so this is what happened. i was driving along and then i hit a bump and my car shut off. the bump wasnt even that big. anyway, i tried to restart it but it wouldnt start and i noticed that my fuel pump wasnt kicking. so after numberous tests, we found that the main relay "backup" fuse (fuse #4) kept blowing everytime we replace it and put the key into the on position. so now we narrowed it down to a couple of possibilities:

1 - the fuel pump is causing the fuse to blow
2 - there is a short along the fuel pump wire connection
3 - the relay is causing the fuse to blow.

are these reasonable possibilities? our next step is to disconnect the black/yellow wires that connect to the fuel pump and put the key into the on position to see if the fuse blows. if it does, then that means that there is a short along the wires to the fuel pump. if it doesnt, then that means that the fuel pump is causing the fuse to blow. are these conclusions correct given the tests?

has anyone else ever had this problem?

also if the fuse does not blow, then it could be the fuel pump. but how do we know that it is not the relay causing the fuse to blow? is there any possibility that the relay would cause it to blow?

also...is there any other possibilities as to what would make the fuse blow?

sorry for the novel

 

bump for some help

 

Check the wire from the fuse box to the relay with your ohm meter and see if it's grounded, if yes=short.

Do the same for the wire that run's from the relay to the pump. Sounds like a short somewhere definaltely.

Make sure all the associated wiring is good and safe and go from there.

 

now the fuel pump only kicks if i jump the relay. but it still wont start...now i have no spark. definitely a big electrical problem somewhere

maybe it's between the relay and the ignition itself?

it still blows fuses if u connect the relay and put the key in the on position. but it does not blow the fuse if u jump the relay.

i do have continuity from the fuse to the corresponding wire in the relay harness

also i guess ill be selling my BRAND NEW relay now and my old walbro fuel pump which is in working condition after all. help me out and take these off my hands!

 

you bought a new pump before you even figured out the problem?

you won't get spark if the relay isn't in there, and from the way you're describing it, the relay isn't in because it is blowing fuses all over the place.

Just take the connector that plugs into the main relay. Leave the keys out and put a good fuse in that slot that keeps blowing. Probe each pin and check for resistance to ground.



make sure that each pins the battery pin has infinite resistance to ground and gets 12v. make sure pin 2 has zero resistance to ground. then check 5,7,and 8, they should all have infinite resistance to ground.

get back with those results

 

yea...we did check those pins, and they were all fine. i thought u could start ur car if u dont have the relay in, but u just jump 5 & 7.

this is the test i performed (from the service manual):
continuity between 2 & ground
voltage between 1 & ground
voltage between 5 & ground (ignition switch on)
voltage between 6 & ground (clutch in, cranking key)

all with positive tests.

 

i found the problem...the o2 sensor shorted. aparently the o2 sensor is connected to the relay somehow. for future reference, dont forget to consider this!