pwb

How to find out if one of the injectors are open all the time?

country_boy454

You can use a stethascope to listen to each injector. They should make a rapid clicking for every spray of gas. The one that doesn't is your bad injector. More than likely it isnt stuck open but closed or clogged.

pwb

Ok, thanx

jnicewan

Stethoscope may be enough to tell, but it usually does make a bad injector sound different. You can put a fuel pressure guage on it and see if the fuel pressure drops after you turn the key off, but the loss of fuel pressure could be a couple other things too. Most of the time a stuck open injector will flood a cylinder bad enough to get raw fuel out of the exhaust (white smoke, smells like raw gas) And a spark plug that is either severely black or wet with gas. Other than that you can pull up the fuel rail with the injectors attached and have a buddy cycle the key on and see if any are leaking fuel.

ChristopherI

You'll need a multimeter to test your injectors accuratly.

Start your jeep and let it warm up to normal operating temp. Then turn it off, set your multimeter to OHMs and then unplug all your injectors, make contact with both red and black probes to the contacts of the unplugged injectors. You should get an identical reading for each injector. If one injector reads different than the others then it is bad and needs to be replaced.

For a more detailed description and walkthrough troubleshooting injectors check out this site.

http://troubleshootmyvehicle.com/ind...articles_1.php

the method is the same for the 4.0L's and the V8's.

David Starkweather

Cylinders 1, 2 and 3 spark plugs black. The rest are ok. Starts hard like it is flooded. Started misfiring when started after driving and then parked for 2 hours. Changed plugs and noticed 1, 2 and 3 fouled. It was hard start after changing plugs. Smooths out at 1500+ rpm. Anyone had this happen? Are injectors fired at same time for 1,2,3? Or is the SEFI type.

dave1123

No, it's timed port injection where only each cylinder is supplied with fuel on it's intake stroke. Yeah....okay....sequential. If you do pull the rail with all the injectors on it, make sure they are tied down to the rail before you pressurize it because 50 psi may blow them out of the rail. Some cars have retainer clips, but jeeps bolt down the rail instead.

97grand4.0

Mine have clips I pressurized the rail with them out last week no issue