92hatchboi

here is the problem. the car isnt starting. so i narrowed it down to it not getting any fuel. i thought it was the main relay so i changed that and now it still doesnt start, but when you jump the main relay connector for the ignition and fuel pump then fuel comes pouring out. any ideas as to what the problem is. my buddy has the same problem on his prelude.

92hatchboi

anybody got anu ideas

92hatchboi

nobody has any ideas. is there something that i am missing

spoon_ek9

the ecu have to send out a signal in order to activate the fuel pump, check that

nihad

iTrader: (2)

can you hear the relay click make sure the wire arent cut.

fridaytech

hey you check all fuses... check 12, 24,31 and 16 all related to fuel pump operation. note ecu dosn't send sigal it switch to ground to operate main relay. if you need wiring diagram hit me up i think i can email it to you

OisinT

i just ran into this problem. borrow a working ecu from a friend and plug it in... should work then. Thought the same thing at first did the whole A/S/F test... was missing the fuel... then replaced the relay per my mech. friends advice and after jumping the pins and it worked. still nothing. then i pulled the code from the ecu. light was steady... Code 0 aka ecu code. so had a friend with a known working ecu come over, plug it in, and everything worked... Currently borrowin a CX ecu so i can at least drive my car while i find another P28.

fridaytech... Your saying that the ecu switches a ground to act the fuel pump... do you think that if i add in a switched ground that i might be able to get my ECU to last longer since thats whats causing the problem?

92hatchboi

well we swapped ecu in y buddys car and still nothing. but we couldnt leave his car in the lt where it was at so we jumped the main relay and plugged it back in just to get him moving but i dont think its safe to drive the car like that.

spoon_ek9

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92hatchboi &raquo;</TD></TR><TR><TD CLASS="quote">well we swapped ecu in y buddys car and still nothing. but we couldnt leave his car in the lt where it was at so we jumped the main relay and plugged it back in just to get him moving but i dont think its safe to drive the car like that.</TD></TR></TABLE>

yea, it is not a safe way to operate a car without ecu controlling the fuel pump, in a case of an accident, ecu will not shut off your fuel supply and it might get your car on fire if the fuel line is cut.........

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fridaytech &raquo;</TD></TR><TR><TD CLASS="quote">hey you check all fuses... check 12, 24,31 and 16 all related to fuel pump operation. note ecu dosn't send sigal it switch to ground to operate main relay. if you need wiring diagram hit me up i think i can email it to you</TD></TR></TABLE>

yea, ecu send gorund(low side) or 12v(high side) to control device like fuel pump and fan, thank for clear it up, sometime "signal" is easier for noob to understand.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by OisinT &raquo;</TD></TR><TR><TD CLASS="quote">i just ran into this problem. borrow a working ecu from a friend and plug it in... should work then. Thought the same thing at first did the whole A/S/F test... was missing the fuel... then replaced the relay per my mech. friends advice and after jumping the pins and it worked. still nothing. then i pulled the code from the ecu. light was steady... Code 0 aka ecu code. so had a friend with a known working ecu come over, plug it in, and everything worked... Currently borrowin a CX ecu so i can at least drive my car while i find another P28.

fridaytech... Your saying that the ecu switches a ground to act the fuel pump... do you think that if i add in a switched ground that i might be able to get my ECU to last longer since thats whats causing the problem?</TD></TR></TABLE>

dont think adding a switched ground will help prolong the ecu. if it fails, it just fail, and it is a rare case, unless u wire something up and that device get back feed thru the ecu, then it will fry something in the ecu.

fridaytech

what are you missing at main relay...ground from ecu or power....do you have a test light or power probe..

92hatchboi

it was missing the ground from the ecu. i swapped out the ecu and it started up like a charm

fridaytech

dam well i guess you needed an ecu... oh just so you know the ground on your thermostat housing is the main ground for your ecu.. check that for any rust or build up that would hinder ground capability.