Ben951S

Still getting my car squared away.

~40psi after being run. Within an hour of sitting, it's less than half. 2 hours of sitting, it's at 0.

Oil smells gassy, gas runs on 3 cylinders in the morning (likely from leaky injector flooding a cylinder).

How quickly will the contaminated oil be a problem? Should I stop driving the car completely?

Lastly, are new injectors the only way to fix this (or could it just be a rebuild with the little service kits (new cap, o-ring, etc)? I think 944online had the best price on a set of injectors.

Thank you for your thoughts RL.


[My main concern is
1) Running rich (low 19-22mpg), 3 cylinders on an overnight start
2) oil smelly gassy

Replaced the DME Temp sensor already too, wiring seemed good. Using A-Tune, and other stuff in my sig]

dillon410021

mine does that too.

Ben951S

I am just worried about all the 'washing the cylinders'/wearing things out...

SamGrant951

A bad fuel pump check valve will cause the pressure to drop quickly.

Ben951S

Will it cause my running rich/3cylinders thing?

And am I losing pressure at a regular interval or is it likely due to a leak? Clarks garage only mentions the 20 min test and it's a bit cold and windy for that.

PorschePower

You can pinch off the return and supply lines to isolate parts of the fuel system. Take the injector rail out, pressurize the system and let it sit. You'll be able to see the injectors leaking.

Ben951S

If I didn't live in an apartment complex and wasn't 30 degrees outside, I'd consider it.

I just need to know the 'normal' going to zero amount of time.

Also, I just did the (from searching) take the dipstick out and see how long it takes to drip onto a rag. It takes over 60 seconds. That's on cold oil (mix of 0w and 15w (0-40, 15-50 mobil1)). So that kind of cheers me up.

Thoughts?

xsbank

Gas in the oil is annoying but the worst effect is the washed cylinder walls from the leaking injectors, then starting that very expensive engine with 'clean' cylinder walls. Not good. Back in the dark ages, aircraft (radial - don't know about inline) engines had an Oil Dilution pump which injected gasoline into the oil to thin it out for starting when the O.A. temps were very cold. It just evaporates when the oil gets hot and there wasn't much in the actual engines as they were dry sump. Don't know what this has to do with Porsches but old farts do tend to ramble...

gtroth

Sounds like it might be fpr. When it fails fuel pressure will leak down quickly and fuel pressure will go way high (>100psi), causing engine to run rich. And a fuel injector may not work at that pressure.
Measure fuel pressure and fuel pressure leak down.

Ben951S

Fuel pressure seems 'good'. It's a new Bosch 3bar. I run around 41 if I recall correctly, the 'peak' was about 55 (full boost, I make about 14psi). So it seems to be in range. Thanks for the input thusfar.

The rough cold start/3 cylinder idle makes me think a stuck or leaky injector (from searching).

bad_monkey

For what it's worth my NA has sat for a longish period (about 2 months) and retained fuel pressure. I don't know how much - it was a bit of a surprise when depressurising the rail though.

I'd suggest checking the return valve first - I always check the cheaper fix, although the stuck injector might come good with a clean - or send out to one of those ultrasonic cleaning places.

Good luck!

dontnow

After a cold start how long does it run on 3 cylinders? ie..If it lasts for 5 minutes, I would start it, run for 2-3 minutes turn off and pull the plugs, one may be fuel fouled. If it is, I would start with an injector rebuild.

Ben951S

3 cylinders for about 30-45seconds (I usually give it gas so the car doesn't rock side to side, which accelerates the recovery to a smooth idle).

I pulled injector wires today and was not able to ID a specific injector that was problematic. Though it did seem to settle out pretty well once I stopped pulling them. I will pay close attention to the injector harness itself, and see if it continues tomorrow. Took me all of 30-50 seconds to pull each injector wire (I had pre-removed the metal clips prior to startup).

dontnow

How about the spark plugs?

Ben951S

Spark plugs have less than 500 miles on them.

Here's some fun though. I've been working with Rogue Tuning (never blamed my A-Tune, but seemed to happen right at the same time (though got the car back after 2 months away too) ). He linked me to...

http://dorkiphus.net/porsche/showthread.php?t=16863

Which shows the carrera DME board. Geee, look familiar? and I remember messing with those (11 at least) injector areas too, trying to clean them up.

First clean up attempt in October:


Cleaned up now (used isopropyl and qtips to clean the brown, which should not do anything), and reflowed, again:


So far so good, I will know tomorrow morning for certain. Car still runs rich, but at least it is firing right.