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996 3.4 DIY Clutch & Fly etc turns into mini restoration

wasz said:
Got my car back! Brakes are great.

However the idle is wavering around, starting it was tough as it stopped immediately, has to put some gas on.

Anyone know if the DME adaptation reset works for a 3.4 cable throttle? ignition on for 60 secs and then off for 10 secs. Then a few hard pulls through the gears.

or have I got a vacuum leak.... vacuum at oil cap seems normal.
You need to disconnect the battery to reset the early DME but I doubt that is your problem.
It does sound like it could be drawing air.
 
Did you clear any fault codes ?

Did you have the battery disconnected ?

The car may have a fault which it had previously adapted to but with the above it needs time to re adapt .

Well .. i tryed to come up with other ideas ..

Give it a few miles just to make sure , the aos could have been faulty and the car needs to adapt to the new one .. opposite of above .. you have fixed a fault but its still on the old adaptions . .

Im only aware of a fault code and a clear of said code resetting the adaptions , thats how i do it anyways .. induce a fault .. clear the code .

If not .. i dont think i need to continue here :(


I prefer your post in the 996 forums .. i keep missing it in here .
 
Hi yes the battery was disconnected for the best part of 3 months....i suppose that means all old adaptations were cleared?

I took it to work yesterday and today, cold start stalled, then 20mins B road, 20 mins motorway pulling through the gears, a bit of idling at lights etc.

There was oil residue in the vacuum ports of the old AOS, so i assume that was letting by a little.

How long do they take to adapt....?

Will scan for codes tomorrow.

Not sure how this thread ended up in 996 FAQs, I started it in the main 996 forum....mods?
 
When I was fumbling around with the AOS, I saw a black and white vacuum valve like in the bottom right of this picture, with one end disconnected just lying on top of the engine.

I just plugged it into a nearby vacuum line end that was also loose....so both ends of it were on thin lines.

However I suspect this should have plugged directly into the intake manifold (no line or pipe), maybe the line I plugged it into was going somewhere else.....this would explain a vacuum leak as the manifold would be open to suck air it.

Is the '99 WITHOUT Secondary air pump vacuum line layout just the same as this:


kJ21Tse.jpg


Perhaps i don't have the reservoir or changeover #2 either?!
 
That black and white valve plugs in to the left of the throttle body into the large intake pipe, there should be a rubber joint between the hard plastic throttle body part and the intake manifold, it has a hole in it to take this valve.

But this also means if you plugged this valve into something else you have another pipe to find a home for.
 
Thanks all.

I went out to my car and drew this:

9LqzCoB.jpg


Which appears to tally up with the wonderful Kelly Anne Porsche image http://www.kellyanneporsche.com/enginedrop.htm:

f6QjjSY.jpg


Note this is an early 3.4 without secondary air or exhaust valves.

"dunno ?" top left in my pic must go to the vacuum reservoir. I pulled the line off the pierburg valve above the alternator that goes to the t piece and there was vacuum present. I plugged the line with my finger and the car idled the same, hunting and a bit high (1000 and just over), maybe there is an issue further back... I could try and plug the line from the intake (vac source).

The line from intake to black and white valve is the one I disturbed and reconnected when doing the AOS, it slipped back on very easily. hmmm.

I sprayed some carb cleaner on all the joins in the intake I could get to too and hard to tell as it hunts anyway but not really any change. I couldn't get to the big vac line connections on the aos.

I might try and build a smoke machine to test for leaks?

To pull codes I need to borrow a windows laptop....I forgot about durametric when I got a mac....its been so long since I needed it.
 
If you replace the dunno with the vacuum cylinder then it is correct. The white/black cylinder is a one way valve. The intake vacuum sucks air out of the reservoir, the one way valve keeps it there. The reservoir does what it says and the valve with the wire turns the vacuum on and off.

MC
 
MisterCorn said:
If you replace the dunno with the vacuum cylinder then it is correct. The white/black cylinder is a one way valve. The intake vacuum sucks air out of the reservoir, the one way valve keeps it there. The reservoir does what it says and the valve with the wire turns the vacuum on and off.

MC

Thanks that all looks correct. Although there are some reports on US forums of the vacuum reservoir cracking and leaking bit, and my rubber connections are looking a little past it but seem OK.
 
Borrowed a laptop just now:

P1602
Factory fault code 108 - power supply
Open circuit

P0506
Factory fault code 32 - idle air control - engine speed too low

P0150
Factory fault code 18 - oxygen sensor ahead of catalytic converter (cylinders 4-6)
Short circuit of wires or limited voltage increase

P0102
factory fault code 115 - mass air flow sensor
Below lower limit

P0112
Factory fault code 124 - intake air temperature circuit
Low input


These must have been logged since I reconnected the battery - I'm guessing disconnecting the battery for 3 months clears the codes? The first code must be for this (?)

The last two will be from when I pulled the MAF to see the effect (engine stumbled then adjusted).

I watched the live values from the oxygen sensors and they were all changing.

Need to go for a drive again and see what is logged as it is not logging anything at idle.

Revs at idle 1040-1250 (I didn't wait long enough for it to get hot as baby called).
 
Right.... made a smoke machine.

You will need:

- glass jar from uncle bens sweet n sour
- biro lid
- football pump adapter
- pump compressor thing
- rag
- baby oil
- soldering iron
- glue gun
- flexible pipe
- gaffer tape

Then:

- drill a 20mm hole in the lid of the jar and glue the soldering iron in.
- drill a 4mm hole in the lid and glue the briro lid in
- drill a 2mm hole in the lid and glue the football adapter in.
- soak the rag in baby oil, stick in jar
- screw lid on switch on
- hook the compressor up
- gaffer tape the pipe in your throttle body, wedge the throttle open

Take the lid off the oil filler.... you will see smoke puffing out. Put the lid back on.

Smoke will be puffing out of any inlet or vacuum system leaks.

s4WBK3b.jpg


wQDMpyp.jpg


My fear was confirmed..... my leak is at the lower AOS vacuum line.

I managed to pull it off and put a new o ring in (old one was hard and damaged)...still leaks. Maybe my new o ring was undersized.

Will try again when its not freezing outside.
 
Dammit .. i keep missing this thread of yours tucked away in here .. sigh .

Air leak from the fault codes which you already know ..

Smoke machine .. bloody brilliant .. its a hell of a usefull tool to have in your arsenal and that young man is very impressive .

Although what you have found isnt so pleaseing .

Baby oil with pressure gives off smoke ?
 
Demort said:
Baby oil with pressure gives off smoke ?

+ heat from the soldering iron.

Gives off loads of smoke! and the compressor pushes it through the pipe and your inlet.

I whipped it up in about 20 minutes, inspired by a youtube video.

Have a fire extinguisher handy....
 
im well impressed young man .. i use a smoke machine at work .. its solved some difficult to trace problems for me .. for you to make one .. well ... :thumb:

Not sure bent valves is the best use of this machine but leaks .. hell yeah !

Never had anything like this at OPC .. at indy though .. all the tricks .. learnt a lot being on this side of the fence i can tell you .
 

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