I worked on my 93 VG to try to remove upper intake manifold. I will
quote the instructions given by Haynes below. I got a few questions:

1. From Haynes manual, I only need to remove some hoses and elec
connectors on throttle body, besides those bolts. Then I can remove
the upper intake manifold with throttle body attached. But I found
that this part is connected to flare tube through some very tight
bolts. I am wondering if I need to remove these bolts? Or, exactly,
how did you guys remove the upper air intake manifold when servicing
injectors?

I can't remove either IAC/air cut valve assembly(the silver metal on the upper left corner), or EGR valve and flare tube (the red metal
one down there). Looks like I don't have to remove the air cut valve
assembly, but I do have to remove the flare tube. There are two big
bolts connecting it to the upper intake manifold. Could anyone tell me
how to do this? (maybe I need to buy some lubricant to loose the
bolts ?)

(click below to see picture)
http://www.cs.ucsd.edu/users/zqin/ho...e_manifold.jpg

2. For VG engine, which is the one I have, I have to remove lower
intake manifold to reach the injectors? Is that correct? I was able
to move the upper part around a little bit (I even smelled the gas),
but the injectors are still under the lower part. How did you guys
do that without removing the lower instake manifold? I referred to
the Haynes manual and it said I only need to remove the upper part.

3. What is ground strap?

Here is the complete quote of the manual for removing upper air intake
manifold:

1. Disconnect the cable from the negative terminal of the battery;
2. remove the air intake duct;
3. Disconnect the accelerator cable, cruise control cable (if equipped),
hoses and elec connectors from the throttle body. Be prepared for some
coolant spillage and plug the hoses immediately to prevent excessive
coolant lose.
4. Detach the spark plug wires from the spark plugs and remove the
spark plug wires from the retainers on the plenum. Remove the
distributor cap from the distributor and position the distributor cap and
spark plug wires aside. Label and disconnect the hoses and elec
connectors attached to the plenum.
5. Remove the ground strap attached to the upper plenum and
loosen the upper intake manifold bolts in the reverse order of the
tightening sequence. Remove the upper plenum with the throttle body
attached.
6. 7. are for installation of the manifold.

 

Follow this link- I used it when I did my first injector change, and it helped me out.

http://www.4dsc.com/articles/drivetr...lacement.shtml

 

Thank you, broncoguy. I've attached two pictures with my questions
on them. Can you please take a look? Is your engine also VG?

pic 1:
How to
remove flare tube?

pic 2:
Do I detach throttle body from the intake manifold?

Many thanks.

 

i would just remove the intake pipe in front of the throttle body. no need to take the tb off. you also should take the throttle cable off along with the metal piece on the back of the manifold holding the throttle cable and cruise control cable in place. this will allow you to get to that allen bolt under there. for the egr you can take it off with those two nuts but you will probably need a new gasket for it. another way, if you have a big enough wrench, is to loosen the tube on the exhaust and then totally unscrew the tube off of the egr valve so you can spin it out of the way.

 

I agree with mtcookson. I did not remove the TB, and I unbolted the EGR from the intake. (2 bolts) Didn't replace the gasket, but it was OK. Yours may need to be replaced.

 

Thank you guys for all your kind replies. I've been able to reach the bad injectors. So just one inch away from taking it off. I just can't... According
to Bryan's writeup, I used a pair of pliers to try to twist it off. Anyway,
the picture is attached here...

How do I take off the injector?

As you can see, I've broken some of the plastic socket but still the injector
was too tight to be pulled out. I've been able to twist it a little bit, but I
just can't remove it. Then I thought the fuel rail had improper pressure (
I did release the pressure, but a few weeks when I started the repair), so
I unplugged the fuel filter upper inlet hose. No change on the injector.

I was wondering, how did you guys get it out?

 

Well that killed the core value.
There actually is a special tool made to remove the nissan injectors.
but try grabing around the head of the injector not the connector and wiggling it to get it loose

 

You mean I can't return the injector to directauto for trade-in?

 

at least not with the co's I deal with. they have no way to repair the connector. and would you put an injector in your car with a broken connector?
I wouldn't it would corrode faster than normal

 

That's fine... Where do you buy new or refub injectors? Are they reliable for VG?

I saw a website selling new ones:

http://shop.nissanpartstore.com/?make=NI&year=1993

How is this one?

 

does that injector not look stock to any of you guys? that looks a bit different than the ones in my car... i looks like the connector is more of an oval than a rectangle.

 

It is because I pinched it too much? Anyway, it's on a VG. Could that be another cause?

 

i have a vg as well. the little tabs that allow you to put the connector on only one way look different than mine too. they look thinner and longer.
you have a 93 so that could be why... but i don't know. i'll check my fsm and see if it says anything.

 

Mt- you guessed correctly that is 92 and up's design 89-91 (the NG VG injectors) have a thicker connector. but the color still looks wrong to me.

 

You have a later VG so the problems with reman injectors aren't as bad as the older one.
That isn't a bad price for new bosch ones.
Maybe if I remember I'll check my cost on monday