ChattanoogaJSB

Assuming a guy has good hobbyist proficiency in mechanical work and the desire to get the job done quickly at the expense of drinking many beers and chatting it up along the way...

How long do you think the job of replacing the fuel injectors will take?

Heck, let's make it a poll!

GREGGPENN

Long enough that I decided the need to stroke it while "in there".

http://forums.corvetteforum.com/c4-g...light=injector






BTW... I chose 4+ hours knowing there's too much chance you'll think about other things like: EGR, sensors, tanking parts, porting, etc... just to throw it back together.

ChattanoogaJSB

Ha! True, if it were mine I would probably get carried away, but it's a friends car and it's a true get-it-back-on-the-road job, probably stick to the program...

Aardwolf

It really doesn't take long. Leave the runners, pop the plenum up, remove fuel rails (might have to pop an injector off), then reassemble.

ChattanoogaJSB

Thanks, I was wondering and had been searching around about leaving the runners on. Wonder would the throttle body move with the plenum enough to allow me to leave it in place as well?

leesvet

Nawwwwwwww !

never ever do this without replacing ALL the rail O-rings !

Take the rail off, take it apart, clean it all and replace every O-ring or risk the obvious...a leak AFTER you have everything assembled. I skipped the damn short pipe on the regulator once....
where's it leak a month later?

Seen too many gas fires, had too many close calls. Its not worth saving 2 hrs. Do the O-rings. Thats why Jon includes the whole set in his injector kit. Besides, the new o-rings are alcohol compliant...once disturbed the old ones will certainly gush gas. All it takes is something twisting around just a hair when you lift the rail off the injectors...

FWIW
when they say leave the runners on,. you still have to loosen the lower runner bolts to lean them back a bit, otherwise the rails cannot clear the top of the runners enough to lift off the inj...

Try to have the top of the intake clean before you do this work or you will knock a bunch of trash down into inj ports straight into cylinders. Wash it off or blow it clean with compressed air. Just so there is nothing loose on top.

ChattanoogaJSB

ch@0s

When I did the Intake on my 86 it took just a little over 2 hrs. This was done with power tools and no painting cleaning other that gasket surfaces. When I did the 91 it morphed into an LSX over a 2 year period..and there was some painting and cleaning.

ChattanoogaJSB

I can relate to project creep... in this case it's close to Christmas and we're gonna have to knock this job out. I'm going for functional and mechanically sound. Truthfully the car is pretty spotless as it is, I don't think my buddy will be dragging his feet to clean too much more.

ch@0s

Just make sure you have everything you need. Otherwise, 30 minute runs to the parts store will turn it into an all day job. when I did it in 2hrs I had a whole parts department 20 yards from me and a parts cleaner(machine). I also started soaking the bolts with WD40 a few days earlier. GL

ChattanoogaJSB

Check. Nothing sets me back more than a trip to get something at the parts place. That and dropping into the abyss an extremely necessary tool I don't have a duplicate of. I'm reasonably certain I have never sold one car that I didn't permanently contribute at least a stray socket to.

ghlkal

It's like any other job. The FIRST time will take you much longer than the second, third, etc time. 2 hours start-to-finish is likely for those who have done it before and prepped beforehand. I'm sure the first time I did my L98 is was 4 hours.

Chilliwack vettes

leesvet

The biggest delay will be the reversed lower runner bolts...
this is why you want several ext, wobblers and a torx bit socket...1/4" works best. its tight.

The d/c sequence is simple...
drain fuel system by running it dry before you begin. You may need to access the tank fittings to pinch a line if it tries to siphon.

D/C air intake duct

Pull TB, cables and assorted vac lines off TB and set aside.
pull plenum, 4 bolts per side. lift up and out. Have some douche ready, it'll be nasty inside.

I pull the dist just to have more working room....most skip that.

Loosen lower runner bolts 1/2 way..lean runners back. 1 bolt each side is reversed..takes a colelction of stuff to access that bolt on the driver side rear...

d/c the 2 fuel lines, have rubber caps ready in case they still flow fuel out.
FIND the o-rings on the steel lines! D/C cold start line.

pull 4 rail hold down bolts.

d/c all inj caps/plugs and pull away from rail assy. Tie wire them out of the way.


rock the rails as you lift...it sometimes takes a pry bar to help lift...use good judgement when placing the bar on things around here.If they are stock inj they have locking tabs. Rotate to unlock so inj can come out of rail or pull rail and inj as assy.

remove rails, set aside for disassembly and cleaning.

pull inj out, be sure to account for each O-ring top and bottom of each inj.
use paper towels to plug inj holes in manifold.

