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Fuel Pump Electrical Help

G

GinisKratos

NAXJA Forum User
Location
Centralia, WA (Olymipa)
Ok so ive replaced my fuel pump twice and each time it works for about a month then starts giving me issues again. Kinda sounds like the pump is starting up but takes awhile to start... and JUST before it starts i really hear the pump kick in and it starts. So it still starts but sometimes takes literally 3-4 min of cranking it before it catches... and yes i really mean holding the key on and the starter kicking in. Good things i have a new batt also :wierd:

SO what im thinking is that 3 fuel pumps, its not the pump thats the trouble. But more the power getting to the pump. But im a gimp when it comes to wiering. Chilton's isnt being very helpful even tho there is a wiering diagram in there. Can anyone shead some light on where to start? tonight im going to trace from the pump as far as i can to see if there is a short or break inthe wiering. But some assistance would be great =)

Ed
 
I have a similar problem, but I try to start for just a few seconds and after two or three attempts it starts right up. Seems like the fuel pump isn't sending enough pressure to the fuel rail.
 
Sounds more like a fuel rail pressue problem,what year are you talking about?
 
Sorry =) its an 89 4.0 and it is a fuel pressure problem... the pump isnt running so its not getting pressure ;) but the thing is this is the 3rd pump. and they are all acting the same. They are good starts right up for a bit then takes longer and longer... then it will fire up just fine maybe 2-3 seconds of cranking... then it goes back to taking forever again.

So either the original and 2 new ones I bought were bad... or there is some other electrical issue. Which both could be, but I'm leaning more for the electrical at this point :helpme:
 
Frank Z, do you know what the sufficient voltage for the fuel pump is?

My understanding it's 12 volts without the ballast resistor and 5 volts with the ballast resistor
 
Last edited:
GinisKratos said:
Ok so ive replaced my fuel pump twice and each time it works for about a month then starts giving me issues again. Kinda sounds like the pump is starting up but takes awhile to start... and JUST before it starts i really hear the pump kick in and it starts. So it still starts but sometimes takes literally 3-4 min of cranking it before it catches... and yes i really mean holding the key on and the starter kicking in. Good things i have a new batt also :wierd:

SO what im thinking is that 3 fuel pumps, its not the pump thats the trouble. But more the power getting to the pump. But im a gimp when it comes to wiering. Chilton's isnt being very helpful even tho there is a wiering diagram in there. Can anyone shead some light on where to start? tonight im going to trace from the pump as far as i can to see if there is a short or break inthe wiering. But some assistance would be great =)

Ed
Click to expand...

i know when i replaced the pump on my 89 the + and - terminals were reversed on the new replacement pump. maybe your hooking it up backwards(reversing the polarity)?
 
One thing you might want to look at is the fuel sending unit. I was having a similar problem in my '87 4.0 and that's what it turned out to be. Low fuel pressure at the fuel rail is a symptom.
 
On a side note, you are KILLING your starter by cranking for anything more than 5 seconds at a time. The starter motor is not designed for that, and will fail leaving you stranded after doing this consistently. you should crank for five seconds, then wait five seconds and repeat as needed. That helps keep the starter motor from overheating and burning out.
 
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