SteveG

Pros use a smoker. I have no idea as to a recommendation, but this would be something that could probably be accommodated by Dwayne's thingy or a commercial product, maybe something for the OC to consider renting out.

17prospective buyer

Lol just go to a shop that does emissions work, explain that you just want to smoke test the intake system. Then get them to write up a phony work order about smoke testing the EVAP system (which is what it's usually used for).

westija

Update:

New gasket arrived yesterday and I've replaced it. Fixed that leak (intake manifold side cover).

Then found a second one, at one of the lower bolts of the Passenger (RH) side Valve Cover. For those who have been there, this is a bolt that is very hard to reach, as it is located close to / behind two lines. It was not fully torqued and some air was leaking around the bolt. Retorqqued it and fixed that too.

Now I can maintain pressure just a few seconds longer. And I can hear another one around the MAF. I have removed it, retightened its rubber seal, retightened the lines that are connected to the rubber seal sides and reinstalled the MAF. Leak is still there. As I push the MAF back and forth I can hear a slight change in the leak, but think it is not that (only). Taking a break to get more patience and think about it.

Any tips appreciated.

Thank you

1989 928 S4 5 speed

Mike Frye

Lots of stuff in and around the MAF, but if you haven't replaced that O-ring at the base of the MAF you might want to do that. It might seem OK and pliable but you'd be surprised at the OD of a brand new one. It should be pretty tight to slip the MAF in and out with a fresh O-ring even with some lube on it.

westija

Mike,

Thank you.

When I install my MAF into the seal, it is not hard at all.
If it is a tight fit, that might be my problem, although it is very hard to say if that is exactly where the leak is coming from.

Are you referring to item # 6 below (air guide cowl) ?

westija

Update

Thank all for the suggestions. I've been travelling extensively and just lately got back to this.

I followed Mike's advice and replaced the MAF Rubber Seal/Cowl and fixed the leak there. Thanks Mike, good suggestion!
As I was reassembling the whole thing I ended up breaking one of the plastic "Y" that connects to the MAF, so had to replace that too. No big deal other than time.

Now, as I pressurize the system I get leaks at the base of the injectors on the driver's side. Initially I had leaks on the front two, then disassembled and reassembled and had a leak on the second one and after trying again I still have the second injector base leaking. FYI I replaced the injector seals, so they are new.

Is there any trick to assemble the Fuel Rail and Injectors ?

I assembled the Fuel Rail with the injectors (and their metal clips / retainers) already in place. The Fuel Rail end tubes have to go inside the fuel dampeners (?) and the two rail brackets have to mount on the Intake studs and the injectors to their places, so the whole thing gets twisted as it is assembled and I suspect that this is not allowing me to sit the injectors as they have to.

In my second attempt to eliminate the leak, I tried to fit the injectors to the manifold first and then install the Rail, but I could not ensure a good seating of the upper part of the injectors to the Rail neither have a good feel to install the injector metal clips/retainers to the rail.

What am I missing? Any ideas are welcome

Thank you

Speedtoys

I put the inejectors in the rail, then the clips on them.

Then line up the four injectors to the intake manifold holes...then give each a little spray of WD40.

Press down evenly on the rail a little, then MORE on one end and wiggle em down into the manifold from one end. The WD40 does the trick for me.

The the nuts and rail connections arent so bad after that at all.

dr bob

Some thoughts--

- Turn the engine to any 45-degree position, like the 45 BTDC position used for 32V can belt installation. No pistons will be at top, so valve overlap is avoided completely.

- use a good assembly lube on the o-rings at the injectors. It kepps the o-ring from rolling as you install the injectors.

- use Hylomar or similar sealer on the side cover seals, particularly in the groove in the cover. Just a very thin film is plenty. It helps seal the rough casting surface in there.

- use the same Hylomar on the cam cover seals, including the plug well seals and the bolt seals. I used tie-wraps to hold the cover seal in place until the cover was in place. Then snip them one by one and replace with bolts. For the pkug well seals, I used a small inspection mirror down the plug well to insect that the seals were still square in place as te cover was fitted. Took a few tries, as the Hylomar is kinda slippery. I used a thin film on the bolt seals inside and out, and on the o-rings for the blanking plugs. Still need the RTV at the corners where the head and intake meet, per WSM.

westija

Update

Once I lubricated the Injector Seals with WD-40 and assembled carefully it sealed very well. I got the pressure to be maintained fairly well, so, it seems I got it resolved.

Finally. It takes patience to cure all leaks.

Now I will finalize the Intake and test to see if everything works and if my Idle Speed is fixed. Fingers crossed!!

Many thanks guys. I owe you

westija

Quick update - Thank you all for your ideas and tips and Dwayne for the write-up.

I finally finished the Intake Refresh. Fixed all leaks, replaced all gaskets and seals, ISV, mostly all hoses, CPS, Knock Sensors, Hall Sensor connector, isolated the Fuel Rails and Fuel Cooler, replaced MAF Cowl (one of the leaks), powder-coated Cam Covers and Intake (preferred not to go crazy, just basic aluminum/silver with no lettering, so far), etc.

Engine started as soon as the fuel filled the rails and hoses (a couple of cranks) and idled well at around 700-750 rpm maybe.

Had a small fuel leak at the passenger side rail but fixed it after reinstalling it with WD-40 (thanks!).

Now I am working on the coolant expansion tank - will open a separate thread for that and then will do a test drive once I finished that and a steering hose leak.

Thanks for all the help. Some pix below of before and after.
The PO had the upper bar poorly painted and with red ends and I hate it, so as I lower the car after finishing everything, I will remove it and paint it flat black.
If you see any incorrect routing (I suspect the vacuum line that goes to the front could be better positioned).