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Old 11-12-2015, 06:09 PM   #1
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HELP!!! rough idle missfires after work on ps

Hi, I need some advise on this thing.
This is 99 boxster new to me, just bought it a while ago, when i got it it had a typical burned by headers power steering high pressure line and previous owner installed a banjo fitting with clamps that was leaking, so I removed the entire line and replaced with a new one, after doing this the car runs very rough at idle like is running on 4 or 5 cylinders and wants to stall on idle, the car was running great before I replaced the power steering line.

My first impression is that it has a vacuum leak and I checked everything that I disconnected and removed over and over:

plastic tube from airbox to throttle body
snorkel clamp
clamp from tube to throttle body
little rubber hose under Throttle body
two little plastic hoses that insert into the boots
four clamps on the intake boots
gasket on passenger side intake manifold as I have to loosen it to remove ac compressor bolts to move it out of the way to get to the power steering line

additional things that I did that can provide more clues:

cleaned the throttle body with solvent and a brush (did I brake it?)
cleaned all the plastic intake tubes
connected and reconected the two electrical plugs into the throttle body

I did not disconnected the battery at all during the process

One thing I did also was trying to start it without the j-shaped plastic tube that goes from throttle body to aux air pump and of course it did not start, I forgot to install it and then I noticed it, then installed and it started right up but rough.

I wiggled the intake manifold a lot when it was loose and perhaps I disconnected something else like injectors or? I visually can't find anything wrong with it.

When running I sprayed a little engine starter on the probable sources of leaks and the idle does not change except when spraying close to the air box, which I assume is normal.

The codes I'm getting with my cheap obd2 scanner are all missfires

P1319 GENERAL MISSFIRE
P1314 MISSFIRE CYL 2
P1316 MISSFIRE CYL 4
P1313 MISSFIRE CYL 1

Please note that I can not take it to a mechanic since I live up in the mountains in central mexico (I live here for half a year since I'm semi-retired) and mechanics hera are far away and do not know anything about porsches, lol.
anyway... HELP!!!!

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Old 11-12-2015, 07:21 PM   #2
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Misfires are typically electrical or timing related. Re-check the electrical connections that were disconnected/re-connected. Are you sure that nothing else electrical was disconnected or knocked loose (like a wire from the flywheel sensor or cam position sensor or something similar to that)?
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Old 11-12-2015, 10:22 PM   #3
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Quote:
Originally Posted by thstone View Post
Misfires are typically electrical or timing related. Re-check the electrical connections that were disconnected/re-connected. Are you sure that nothing else electrical was disconnected or knocked loose (like a wire from the flywheel sensor or cam position sensor or something similar to that)?
Thanks, It is possible that I knocked sothing loose when I was working on it as snaking that ps line is a pita, where are the connectors for the cps or fs? Would the obd2 reader detect those being unpluged?
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Old 11-13-2015, 05:35 AM   #4
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Take a look at the hoses that go to the throttle body from the AOS (air oil separator). I just had mine disintegrate when it was messed with.



I think you are chasing a vacuum leak.

The CPS is on the pass side of the engine and the car will not run if unplugged.

The 99 has an idle stabilization vale on the side of the throttle body.

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Last edited by jcslocum; 11-13-2015 at 05:42 AM.
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Old 11-14-2015, 03:54 PM   #5
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Ok got it running great, the bad thing is that I do not know what was the problem but is running even better than before

This is what I did in case is helpful to someone:

Cleaned throttle body, idle control valve, and mass airflow sensor with the correct spray cleaner, all of them were very dirty specially the ICV. Performed an AOS bypass by plugging the port on the throttle body and connecting the AOS to the airbox to burn crankcase fumes as much as possible (this works in all my other cars and I do not get emissions inspection here and Im a republican so I don't care, lol)

My guess is that it was a combinatios of things but mainly that plastic tube fron TB to AOS, that clip o ring system looked a bit tired,
Anyway thanks for all the help

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