Have any of you guys ever had leaking injectors? If so, did it cause your car to not start once in a while due to the leaking injectors flooding the engine?

Tim

 

The best way to test for leaky injectors is hookup a pressure guage to the shrader valve. If after about 20 minutes or so, your pressure has dropped dramatically, then 99% sure you have leaky injector/injectors.

 

When I shut my car off the fuel pressure drops from about 48 to 30, then stays at 30. Is this OK?

 

That's not a good way to check if your injectors are leaking because the fuel just leaks back past the regulator through the return lines. The best way to tell is the physically remove the fuel rails with the injectors and fuel lines attached, prime the pump, and watch for leaks. Of course you could clamp the return line and then prime the pump, then watch your guage.

 

I agree with Rezinn. I had leaky injectors and I confirmed that by pulling the plenum and runners off, popping the fuel rail up so that the injectors are clear of the manifold (use of a small wooded block to support the rail assembly is helpful), then put paper under each injector and prime the pump (turn the key on - DO NOT START!). I had gas instantly on 7 of 8 injectors, with a couple actually pooling on the paper - not good!!

The symptoms... really hard starting after the car sat for more than 10 minutes (except for the very first cold start of the day - always started first crank). The gas leaks down into the sylinders and floods them - if I restarted within a few minutes (like when gassing up) it would start OK, but if it sat for any length of time it had to crank and crank - sometimes I would floor it to clear the flooded condition. Had the injectors rebuilt and it starts good all the time.

Good luck!

Eric

 

Some people need to actually see the fuel leaking...I trust the guage

On many different EFI Multi-point systems, simply using a fuel pressure guage on the schrader valve on the rail will be fine...

In fact, maintaining close to full pressure after the key is turned to the "off" position for a few minutes after will show the problem. If you don't really drop any pressure after 20 minutes, leaky injectors are likely not your problem.

Case in point: on my car with stock FPR and stock injectors, the reading was 43 psi with the rail pressurized. Then turn the key off and the readings dropped dramatically within 10 seconds. It doesn't leak backwards in the system, the injectors were leaking. Simple as that.

HTH,

 

Another easy way to tell...

Take off the TB ducting. Turn key on to prime pump. Go out and open throttle body to WOT and listen carefully. You will hear a mini Niagra Falls sound. If so, at least one injector is leaking, so you might as well buy a whole set.

 

Use the pressure gauge to test it, but be prepaired with 2 vice-grips. Have someone turn the key on, and when the pump stops, clamp both the main line and return line. By doing this, you eliminate the possiblity of it being the regulator or pump. I tried this on my car, without using the vice-grips, I loose ALL pressure in a matter of 5 secs. Clamp off the lines, it holds a steady 43psi. By clamping off the lines, the fuel has nowhere else to leak but the injectors, if they hold, all is ok.

 

I heard or read somewhere that when you turn the key off it makes the pump run backwards for a second to depressurize the rail. Some safety thing or something, is that right, or was someone blowing smoke up my a$$?

 

You can also remove a single spark plug at a time and BUMP the ignition. If fuel comes out of the spark plug hole, then you have found the bad injector. I found this out when an Accel failed and hydro-locked my engine.

Hope this helps!

 

As a master tech this is a more proficient way of doing it and in my flat rate world no one will ever waste there time for no reason when you don’t have too unless you like throwing away money and time is money. So this is the more efficient way besides my favorite way but not everyone has access is the pulse width modulate way with a labscope but again not everyone has one or knows how to use one. But you are correct 💯 and these DIY guys must have time to spare but real techs don’t. Great job well 👍🏾 👍🏾

 

Careful with this. Prime it, then pinch off the line after the pump stops or you risk blowing the regulator diaphragm. Ask me how I know