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Discussion Starter · #1 · (Edited)
I saw a YouTube video by Ali mech where he cleaned his fuel injectors by running the engine in carb cleaner. He injected the carb cleaner into the fuel rail and disabled the fuel pump. Nice little trick.

I grabbed a spare fuel rail from the wreckers and I cut the fuel line and glued in a straw for a spray can. The problem is when I pull the fuel pump fuse under the dash I realized that it disables the fuel injectors too.

is there a relay that is specifically for the fuel pump? I was thinking of disconnecting the electrical connection directly at the fuel pump under the back seat but it’s a bit hard to get to and no doubt it will be hard to even disconnect that connector.
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On my 2007 CRV, there is a fuel pump relay.
PGM-FI relay one and two.
Not sure about yours.

Try, ....
Look at the engine bay fuse box.
See if there are relays marked fuel pump.
Try taking the relay out.
If there are two then try the second one.
 

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Discussion Starter · #3 · (Edited)
On my 2007 CRV, there is a fuel pump relay.
PGM-FI relay one and two.
Not sure about yours.

Try, ....
Look at the engine bay fuse box.
See if there are relays marked fuel pump.
Try taking the relay out.
If there are two then try the second one.
Thanks!!!
I figured it would be as simple as that. I never tried to look there but I spent all the time to swap out the fuel rails lol.
I realized after the fact that when I pulled the fuse the engine dies instantly but it should run until it runs out of fuel pressure. I suppose that if I pull the relay you mentioned the car should run for a little bit and then die.
 

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Fuel injectors requires about 40 to 55 psi for it to work properly.
Carburetors only need about 4 psi.
So would assume the engine to stall at a much quicker pace than you expect.

As far as I know, the fuel pump relay should go only to the fuel pump.
So, pulling the relay out should disable only the fuel pump.

Why the urgent need to clean the fuel injectors??
Usually I just use a bottle or two of fuel injector cleaner in the gas tank
 

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Discussion Starter · #5 ·
Fuel injectors requires about 40 to 55 psi for it to work properly.
Carburetors only need about 4 psi.
So would assume the engine to stall at a much quicker pace than you expect.

As far as I know, the fuel pump relay should go only to the fuel pump.
So, pulling the relay out should disable only the fuel pump.

Why the urgent need to clean the fuel injectors??
Usually I just use a bottle or two of fuel injector cleaner in the gas tank
Maybe no need. I changed the timing belt and then had a mystery misfire that didn’t throw any codes. Turned out to be the timing needed adjustment lol go figure. It was troubleshooting that problem that made me wonder if the injectors are clogged. No real urgency. It is just a 22 year old car and the intake plenum is crazy gummed up with deposits. The throttle body is nice and clean. It’s problem one of those “if it ain’t broke don’t fix it” times. I went to all the trouble to make my nice little cleaning rail though 😭
It may get me better performance (although it drives with lots of power)
 

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Check a fuel injector tester, around $30 ebay. It has pulsating modes that mimic the ecu. You can do that spray cleaner trick with it. But it works on a single injector at a time.
 

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Discussion Starter · #7 ·
Check a fuel injector tester, around $30 ebay. It has pulsating modes that mimic the ecu. You can do that spray cleaner trick with it. But it works on a single injector at a time.
I was thinking of just hooking up a battery to the injectors and cleaning them outside the car in my cleaning rail. I can cut off the connectors from a car at the wreckers. Safer that way I guess. I’d still like to know how the fuel pump relay system works… bugs me not knowing. I looked at the circuit diagram but couldn’t figure it out from there. Maybe I’ll look again….
 

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Discussion Starter · #9 ·
The main relay is what powers the fuel pump.
But it powers the ecu. Best is to just unplug the fuel pump.
Thanks! I don’t want to be messing with the ECU.
At this point I will clean them outside the scar with a battery, or not at all. I’m also not too keen on disconnecting the fuel pump. I hate mucking about with these connectors that have been on there for 22 years and don’t want to disconnect.

thanks for the help!!!!!

I will post follow-ups of the cleaning rig (if it works).
 
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