My vette seemed to be running fine, a tad rich on it's original injectors, but is making a healthy 260 hp at the crank.

I bought 9 refurbished injectors off a '93 LT1 owner. He said he bought one extra because he thought one was bad, but they all checked out fine for the flow test/cleaning.

I put em on the car... it ran like crap. Poor fuel economy... no power, feels like a miss or way too much fuel somewhere. So.. I'm assuming one of them IS in fact stuck open or otherwise junk. But I have no way of finding out which one without sending them in to get checked do I?

I put my original injectors back on... car runs fine again. (3 of them leak though).

Just today I tried installing the other ones again...same thing, runs like crap. I tried unplugging each injector one at a time while the car is running.. it stumbles on every one except #8 and #4. I notice no difference driving with either of these injectors unplugged, or BOTH unplugged! :banghead: I could feel all of them pulsing except for #8, I feel nothing. Also, cylinders 8 and 4 are next to eachother in the firing order...

My next step is to pull it all apart again, and change out the #8 injector. I sure hope the #4 one isn't bad also.

Do you guys have any ideas? Or should I just cut my losses and get MORE injectors?


[Modified by CentralCoaster, 12:30 AM 3/22/2004]

 

Central, buddy, why go through all that? What is the fourm gonna tell ya? Get the ford SVOs. Of course, I don't have them , but they seem to be the forums choice of injector. I'm impressed by your diligence at tearing that mother down so many times - not my favorite thing. :seeya

 

I see they were "checked " out. Who did the checking? Have you checked the impedence of all 8? Just wondering.

 

:iagree: I have 25# Bosch and the car is really rich. Everyone says use the SVOs. Must be a reason. :thumbs:

 

After I bought new injectors, I tested the old ones.
I held them upside down and placed a drop of WD40 on the pintle.
I then applied 40, 30 and 20 psi to the intake side of injector using an air gun with a rubber tip.
Air bubbles appeared on 4 out of 8, at all those pressures.
Before I couldn't keep any pressure in the rail for 20 minutes.
I installed my new injectors and pressurized the rail 3 weeks ago and my gauge still shows pressure on the rail :hurray:
Anyway, try this test out. It might shed some light on the subject :smash:
:cheers:

 

Never mind, I just re-read your post and it seems you know which ones are bad already. so my original suggestion wouldn't have helped you anyway...


[Modified by tobijohn, 10:59 AM 3/22/2004]

 

If they are stuck open you can try this little trick. It'll be harder on a TPI but still possible. Pull the fuel rail off the intake and set a glass jar under each injector. Turn the key on to pressurize the fuel rail, look for leaks. If there are no leaks try cranking the car over a few times and look for fuel in each of the jars. :cheers:

 

Make sure you push the injectors up into the fuel rail all the way before you test them if you are going to do this. Otherwise, you will make a mess, and get very wet when one of the injectors decides to come out. Don't ask me how i know this. :lol:

 

thats a great tip. :cheers:

 

I tried a similar method.. I put paper underneath each injector.. and primed the pump. That's how I found 3 of my factory injectors leak. None of the 'new' ones do.

Hmmm... I might try that this time around. I think one or two are either flowing too much when the ecm pulses it, or flowing not enough.

Been there done that! I don't have the clips in there.. so those things shoot out with some force! I blasted two of my original injectors out of the rail that way, and broke the tips on both of them! Now I'm commited to these other injectors.. or new ones. :smash:

 

What persistence you have. Spend the $200 and eliminate the injectors from being the problem. How did you tighten the inside lower mounting bolts for the runners?

 

Are you talking about the ones that go in backwards? The passenger side one is easy... the drivers side one requires a 6" extension, a u-joint, and a 3" extension with T-40.

I just tore it down again today.... took me 1/2 hour to get it down to the fuel rail!

 

Hmm. Takes me a 10mm wrench to get the fuel rail off.
Of course that doesn't change the fact that it still holds pressure for hours. Ask me how I know that!