem Ford Mustang Running Pony Grill Emblem.. 1993 Cobra Interior Exterior Parts 16
0 SOLD 1993 Ford Mustang Svt Cobra #1554 73k Original Miles $9200 Fox Body Mustangs For Sale (1979-93) 0
9 SOLD Fs/ft 1993 Mustang Svt Cobra #2352 - Vibrant Red - 68k Miles - 5.0/5spd - Immaculate! Fox Body Mustangs For Sale (1979-93) 8
Josh1892 Expired 1993 Mustang Gt Supercharged Silver W/black Interior, Cobra Upgrades Fox Body Mustangs For Sale (1979-93) 5
tacomatrx450f Expired 1993 Mustang Cobra, Turbo Coupe Stoptech Rotors. Pair Wheels Tires Brakes 3
tacomatrx450f Cost of a 1993 cobra, or mustang 5.0 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 5
fordmanforever1 Expired 1993 Ford Mustang Cobra Project Car Fox Body Mustangs For Sale (1979-93) 1
3 SOLD Original 1993 Mustang Cobra Upper Intake Engine and Power Adder 1
Blake02GT SOLD 1993 Mustang Cobra Supercharged (fs/ft) Fox Body Mustangs For Sale (1979-93) 5
C *F/S*1984-1986 Mustang SVO & 1993 Cobra Tail Lights w/ BLACK STRIPES Interior Exterior Parts 0
K 1993 SVT Mustang Cobra Fox Body Mustangs For Sale (1979-93) 1
3 1993 Black SVT Mustang Cobra for sale Fox Body Mustangs For Sale (1979-93) 4
RAYZEN CAINE 1987 - 1993 Mustang Cobra grille insert kit. New!!!! - $50 Interior Exterior Parts 0
S 1993 Mustang Cobra OEM Wheels Wheels Tires Brakes 0
S 1993 Mustang Cobra OEM Wheels Wheels Tires Brakes 4
FORDRACING19 1993 Ford Mustang Cobra Fox Body Mustangs For Sale (1979-93) 0
B Looking for a 1993 Mustang SVT Cobra? Fox Body Mustangs For Sale (1979-93) 4
B 1993 Ford Mustang Cobra (Real) Fox Body Mustangs For Sale (1979-93) 2
T 1993 5.0 Cobra Mustang?? Fox 5.0 Mustang Tech 11
M 1993 cobra mustang authenticity 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 16
D For Sale 1993 Ford Mustang LX Convertible 2.3L NE Wisconsin Fox Body Mustangs For Sale (1979-93) 0
S Electrical 1993 Mustang Clock Spring Fox 5.0 Mustang Tech 6
kjohnson1 For Sale 1987-1993 Ford Mustang Coupe Sedan Notchback Opal Grey Cloth Rear Seats Interior Exterior Parts 2
79pace Electrical 1993 Mustang GT Clock Spring Fox 5.0 Mustang Tech 18
9 1993 Mustang lx 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 9
S 1993 Mustang GT will not display check engine light until it is turned over and will not throw codes... Fox 5.0 Mustang Tech 9
S For Sale For Sale 1993 Mustang GT Triple Black Convertible Fox Body Mustangs For Sale (1979-93) 0
mercurycapri302 1993 mustang 2.3l lx fuel lines 2.3L (N/A & Turbo) Tech 1
K 1994 Ranger 2.3l into a 1993 Mustang LX 2.3l? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 4
K 1993 Mustang LX 2.3 won't rev past 2k 2.3L (N/A & Turbo) Tech 8
B For Sale For Sale 1993 Mustang SSP Coupe Fox Body Mustangs For Sale (1979-93) 0
A 1993 mustang convertible Quarter Windows problem Fox 5.0 Mustang Tech 5
A Help!!!!! 1993 Mustang coolant sensor inline T housing 2.3L (N/A & Turbo) Tech 4
scott hamilton SOLD 1993 mustang lx Fox Body Mustangs For Sale (1979-93) 2
H 1993 mustang gt sparks problem!! Fox 5.0 Mustang Tech 4
JCBeaver Drivetrain Excessive Vibration at 4K+ RPM while in gears - Any ideas why? 1993 Mustang GT 5.0 with T5 Fox 5.0 Mustang Tech 11
G For Sale 1993 mustang gt 5.0 $3500 obo Fox Body Mustangs For Sale (1979-93) 0
Similar threads