I use vasoline to lube inj for new o-rings and use a sharp pick to help install so there is no tearing of the rubber.

set inj in place, set rebuilt rails on top. NOTE: Most of the B-III inj are shorter than the stock and the B-III do not use the retainer clips.
Once rails are positioned on all inj, and everything is lined up, push down firmly and bounce on the rails to get the inj to "snap" in place. Keep applying pressure until you hear/feel the POP or SNAP as they seat. Have the inj turned where you want them before seating...once seated its not good to twist the inj. This tears the o-rings.
Bolt it down, NOW connect fuel and CS lines.Once the lines are reconnected, TURN the key to RUN and listen for the fuel pump. You want to pressurize the system NOW and look for leaks. Smell it, look, watch the pressure gauge for a drop...dropping pressure means its going somewhere. IF not leaks in the rails or the inj...proceed with the assembly.
The rest is cake.

This is more or less my process...I'm 100% sure I forgot something that I'd catch if I were doing the job, but from memory...I'm sure I left out something critical..

testing once the system is secure is a biggie. You do not want to reassemble everything THEN see a wet rail pipe or a wet injector...

Oh yeah, before setting the TB and plenum, I apply a thin coat of anti-seize to the gaskets to prevent sticking. This is for next time, and there will be a next time to pull the TB or plenum. I also replace the vac hose to the EGR while I'm there and do any housework that needs to be done on top of the intake. Some folks like to torque test the intake bolts. They are known to get loose....Use a flare nut wrench on the fuel lines at the rail. The nuts strip or round off very easily so use the flare nut wrench with a back-up. Be sure to use the right O-ring on the steel lines...
I use vasoline on the o-rings because its clean, it melts away the instant heat comes, and its not harmful to anything under the hood. Melts away to nothing as soon as you fire it up. I'm sure plain grease works too. Try to douche out the TB air passages and the plenum too. They handle EGR gas and its sticky gummy stuff.

First time took me all afternoon....After that, it was more like 4 hrs, but I DO completely tear down the rails and the regulator. ALso brush all the bolts. I also use allens on everything except the lower runners...didn't have enough new bolts last time...They are already in my box for next time...More choices for allen bits is the biggest reason.

Its not a bad job. Have the tools ready, a cordless driver helps to speed up running bolts in/out, or whatever power tool you have available. I always have multiple bits so the ratchet has one and the power tool can be ready with another. break bolts with the ratchet then zip 'em out/in with the power tools.


Hope this helps. 1st time is always the hardest. After a successful inj swap, it gets easy.

Aardwolf

I don't mess with the lower runner bolts, it's what makes this way so quick. Yes leave the throttle body on. If you really want to be quick you don't even have to disconnect the fuel lines. Pop the rails up and pop in each new injector as you remove the old one.

BGZQ8

So this can be done WITHOUT TOUCHING the lower runner bolts any at all ? Heard yes and no.

ChattanoogaJSB

I'm going to do this job tomorrow, thanks for all the replies so far including leesvet who took a lot of time! As for the last few replies, I'll be waiting to see if anyone has any more confirmation, or dissenting opinions!

Honestly it seems like the only thing that will prevent me from doing this sub-4, or even sub-3, is getting deeper into the fuel rails. Based on the common youtube video that gets passed around I had not counted on doing more than installing the injectors once I got the rails in hand.

GREGGPENN

I think the biggest issue -- doing it the first time -- is the metal/mesh reinforced factory gaskets. And how "welded" to the intake they get over time.

I didn't keep track but I wouldn't be surprised if I took 4 hours JUST to clean off every intake gasket. (I removed my entire intake to build the 383.

(Picture chipping 1/8"-square BITS of material over a long period of time. Also, picture 2-3 layers of this total BS!)

For the upper runner gaskets, it might take an hour. You might not be happy after an hour. Mine were literally petrified to their mounting surfaces. I'm quite certain it's the worst gasket removal job I'll ever face in my life! Yes...it was THAT bad.

Sure, I considered options like a best sander and even a planer at a metal shop. It's because of the impregnated metal.

After the 1st iteration, most wouldn't need to deal with this -- as their are many aftermarket gasket sets that aren't reinforced. (I bought 3 separate ones...and none were reinforced.)

Because the surface is aluminum you must be careful not to gouge the alum during gasket removal. So, it's a balance of brute (hand) force and delicacy. I can not emphasize enough -- how NOT fun those gaskets are!

Without removal/loosening of the lower intake bolts, I question one's ability to "pop" the plenum loose from the upper runners. The best method had to be the use of a crow bar UNDER the plenum. I'd certainly try this (before loosening the lower bolts) to see if it'll come loose).

With subsequent removal, I'm 99% sure it'll come loose. But, then again, you won't have insidious factory impregnating, metal mesh gaskets digging into opposing surfaces. Did I mention petrified?

I've only done my '89. So, I don't know if gasket material is the same for all years. If not, it could explain the discrepancy in the need for lower bolt loosening/removal.

While you can hope for a two-hour job, it sure wouldn't hurt to plan on four.

ch@0s

Greg I used Rolock aluminum disks with an angle air grtinder and they came right off.

Joe C

under 2 hours - - it would take me two hours just to think about changing the injectors on an L98. i've done it 3 or 4 times, and i'd say, on average, it's an all day job. hell, i can't change the frickin' oil in two hours -