Testing Injectors for Leaks

I replaced the injectors in my 3.4L Tacoma, put it all back together, started it up, and found a fuel leak at the rear of the passenger-side fuel rail. So now I have torn it back down and installed new washers in that fuel rail.

I don't want to do all this work a third time. I'm thinking about leaving the injectors and the coil packs disconnected and then reconnecting the battery and cranking the engine to see if the injector rails leak. Thought I check here first though...

 

I advise against it. Without the pressure of the rail being bolted you're going to leak fuel from everywhere and possibly launch your injectors out of the rail itself

 

Ideally you leave the rail attached to the plenum and lift the plenum out.

Also you can simply just cycle the key and inspect through the spark plug holes.

 

I recently tested my new injectors and rail off the engine. I connected the rail to another car that has a fuel pump that runs as soon as you turn on the ignition without attempting to start the car.

Its a lot of work using this approach and requires a spare fuel line that can be used to drive the test. It can be done though.

https://www.tacomaworld.com/threads...st-gen-edition.138573/page-9105#post-20775544

 

What I meant was -> the rails are bolted and torqued, and the banjo bolts are torqued. The spark plugs are in and the coil packs are not connected. I am ready to put the lower plenum back on. I don't need to test the injectors, I just need to double-check that the banjo bolts won't leak.

With that in mind, I think I should be able to crank the engine without any problems. The fuel pump will operate and fill the rails. Hopefully this is a bit clearer... so what do you think?

 

10-4. My bad, I thought you were talking about the O-ring on the top of the injectors and my brain glitched imagining a loose fuel rail with injectors pushed into it just hanging out in space and then applying 40psi of fuel pressure behind it lol


Yes, I would trust the setup you've got described to test for leaks at the banjos no prob

 

Just don't flood the engine...obviously.

As an alternative method... there is a wire under the driver kick plate you can tap into to toggle the fuel pump. That would test all but the injector opening/closing.


Edit: Also, PLEASE make sure your coil packs are disconnected. The last thing you want is a stray spark igniting fumes.

 

Woooo buddy, that reminds me of a time a fellow shop guy lit a trash can on fire with sparks from a grinder because it was full of rags used to wipe up brakekleen

OP mentioned taking coilpak plugs off but you can never have enough safety when it comes to gasoline

 

I speak from experience. :/

 

If you have all new banjo bolt washers and torqued to spec, you should be fine. I didn't have any problems.

 

@CS_AR
How did you torque those banjo bolts? I found it pretty tough to get the rear harness shield back far enough to allow space for a torque wrench. (And what a torque wrench - a real piece of crap straight outta China.)

So I ran my test - no leaks. Put everything back together, drove the truck a few miles. No more CEL, no more rough idle. I'll keep an eye on it the rest of this week. Then it's back to the mountains for this puppy .

 

Last week I threw out the Harbor Freight 1/2 drive torque wrench and bought one from NAPA. Seems to be more predictable. I couldn't trust the HF model. Though I have a big 3/4 drive torque wrench that I bought at HF 10 years ago that has been very good.

I actually had the wiring harness loose and back out of the way for the main fuel line. I replaced the fuel line at the same time.

I think using a crows foot with a torque wrench would be the way to go without working room.

Have a good mountain trip! Enjoy!

 

I used a crow's foot on all three banjo bolts. It was doable, but just barely, on the front, but the first time around I just couldn't get the rear harness cover back far enough to get the wrench straight on the rear passenger bolt. The torque wrench never clicked as I tightened the bolt and I ended up by rounding it off. I got a replacement wrench at O'Reilly's. When I finished and started the engine, that banjo bolt leaked and I had to buy a new bolt along with six new sealing washers.

The second time around I started out by torquing that bolt first, and I was successful. Next I torqued one of the two front bolts but when I tried to torque the other, the replacement torque wrench wouldn't click. Again.

To make matters worse, the wrench somehow flew off the bolt and came to rest on the skid plate, so I had to stop, remove the skid plate, retrieve the torque wrench, and put the skid plate back on.. Put everything back together and resumed working.

Then like a fool I let the throttle cable standoff slip through my butterfingers and it too went down to the skid plate. Again, remove the skid plate, retrieve the standoff, continue working.

The name of the torque wrench is "Power Torque" model 3004. It is supposed to handle torques up to 900 inch pounds, but it just isn't long enough to pull that much torque. When I read the reviews, most of them said that wrench was crap. I'll wait a week or so and then return it for a refund of my $22.

Thanks to everyone who replied to my original post!

 

I'm with ya bro. I've had many a day like that. And then something works out.