'99 Accord Blinking Oil Light -- sanity check

Hi,
Before anyone flames me...no, I'm not taking any chances with a
blinking oil light - the car is not going to be driven until I figure
out what to do. I just want to take a shot at fixing it myself before
I get into the $70 per hour rate at the dealer. Here's the skinny:

1999 Honda Accord 4 cylinder with 116K miles. Bought used about 1K
miles ago.

I changed the oil, and put on a non-Honda oil filter (STP). Car ran
fine for about 1K miles -- now the oil light blinks intermittently. It
will blink for about a minute, then go off for 10-15 minutes, then
blink again. No matter what the driving situation. After the first
couple of times I saw this, I stopped driving the car, it's sitting in
my garage now.

I called the dealer, and the lead service guy told me that when they
see this it is always the oil sender switch. He said if it were really
a mechanical problem, the light would blink all the time.

So, I figure that for $10 (cost of switch), I'll just change it, and
I'll also switch to a Honda labeled oil filter, from the dealer.

Questions: Anyone else been through anything like this? Could the STP
oil filter have been the culprit? Does the analysis/conclusion make
sense -- that if it were really a mechanical issue, the light would
stay on all the time?

Thanks,
Randy

"Randy Brick MacKenna" > wrote in
oups.com:


>
> I called the dealer, and the lead service guy told me that when they
> see this it is always the oil sender switch. He said if it were really
> a mechanical problem, the light would blink all the time.
>
> So, I figure that for $10 (cost of switch), I'll just change it, and
> I'll also switch to a Honda labeled oil filter, from the dealer.
>
> Questions: Anyone else been through anything like this? Could the STP
> oil filter have been the culprit? Does the analysis/conclusion make
> sense -- that if it were really a mechanical issue, the light would
> stay on all the time?


On B-series engined cars, the oil pressure sender is right next to the oil
filter. If the proper filter socket is not used to remove the filter, the
strap/chain/bar/whatever can foul on the sender, cracking the connector.
The usual result of this is a non-functional pressure light.

I don't know where your sender is or how it works, but mine works opposite
to an old-fashioned hydraulic brake light switch, grounding the light if
pressure is too low. Break the connector, and ground can't be established.
Having said that, it's possible your switch is bad, and that would be easy
enough to check by wiggling the wire at the connector with the ignition on.
If the light flickers or goes off, the sender is damaged.

It is not likely that the STP fileter is the cuplrit. If it was, and if it
were the wrong filter for your application, the most likely visible result
would be that the oil light would take an extraordinarily long time to go
off on a cold start.



--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Thanks for the replies. I had to use an 18" channel-lock pliers to get
the old filter off, so there is a chance I nudged the oil sender. But,
the car ran fine for a week with no flashing light...so the
cause/effect is kind of hard to link on that point.

I guess my course of action is to replace the sender switch (less than
$10), and just to be sure, switch to a "genuine" Honda filter (probably
around $6)....if the light still comes on after that, then I guess I'm
off to the dealer (gosh I hope not!)

-Randy

Randy Brick MacKenna wrote:
> Hi,
> Before anyone flames me...no, I'm not taking any chances with a
> blinking oil light - the car is not going to be driven until I figure
> out what to do. I just want to take a shot at fixing it myself
before
> I get into the $70 per hour rate at the dealer. Here's the skinny:
>
> 1999 Honda Accord 4 cylinder with 116K miles. Bought used about 1K
> miles ago.
>
> I changed the oil, and put on a non-Honda oil filter (STP). Car ran
> fine for about 1K miles -- now the oil light blinks intermittently.
It
> will blink for about a minute, then go off for 10-15 minutes, then
> blink again. No matter what the driving situation. After the first
> couple of times I saw this, I stopped driving the car, it's sitting
in
> my garage now.
>
> I called the dealer, and the lead service guy told me that when they
> see this it is always the oil sender switch. He said if it were
really
> a mechanical problem, the light would blink all the time.
>
> So, I figure that for $10 (cost of switch), I'll just change it, and
> I'll also switch to a Honda labeled oil filter, from the dealer.
>
> Questions: Anyone else been through anything like this? Could the
STP
> oil filter have been the culprit? Does the analysis/conclusion make
> sense -- that if it were really a mechanical issue, the light would
> stay on all the time?
>
> Thanks,
> Randy

The oil pressure warning indicator is controlled by either the sending
unit switch or by the driver multiplex control unit. The driver mpx/cu
can command the indicator to flash; if it thinks there is a momentary
drop in oil pressure. The same thing would happen if the sending unit
wire was shorted to ground for a short time.

