View Full Version : How do you check for a leaky injector?

John B
04-02-2006, 03:16 AM
My fuel rail doesn't stay pressurized (after I turn the engine off for a while)and I can't find an external leak. How can I determine if an injector is leaking?

5sp. mini
04-02-2006, 11:07 AM
i heard that you remove them with the fuel rail hooked up and turn on the key to presser up the inj. and see if they leak. AL

04-02-2006, 11:08 AM
You could crimp off the fuel feed and reutrn line with vise- grips with a fuel gague hooed up. If the fuel pressure drops then you know it's an injector. Or if the pressure doesn't drop, remove 1 vise grip at a time. If the pressure drops when the feed side vise grip is removed, it's likely a bad fuel pump check valve.
If the pressure drops when the return side vise grip is removed, it's likely a bad fpr.
If the pressure drops with both vise grips attached, unbolt the fuel rail, put some dry rags under each injector tip and see which one(s) are leaking.

"Top Fuel" Bender
04-02-2006, 11:08 AM
If the engine doesn't run rough when first starting
(from the extra fuel)
I'd lean more torward a leaky check valve at the pump
Nothing really to worry about though
most cars loose fuel pressure