• Subscribe to a Magazine
123 Last
Item Posts    Sort Order

Fuel pump won't work

 
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 06/27/13 01:25 PM

test part 3.
now... with the fuel pump relay ready for testing... do you get power on the GREEN and yellow striped wire coming out of the fuel pump relay for 2 seconds when you first turn the key on.. and while cranking??????? yes or no...

can you hear the fuel pump run..???  does it build fuel pressure when you test it at the fuel test port on the fuel rail using the special adaptor and a fuel injection pressure tester..???  

Post Reply
jeff69
New User
Posts: 16
Joined: 06/13
Posted: 07/04/13 06:49 AM

O.K after taking a few days away from the mustang, I went back to it for a bit today.  I cut the top off the eec relay to see if was closing, and it was.  But there is no power to the green/yellow wire to fuel pump. So then I jumped power to it from the pink/blk wire and it ran continuously.  I then tried to start it but didn't go.  I checked the fuel rail while pump ran and there was pressure, but no start.  Is there a way to check to see if the injectors are firing? and why is pump running all the time when I jump the FPR?  Is there a short in pump or from the EEC relay to FP relay.  Soon gonna just take it to the dealer and pay the price to get it going.  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 07/04/13 10:32 AM

do me a favor...

there are multipin connectors on the back of the motor where the engine harness is connected to the chassis harness...

can you take those apart and put them back together a few times..

you might actually have to massage the shape of the female terminals to grasp onto the mail terminals tighter...

i saw this on another forum...

do you have SPARK???? coming from the coil???? when you crank it?

there are NOID light kits at some parts stores in the loaner tools so actual cost is zero when you return them.. check the counter mats..

you could also have a bad computer.. or several other problems..

i am going to have a look at what we have covered..

and jeff...  when you are logged in...  find the place you log out at... .. note that you have a message to the left of it.. click it.. use the number.. i am around today...  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 07/04/13 10:43 AM

the fuel pump relay circuit power supply circuit..

1....
the PINK and black stripe wire from probably the starter relay..
this pink and black wire has to have CONSTANT POWER... if it does not.. that is your issue..

1b....
when you squeeze the contacts closed on the fuel pump relay.. does the green and yellow striped wire get power??



2.....
please also verify that there is constant power to the Yellow wire coming into the main relay ...

2b___

lets look at the main relay output...

start at the ignition coil positive??? got power there with a test light??? red and light green wire plugged into the ignition coil...  yes or no.???

2c.... use your test light.. find the red wires going to the fuel injector.. .do you have power there when the key is turned on???

when the ignition key is turned on.. it supplies power to the red and light green wiring.. powering the ignition coil positive and turning on the main relay...   the main relay stays on as long as the key is on..  

Post Reply
jeff69
New User
Posts: 16
Joined: 06/13
Posted: 08/16/13 10:37 AM

O.k I'm back.LOL  I bought a used computer last week and put it on.  Pump didn't run at all.( no change).  I then played with the relays and turned the key and NOW the
pump RUNS(all the time) with key on.  It won't just run for the 2-3 sec like it should.  Any ideas???  Can it be a short in the pump ??  It runs like it would when I ground the pump on the test connector.  I think that it might be a short in the ground or a short in the pump.  What tells the pump to only run for the 2-3 sec?

I even have power to the injectors , but car won't start.   Any help??  LOL  

Post Reply
jeff69
New User
Posts: 16
Joined: 06/13
Posted: 08/16/13 10:38 AM

O.k I'm back.LOL  I bought a used computer last week and put it on.  Pump didn't run at all.( no change).  I then played with the relays and turned the key and NOW the
pump RUNS(all the time) with key on.  It won't just run for the 2-3 sec like it should.  Any ideas???  Can it be a short in the pump ??  It runs like it would when I ground the pump on the test connector.  I think that it might be a short in the ground or a short in the pump.  What tells the pump to only run for the 2-3 sec?

I even have power to the injectors , but car won't start.   Any help??  LOL  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 08/16/13 07:37 PM

this is SO CONFUSING...

the IGNITION KEY turns on the MAIN relay...
this powers up the computer, and also sends power to the positive side of the injectors..

it also supplies current to the ONE side of the fuel pump coil winding..

the other side of that winding is controlled by the computer.. it connects it to ground when the computer wants..

what i don't understand is WHY... when you shake the relays.. you get things to work in weird ways...

91 93 50 EEC4 Enginecontrolwiring Zps655c81e0  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 08/16/13 07:50 PM

your engine harness has quick connect blocks where the engine harness is attached to the body harness... please unbolt those and examine them for corrosion....

examine them for loose terminals..  


next  

unplug the computer   turn the key on.. can you hear the main relay click when you turn the key on and off..

if you ground the wire to PIN 22.. or the proper pin on the EEC 4 connector #926 as shown above. .. light blue and orange stripe..  does the fuel pump turn on???? you should be able to hear fuel running thru the fuel rail...  

Post Reply
jeff69
New User
Posts: 16
Joined: 06/13
Posted: 08/17/13 07:39 AM

Could the problem be the regulator is just leting the fuel cycle back to the tank and not building up pressure in the rail to tell the computer that there is pressure??  Just wondering..  I'll try what you said tomorrow. got to go to work today.  hope I get this fixed.. Frown  

Post Reply
jeff69
New User
Posts: 16
Joined: 06/13
Posted: 08/17/13 07:52 AM

O.k, I just went out and did what you said.  I grounded pin 22 to the body with puter unpluged and the pump runs.  Now what?  LOL  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 08/17/13 07:54 AM

jeff.. your car is acting so strange. it could be a bunch of things..

loose ground wires ...

bad connections...

do you have access to the ford service manual.. or electronic info... so you can follow step by step...

lets check the grounds...

1992Mustangunderdashharness

1992Mustang50batterycablegrounds  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 08/17/13 07:59 AM

can you also.. disconnect the PCM .. and OHM pin 20, 40, and 60 to the engine block..

see if you have close to 0 ohms of resistance...

20, 40, 60 if you look at the right side of the wiring diagram are the PCM grounds.

if any of those is open.. you will have issues..

please don't forget to verify the ground connection thats near the PCM.. that has to be hooked up properly also...  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 08/17/13 09:11 AM

jeff.. here is the body side of the harness

88Mustangefiharness Zpsd8a5c042  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 08/17/13 09:44 AM

i have spent the last 2 hours grabbing and marking images..

start cleaning grounds...
G100 on drivers side shock tower
G102 on drivers side core support
G103 on passenger side core support
G104 on drivers side inner fender beside battery
G105 on engine block.. lower drivers side front just above oil pan.
G109 is under throttle body on lower intake manifold..

there is another ground connection into the harness that connects to the back of the passenger side cylinder head.. shown above.. but not on this image

and one near the ECM ... shown in the lower picture here..

92 Mustang 50 Componentlocator Zps9025fcf1

92 Mustang50ecmconnector Zpsbf55ea49

this is where we start...  

Post Reply
waynep712222
User
Posts: 124
Joined: 03/13
Posted: 08/17/13 09:51 AM

and again.. if the grounds are funky.. the system will work funky...

this should take you less than an hour to  remove, clean and reinstall all these ground  ring terminals with a stainless steel wire tooth brush.  don't forget to clean the surface they are mounted to .. and the underside of the fastener..

do you have anything to help you run the KOEO and KOER tests???

a scan tool..  or one of these actron code readers... about 30 bucks at most parts stores??

Cp9115foreeciv KOEO Koertesting Zps6f1f70a0  

Post Reply
123 Last