dporto

There is also a small plastic vacuum hose that connects somewhere behind the throttle body (I don’t remember exactly where - I think it’s to the intake plenum or runner right behind the right side of the throttle body… it’s been a few years since I did mine) it’s possible this has become disconnected or cracked…

juju38

Today I disassembled / reassembled everything (plenum and resonance tube) when reassembling I made sure that the sleeves were in place.
i controle everithing with inspection miror
vaccum of resonance tube is ok
vaccum in 2 sleeve's plenum is ok , I see them well exceeded between the plenum and the intake manifold when passing the mirror in the plenum



I just had time to start and warm up the engine but it already seems better

I no longer have the fault P1504 : factory fault code 410 = Throttle jacking unit, emergency air position = signal implausible , after recalibration throttle body.

Idle is more stable.

I took values (FRA are identical 0.99%)



it looks like i still have a leak ?

Like I have manyfold, 200cc sports cat and silencers from top gear uk, , it could not force to inject more gasoline because less braked on the exhaust?
RKAT must be at 0 even with modifications to the engine?


I made a smoke machine, I receive the oil tomorrow and I will do the smoke test on Thursday.

Tomorrow I'm going to drive a few kilometers with the engine warm to see what's going on.

thanks for your help

De Jeeper

Get some miles on it now and see what happens. U can pull the ground off the battery for a couple minutes and it will clear all the old saved info. That may help the adaptations to look better now that u hopefully have the leaks sealed.

Porschetech3

It's better but it is still adding a bunch of fuel to compensate for air leaks/ lean condition...

When you smoke test it, looks for leaks around the power brake booster hose to intake and the oil fill tube also, these are two more places that are common to leak. Air/vacuum leaks are one of the biggest problems of poor running and poor fuel trims for 996 cars..

Your RKAT is better than it was before, but +/- 0.36ms is the MAXIMUM before it starts setting fault codes...Preferably as close to +/- 0.00 as possible...

juju38

ok, I'm going to focus on these 2 parts,
in addition these 2 parts have never been replaced and my car is 22 years old so the plastics have had time to to heat up and harden / break

dporto

Obviously, the smoke machine is “the best” test, but all that is really needed is a can of carb cleaner sprayed around the suspect components while the car is idling. If there is a vacuum leak the carb cleaner (or other volatile substance) will be drawn through the leak and into the intake system which will cause the idle to increase…

juju38

investigations are progressing

this morning I did 40km and no psm+abs fault, no fault code detected
I did not take the values from RKAT

the baby oil has not yet arrived I did a test with brake cleaner, as I do not have a start pilot

by spraying towards the brake vacuum line the engine speed varied. I therefore changed the small 11*2.5 O-ring and made a paper gasket to improve the plastic/plastic seal










I did the test by unscrewing the oil cap, it is hard to unscrew and I hear a loud suction noise.
if the oil filler tube was cracked that would do it too?
I bought an o'ring for the oil filler tube, I think that in any case I would replace this o'ring

how to test the oil filler with the smoke machine?


I received the baby oil, the smoke machine is ready.
we'll see tomorrow, to locate any leaks

juju38

I did my search for leaks.




plugged into the TB, I slipped the pipe under the butterfly so that the smoke goes all the way through the intake




another leak at the brake vacuum hose




ideally I think I would have to change the part, but for the moment I have sealed as much as I could


admission test at the intake manifold


oil filler tube test


First of all, I don't have any leaks. (i think)

now i must do a run for test and take the values.

for the moment I do not go up the kn, I stay with the Mahle paper filter

juju38

I'm not going to say it's good yet but it's on the good way

before i reset DME by disconnecting the battery, doing an adaptation of TB and a 75km drive.

no fault and



The car works very well, even much better than before, between the leak and the IPD + TB82mm plenum.
I have a lot more torque from 3000rpm.

And funny thing, I have more attack when braking and I have the impression that the clutch is also going better.

juju38

today, 200 km, in all situations, national, city, traffic jam, motorway..
no fault
values check is topl and most importantly, it works!!!
I recovered a lot of torque from 2055/3000rpm
I validate

De Jeeper

Good deal. Can u report back with your current fuel trim numbers?