1999 v70 fuel pump relay after capacitor replacement

voom8 · Post by **voom8** » 13 Apr 2015, 17:40

My car was not starting and I traced it to the fuel pump safety relay.
So I found a thread that instructed on replacing the capacitors in the fuel pump safety relay.
Which I did. I double checked what I did compared to the instruction and double checked the solder
connections.

The car now runs and does not stall.

But now I noticed that the fuel pump still runs after I shut off the car "OFF position"
until the main relay clicks off.

Also, when I put the car in the "on" position but with no start, the fuel pump comes on,
but appears to stay on indefintley until I shut the car off

Also, if I stall the car out and the key remains in the "on" position...
the fuel pump appears to stay on indefintley.

What is the correct behavior for the fuel pump safety relay?
Is it only for accidents?

Post by **northernlights** » 13 Apr 2015, 17:57

Uh oh. That doesn't sound right.

When you replaced the capacitors, is it possible that they are a different size, different capacitance? I'm wondering if one is large enough to hold enough charge to keep the relay powered for a while even after key-off.

Also, some capacitors are polarized, i.e. the have a + and -. Any idea if yours were marked as such? Off the top of my head I think only the electrolytic caps that look like cylinders are polarized, not the flat disc type.

voom8 · Post by **voom8** » 13 Apr 2015, 18:01

Hi!

Yes 100uF and 22uF with the negative side facing away from the relay base (positive side facing down)
They are both rated at 25V

I will double check tonight.

Need to get the car inspected... and the computer has a code from when I used a paper clip!

Perhaps I should clear the computer codes and see if it makes a difference.

Post by **Ozark Lee** » 13 Apr 2015, 20:17

Resetting the codes will likely hose you on the readiness monitors if your inspection is that quick. I think you can get past inspection without all of them set but that is beyond my expertise - after the state legislature figured out that vehicle inspections were a license to steal they simply did away with them here.

...Lee

voom8 · Post by **voom8** » 13 Apr 2015, 21:02

Okay... I have to admit it... even though I was being careful
I put one of them in backwards! The 22uF was in backwards...

I'll try again tomorrow... since I have a new cap in there.

speaking of inspection... here in MA inspection is very difficult for older cars...
You can fail for safety or emissions.

A Safety as a reject sticker is a moving violation if you get pulled over
Emissions as a reject sticker is a 30 day to get fixed and then it's a moving violation.
On top of that, they have an Excise tax that comes in the mail every year.

Don't get me started on this state...
The pot holes are nice and big... and the driving is....

voom8 · Post by **voom8** » 13 Apr 2015, 21:04

so the idea is is to get it inspected and to pass safety...
and then they will reject it because the computer isn't ready...
and I have 30 days until the computer finishes it's testing...

They won't retest safety at that point.

(at least this is my experience)

Post by **cn90** » 14 Apr 2015, 07:04

Get some fuel relays at junk yard for cheap.
Make sure you build a jumper wire (with proper spade connections) for emergency, in case you need to jump 15 and 87 to get home.