I have I fuel leak. I think it's the PD because of where it's leaking from (down the back of the block), but I can't tell for sure. Last time I started it, it ran for about 5 minutes, then started leaking. I couldn't find where it was coming from, so I turned it off. By then, it was warm. I started it again, and it didn't leak. I let it run and even revved it a few times up to 5-6k.

Later, I jumped the fuel pump, but i didn't see any leak, so that didn't help. Now I have taken off the intake/tb and vdi stuff, etc. So all the fuel lines are visible. (The secondary fuel rail is also disconnected.)

My question for now is can I jump the fuel pump as is? Do I need to somehow plug the line going to the secondary rail, or can I reconnect it (leaving the injectors hanging) and then jump the fuel pump to find the leak?

Needless to say, I'm a bit confused about what I should do at this point, so any advice is welcome.

 

im betting its not your PD.

im betting its a pinched injector o-ring.

you might as well buy a new PD $150 give or take(a banjo bolt does good too)
and change all injector o-rings.

tighten down all connections on your fuel lines.


you can jumper the fuel pump with the LIM/UIM off.

make sure when working anything fuel or electrical related to have a fire extinguisher nearby. better safe than sorry

 

why not? just curious.

the S5 PD is 226 from mazdatrix.

I'll replace the o-rings, then. What about the grommets? Should I replace those too? (not sure quite what they are)

 

use a match.it'll pinpoint it right away.

anyway,also check the hose for the return line.hell,might as well replace it.see if that stops the leak.

 

You just pull the dynamic chamber off and then jumper the fuel pump check connector. Turn the key to ON and look at all the fuel componets including the PD and fuel injectors. Let the key stay to ON for ten to fifteen minutes.

Turning the engine on and reving is not helpful. Engine off means no vacuum to the FPR so the fuel pressure will be at its highest with the engine OFF.

 

what kind of clamps should I use for the hoses?
last time I changed a hose, i put a screw type clamp (2nd pic) in place of the original spring type (1st pic), but I heard that the fuel lines expand and contract, causing the clamp to loosen over time, so I may need to put on a different type of clamp. I'm not sure

and I need 4 o-rings correct?

 

Really? Won't that build up pressure and damage the pump? There won't be any gas coming out the injectors (or anywhere else).

I know it's not helpful. My point was just that after it warmed up it didn't leak. I thought the higher fuel flow and fuel pressure might cause it it to start leaking again, but it didn't. A few weeks later, I started it again just before I took everything apart, and it started leaking after a minute or two.

 

If you have the fuel system sealed you can pinch off the fuel return line. That would put the system under the highest possible pressure( most of the time i do this with engine off). I would only do this for a few mins since you can't tell the condition of your fuel pump.

 

No. The FPR regulates the pressure in the fuel rail. Anything over approx 39psi in the scenario I described will be bled off back to the fuel tank. IF you start the engine, then vacuum is put on the FPR and the pressure in the rail will fall to approx 28-32psi.

In other words fuel is always being cycled back to the fuel tank anytime the pump is running. It's the FPR that determines the pressure in the rail, and it's the FPR that bleeds off excess pressure back to the tank. Fuel is Always flowing back to the tank. It Never dead heads in the rail.

 

ok, I ran the fuel pump for a few minutes and saw no sign of any leaking. I've taken the injectors out to send them for cleaning and to have the o-rings and grommets replaced. (https://www.rx7club.com/group-buy-center-69/%7E%2A%7Efuel-injector-cleaning-special-rx7club-members%7E%2A%7E-700925/)
I'm not sure what else to do.

 

Any ideas why it leaks with the engine running, but not with just the fuel pump on?

 

I just looked at my car again and realized that I don't have the spacer that goes between the primary rail and the center housing. Would that cause a leak

Also, when I pulled the injectors, the lower grommets were (and are) still attached to the secondaries, but not the primaries. Does this mean the primary grommets were loose or something?

sorry to keep posting, but I can't edit my earlier posts.

 

yes you need that plastic spacer. If you don't have it the injectors will leak. Also make sure you don't pinch the injectors o ring when you are reinstalling them.

 

Would the lack of that spacer be the reason why it leaks when the engine is running (injectors operating), but not just the fuel pump (injectors closed)?

 

yup, er- wait...... what?

 

My car was leaking gas from somewhere under the intake manifold while the engine was running. I took off the manifold(s?) so I could see the primary rail and the pd. With the secondary rail/injectors just hanging loose (not connected to the manifold), I jumped the fuel pump check thing and ran the fuel pump for over five minutes and saw no leak at all.

When engine is on and idling or revving, the injectors are working, but when just running the fuel pump, the injectors aren't spraying any fuel, so I assume this means the leak is where the primary injectors fit onto the block. (I know it's not the secondaries because a leak there would have been obvious before taking things apart.)

 

Well it's fixed, so I thought I should post in case someone finds this thread in future search and wonders what happened.

I'm not sure exactly what the problem was. I suspect it was the missing injector spacer because nothing leaked when I just ran the fuel pump. I also replaced two fuel lines (putting two clamps at each end), and tightened the clamps on the newer line that I didn't replace.

The leak could have been from a bad hose, loose clamp, the missing spacer, or a combination of those things, but the point is it's fixed and seems to be fine (for now ).