924Board.org

CorsePerVita · Joined: 25 Jul 2008 Posts: 1992 Location: Redmond, Oregon

so after changing the timing belt, lots of troubleshooting and progress today the car acts like it's missing. come to find out it's running REALLY rich.

sprayed some carb cleaner around the throttle body, we have some serious vacuum leaks. new gaskets on order... can i assume it's strictly due to the massive amount of vacuum leaks or should i be looking more towards the cold start injector?

PS: the timing belt is the easiest timing belt setup i've ever changed, that was a cakewalk, not sure why i was worried.
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- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

Unmetered air (vacuum leaks) will cause it to run lean. How do you know it is running rich? Black exhaust, gas smell from the exhaust?

Definitely fix the vacuum leaks. On the rich running, try unplugging the CSV to see if that helps.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

CorsePerVita · Joined: 25 Jul 2008 Posts: 1992 Location: Redmond, Oregon

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

Make sure it isn't oil as oil in the combustion chamber will absorb fuel and smell like it. If your 924 isn't equipped with a catalytic convertor, that much extra fuel would be indicated by a black exhaust. I would also check the spark to make sure it is adequate to properly burn the fuel. If weak, the plugs can't heat up enough to provide proper combustion. IIRC the 77 MY has a points type ignition. Have you checked the gap/dwell?

Dennis
_________________
81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

CorsePerVita · Joined: 25 Jul 2008 Posts: 1992 Location: Redmond, Oregon

plugs are good, gap is good on the plugs, exhaust is clear. new wires, new plugs, new cap, new rotor on the distributor.
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

CorsePerVita · Joined: 25 Jul 2008 Posts: 1992 Location: Redmond, Oregon

2Fast · Joined: 09 Dec 2007 Posts: 459 Location: Klamath Falls, OR

Are you sure its oil fouling and not just carbon build up? Your car, like mine, has been sitting around for a long time, it would be normal to expect it to run a little awkuard for the first few miles or so. I know my plugs (which were new) at first were oil fouled, and after running it for awhile, I found that i was getting better oil control, and my plugs switched from oil fouled to carbon baked lol. Before replacing the rings, (if that is where you are headed) I would definitly drop a quart or so of ATF fluid in there, and let it run for awhile with it in the motor. It did wonders for breaking in my motor.
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=====>Alex<=====
1979 Porsche 924 NA 5spd
1979 Parts Porshce 924 NA 5spd

2Fast · Joined: 09 Dec 2007 Posts: 459 Location: Klamath Falls, OR

CorsePerVita · Joined: 25 Jul 2008 Posts: 1992 Location: Redmond, Oregon

could be several. sounds like i've got a few things to keep looking at and I will check into them next weekend. my 4 day off spree of my garage vacation of working on the porsche is over, and it's back to work. it was fun while it lasted but it'll have to wait till next week. at least it's in condition now that i feel comfortable driving it around. i may go drive it a bit this week after work to run it a bit.

i've also found some nasty coolant leaks.
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS