Hello all, I’m new to the forums, corvettes, and wrenching in general, and I got a few clarifying questions regarding the Bosch 3 22lbs injectors I picked up for my ‘86. I dropped them in once before without testing the seals and had major leakage and misfiring(most likely related as like 3 injectors weren’t getting fuel) this time around I’ve turned the ignition numerous times and no leaking! ( I put some of the original o-rings on the questionable injectors as they’re more beefy) But I do hear something like air escaping (maybe thru any of the unhooked vacuum lines) I did also put a fuel sniffer near the fuel pressure regulator vacuum port and it went crazy so maybe it’s that.

There are also slightly different reveals on some of the injectors (like some are farther in the rail/intake than others, you can see especially by looking at how much room you have to plug them in) but, if there are no leaks than they should work fine then? Assuming they’re a plug n play injector right? (Another thing I need clarification on)

I am only wondering bc I cannot find an image of my exact injectors in an L98 and looking to hear from someone who has done it, these are what the forums recommend after all right?

I got them from Zip Corvettes and thru South Bay Injectors

Thanks! Just wanna know before I waste more time putting it back together and taking it apart

 

They look okay to me. Two o-rings on the bottoms, correct? Push them up into the fuel rail as far as they will go.
I have the same injectors on my '87 and '90 with no issues.

 

there are single o rings on the bottom that aren’t your typical rounded off ones, they’re flat and kinda squared off

its just that some of the injectors are farther in the rail than others, but I try to bring them up and they either don’t budge or spring right back, some can also go farther into the intake but idk

 

Welcome to the forum,
South bay usually uses an extended pintle on the end of the injector with a single flat oring.
What are the part numbers on your injectors ?
If you re-used 30 year old orings that are "more beefy" they might sit different, I would not have re used old orings.
With all this apart how is the fuel pressure regulator diaphram?
If you hear hissing a vacuum leak would cause poor running. You should find this sound.
My 87's and most others distributors point 90° (using the bullnose between 2 and 7) from the front of the car. Yours is turned back toward the windshield quite a bit.
Not a problem if it actually achieves 6° advanced timing. What is your timing ????
Put a vacuum (your mouth and tongue can do it with a hose) on the EGR valve and make sure that diaphram is good while your in there.
.
.

 

I don’t know my timing, I’ve never really messed with it, and I obviously haven’t fired it up without the intake so the hissing when ignition is turned I assume is normal bc again, no vacuum is hooked up yet. My fpr looks fine to me. Part #for injectors: 0 280 155 710

and my reasoning for using the old o-rings is bc the ones that came with my injectors obviously didn’t seal completely, it also was my dads suggestion as the old rings looked good to him (unless it was user/installation error, however, if the rail is bolted down and the injectors are in the intake they should seal right?)

 

Do those injectors have a slot up top to reinstall the original locking metal C-clip that the OEM injectors have? Most of the Bosch III that I've seen have that slot up top, just like the OEM, and you're supposed to use the metal clips which rotate to lock the injector up into the fuel rail. This avoids leakage further down the line if the injector has freedom of movement up and down after everything is bolted in.

Your question about the injectors sealing right if the rail is bolted down; it depends on the length of the injector. Contact the supplier to find out if the new injectors are original-fit - same length as the OEM ones. If they are slightly shorter, then they can move up and down like it appears yours have done.

I recommend NEVER reusing old O-rings on injectors. It's too critical a part to have to depend on old ones that have seated with a different injector, and could be nicked or cut during previous deinstallation. Just use new O-rings - always - including the tubes between the left - right rails which cross over, and the fuel pressure regulator O-rings as well. They are usually supplied as a full set from Napa, OReilly's, etc.

 

thanks for the insight, the instruction sheet that came with the injectors says actually to not use the clips, to set the injectors in the manifold, and then to bolt the rail down

 

The fact that your reveals are different lengths tells me that you actually need those clips.

FWIW, I installed Bosch III Exact Fit injectors from Fuel Injector Connection (who were great by the way), and the instruction sheet they sent with the kit was wrong. The sheet tells me not to use the clips for Bosch III (no mechanical value), but I called them to check and they said "Yes, you should use them, the instructions are wrong". Maybe this is what happened with yours.




Either way, your injectors coming down out of the rail shows that your application would probably benefit from the clips - in my opinion. If the injectors have the slot up top, I advise you use clips. Your call though.

 

Those only lock the injector into the rail for installation. The injectors are held in by being squeezed between the aluminum fuel rail and intake by bolts. You do not need those if properly aligned and bolted down. My Bosch III's did not have a space for the locks and I did not use them.
Install them in the intake first and use a "small" amount of engine oil to lube the orings. Make sure the intake holes are clean.

Install them into the INTAKE MANIFOLD first.

 

ok I’ll definitely try this one out, but just because I’m curious, what difference does it make? Is it because if you stick them in the rail first they don’t reach the seat in the manifold?

 

It is what South bay and I believe FIC both say.

FIC= Fuel Injector Connection

 

Will try the suggested installations tmrw and check for leaks, will update, but still skeptical of these smaller o-rings, as when they were leaking, it was like there wasn’t even an o-ring there

 

Read this, 4th post down. it is the South Bay rep talking to a forum, on the left you see he is listed as a sponsor.

https://www.thirdgen.org/forums/tpi/...y-perhaps.html

 

I see, I appreciate the insight!

 

You still have all the flat bottom orings right ?

 

Someone posted the instruction sheet for bosch III's in a post above. In line 3 of that instruction sheet is says to install bosch III's in intake manifold first.

 

I had the Bosch III injectors from Southbay on and off my car a few times. No issues. Reuse the orings they came with or replace them with new ones of the same size. Use liquid dish soap and lightly lube them up. Injectors go into the intake first. Rails go on next. You shouldn’t have any issues. Take your time and make sure they are seated right.

 

yes and they sent me extra

 

I gotcha, I think on the first time around I cut too many corners.

Its also good to know that there are still super active and helpful people here!

 

Also, should they be able to move up and down, and also swivel? My dad and I were wondering if that was normal the first time around