DaveFromColorado Posted February 16, 2006 Report Share Posted February 16, 2006 Howdy all - sparked by an other topic, I thought I'd post this (maybe for the FAQ section) For starters, when replacing one or more injectors, this is the time to replace ALL the o-rings on ALL the injectors. Clean the area arround the injectors before removing them, clean, clean clean - you don't want any debris falling into the engine When putting the injectors back on the rail, or onto the manifold you will need to lube the o-rings, for this I recomend Sil-Glide, it's a break caliper grease, I know Napa sells it, not sure who else does, but it won't harm the o-rings, and it works very well, I've never had an o-ring fold over, rip, or get dammaged on me when using this product ... Remember tho, before putting the manifold back together, pressurize the fuel rail to make sure you have no leaks - you don't want to have leaks where you can't see them with the manifold back on. if you follow these four tips (clean, use new o-rings, lube and pressure test) your chances of having problems installing the injecters will be almost non existant. --DaveFromColorado. Quote Link to comment Share on other sites More sharing options...
chadz34 Posted February 16, 2006 Report Share Posted February 16, 2006 I needed that, thanks Dave. Quote Link to comment Share on other sites More sharing options...
Brian P Posted February 16, 2006 Report Share Posted February 16, 2006 I'd like to add: before removing the fuel rail/injector assembly, be sure to vacuum around where each injector meets the lower intake. Dirt loves to collect there and some will go into the engine when you remove the injectors. I recommend an old school electrolux. Gonna add this to FAQ Quote Link to comment Share on other sites More sharing options...
Bossman429 Posted February 16, 2006 Report Share Posted February 16, 2006 This doesn't just hold true for injector o-rings either. Any fuel line with an o-ring should have the o-ring replaced before re-assembly. I learned this first hand on my TSTE...I did a fuel filter on it as a normal maintenance procedure. It is the setup with flare fittings on each side, and thus, an o-ring on each side of the filter. I slapped the new filter on without even considering the condition of the o-rings. Well low and behold, a month later when letting my car warm up in the shop for an oil change, I had a 2 foot diameter puddle of fuel under the car after running for 5 minutes. :shock: After disassembly I noticed that one of the o-rings on the fuel line was slightly torn by a burr in the metal fuel line. The ring was NOT torn through or anything, just slightly nicked, and it was enough for a fuel leak. So now...and when I do a fuel pump, etc...ANY fuel line disconnected gets a new o-ring. Just good insurance. Quote Link to comment Share on other sites More sharing options...
slick Posted February 17, 2006 Report Share Posted February 17, 2006 Very good tip on both the Sil-Glide and the vacuuming. I know last summer when I replaced the LIMG on my 3.4 (on had about 20,000 miles at the time), there was already a nice size amount of build up of dirt and grime in the area. I just used a rag to wipe it away as I had no way of getting a vacuum to my car in the middle of an apartment complex. 1 thing I always forget, and probably should be mentioned in this topic is the O-rings. How much do they cost, and how many need to be used per engine? Been a while since I've had mine down that far, but IIRC, the 3.4 uses 12? Quote Link to comment Share on other sites More sharing options...
Bossman429 Posted February 17, 2006 Report Share Posted February 17, 2006 Should be 12, that would be 2 per injector. One is between the injector and the head/intake, the other is between the fuel rail and the injector. Quote Link to comment Share on other sites More sharing options...
slick Posted February 17, 2006 Report Share Posted February 17, 2006 Should be 12, that would be 2 per injector. One is between the injector and the head/intake, the other is between the fuel rail and the injector. Thats what I thought. I just thought I remembered reading a while back that someone was saying the 3.4's used more than normal, but didn't make any sense to me. Like I said, it's been a long as while since I've had it torn apart. Quote Link to comment Share on other sites More sharing options...
Bossman429 Posted February 17, 2006 Report Share Posted February 17, 2006 Most injectors I have seen use 2 per, that's one on each end. If a particular application used multiple on one end, then yeah, there would be more, but I have never seen that. Quote Link to comment Share on other sites More sharing options...
DaveFromColorado Posted February 17, 2006 Author Report Share Posted February 17, 2006 I haven't seen any fuel injector that uses more then 2 o-rings - or less for that matter (well, gas injectors, diesel injectors are a totally different story) The Sli Glide is also good for connecting the vacuum lines, and it's really good as a break caliper slide grease (what it's actually made for) The injector O-Rings are fairly cheap 2.99 for 4 O-rings part number ES70599 with Checker/Shucks/Kragen as found on http://www.partsamerica.com so all 12 O-Rings are under $10.00 Like bossman said, any time you change anything that has an o-ring on it, get a new o-ring, it's cheap insurance! --Dave. Quote Link to comment Share on other sites More sharing options...
Miko K Posted February 23, 2006 Report Share Posted February 23, 2006 It also helps if you lightly brush the injector holes on the LIM, the aluminum there is usually coroded. The best way to do that is with a dremel tool and stick a vacuum cleaner in the throttle body and put it on "blow"(if you have a shopvac), so the dirt is being blown out of the LIM. My $0.02. Quote Link to comment Share on other sites More sharing options...
IRONDOG442 Posted July 17, 2006 Report Share Posted July 17, 2006 I dont know why but thsoe stupid o rings on the high pressure inlet going into the fuel rails seem to JUMP right off when you remove them and the damned O rings find the strangest places to land if you find them at all. Autozone sells a HELP various size fuel injector O ring kit for $8.00 a TRUE must for anyone working on GM fuel injectors constantly. Quote Link to comment Share on other sites More sharing options...
slick Posted July 19, 2006 Report Share Posted July 19, 2006 I dont know why but thsoe stupid o rings on the high pressure inlet going into the fuel rails seem to JUMP right off when you remove them and the damned O rings find the strangest places to land if you find them at all. Autozone sells a HELP various size fuel injector O ring kit for $8.00 a TRUE must for anyone working on GM fuel injectors constantly. Harbor Freight and Tractor Supply Company always have a container of a couple hundred O-rings for usually pretty cheap also. Good thing to have around when replacing anything with o-rings. Quote Link to comment Share on other sites More sharing options...
Slade901 Posted September 12, 2006 Report Share Posted September 12, 2006 I would suggest using a compressed air to clean around the fuel injector before removing the fuel injector itself. The same thing with the sparkplugs, you never know what falls inside the hole when you remove the spark plug. I would suggest using compressed air as well. Quote Link to comment Share on other sites More sharing options...
slick Posted September 17, 2006 Report Share Posted September 17, 2006 I would suggest using a compressed air to clean around the fuel injector before removing the fuel injector itself. The same thing with the sparkplugs, you never know what falls inside the hole when you remove the spark plug. I would suggest using compressed air as well. I also do the same thing(assuming compressed air is available), and I strongly recommend the spark plug idea on the 3.4 DOHC. Quote Link to comment Share on other sites More sharing options...
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