Opps, fule, not fule. Duh


Ok...fuel pump not coming on.

Checked for voltage at pump. None.

Replaced Main Relay. No fix.

Test new main relay. Passed test.

Test main relay wire harness. Passed test. <-- says to check pump.

Check wiring between main relay and pump....can run pump from the main relay harness.

Hot-wired pump to a battery. Pump runs fine.

Plug it all together, no pumpie turn onie.

So basically, the main relay is good. All the wiring is good. The pump runs on it's own. But nothing works together.


It is possible that the wiring to the pump is damaged. It is weird. I am not getting a light at the pump end of the harness, but when I jump the relay wiring I can make the pump run (it runs poorly, but it does run).

I thought the poor running might suggest a break in the wire, but when the relay is hooked up the pump does not run at all!!! Like, NOT EVEN A LITTLE.

I then thought the poor running meant the pump might be going bad, but when I hot-wired it the thing ran great.

After the heat wave we had I thought for sure the relay was bad, but my new one did not fix the issue.

Anyone have this problem before?

 

you did pretty much what i would have done, the only thing i would have tried is to run a wire from the main relay to the pump. if its good then its probably the wire or connector.

Nick

 

well your ECU has to give the signal to the main relay to turn the pump on. is it doing that? I mean if you can run a wire from the battery to the main relay harness and that turns the pump on... and your main relay is good.... then a bad ECU is the other logical possibility. and they can go bad

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bbarbulo &raquo;</TD></TR><TR><TD CLASS="quote">well your ECU has to give the signal to the main relay to turn the pump on. is it doing that? I mean if you can run a wire from the battery to the main relay harness and that turns the pump on... and your main relay is good.... then a bad ECU is the other logical possibility. and they can go bad </TD></TR></TABLE>


Hmmm...but I did the wire harness test, which the car passed. This involved checking for power at the relay harness at different pins under ignition and cranking.....it passed these tests.

 

The Main Relay has two relays inside of it. Only one set of contacts is responsible for feeding the fuel pump with battery voltage. This set of contacts is activated by the ECU fuel pump control signal.

Aside from all the testing you've done, if you throw your meter on the fuel pump control wire, does that voltage change during the initial 2 sec prime with the key 'on' engine off?

What is involved with the wire harness test? Can you describe what you did?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">The Main Relay has two relays inside of it. Only one set of contacts is responsible for feeding the fuel pump with battery voltage. This set of contacts is activated by the ECU fuel pump control signal.

Aside from all the testing you've done, if you throw your meter on the fuel pump control wire, does that voltage change during the initial 2 sec prime with the key 'on' engine off?

What is involved with the wire harness test? Can you describe what you did?</TD></TR></TABLE>


Basically the harness test is a procedure in the service manual that walks though the main realy wire harness pins checking got power under different ignition switch positions, and includes one jump that is supposed to activate the pump....

That specific jump is the only iffy thing going on....when I jump it, the pump runs, but it runs shitty. I am not sure if this is due to a poor connection on the jump or what, but with the relay connected there is nothing goin on with the pump at all....I figure there should be some power there, at least something!


I guess I am going to go back and try to triplecheck everything....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MrHeeltoe &raquo;</TD></TR><TR><TD CLASS="quote">That specific jump is the only iffy thing going on....when I jump it, the pump runs, but it runs shitty. I am not sure if this is due to a poor connection on the jump or what, but with the relay connected there is nothing goin on with the pump at all...</TD></TR></TABLE>Check the socket that plugs into the main relay. Is that wire half pulled out from the socket? Is the metal connector thing bent up inside the socket? I like to rule out the simple stuff first & then work my way back without taking anything for granted.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">Check the socket that plugs into the main relay. Is that wire half pulled out from the socket? Is the metal connector thing bent up inside the socket? I like to rule out the simple stuff first & then work my way back without taking anything for granted.
</TD></TR></TABLE>

I wish that was it...already checked. I am going to mess with it more tonight.

 

Dammitt.....


Ok, tested the old relay, it was good. So, that for sure was not it. But I am keeping the new one anyway. They do go bad you know.

Checked continuity between the relay and the pump, and ground at the pump...all is good.

Added more grounds on the engine (at the suggestion of at least 3 people). Did nothing. As I suspected it would not, since the car ran fine on the untouched grounds I already had.

Another ***** in the chain.....I am not getting spark either.


I fear the worst. My ecu (along with my Hondata S100 and tuning) may indeed be bad. I have an associate coming with another OBD1 ecu to try it out....

 

Can you try de-pinning the fuel pump control wire and then grounding it - does that turn the fuel pump on?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">Can you try de-pinning the fuel pump control wire and then grounding it - does that turn the fuel pump on?</TD></TR></TABLE>

You mean hardwire the pump ground? I don't see the point....the ground from the pump has continuity with the chassis...

 

No, the fuel pump control wire that the ECU uses to control the relay. Depin and ground it - fuel pump turn on?

 

bad ecu. I had the same problem. there is a website that showed how you can repair the fuel circut on the ecu. maybe you can find it on google or something

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">No, the fuel pump control wire that the ECU uses to control the relay. Depin and ground it - fuel pump turn on?</TD></TR></TABLE>

Not that it matters any more...I am not getting spark either. I think the ecu is badski..

Yeah. Need a tester for my piece. Who gots a P06 MT local that wants a future favor? Socal.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MrHeeltoe &raquo;</TD></TR><TR><TD CLASS="quote">I think the ecu is badski..</TD></TR></TABLE>

Kind of sounds like it. But you can still check for fuel pump operation by grounding that wire to be sure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">No, the fuel pump control wire that the ECU uses to control the relay. Depin and ground it - fuel pump turn on?</TD></TR></TABLE>
There's no need to de-pin it, a jumper wire to ground would do nicely.

 

also check the ecu fuse thats in the engine bay

 

Well everyone, thanks for the support....

The ECU itself is bad....

ramennoodles wins a gold star.