92 Accord fuel pump runs after engine turned off

Hello,
The fuel pump in my 92 Accord LX (auto trans) runs for a while after
driving and key is removed from ignition. It starts off running
continuously, then cycles off and on with the on times decreasing and
off times increasing until it finally stops after several minutes.

What the heck is going on? Relay problem? Sensor problem? Gas cap
problem?

Thx!

 

The fan on my accord does exactly this as you describe, check and see if it
is the fan. If it is indeed the fuel pump, than I am stumped.

 

I would suspect a leaky injector.

mike hunt

 

The only way a leaky fuel injector would cause that symptom is if there
is a control loop that actively maintains fuel pressure when the
ignition is off. I am not aware of any car where this is the case.
Perhaps you have some references on this?

 

If your fuel pump is running then it is a stuck relay as opposed to leaky
injector as posted previous. The drop in fuel rail pressure caused by a
leaky fuel injector would not cause a pump to operate at all with the key
off. If by some paranormal chance that the fuel pump was wired up to
maintain fuel pressure at all times it would not take more that a couple
seconds to do so. If an injector was leaking that bad then you wouldn't be
able to start your engine due to hydraulic lock of the piston in the
cylinder.

I have seen water injested into an engine which caused hydraulic lockup and
it through a rod through the side of the block. Little side note

CaptainKrunch

 

Consider the source....

 

(Sigh)...a leaky injector would not create that situation...fuel pumps wont
run in *any* car after the ignition is turned off.

It is indeed a relay problem...and ignore this dolt in everything he
says...he pulls shit out of his ass, and has no real car experience
whatsoever. He has also been caught lying on *many* occasions.

Good luck.

--
'03 S2000
'94 Accord

It's just about going fast...that's all...

http://home.insight.rr.com/cgreen/

 

OK; would this be the "main relay" (which I understand controls the
PGM FI), or is there a separate fuel pump relay? And if so, do you
know where it is? Thx!

 

Indeed a stuck relay is another area to check. If you believe
turning the key to the off position instantly cuts all power to
the fuel system, how then would the relay still be powered and
the pump still be running? Since the fuel loop system is powered
through the F/A ratio process controller. If the relay was
burned in the on position then the pump would stop as well when
the key is turned to the off position, if not it would be
constantly running. Because it is a complicated system beyond the
understanding of the overage owner I would have suggest he have
the vehicle connected to a system analyzed and have a technician
determine the reason for the fault. Doing that however brings a
bunch of crap about how we can fix our own
cars why pay a diagnostic fee. That is all will say on the
subject


mike hunt

 

I thought you suspected a (LOL) leaking injector?

Its *NOT* "powered"...its stuck!

Only an idiot wouldn't know the difference...sheesh...

(Yawn) No its not. F/A ratio is determined by injector pulse widths. The
fuel "loop" system is of very basic mechanical premise.

Yet again, you talk out your ass, and prove, yet again, you know nothing.

Again wrong.

Its actually a very basic system. And anybody who wanted to take 30 minutes
could understand very easily.

It is complicated (obviously) beyond the understanding of you maybe.

Here we go...

Take some basic english classes, will ya Mikey?

Good...no more lies and crap pulled from your ass.

--
'03 S2000
'94 Accord

It's just about going fast...that's all...

http://home.insight.rr.com/cgreen/

 

The Ford trucks seemed to like doing this. Obviously it was a stuck relay.
Took a few minutes to fix on those. The thing is that these fuel pumps
relied on fuel going through them to cool them down. As is my understanding
of it. And if they are running all the time without any flow then they are
not getting any fuel from the return line and the pump would wear out
prematurely if not corrected soon. It can also cause a battery to drain.

CaptainKrunch

 

What year of Ford truck was this?

Any post 1980 system had a pressure relief valve in the rack, that would
release when a certain head pressure was reach by the pump. This overflow
was routed back thru the return line, into the tank.

Any post 1990 system had a end-of-line pressure regulator, that acted in the
same way...routing excess fuel back to the tank.

In either scenario, the pump was never "dead-heading", thus, there was
always "flow" thru the pump.