What should you do?
Check the oil pressure.
Then disconnect the sending unit wire; run the engine. If the light
starts blinking again, either the wire has a short or the mpx/cu is
faulty. Sending unit failure is rare and usually results in the oil
indicator either not coming on at all or stays on solid.

ouch...that would be bad. I'll try the disconnect check as you
suggest. The dealer seemed to say that they see this problem (blinking
light) once in awhile, and they typically end up changing the sender.

Your comments make sense, but I'm really hoping that I'm seeing a
sender that's teetering on the edge of failure.

Since there are three modes (light off, light blinking, light steady
on), doesn't that mean that the output from the sender must be analog?
Like, variable resistance based on pressure, right?

Also, to check by disconnecting, I think I'd have to ground the lead
back to the computer, correct?

Thanks,
Randy

Well...I replaced the oil sender...it was cheap & easy. The only
warning I'd give to anyone who might read this is that you have to be
very careful tightening the new unit into the back of the engine block.
The block is aluminum, and the sender is small with a pretty fine
thread pitch. You have to use a large (around 22 mm ?) socket, so
likely a 1/2" drive. Very easy to over torque and ruin the thread in
the engine block. I don't know what the torque spec is on this thing,
but I tightened it just a bit more than 'spark plug' torque.

Anyway, after a day's worth of driving it seems to have solved the
problem...hope it holds up as the solution.

BTW, the service guys at the dealer said there were no issues with
using a department store oil filter.

-Randy

This has nothing to do but in my 91 accord alot of times after I leave from
school i have the "brake light" light on in the dash, I know nothing's wrong
with my brake lights (it's doing that since I own the car), I'm just curious
this thing always light up every now and then, why!

RAT

"Randy Brick MacKenna" > wrote in message
oups.com...
> Hi,
> Before anyone flames me...no, I'm not taking any chances with a
> blinking oil light - the car is not going to be driven until I figure
> out what to do. I just want to take a shot at fixing it myself before
> I get into the $70 per hour rate at the dealer. Here's the skinny:
>
> 1999 Honda Accord 4 cylinder with 116K miles. Bought used about 1K
> miles ago.
>
> I changed the oil, and put on a non-Honda oil filter (STP). Car ran
> fine for about 1K miles -- now the oil light blinks intermittently. It
> will blink for about a minute, then go off for 10-15 minutes, then
> blink again. No matter what the driving situation. After the first
> couple of times I saw this, I stopped driving the car, it's sitting in
> my garage now.
>
> I called the dealer, and the lead service guy told me that when they
> see this it is always the oil sender switch. He said if it were really
> a mechanical problem, the light would blink all the time.
>
> So, I figure that for $10 (cost of switch), I'll just change it, and
> I'll also switch to a Honda labeled oil filter, from the dealer.
>
> Questions: Anyone else been through anything like this? Could the STP
> oil filter have been the culprit? Does the analysis/conclusion make
> sense -- that if it were really a mechanical issue, the light would
> stay on all the time?
>
> Thanks,
> Randy
>

"Rattus The RAT" > wrote in
message m...
> This has nothing to do but in my 91 accord alot of times after I leave
> from school i have the "brake light" light on in the dash, I know
> nothing's wrong with my brake lights (it's doing that since I own the
> car), I'm just curious this thing always light up every now and then, why!

Leaky tail lights, and subsequent corrosion on the main connector.


> "Randy Brick MacKenna" > wrote in message
> oups.com...
>> Hi,
>> Before anyone flames me...no, I'm not taking any chances with a
>> blinking oil light - the car is not going to be driven until I figure
>> out what to do. I just want to take a shot at fixing it myself before
>> I get into the $70 per hour rate at the dealer. Here's the skinny:
>>
>> 1999 Honda Accord 4 cylinder with 116K miles. Bought used about 1K
>> miles ago.
>>
>> I changed the oil, and put on a non-Honda oil filter (STP). Car ran
>> fine for about 1K miles -- now the oil light blinks intermittently. It
>> will blink for about a minute, then go off for 10-15 minutes, then
>> blink again. No matter what the driving situation. After the first
>> couple of times I saw this, I stopped driving the car, it's sitting in
>> my garage now.
>>
>> I called the dealer, and the lead service guy told me that when they
>> see this it is always the oil sender switch. He said if it were really
>> a mechanical problem, the light would blink all the time.
>>
>> So, I figure that for $10 (cost of switch), I'll just change it, and
>> I'll also switch to a Honda labeled oil filter, from the dealer.
>>
>> Questions: Anyone else been through anything like this? Could the STP
>> oil filter have been the culprit? Does the analysis/conclusion make
>> sense -- that if it were really a mechanical issue, the light would
>> stay on all the time?
>>
>> Thanks,
>> Randy
>>
>
>