S2 not firing properly

chills2 · 12-31-2010, 05:35 AM

Just a bit of history I have had my S2 for 6 years sitting in the garage I started it at least once a month it always started up and ran no problem I would usually let it run for 15 minutes or so. I recently started driving it back and forth from the body shop about ten miles away as I did it started running worse and worse everytime i drove it. The car only has 80k on it and it is stock never touched. It almost seems like the cat is clogged the front of it was glowing red so I cut it off and checked it, it was as clean as the day it was new. I started it up without the cat no difference but i could see wet unburned fuel spraying out of the pipe. I had a full tank of premium with Stabil fuel stabilizer in it I drained it all out and put a new fuel filter in it, i also put a new cap and rotor on the wires looked fine. I can wrench but I am ilterate when it comes to electrical. Please help!

guru944 · guru944's Garage

Chill2:

Replace Oxygen sensor. Check fuel Pressure at idle and without vacuum. Maybe you also have a bad Fuel Injector or pressure regulator. Recommend replacing fuel filter as well.

Hope this response helps...

guru944 · guru944's Garage

Chilli2:

Your Ignition wires may be bad, every 2-3 years you should always replace them.

Later.

djnolan · djnolan's Garage

What do the plugs look like? The color of the soot on the plugs will tell you if it is running rich, oil fouling, lean, etc. Here is a link to a spark plug chart...

Spark plug reading

http://www.4secondsflat.com/plug_chart.html

A little bit crude for a porsche site but you can determine a lot by looking at the plugs.

bazar01 · bazar01's Garage

Quote:

Originally Posted by chills2

Just a bit of history I have had my S2 for 6 years sitting in the garage I started it at least once a month it always started up and ran no problem I would usually let it run for 15 minutes or so. I recently started driving it back and forth from the body shop about ten miles away as I did it started running worse and worse everytime i drove it. The car only has 80k on it and it is stock never touched. It almost seems like the cat is clogged the front of it was glowing red so I cut it off and checked it, it was as clean as the day it was new. I started it up without the cat no difference but i could see wet unburned fuel spraying out of the pipe. I had a full tank of premium with Stabil fuel stabilizer in it I drained it all out and put a new fuel filter in it, i also put a new cap and rotor on the wires looked fine. I can wrench but I am ilterate when it comes to electrical. Please help!

Could you elaborate some more what you meant by it started running worse and worse. Worse in what way? Is it missing, surging and at what gear and rpm? You probably need to drive it a little harder like doing an Italian tune up. There might be lots of carbon build up in the chambers and valve seats from just idling in the garage.

carsonmx114 · 01-05-2011, 06:29 PM

If you haven't checked the plugs it could just have fouled one or more of them. I work on motorcycles and we have this problem alot on bikes and 4wheelers that we pull in and out everyday. When ur engine is cold the fuel mixture is rich so if you don't heat cycle the engine before you shut it off ur plugs get wet and foul out. The cat is glowing because the cylinder(s) that are down are passing raw fuel into it.

djnolan · djnolan's Garage

If he has a misfire problem maybe the four electrode Bosch platinum plugs will fire up more quickly.

commdiver · commdiver's Garage

All 944 cars have a AFM and when you suck air in it gets metered precisely to let computer meter fuel requirements! So if you have lots of small vacuum leaks or little big ones?? This creates a huge problem as the air that your engine is using is not being metered and computer does not know what to do? Try starting it and spraying brakleen all around and under intake system and manifold??? If idle goes crazy you know you need to pul intake manifold and start changing hoses!

Second item is the 16 valve cars have a timing sender on top of the front camshaft housing make sure it is in good shape and plug is not broken or corroded? Also check rear timing reference sensor on top of clutch bellhousing to see if this is brittle, broken or exposed wires?

S and S2 have an ignition module in engine compartment thats controls spark and ignition parameters! Its right behind the drivers side headlight attached with 3 small screws! I have a known good one, they are screwed to a heat plate and need di-electric grease in between. It might be the culprit as I have experienced a few S2 owners with this lately! Good luck

chills2 · 01-10-2011, 04:19 AM

thanks guys I drained down all of the gas and installed a new filter. I cannot keep it runing long enough to test the O2 sensor but the plug wires are original so i should put new ones on anyway i have put a new cap and rotor on but that didn't solve it. The reference sensor looks in good shape. The plugs look fine just very wet with gas i think that only one cylinder is firing at this point. Plenty of gas so that leads me to think that the injectors are ok.

What ignition wires do you recommend?

carsonmx114 · 01-12-2011, 08:02 AM

I hate to keep saying the same thing, but have you replaced the spark plugs? If the plug is wet the spark doesn't need to jump the gap, it just travels to ground through the gas on the plug and never makes a spark. Think more simple and work your way up the big stuff.

chills2 · 01-14-2011, 04:52 PM

Ya I ordered new plugs and wires this week we will see if that works.