ok, heres what happened, i was driving on the highway, i turned the ignition off and then back on, but the car didnt start back up. the fuel pump would not turn on. so i put another ecu in it and drive back home. well the next day i try the ecu to try to see whats wrong with it, but the car starts this time. WTF so i drive all day long with the ecu turning the car off and then starting it back up numerous times. and then for some reason it doesnt start again. WTF!!! so i put my spare ecu back in, and drive it back home.

So i have narrowed this problem down to the ecu, but what i cant figure out is why the ecu worked the second time? im guessing i fried a resistor, or something. does anyone know what part of the ecu turns on the fuel pump, or main relay??? got any pictures?


BTW... i put in the bad ecu today, and it wouldnt work, so i popped the hood to see if i had voltage at any of the sensors. i touched one of the yel/blk wires with my test light, and as soon as i did, the fuel pump kicked on. ????? cant figure why it did that.........


BTW nothing in the ecu looks fried, it didnt smell bad either


Modified by hybridb18 at 12:42 AM 4/5/2004

 

could it be your main relay ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtekstorm &raquo;</TD></TR><TR><TD CLASS="quote">could it be your main relay ?</TD></TR></TABLE>
Sounds like it could be to me. ECUs rarely cause intermittent problems.

 

i doubt its the main relay, the minute i replaced the ecu with another one, it ran perfect. and has ever since.

btw i put in the bad ecu today, and it wouldnt work, so i popped the hood to see if i had voltage at any of the sensors. i touched one of the yel/blk wires with my test light, and as soon as i did, the fuel pump kicked on. ????? cant figure why it did that.........

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridb18 &raquo;</TD></TR><TR><TD CLASS="quote">... i put in the bad ecu today, and it wouldnt work, so i popped the hood to see if i had voltage at any of the sensors. i touched one of the yel/blk wires with my test light, and as soon as i did, the fuel pump kicked on. ????? cant figure why it did that.........</TD></TR></TABLE>Which sensor? Which wire?? Once you answer that, hope someone with a wiring drawing for your car/year can post something...

The ECU runs the pump by completing the ground side of a circuit to energize the main relay. Maybe you completed that circuit thru the test light. That's one reason why a DMM is more useful (safer?) than a test light...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">Which sensor? Which wire?? Once you answer that, hope someone with a wiring drawing for your car/year can post something...

The ECU runs the pump by completing the ground side of a circuit to energize the main relay. Maybe you completed that circuit thru the test light. That's one reason why a DMM is more useful (safer?) than a test light...
</TD></TR></TABLE>

well it was one of the yel/blk injector wires. i dont need a wiring diagram, have plenty of those.
Oh yea, i tried to use the testlight on the yel/blk wire again, but it didnt work this time

What wires off the ecu go to the Main Relay??? And which wire is the Ground??? its a p28 BTW

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridb18 &raquo;</TD></TR><TR><TD CLASS="quote">well it was one of the yel/blk injector wires. i dont need a wiring diagram, have plenty of those.</TD></TR></TABLE>That'll tell you which wire is which... So it's got the answer to your original question.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridb18 &raquo;</TD></TR><TR><TD CLASS="quote">Oh yea, i tried to use the testlight on the yel/blk wire again, but it didnt work this time</TD></TR></TABLE>The +12v powered wire to each injector comes from the main relay, as you can see on your wiring diagrams. If the main relay isn't always closing, then sometimes you don't get power there.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridb18 &raquo;</TD></TR><TR><TD CLASS="quote">What wires off the ecu go to the Main Relay??? And which wire is the Ground??? its a p28 BTW</TD></TR></TABLE>The 'main' relay includes a couple relays, one for the fuel pump. On my Integra the ECU energizes that relay by closing A-7 to ground.

The other main relay wires (A-25 & B-1) are supplying power TO the ECU from the main relay. But maybe it's different in your p28?