testing fuel injectors for leak? (also 134a conversion info)

[R Dubya]

What is the best way to test my injectors for a fuel leak when pressurized?  Remove the rail, unbolt the hoses from the LIM and turn on the key?  I am concerned with my hard starts when warm that I have an injector or 6 leaking fuel and causing my hard start. 

Wish these cars were OBDII.  You can fire each injector separately and watch them bleed down. 

Old technology.   :laugh:

[GOT2B GM]

You could attach a fuel pressure gauge to the schrader valve on the rail, and then turn the ignition on for a few seconds to pressurize the system. Turn the ignition back off again and just watch the guage to see if it drops. At least then you'll know if you have leaking injectors or not.

[TGPilot]

With the proper GM diag tools you can do the same with these. Only problem is finding the tool anymore! :icon_rolleyes:

Honestly I do not know how to test these without the diag tool though. For all intensive purposes...you can get a set of injectors for $170. Replace them and don't worry about them anymore. ;) :icon_cool:

[TGPilot]

You could attach a fuel pressure gauge to the schrader valve on the rail, and then turn the ignition on for a few seconds to pressurize the system. Turn the ignition back off again and just watch the guage to see if it drops. At least then you'll know if you have leaking injectors or not.

or know that you have a bad FPR that is bleeding back. :icon_biggrin:

[R Dubya]

With the proper GM diag tools you can do the same with these. Only problem is finding the tool anymore! :icon_rolleyes:

Honestly I do not know how to test these without the diag tool though. For all intensive purposes...you can get a set of injectors for $170. Replace them and don't worry about them anymore. ;) :icon_cool:

who knows I may be able to get my hands on that at work.  Where are these mystical $170 injectors?  I have never seen anything and they would cost me about $500 at work, and I get them for GM dealer cost.  Are we talking aftermarket, Bosch?  I don't know how I feel about Bosch, at least their plugs and wires.  Got a part number???

[Prospeeder]

last i herd they were 170$ AN INJECTOR!

[GangstGP]

You could attach a fuel pressure gauge to the schrader valve on the rail, and then turn the ignition on for a few seconds to pressurize the system. Turn the ignition back off again and just watch the guage to see if it drops. At least then you'll know if you have leaking injectors or not.

This makes total sense to me.  OBDII :smile24: :new_all_coholic: :thumbsdown:

[tcristea]

Sounds more like the FPR than an injector to me.  I would see if you have fuel leaking from where the FPR is attached to the fuel rail.  Small leaks like that kill starts and performance and usually go un-noticed because they are so small and under the plenum and the gas burns up before you have a chance to smell it or see it.

[TGPilot]

Where are these mystical $170 injectors?  I have never seen anything and they would cost me about $500 at work, and I get them for GM dealer cost. 

http://www.tgpforums.com/index.php?topic=2954.0

[R Dubya]

thanks!!!!  :icon_mrgreen:

EDIT:
well I talked with the guys at the shop today and they have the kent moore injector tool, which will tell you pressure and drop when each injector fires, but it doesnt necessarily provide you with the best judgement if one or more is leaking.  I am going to pull the turbo here pretty soon to tie up some loose ends in the engine bay, and install my CAI, fix the AC and so on.  I will pull the rail and undo the bolt that holds the metal lines to the rail so I can flex them and then pressurize them to see if one or more is dripping.  That should give me a good idea of what's going on if there is a problem there.  I will post an update in a week or two.

[R Dubya]

I pulled the rail today and pressurized and I found I have 3 maybe 4 leaking.  So it looks like I'm in the market for some injectors.  Changed my accumulator today with the 4 Seasons one with the low side port built in, new o-rings and orifice tube.  Going to get it charged next week or whenever I get new injectors. 

Quick question- on the injector harness connectors there is a small red piece of plastic that I assume insulates the connector to the injector.  One fell inside the LIM and is sitting on the intake valve, I'm assuming it won't damage anything and I'll be damned if I'm going to pull the LIM for that.  Got the bolts into the bracket on the rear head (no more rattle!!! YEAH!!) also today.

Coming together hopefully next week early, then onto the truck to swap out the engine. 

[sleeperred90tgp]

You could attach a fuel pressure gauge to the schrader valve on the rail, and then turn the ignition on for a few seconds to pressurize the system. Turn the ignition back off again and just watch the guage to see if it drops. At least then you'll know if you have leaking injectors or not.

Not true unless you can see an injector leaking. You have to take the fuel  rail loose so you can see the bottom of the injectors.  Good start  :icon_cool:( I have done that to see how much an injector flowed in a mason jar with a stop watch.) The FP check ball could be bad which will dictate a drop in pressure back to the tank so without the injectors hanging in the air you won't be able to tell which is bad. I would be ready to put a fire out. :icon_frown:

Jud

[Invasion1]

Replacing them all??

a costly venture even for those working at a GM dealer....as i recall

here is what myself an Luke have

http://cgi.ebay.com/ebaymotors/Chevy-GM-3-8L-231-K-Bosch-Ford-22lb-Fuel-Injectors-NEW_W0QQcmdZViewItemQQcategoryZ33554QQitemZ7997396000

[LukeZ34]

Yea, the injectors have breathed new life in to the car.. No more little drivability problems that it was plagued with before.

Ryan, where did you purchase the parts for the AC? I need to do the R-134a conversion on ours, and I at least want to replace the accumulator before I do it.

[sleeperred90tgp]

Yea ebay is the least expensive way. I have bought about 6 sets and never a failure ranging from about 26# to 40#. The 40# were just to big, I had visions of grandeur. :laugh: Was looking for 12's when I hadn't got to 13's. :laugh: :laugh:

Jud