gintaras

I want to test my fuel injectors, and I figured an easy way to do this is to remove the rail and injectors from the intake while leaving the fuel supply attached.. then turn the key to pressurize the system and then "turn on" the injectors to watch them spray.. the only problem is, I don't know how many volts are applied to our injectors at runtime..

This would be an easy way to check for dirty/clogged injectors, anyone know the voltage to apply to turn them on without brning them?

cherokeefreak

just take a swig of fuel and blow it through the injectors

gintaras

yeah, that's not going to work because you have to cycle them on to get a flow through them.

I thought this was Cherokee Technical discussion?
Maybe I should ask about a lift

SeriousOffroad

12vdc

Don't apply the votage too long, you'll burn it up.

Hommersimpson

you can just leave everything hooked up.. and just stick each injector in a soda bottle.. and watch them... ofcourse you need 6 soda bottles :} lol

gintaras

thanks. that's what I was looking for, 12v it is..

And I am pretty sure I have some majo FI clog.. I attached a fuel pressure gauge to my fuel rail yesterday and a whole mess of yellow goo came out of it. So I plan on taking off the rail, and energixing each injector to test for spray.

cherokeefreak

come on now, i was just joking around

98 JeepJeep

or exhaust.......

gintaras

wow... OK, so I took off the fuel rail, and I rigged up 2 wires, one wire I put on the pos battery terminal, and I put a butt connector crimped to the other side, leaving a shielded end so I didn't arc on anything. The other wire was a test light just clamped to a screw on the rad support.

I laid the fuel rail in a box so I didn't get fuel everywhere, and I turned the key to pressurize the system to 145 psi

I put the hot lead (with the butt connector shield) on one progn, and then I used the point of the test light on the other prong.. I got streams of fuel, no atomization, and weak streams at that, like they were pissing into the box..

Right now I got them all soaking in a tub of lucas fuel injector cleaner, I hope it help some, but I know I will need to get new injectors or sendthese in for servicing.

SeriousOffroad

Don't pay someone to clean 'em!! There's alot of info on the web pertaining to cleaning your own injectors. Seriously, it really is not that difficult.

96Cherokee113

Definitely don't pay to have them serviced. For what they charge you, you can get refurbished injectors. Here's a link to a great video on how to clean your own injectors . Also, you can get a "rebuild" kit off ebay for under $20.I just scored this set for $18 http://cgi.ebay.com/ebaymotors/ws/eB...T#ht_500wt_975 . I'm sure the same seller will post another one considering after the last set he sold, he put another one up for auction. You'll probably pay $20 per injector for servicing and you can rebuild your own in under an hour.

5-90

That would test the injectors proper.

Test the firing circuit using a "noid light" - available at well-stocked parts houses for a few bucks. Plug the light in in place of the injector, either with the engine running or being cranked, and watch for the lamp to flash.

If you do it with the engine running, expect it to act like it's got a "dead hole" (it will - until you plug the injector back in...) but you'll still see firing pulses for the injector.

Don't use a meter to test this - you won't get an accurate reading. You can use an oscilloscope to check the waveform (in most cases, it should be a square wave,) but that's probably more in-depth than you'd care to get.

gintaras

OK, next step is the noid light.. maybe one of them is not getting juice, I know that ALL of the injectors read 12.0 ohms, so they are good..

I am about to give up and drop her off at the dealer but I am afraid about how much it might cost to find some simple problem...

I am a bit lightheaded from the carb cleaner and tired too.. I am beat, i am so sick of trying to find this rough idle.. maybe I just have some stupid little problem like a bad cap or something, but I dont think so because if I pull #1 plug it runs even worse.. I rarely give in on problems but I am about to on this...

SeriousOffroad

145PSI? Where in the world did you get a fuel pump that puts out 145PSI??!?!?

gintaras

that's what the gauge said when I turned the key... maybe I read it wrong?.. maybe I just have a bad fuel pump? ugh... I'll recheck the fuel pressure this weekend...