911 2

Anyone have the shop manual instructions on how to remove the inlet manifold on a 91 3.3 turbo, some of the inlet manifold nuts were loose so thinking I may need to change all the gaskets,
Reading, it seems this is a common problem, could this be causing my low idle and cutting out when coming to a stop

peterpullin

this is an easy thing to do. lots of work but nothing complicated.
the biggest problem is to remove all parts in the way.
start with intercooler. lower the engine about two inches. then remove air filter housing complete.
then there is lots of tubes and bracets in the way. if you locate all the 12 bolts that hold the intake housing you
can find all the parts to remove. to remove the complete thing it may be necessary to remove fuel head and lines.

most of the work is done by common sense.

care about washers and nuts - hey tend to fall in every hole ...

911 2

I had a look and yes a lot of it is common sense and take your time, if I had the instructions form the manual it may make it a little easier, also need the torque settings form reassembly
Intercooler and air box is already off, will i still need to lower the engine
Do i need to remove the whole inlet manifold from the engine to change the gaskets
If removing the fuel head will any calibration be needed on reassembly.

fritz k.

If you do not remove the engine you'll find some difficulties.

The lower seals and sealing surfaces ( which have to be cleaned) are only good accessible if the air duct is also removed. This requires removing the blower, alternator and engine wiring harness. In addition, some of the studs will be find loose, which then have to be re-inserted with screw lock and at the correct height. Everything is easier when the engine is removed.

If you don't want that I just would first try to tighten all 12 nuts evenly.

Fritz

PS: There is no decription of intake manifold removal in the WSM.

fritz k.

There are 12 seals, one obove and one under the spacers in which the injectors are mounted. The fuel distributor can be removed without having to calibrate anything during re-assembly.
The most important torque is for the 12 nuts fixing the manifold and this is missing in the WSM. I recomend 18 -20 NM.

Fritz

Igooz

I agree with Fritz! I take no pride in saying this, but I can drop the engine in about an hour now having done it 3 times in a short amount of time.

You should be able to drop the engine nice and easy in a couple of hours, and then you will have full access. The injector blocks that Fritz mentioned will most likely have hairline cracks in them as well, so plan on buying them new as well as the gaskets.

And yes, some of the studs will be loose! So plan on Loctite in correct height.

fritz k.

Yes, the injector blocs. The problem is not just hairline cracks, the sealing surfaces after 30 years are no longer flat. And it was quite difficult to get new ones at all.
I've also seen replicas made of aluminum. That makes no sense, the blocks are made of plastic to thermally decouple the intake manifold from the cylinder heads.

Fritz

911 2

So are you saying I have no choice but to drop the engine if i want to remove the inlet manifold or is there a possibility to remove the inlet without dropping the engine, I dont mind dropping the engine but at the moment I do not have the garage space to do this.
I can get hold of new plastic injector blocks,
So its not the nuts that are just loose but the studs, can i remove the studs only and reinsert with Loctite and tighten until i can drop the engine and look at anything that needs doing
The aluminium injector blocks come with a heat resistant gasket a few mm thick and then the standard gaskets

fritz k.

What I wanted to say is this:

- The engine does not have to be droped to remove the intake manifold, but everything is much easier when the motor has been droped.

- If the engine not has been removed, I would be satisfied with just tightening all the nuts evenly at first. This is possible even if the stud bolt is no longer quite tight. Almost all nuts are accessible except for the one on the 3rd cylinder under the fuel distributor.

- With the intake manifold in place, you can't get the studs in or out.

Fritz

911 2

Thanks, dont mind if it takes a little longer with the engine in, just dont want to start dismantling and then find out i cant take off or access a certain nut/bolt and I am unable to move forward
Im assuming im not having to touch the turbo.

fritz k.

It's not far from here......

911 2

so you removed the fuel distributor and air con pump, does the fan stay where it is and the throttle body comes away with the inlet manifold, two of my injectors have also come loose, not sure how, car has only done 61k miles

fritz k.

Yes, the blower can remain mounted and the throttle body too, that comes out with it the manifold. As I said, the problem is the air duct when you want to get to the lower sealing surfaces on the cylinder head for removing seal debris. It would be manageble, but it's fiddly.

Loose injectors are mostly a result of an assembly error. When loosening or tightening the union nut on the fuel line, always hold against the injector on its hexagon.

Fritz

peterpullin

care about all tiny parts that tend to drop in the inlet.

and right, from there it is only removing tubes and brackets.

the lower gaskes tend to be fixed to the head. you will need to use a blade or similar to remove the left pieces. and again: close the inlet with some sort of paper. once you remove this use a vacuum cleaner to remove debris.

and do not scratch surface to heads. that is why it is easuer with engine out. i did first time wirh engine in car. second time while a rebuilt. that was easier…

fritz k.

+1, could'nt decribe it better

here is what it looks like with manifold off, air duct on: