Gene Posted March 15, 2017 Share Posted March 15, 2017 Hi everyone, I've done a lot to my Comanche over the years, but I've never touched the fuel injectors. I've ordered a set of 746s. I'm wondering if there are any tips for replacing these. It looks like there are four bolts securing the fuel rail to the intake manifold. Then the fuel line and return line look like they have a plastic clip, squeeze with a pair of pliers and remove? Then each of the injectors has the electrical connector. I've been warned to be careful with these as they can easily break. My main question involves what comes next. Do you pull the fuel rail and all the injectors together? Or do you disconnect the injectors at the rail, just pull the rail, and remove the injectors individually? Finally, I've also been warned that the O-rings can become very very hard with age, and removal can actually be quite a bear. Advice from the collective wisdom of the group will be greatly appreciated. Thanks so much! Gene Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 15, 2017 Share Posted March 15, 2017 Don't use pliers on the fuel line clips; they might break. They come off quite easily just squeezing with your fingers and pulling them off. THIS is an excellent writeup w. pics. It's for an HO but the procedure is basically the same for Renix. Don't forget to mark your electrical connectors. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 15, 2017 Share Posted March 15, 2017 Keep a track of the injector clips, if you lose one you're in trouble. Also be careful when putting in the new injectors that you don't damage the O-rings. Also turn on your ignition to check for leaks before and after you bolt everything back together. I learned all this the hard way. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
Gene Posted March 15, 2017 Author Share Posted March 15, 2017 Hi Don, Thanks for the link. Great writeup! I especially liked step 19! Hi desbennett, Thanks for your experience. Gene Link to comment Share on other sites More sharing options...
DirtyComanche Posted March 15, 2017 Share Posted March 15, 2017 I wouldn't pull the fuel lines off the rail. If you do you need new clips for them or they might blow off on you, and you will probably burn the truck down if that happens. I'd just pop the rail loose, pull the injectors off it, and stuff the new ones on. Lube the orings with something slick, I use thin silicone grease, but WD-40 or clean oil works fine. For that matter hitting each end of the injectors with WD-40 before trying to pull the rail makes it a lot easier to get them out. I also paintpen mark the injector electrical connectors rather than taping them, but that's me. Also, I have no idea why one would remove the fuel cap as suggested in that writeup? Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 15, 2017 Share Posted March 15, 2017 I wouldn't pull the fuel lines off the rail. If you do you need new clips for them or they might blow off on you, and you will probably burn the truck down if that happens. Also, I have no idea why one would remove the fuel cap as suggested in that writeup? Pulling the fuel lines off the rail is a matter of choice. I always detach them and have never had a problem with the clips "re-latching" as long as you lube them up a little. With the fuel rail removed it's easier inserting the new injectors and there's no stress caused on the brittle plastic fuel lines by moving the rail around when they are still attached. I guess removing the gas cap thingy is in case there's pressure in the tank in the newer XJs with the regulator in the tank? :dunno: Link to comment Share on other sites More sharing options...
cruiser54 Posted March 15, 2017 Share Posted March 15, 2017 Always a good idea to run it and pull the fuel pump relay so it stalls before beginning the job. On a Renix it's super simple to leave the fuel lines connected while swapping the injectors. HO isn't much harder. Get the clips off the injectors and unbolt the rail. Using even pull on the rail with both hands, give a yank. Note which o-rings are where and account for them. I clean the holes in the intake manifold with an old diesel injector brush. Install the injectors into the rail, line the injectors up in the manifold holes. Give the rail a push evenly on both sides. Motor oil is a good lube for the o-rings. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 16, 2017 Share Posted March 16, 2017 On a Renix it's super simple to leave the fuel lines connected while swapping the injectors. HO isn't much harder. Mine's harder. With the 01 intake and the 04 TJ steering pump, there's very little wiggle room for the fuel lines. I had to bend the fuel rail nipples slightly to fit them in. Thus I disco the fuel lines when changing injectors. Link to comment Share on other sites More sharing options...
Hypoid Posted March 16, 2017 Share Posted March 16, 2017 On a Renix it's super simple to leave the fuel lines connected while swapping the injectors. HO isn't much harder. Mine's harder. With the 01 intake and the 04 TJ steering pump, there's very little wiggle room for the fuel lines. I had to bend the fuel rail nipples slightly to fit them in. Thus I disco the fuel lines when changing injectors. Last time I disconnected the fuel lines from the rail in my RENIX Jeep, it cost $25 to put them back together. The FSM says to replace those little plastic fittings if you disconnect them, it is a "disposable" seal. Guess what, those little plastic thingies are out of production, last I heard.... My last engine swap, the fuel rail was hanging off to the side, still connected to the fuel lines. No leaks there, yet. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 16, 2017 Share Posted March 16, 2017 On a Renix it's super simple to leave the fuel lines connected while swapping the injectors. HO isn't much harder. Mine's harder. With the 01 intake and the 04 TJ steering pump, there's very little wiggle room for the fuel lines. I had to bend the fuel rail nipples slightly to fit them in. Thus I disco the fuel lines when changing injectors. Last time I disconnected the fuel lines from the rail in my RENIX Jeep, it cost $25 to put them back together. The FSM says to replace those little plastic fittings if you disconnect them, it is a "disposable" seal. Guess what, those little plastic thingies are out of production, last I heard.... My last engine swap, the fuel rail was hanging off to the side, still connected to the fuel lines. No leaks there, yet. Guess what, I got spares. Link to comment Share on other sites More sharing options...