You are correct tho, in that the fuel flow is the coolant for a fuel
pump...it is also the lubrication as well.

I did replace quite a few Ford in-the-tank fuel pumps in the 80s. It seems
the Ford pumps were much more sensitive about the needed lubrication...it
was common to burn up a Ford pump by simply running out of fuel.

Take care.

--
'03 S2000
'94 Accord

It's just about going fast...that's all...

http://home.insight.rr.com/cgreen/

 

Again, only in your small world does the microprocessor not
control the F/A ratio and the fuel loop. Just what does control
those pulses in your small world anyway, sun rays? Where does
the power come from, that you say goes through
that burned 'stuck' relay, if the power goes off with the key?
Explain to us again how a master technician like you gains
leverage on a breaker bar by using a pipe. Keep replying, I
will pass them to on to our tech stations, they love to laugh
at your postings. LOL



mike hunt

 

I hope you're kidding.

 

Again, only in your small world does the microprocessor not

The micro controller regulates the air/fuel ratio but it does not
regulate the fuel pressure. Fuel pressure is regulated with a mechanical
pressure regulator, and the fuel pump is running continuously when the
engine is running.

If the relay contacts get power from the battery and the relay coil is
powered through the ignition switch, then a stuck relay could cause the
fuel pump to run when the ignition is off. Is the '82 Accord wired this
way? I don't know.

 

The system is probably similar to my '94 GS-R. When functioning
properly, the pump will run continuously as long as the engine is
running (and for two seconds whenever the engine is cranked.)
Pressure is controlled by a mechanical regulator that releases fuel
back to the tank. A leaky injector will not cause the pump to run
any time it would not ordinarily be running.

A "stuck" relay shouldn't cause the pump to run with the ignition off.
The actual power for the pump comes from the ignition switch so even
if the relay switches are on, that circuit is not energized. However,
battery voltage is present within the relay so an internal fault could
possibly send voltage to the pump, although this would seem like an
atypical failure mode.

Any chance that someone (alarm installer?) did any rewiring on this
car. Even if the wiring from this job may have worked for a while, it
is likely more prone to failures (shorts) than is the factory wiring.

Contrary to Mike Hunt's hand waving, this problem should be relatively
easy to solve with a VOM if you have a service manual and a little bit
of electrical aptitude. There is nothing high tech that could be
causing this problem.

 

The main relay controls power to the PGM-FI and the fuel pump.

 

Hi Joe, my 92 Accord 5 sp does the same thing. I have a main relay that I
need to replace in my 91 Accord and was going to try it in my 92 and see if
that fixes the problem, but haven't had time. I hope to get time after the
first of the year. BTW, this FP problem is there about 90% of the time and
back in late NOV it was quiet while at the dealer for an oil change. <sigh>
If you find out what the problem is, please post back.

 

Your kidding me I hope.

The CPU controls the injector pulse widths, but the "fuel loop" is
mechanical, aside from a relay turning on...or off the fuel pump.

Wow...you're a piece of work...

When two contact "fuse" together from arcing, they are...now read real slow
here Mikey..."stuck" together. When the coil of the relay is powered off,
the "stuck" contacts continue to supply power to the device.

Come on...even you cant be this stupid.

I'm not giving any physic lessons to double-digit IQ people today.

Says more about you and your shop guys, than you can even fathom...


--
'03 S2000
'94 Accord

It's just about going fast...that's all...

http://home.insight.rr.com/cgreen/

 

I agree that a "stuck" relay shouldn't cause the pump to
run unless an internal fault inside the pump, or elsewhere.
On the 92 Accord, the relay contacts get power from
the ignition switch. The `92 Helm service manual says
the same. Here, take a closer look at the Accord's main
relay and fuel pump circuit I found:

http://techauto.tripod.com/diatest1.gif

I think:
1. there's a short.
2. the OP might need to remove the main relay and check
the 7-pins for voltages. Based on the picture above, he should
see 12V at only one terminal. If he finds more than one, the
relay is most likely fine. Why? Because the short is most likely
before or after the main relay.
Tib