Sanity check - pull injector relay to prime oil?

apsilon · Postby **apsilon** » Wed May 20, 2020 2:39 pm

Just want a quick sanity check that I'm remembering correctly. It's been a few months since I started the car and wanted to confirm I'm right in recalling I can pull the injector relay and the pump will also not start? Want to crank the car a bit without starting to get some oil circulated first and just want to make sure I'm not going to flood the cylinders or so something else silly.

StuwieP · Postby **StuwieP** » Wed May 20, 2020 2:50 pm

I don't think pulling injector fuse or relay will stop the pump from priming?

But if the injectors aren't, well, injecting, then it won't matter one way or the other whether the pump is active?

RS2000 · Postby **RS2000** » Wed May 20, 2020 2:56 pm

Why not disconnect the fuel pump relay?

apsilon · Postby **apsilon** » Wed May 20, 2020 4:42 pm

Where's the fuel pump relay?

For some reason I have this memory that the injector relay also does the fuel pump which is why I was asking. There's no pump relay or fuse in the engine bay block or fuses and relays.

You're probably right that if the injectors aren't operating the pump doesn't matter. That didn't occur to me either though it's obvious. Trying to do a heap of odd jobs today so was rushing around with several things on the go at once. That's my excuse anyway.

So I pulled the injector relay, cranked it for a bit several times then replaced and started. Didn't hear anything unpleasant so hopefully all good. Battery might need a top up charge from the cranking and not having been dríven. I really should siphon the fuel out and use it in the other car and put fresh in the MX-5. Think I have a low pressure inline pump sitting around somewhere, might turn that into a siphon. Not sure I have enough fuel hose around though.

Red_Bullet · Postby **Red_Bullet** » Wed May 20, 2020 6:29 pm

I don't start mine for months on end, charged battery, and reasonably fresh fuel and off it goes. Oil pressure gets right up there right away. Are you over thinking it?

SuperMazdaKart · Postby **SuperMazdaKart** » Wed May 20, 2020 6:50 pm

As far as syphoning fuel out of the fuel tank, another trick you could use is to use the fuel pump in the car to do the syphoning.

*(optional step) get access to top of fuel pump, start car then disconnect wiring plug to fuel pump, wait till engine stalls from fuel starvation, ignition key to off,

*disconnect fuel line hose going to fuel injector rail (may or may not spill fuel depending on previous step) & connect to another hose going to a jerry can,
*open diagnostics box, bridge GND (ground) & FP (fuel pump) together with a metal paper clip (preferably with insulated plastic except at the ends),
*turn ignition to ON, without starting,
*wait till fuel tank is emptied & turn ignition off
*reconnect original fuel hose line to injector rail,

*(optional step) connect automatic battery trickle charger.

Does your car have working airconditioning? If it does I'd more recommend running the engine with aircon on for 20 minutes each fortnight. Otherwise you risk compressor gas seals drying up & then breaking causing leaks. An expensive avoidable repair bill. You can also use a fuel saver supplement to make fuel last longer in storage. Used a lot for farm industrial equipment.

RS2000 · Postby **RS2000** » Wed May 20, 2020 7:00 pm

apsilon wrote:Where's the fuel pump relay?

Under the dash on an NB8A

StuwieP · Postby **StuwieP** » Wed May 20, 2020 7:32 pm

RS2000 wrote:
apsilon wrote:Where's the fuel pump relay?

Under the dash on an NB8A

Pretty sure it's under there from NA6 all the way to the end of the NB line?

It's green in early models and I think switched to black partway through its life in the NB.

apsilon · Postby **apsilon** » Wed May 20, 2020 7:40 pm

Red_Bullet wrote:I don't start mine for months on end, charged battery, and reasonably fresh fuel and off it goes. Oil pressure gets right up there right away. Are you over thinking it?

Yeah probably but for an extra 2min of work to pull, crank and replace it can't hurt.

SuperMazdaKart wrote:As far as syphoning fuel out of the fuel tank, another trick you could use is to use the fuel pump in the car to do the syphoning.

Yeah have though of that but it's more work than just pushing a line down the filler.
No AC either so that's not a concern.

RS2000 wrote:Under the dash on an NB8A

I'll have to have a look for that but pulling the injector on from the engine bay is a lot more convenient than crawling under the dash. I'll have to try and find some time to have a poke around with the multi meter and see if pulling one, or the injector fuse, cuts the other.

Thanks for all the advice everyone.

ralt · Postby **ralt** » Wed May 20, 2020 8:14 pm

Hi.
I do not get this post. Obviously the poster has little automotive knowledge. The time taken for the engine to start is tiny and if it does not start the oil pump is by way of the starter motor circulating oil around the engine. You are overthinking something which is not going to adversley affect the engine.

bruce · Postby **bruce** » Wed May 20, 2020 8:21 pm

Yup, overthinking it.
If the wear at start-up worries you, can you imagine all the bad things which have already happened to your car when not dríven...

93_Clubman · Postby **93_Clubman** » Thu May 21, 2020 12:16 am

apsilon wrote:
RS2000 wrote:Under the dash on an NB8A

I'll have to have a look for that

Just under the driver side dash, not too far toward the firewall, & IIRC just to the right of the steering column when seated.

manga_blue · Postby **manga_blue** » Thu May 21, 2020 9:12 am

Haven't done that for years but my technique for starting cars that had sat for ages was to remove all the spark plugs, squirt a small shot of oil into each cylinder, let in sit for awhile, turn it over without the plugs for about 20 secs, then replace the plugs and start it. Dry bores were the main risk.