I just purchased an injector rebuild kit because the truck I bought had a fuel leak (seemed like the 2nd injector on the passenger side not terrible but enough to make it a pain to start and leave a puddle in the driveway) and figured new injectors and returns should surely solve it! I installed new injectors, plastic caps, and return lines. I made sure that all the copper crush washers came out with all the old injectors. I took my time finessed the caps on after I greased the o rings with petroleum jelly. When I went to start the truck I left the injector lines loose. Cranked for 5 seconds then I tightened the passenger side front. I repeated that process working my way towards the cab of the truck then switching to drivers side and working towards the radiator. The truck started relatively easy after that, but there’s fuel pouring out so much so I can’t tell if it’s a return line or injector. I have a feeling that it’s my return caps. The old ones I had to put a flathead in between the caps and the injectors to get it to pop loose. The new ones are no where near as tight i can easily pull them off with my fingers. Is this a common issue with these rebuild kits? I plan on putting the old caps on the new injectors, (I checked they are a snug fit like with the old ones) and see what happens from there. Just wondering if anyone else had this issue before or if there’s something maybe I messed up??? the truck is an 83 with a jasper 6.9 it had the old style return lines, the new kit had the old style lines and injectors with code B.

 

new injector cups slide on and off pretty easy when greased up...Personally I always used STP but whatever grease you happy with I guess is fine Petrolatum is a good choice.

you should be able to tell a line leak from a cup leak as the line leak will be from the top of the "B" nut. and the cup leak will be under the nut.

 

do you think the return lines might be too short or long and cocking the return cups do they don’t make a good seal?

 

well, that can be an issue...some of the lines offered are pretty stiff I use the Green Braided Viton line .....

But still you should be able to adjust the lines in or out a bit to fix that issue....

one thing I will mention is on the older IDI like the 83 the fitting in the filter housing that goes to the Return is just an Orifice ..I like to replace that fitting with a check valve or just install an inline check valve to prevent Bleed back to the tank.

the other thing that can cause issues is IF the return line to the tank is restricted or restriction in the select Valve ... this can cause return pressure to run high and cause cups to leak. just saying....

 

Make sure when you install the caps to push down until you feel or hear them click.

I've had my fair share that took alot of pressure to seat. If nothing else try one of your old caps on that specific cylinder.

If that still fails maybe your injector line is cracked under the nut. This normally causes it to run a bit rough though.

 

so the new caps don’t click into place they kind of just float on top of the injectors. The old ones have a positive detent that you can definitely tell when they’re properly seated. I’m going to try and replace the “new” caps with my old ones which feel better to me and see what happens.

 

I swapped out the caps and everything seems to be right and tight. Thank you for the help.

 

I hate most of the aftermarket caps...

My 89 still has oem caps, they not only fit better, but they're thicker and heavier duty imo

 

no doubt about it.