replacing fuel injectors

[winstonsmith]

I have replaced two injector hoses in the past right after I bought the car a couple of years ago. That was not fun. Now I have two more leaking hoses. Would it just be easier to buy all new injectors and put those on instead? Don't they come with the hoses already on them anyway? If so how hard is it to replace the injectors and exactly what is the process for doing it? I see two bolts holding the injector on. Do I just pull off the fuel rail and then unbolt the injector and put the new one on, tighten it down and put the fuel rail back on or is there some special procedure that I have to follow to change the injectors? Do they use some kind of gasket and sealant? Is there something I have to do to make sure I don't end up spraying gas everywhere?

[sblake01]

Do you have an FSM? The procedure to release the fuel pressure is in it as well as the procedure to change the injectors. Nothing special, just perseverance and perspiration!

[DatsunZsRule]

Also if your going to go the extra distance and replace all of the injectors, make sure you get new 0 rings top and bottom and new plastic holders. Kinda common sence but thought I'd mention it

[TomoHawk]

I had all my injectors sent to www.witchhunter.com where they were blasted clean outside, and flushed through. They ended up almost perfectly matched!

Don't forget 8mm FUEL INJECTION hose and new f.i. clamps. Do all 6 on the rail at once.

thx

[First Gen Z]

This is not a job you want to do often. It's important to do everything right the first time. New injectors do come with the hoses attached. You don't need to buy new clamps. I know the FSM says to replace the clamps but I've used the old ones many times without any problems. Check each one to see that they are still good. If your plastic hold down blocks are still good they can also be reused. The injectors are sealed with an 'O' ring. Use new ones. The entire fuel rail does have to come off. It's a tedious job but with patience it will get done. I sent my injectors to Bill Johnson and had them sonic cleaned. They all have exactly the same spray pattern and I expect them to work perfectly. My project isn't far enough along to start the engine yet. Bill's email is:bjcda2000@adelphia.net. Cleaning is far more economical than new. Good luck

Skip

[DatsunZsRule]

"This is not a job you want to do often."

I've had mine apart and in my opinion I don't think it was that difficult just takes a little time and patients but I suppose your right on how you wouldn't want to be doing it often so why would you not want to use new clamps and plastic holders?? I have to agree what the FSM says. seems silly to me if your going the extra length of putting all new injectors in why would anyone NOT install new hose clamps and plastic holders? It's what I call Cheap Insurance. but hey thats just my opinion. Not trying to be a smart a$$

[BuDavid]

I aggree with DatsunZsrule, since I didnt replace the plastic holders, but I had 2 of them allready cracked and I replaced them with used ones, since those parts are not much available in our area, but if they are available and cheep, man, do it at once and ease your mind from the hedache later on!

use a good type of fuel hose, I used a regular hose with clamps, I would tell you that I REGRET IT! those cheep clamps and that stupid hose are the worse thing I have ever done! they leak and they really dont look that they will hold the pressure of the fuel! I'll replace all of them..

and also buy new O-rings, u may also use a touch of silicone arroud the outed surface of the O-ring which will hepl the injector to slide in the hole and get sealed after tightening! it is just my way of doing the O-ring, u just better get the new stuff if u can..

and make sure that u cut the hose in an equal lengths accurately, with matching the older length, coz u might face probles with fuel rail hitting the fuel regulator as I had!

good luck!

[bobs77]

I'm going through this now on my '77. One of the hoses connecting the rail to an injector was leaking so I pulled the rail off to replace all of the hoses in the system (don't want to do this job again). I'm also going to replace the seals for each injector (MSA shows 2 per injector). I'll also check out Bill Johnson's injector cleaning service.

But this brings up another question. After pulling the rail off I noticed several original braided coolant hoses bringing coolant to a housing underneath the AAR, and then to the thermostat housing. One of these makes a sharp 90 degree turn so it'll need a preformed hose--guess I'll have to hit up Courtesy. Any idea why coolant is routed here?

Thanks,

Bob

[sblake01]

When I had my 78 apart, I replaced those coolant hoses you speak of with 250 psi fuel injection hose, even the one with the severe bend. In the two years or so since I did it, I've had no problems. The housing under the AAR is the heater housing for the thermal vacuum valve. The termal vacuum valve allows the egr system to work while the engine is at operating temp. It is closed below 117 deg. and above 208 deg. and it opens between 122 and 203 degrees.

[TomoHawk]

There is also a coolant bypass line from the head to the lower bock near the #1 spark plug (IRC). This could also be ready to replace

[bobs77]

Thanks for the info. I bought extra FI hose so I'll have enough to replace the coolant lines, incuding the one Tom mentioned.

I'm heading out now to remove the hose from the injectors, using the soldering iron method for the FSM.

[winstonsmith]

Well I got a better look at it today and thankfully I don't need any new hoses at all. One of the clamps had a tab that had snapped off. I just put new clamps on the hoses and everything is peachy again. Been driving around all day in it. Glad I didn't have to replace any hoses or injectors.