I noticed the other day when I pressure tested my fuel system by grounding out the fuel pump at the diagnostics box that there was a small hiss comming out of the LIM. I think this may be a leaky injector...

So I guess my question is, when you do the fuel pressure test, should it sound like an injector is running? Like a hissing sound comming out of the LIM runners.

 

What your pobably hearing is the fuel passing through the pressure regulator. If the injector was leaking that bad, you'd be flood almost instantly. When injector leak it's usually just a drip.

 

I always only leave the fuel pump grounded for like 5 seconds cause im scared I will flood it. Everytime I go to start it after I do that too it seems to be slightly flooded. How long would it make that noise if it was the FPR?

 

"Leaking Injector"?.... Hmmn... I hope you have a pair of fire extinguishers ready just encase of something tragic happening........

Dwayne

 

Sam, when I did the fuel leakage test, I unbolted my fuel rails from the car so that it was all sitting above the engine block.

As for sounds - mine was silent.

Dave

 

Thats a good idea. Next time Im in there, Ill definetly do that. Good way to forsure check them out.

""Leaking Injector"?.... Hmmn... I hope you have a pair of fire extinguishers ready just encase of something tragic happening........

Dwayne"

Believe me, with two engine fires already I have multiple fire extinguishers on hand!

 

When the fuel pump is running there is fuel running through the rails and the regulator back to the tank, the regulator acts as a restrictor maintaining the proper pressure in the rails. It's not loud, but there is a hissing sound. Why dgeesaman's was silent I don't know.

If your injectors have not been serviced in the last 60k or so they could be dripping.

 

Haha, oh my god. Now I feel like a complete dumbass. I completely forgot about the fuel return. Sweet. Thanks. Thats probably what the hissing sound is.

As far as cleaned injectors....Yea, the car has 150k on it and I dont know if they have ever been cleaned...Let alone in the past 60k!

 

when my fuel inj's were leaking, my orings were bad so fuel would come out from up top and just sit on top of my rotor housing, it was an explosion waiting to happen but thank god it didnt. the reason why i knew there was something wrong was because i would have a heavy fuel smell even in the cockpit, it was very unusual and strong. and after a hard run you can hear sizzleing if u listen closely. well my buddy aleem troubleshooted it, hes a guru. message him on forums if ur lucky u can get a hold of him "trini"

 

Haha, its not a leak like that. Im talkin leaky injector into the rotor housing.

 

To test for a leaky injector,

1. Key on the engine to pressure up the rail.
2. Observe key on pressure.
3. Turn off key.
4. Observe how long fuel system holds pressure.

Note: If pressure bleeds off fast, say in 5 minutes, the injectors need to be cleaned. If the system holds pressure longer than 15 minutes then probably not.

Joe Geiman
Gasoline Alley Fuel Injection
Speedway, In

www.lindertech.com