leon96z

Hi all.
I have a 96 Z28 LT1 with 187K miles. About 3 months ago the car became hard to start, was running rough, and threw a misfire code. I checked the vac line from the regulator (after reading this forum) and found fuel in it, so I replaced the fuel pressure regulator and all o rings. Car ran fine after that. Yesterday the car started acting the same way, but I checked the vac line and found no fuel. I did smell gas under the hood and looked like a small amount of fuel on the manifold. This morning I turned the ignition to on for about ten seconds and started smelling gas again. When I looked there was visible gas on the drivers side of the intake manifold. While looking for the source, I moved the #1 injector and fuel sprayed out of the well the injector goes into. I consider myself lucky the car didn't catch fire. My first thoght was a bad o ring, but why would there be that much fuel under pressure there? Do I need to replace the injector? If so, I was looking at these:

FUEL INJECTOR CONNECTION - FIC rebuilt Bosch Design III 24 lb

I don't have a lot of money to spend and these look like a good deal. Anyone have experience with this vendor or these specific injectors?
I appreciate any help anyone can offer.
Thanks,
Leon

Injuneer

If I read this correctly, you have pressurized fuel leaking out near the tip of the injector where it inserts into the bung in the intake manifold. That would appear to indicate a leak in the body of the injector. The bottom o-ring seals the external air pressure from moving toward the vacuum in the intake manifold. It does not hold any pressure.

Pull the rails up and take a look at the tip of the injector when pressurized.

If you need a new injector, and only want to buy a single injector, you should buy one (Multec) that matches the other seven. While both may have similar flow ratings, the computer programming for them is not going to be the same. The offsets could be different. Opening and closing times may not be the same. The disc design (which I think is what the Design III is) will not have the same dynamics as the Multec ball/seat type, etc. You want all 8 injectors to match.

If you want to buy all 8, the Design III has received excellent reviews.

leon96z

Thanks very much for the quick reply. I didn't think there should be fuel under pressure there but I wasn't sure. Since the car is 18 years old, if I'm going to replace one injector, I think I can come up with 200 dollars for a full set of replacements. Most of the work is pulling the fuel rail and if one injector has failed, it's possible the others aren't far behind. I don't know if the injectors I'm looking at come with o rings. If not, do you think it would be ok to reuse the ones I have? They're only a few months old. Or maybe it's dumb to cheap out on a $10 set of o rings when spending $200 on new injectors.
Also, I recall there being a small ring on the injector above the o ring on the manifold end. Does this serve any purpose? If the new injectors don't have them, should I transfer them from the old ones?
Thanks,
Leon

Injuneer

The link you posted indicates:

It's 14 years since I used a stock injector, but as I recall, there is a plastic spacer ring that holds the O-ring in the correct position at the tip of the injector. I saw this picturs on ebay of a stock injector - is this what yours looked like:

http://www.ebay.com/itm/94-95-Camaro-Firebird-5-7-LT1-Fuel-Injectors-Set-of-8-Part-17095004/221386273095?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222003%26algo%3DSIC.FIT%26ao%3D1%26asc%3D20131003132420%26meid%3D5302185957238490248%26pid%3D100005%26prg%3D20131003132420%26rk%3D0%26rkt%3D6%26sd%3D151240296966&rt=nc
The plastic spacer would be part of the injector, and not needed on the Bosch injectors, from the picture. I don't see the retainer clip slots on the Bosch injectors.

leon96z

Those do look like mine. I talked to a guy at FIC and he said the injectors I am looking at come with o rings. Now I just have to come up the the $200. I already ordered a fuel pressure tester that attaches to the Schrader valve and has a valve and tube to let me release the pressure before taking things apart. It should be here tomorrow. I will try your suggestion to check the injector once I have it. I got by without it when I replaced the regulator because all the fuel went into the intake through the vacuum line. I'm not sure there's no pressure now - even if the injector is cracked it might not release all the pressure.
I appreciate your help. I have been a member here since 2000. I haven't posted much but I have gotten a lot of very useful infomation, and I look for your name on posts to get really definitive technical data.
Thank you very much.
Leon

Injuneer

To release the pressure, all you need to do is wrap a rag around the Schrader valve and push the pin down. Not a lot of fuel will come out.

Thanks for the positive feedback!

leon96z

I ordered the rebuilt injectors I referenced in the earlier post. They should be here the end of this week. I'm going to wait to disassemble the fuel rail until they get here. I did receive the fuel pressure tester. Even if I don't need it do depressurize the system, I want to see if the pressure is ok on the 18 year old fuel pump. Hopefully it will be ok; the car was running well before this started. I appreciate your help. I will let you know how it all works out.
Thanks,
Leon

leon96z

I got the new injectors I referenced in my original post and installed them. They work great! They are a little different than the originals. As you said, there is no groove for the clips to hold the injectors to the fuel rail, so I installed them in the intake and then installed the fuel rail. There are also two orings on the bottom - one fits down inside the port and the other sits on the bevel at the top of the port. That may be for some other vehicle, but it works fine on mine. FIC shipped them quickly and the price was great compared to buying new.They have a three year warranty too. While they've only been in the car a couple of weeks, based on my experience so far, I would recommend them.
Thanks very much for your help, Fred
Leon

Injuneer

Glad it worked out. I have Bosch injectors, no retainer grooves, but they are sandwiched fairly tightly between the rails and the manifold. No leaks. I wonder if they put the second O-ring on the bottom of yours to help push the injector deeper into the rail?