535i Fuel injection wiring harness removal

[Dash01]

The 535i fuel injection wiring harness is enclosed in a long black plastic housing that is above and parallel to the fuel rail. It has a cap that snaps off, with a couple of internal bolts that go through plastic grommets. I removed these bolts but the harness housing is still firmly attached.

How to remove the harness/housing without damaging it?

[nizmainiac]

take the small clips off the top of the injectors

[shogun]

No need to take the clips off, push the clip in and then it releases.
That is why so many people lose the clips, many people do not know how to open a clip.
Most of the clips on our cars are like that, same the temp sensors.
http://www.autohausaz.com/secure/PartImages/1287013003.jpg

[nizmainiac]

on mine i had to take them off, they weren't the push in type

[Mr Project]

Yeah, my '91 was the same way, had to remove at least one side of the clip to get the thing to release. I usually find it easier to unclip the whole black plastic housing so I can get inside of the wiring channel. There are a number of plastic clips all the way around the black plastic housing that can be unclipped and then the 2 halves of the black plastic will separate revealing the wires inside.

I don't think you have to, but it makes it easier for me to get inside and release the individual connectors for the fuel injectors. Then with a small flatblade screwdriver you can remove the wire clips and pull the connectors off the injectors.

[Dash01]

Bentley, page 130-15 says to "Remove the screws for the injector wiring duct and remove the duct from above the injectors. See Fig 20."

I removed the allen screws but the wiring duct is still solidly in place.

From other posts, I gather that it is held down by the wiring attachments to the injectors themselves.

It is impossible to properly see under the duct, even with a dental mirror.

I gather from other posts above that each injector plug-in is held by a clip, either of the snap-on type or perhaps of the push-in type.

Mine (on a '90 535i) appear to be the snap-on type. Should I try and pry these clips off with a thin flat-blade screwdriver?

Otherwise, what is the best way to remove the wiring duct in order to get to the fuel rail?

[nizmainiac]

use two small flat blades , one to push in one side of the clip and then GENTLY prise out the other side, then grab the clip with a pair of long nose pliers, thats how i did it

[Dash01]

On my '90 535i there is no way to fit a normal flat blade screwdriver or anything else onto the injector harness clips. There is no way to even see these clips without a dental mirror. Bentley is very poor on this. The injector wiring harness housing obstructs view of (and access to) the injectors themselves.

Would first removing the fuel rail help? After all, it's connected to each injector and to the fuel lines. It is in the way of seeing or getting access to the injector electrical plugs, which do not have the push-in type of fasteners. With the fuel rail out of the way, perhaps better sight and access is available to the injector electrical plugs.

Alternatively, since the fuel rail is to be pried off the intake manifold with the injectors still attached as a unit, and since the wiring harness is attached to the injectors, would it work to pry off the entire assembly (wiring harness attached to injectors and fuel rail) as one piece?

Any further details or specific procedures suitable to the '90 535i would be much appreciated.

[shogun]

Not exactly what you wanted, but maybe it helps
http://www.pelicanparts.com/BMW/techarticles/E36-Injector-Replacement/E36-Injector-Replacement.htm

[Dash01]

Not exactly what you wanted, but maybe it helps
http://www.pelicanparts.com/BMW/techarticles/E36-Injector-Replacement/E36-Injector-Replacement.htm


Thanks very much, Shogun, this sheds more light on the problem. As always, you are very helpful.

I have another idea that I would like your thoughts on: Injector cleaner (the type you put in one bottle per tank of fuel) will cause O-rings to shrink and become very loose. (I learned this when I soaked the injectors and O-rings from my Porsche into a jar of injector cleaner, full strength, and let them sit overnight. I figured the concentrated cleaner would work much faster than just adding it to a tank of fuel.) Anyway, the concentrated cleaner was absorbed by the O-rings and it made them shrink: Their inside diameter was larger and their outside diameter was smaller, so they got very loose. When they dried out, they grew back to normal thickness.

Anyway, since on my BMW 535i it seems very difficult to remove the wiring harness, why not put a few drops of injector cleaner on the lower O-rings? They would shrink away from the manifold and become very loose. Then, I could just pull the entire fuel rail/wiring harness/injector assembly up and off the manifold. I could also stop swearing at my car.

Aren't the O-rings what attach to whole assembly to the intake manifold?

What do you think about this idea? I'm going to replace the O-rings anyway.

[shogun]

I pushed the whole rail up. There are only the O-rings which hold the injectors. Eirther they come up with the rail or the rail comes up without the injector.
Here a pic we made just out of fun
http://www.bimmerboard.com/members/take/original/CIMG4248.jpg
Actually, however, I used a wood pice in the same way and a big hammer and hit on the woord till they came out completely.

Just a reminder: this is an M70 engine, not sure if all is same procedure