Hey folks -

I finished a TB refresh a couple months ago because I had what I thought was a timing problem. It didn't help so I started planning an intake refresh. I used Dwayne's MAF tool to check vacuum, first using a MightyVac (couldn't create a vacuum) then a shop compressor. When I hooked up the compressor the manifold blew so much air out the top right at the large T in the intake distributor I could feel it, so I'm pretty sure I have a huge vacuum leak. Another clue is the car has mouse **** all over it and I found a nest in the air conditioning ducts (the cars been in storage for 10 years).

I'm tearing down the intake now but wonder if there are any parts I should be ordering. What's down there that could be blowing that much air? It seems to be right over the throttle body. ISV? I already have the standard intake refresh seals from 928 specialists but I didn't order an ISV.

 

It could be the ISV but more likely one of the hoses has degraded and fallen apart. I know it adds to the time but unless you want to just replace all the rubber you probably need to take it apart and decide what you need.

 

Have Roger put a kit together, did you check your boots you can peel back the boot on the bottom when installing and not see it. Do it right do it once get some intake gaskets pull it apart clean or paint you will be glad you did.

 

The ISV is a wear item,

yes it wears out.

the armature inside the unit will develop holes in it from rubbing on the brushes,
once there are holes then the armature will stick in a certain position,
and thus not be able to move to keep the idle constant

 

Thanks guys. I have the plug wires out, now I'm wrestling with the injector rails, I have the 4 bolts out but I can't pull the rails out. I understood the whole assembly came out but now I'm wondering if I need to unclip the injectors first? Darn thing's stuck in there good.

 

spray some WD40 at the bases of each injector..then they should work loose.

BUT first cover any holes that would be open to the cylinder,
and with compressed air,
blow out the injectors at the bases to remove any loose sand prior to wetting them with WD40,
keep the intake covered

 

WD40, check. Will blow out the whole thing with air before hand. Then I guess I just apply sufficient pressure and pull the darned things out eh?

Will report on progress.

Thanks,
Scott.

 

The fuel rails are held in with 2 small bolts per side on top.
As long as the rails are unscrewed on each end, you can pop the rails out.
It takes some pressure, or some leverage with a long screw driver.
If they have never been out, they are usually caked in with crud.

 

I have them soaking in WD40 now, I'll leave them overnight and try again in the morning. AFAIK they've never been out so they're probably caked with crud. All bolts are out so I'm just fighting friction I think.

I appreciate the confirmation, I hate using brute force on these things unless I know in advance it's necessary

Regards,
Scott

 

Update:

This morning I took a small catsclaw crowbar to the injector rails after soaking the injectors in WD40 overnight. 3 out of 8 injectors came out with the rails but 5 remain stuck in the heads after slipping the rail clips. Now I need advice on which tool to use to pull the remaining injectors. I'm thinking about channel locks?

 

Found the leak this afternoon after getting the injectors out. The part is 928 110 602 00, it's a hose that runs between the center "T" shaped distributor on the intake manifold and the oil filler. You can see the rupture in the attached picture. The tear looks like it was caused by another part putting pressure on the hose from above but there isn't anything directly above the hose. Can't figure out what did it, but it's big enough to stick your finger in.

Doesn't look like mouse damage since the hole seems to be punched in and there isn't any fraying around the borders.

 

Well THERE'S yer problem!

At least you found it. That will definitely cause some problems.

 

And the good news Mike is that I already had the part on hand from an intake refresh kit I got from 928 Specialists last year when I started planning the job

My wife is a bit concerned about this, you have to excuse her, she's Dutch. She looked at the part and asked how much it cost so I told her I thought it was about five bucks (the intake refresh kit I ordered was around $600). I tried to explain that it was always a fifty cent part that was the problem but you never knew which one it was going to be.

I'm not certain she bought it.

Thanks to everyone who came out to play on this one. Tomorrow the adventure continues

 

Oh, I forgot to mention that if awards go to the Best Guess on a thread like this, Roger (aka WICruiser) takes the cake.