DirtyComanche Posted March 16, 2017 Share Posted March 16, 2017 On a Renix it's super simple to leave the fuel lines connected while swapping the injectors. HO isn't much harder. Mine's harder. With the 01 intake and the 04 TJ steering pump, there's very little wiggle room for the fuel lines. I had to bend the fuel rail nipples slightly to fit them in. Thus I disco the fuel lines when changing injectors. Last time I disconnected the fuel lines from the rail in my RENIX Jeep, it cost $25 to put them back together. The FSM says to replace those little plastic fittings if you disconnect them, it is a "disposable" seal. Guess what, those little plastic thingies are out of production, last I heard.... My last engine swap, the fuel rail was hanging off to the side, still connected to the fuel lines. No leaks there, yet. Guess what, I got spares. The ones you use are actually available. The Renix ones aren't. They're really close to a GM part, which I believe I managed to make work, minus that the backup ring (goes between the o-rings) is not available. IMHO the quick connect is a weakness and should be deleted. In a perfect world, that is. On my XJ I wound up just using FI hose and FI clamps, since I put a bunch of HO junk in a Renix chassis and something had to give where the fuel lines met (or didn't meet, initially). Much cleaner would be some AN adapters and some better hose. Link to comment Share on other sites More sharing options...
Airborne Janitor Posted March 16, 2017 Share Posted March 16, 2017 The Renix ones aren't. They're really close to a GM part, which I believe I managed to make work, minus that the backup ring (goes between the o-rings) is not available https://www.amazon.com/Crown-Automotive-83502745-Fuel-Repair/dp/B00B8X56RA These won't work? Link to comment Share on other sites More sharing options...
DirtyComanche Posted March 16, 2017 Share Posted March 16, 2017 The Renix ones aren't. They're really close to a GM part, which I believe I managed to make work, minus that the backup ring (goes between the o-rings) is not available https://www.amazon.com/Crown-Automotive-83502745-Fuel-Repair/dp/B00B8X56RA These won't work? Maybe. You tell me. I had a good P/N for the dealer and they told me it was no longer good, I never found a cross reference for it, the one they had was definitely not right. The pictured setup is not 100% the same as the OEM, but it may or may not be close enough. Link to comment Share on other sites More sharing options...
cruiser54 Posted March 16, 2017 Share Posted March 16, 2017 The Renix ones aren't. They're really close to a GM part, which I believe I managed to make work, minus that the backup ring (goes between the o-rings) is not available https://www.amazon.com/Crown-Automotive-83502745-Fuel-Repair/dp/B00B8X56RA These won't work? That's the one. If you only need the o-rings: Fuel disconnects Quick disconnect part numbers The Napa part numbers for just o-rings *is: Napa 730-5018 3/8 Viton individual o-rings Napa 730-5017 5/16 Viton individual o-rings Napa CRB 212305 fuel line repair kit 5/16 *Remember to re-use your old spacer between the 2 new o-rings!! Mopar repair kits: 83502745 fuel line repair kit 5/16 83504447 fuel line/Trans line repair kit 3/8 Link to comment Share on other sites More sharing options...
Hypoid Posted March 16, 2017 Share Posted March 16, 2017 If you only need the o-rings: Fuel disconnects Quick disconnect part numbers The Napa part numbers for just o-rings *is: Napa 730-5018 3/8 Viton individual o-rings Napa 730-5017 5/16 Viton individual o-rings Napa CRB 212305 fuel line repair kit 5/16 *Remember to re-use your old spacer between the 2 new o-rings!! Mopar repair kits: 83502745 fuel line repair kit 5/16 83504447 fuel line/Trans line repair kit 3/8 That right there is GOLD!!! Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 16, 2017 Share Posted March 16, 2017 The ones you use are actually available. The Renix ones aren't. They're really close to a GM part, which I believe I managed to make work, minus that the backup ring (goes between the o-rings) is not available. IMHO the quick connect is a weakness and should be deleted. In a perfect world, that is. On my XJ I wound up just using FI hose and FI clamps, since I put a bunch of HO junk in a Renix chassis and something had to give where the fuel lines met (or didn't meet, initially). Much cleaner would be some AN adapters and some better hose. The Renix and HO fuel line quick connectors are exactly the same. The Mopar quick-connects are sturdier and easier to change out than the Dorman and Crown junk, but they both work. And yes, AN connectors are the way to go. Some day............ http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2060353.m570.l1313.TR0.TRC0.H0.X83502745.TRS0&_nkw=83502745&_sacat=0 Link to comment Share on other sites More sharing options...
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