so I decided to put in ls1 injectors in my car and I ground down the fuel rail mounts since they are a bit shorter. went to pressure test the system by turning the key forward to start, and the very front pass. side injector leaked from the top. the rest were nice and dry. why do you think only that one would leak?. I was thinking maybe I need to grind down the front mount a bit more to make it fit better up in there but will that really fix the problem. all of you using ls1 injectors jump in here

 

i would start by replacing the Oring...

 

any other ideas on what I might have done wrong. willing to entertain all ideas.

 

Replace the o-ring...and slightly reposition the injector

 

O-ring may have gotten crimped or dinged when installing. It's always a good idea to put them in with a very small amount of Oil or Vaseline to get them to seal properly. Your best bet is to pull the Injector Rails back off, check and re-seat them all, and replace the bad one while you have it out.

 

I use the LS1 injectors and never ground down the the rail mounts. What I am getting at is the other posters are correct. Check your o-ring. Even if it has just been rolled up don't reuse it. Get the GM blue injector o-rings and put tranny fluid on them when installing them. The tranny fluid will act as a lubricant when installing and also slightly swell the o rings when they are installed.

 

funny thing is I did put a little motor oil on them when I installed them. I was thinking maybe the o-ring came off becuse I first installed them all the way in in the rails and then thought I want them more down in the manifold, so I pulled them all the way down into the manifold for the better spray pattern. could this be the problem?

 

Yes, could be contributing to the problem. Injectors need to be tight to the fuel rail, not the manifold. That is why the original ones have clips to hold them in place, thus ensuring that they dont fall down under pressure. Factory ones don't have much room to move, so going without clips isnt going to necessarily pose a problem. But because your LS1 injectors are a different length (shorter), then they have room to "fall down" under pressure. Grinding down the mounting areas may help, but it is mostly just a guess as to the correct length. I think I would definitely get some clips installed to fix the problem. Any leaks will be coming from the top o-ring, because it is the one under pressure. Length of travel into the manifold will not yield a better spray pattern, so no need to worry. Best of luck!

 

Didn't have to ground nothing down they fit right in and work fine, no leaks. they slid right in was very suprised

 

well the rest don't leak so I am just a bit confused. Scott57350, did you place them fully up in the rail or fully in the manifold? and did you modify the groove to use clips?

 

if it was me, i would goto the dealership (ick i hate that place) and get a set of injector clips.

hold the injectors in the correct place on the rail with the clips,
then i would put washers under the fuel rail to put it back at stock height.

 

Could someone do me a favor and measue the injectors. It could turn out to be a real help.

 

MrDude_1, LS1 injectors can't use the clips the original injectors did. the groove in them doesn't go all thje way around the injector. these injectors are also shorter then stock, so if the are all the way up in the rail at stock height it will bareky be in the manifold.

 

ahh.

well, do LT1 manifold clips grab onto the TPI fuel rail? ive never tried it..... thats one idea...

 

Simply bring an injector down until you see the top o ring. Then press the injector back up into the fuel rail 1/4 inch. Note the posistion of the injector and repeat on the next seven. The injectors will not slide down. Clips are not needed. HTH

 

well I cured the fuel leak. twisted the injector up about a 1/8" and is made a snap sound. stopped leaking so I won't blow up thanks for all your help.

 

Since you really didn't do anything to fix it, I'd watch that one really close for a possible leak in the future. Don't want to see her go up in flames, ya know....

 

well it runs great and no leaking under throttle

 

I took the clips and cut the side off with the tab. Seated the injectors into the fuel rail and slid 1/2 of the clip in the slot. Feel pretty secure with that. Could have slid the other 1/2 in too but didn't see the need.

Then, I cut about 3/16" off the fuel rail mounts and that seated the injectors nicely into the intake bores.

All in all, I feel like it's as safe as it can get. Clips and seated nicely.

Also, these things must actually be rated too low (from SLP). I'm still tuning fuel out of it with the constant set at 27# injectors at 39#'s of fuel pressure.

 

So how much shorter are the LS1's compared to the regular injectors?

 

Finally did the SLP LS1 injector swap over last weekend. Read this if you are considering the swap yourself. Results: the car runs great with a 28# injector constant ('89 formula, stock motor and chip). Idle is smoother and car has more power and throttle response is excellent. Original problem was a hunting/surging idle. Found one injector coil at 2ohms, decided at 80k miles was time to change them all.

The LS1 injectors were about 1/8 on an inch shorter than stock so I ground app. .2 of an inch off the fuel rail mounting posts. This was done while the intake was off the car to repair some leaks.First I trial fit the injectors at stock height and was shocked at how little room for error there was! Others have said they run them like that but I didn't feel comfortable with the fit of the intake side as the oring was right at the edge of the bore.... My goal was to leave about 1/8" maximum up/down movement of the injectors between the intake bore and the fuel rail, ensuring a seal on both high and low pressure orings and allowing me to run w/o the stock clips. Burned a chip and fired it up, getting 20+ mpg largely city driving vs. maybe 11mpg before! Still need to do a datalog but so far so good. NOTE: measure for yourself before you decide to install the LS1s. I am happy with my results but I am not suggesting anyone take my statements as a guide for HOW TO, just sharing my experience here. Please decide for yourself whether and how you want to do this swap.

If I had to do it over, I would get some 22# SVO injectors and avoid both changing the eprom and modifying the intake. Extra work and stress (partly due to so many conflicting stories on this message board about flow rate, , size difference, etc.) was not worth the money saved.

Thanks to all the members who contributed their experience and input re the SLP injector swap! My son and his friends think I am some sort of master auto tech!

 

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