Euromagination

Hey all. Not so great news...

I'm over here at my gf's place and we just walked out to my 964 to go shopping about 10 minutes ago, and the Porsche ended up dying on me before we even got out of the parking area...

Let me also state that, if it makes any difference, I just did a valve adjustment, oil change, fuel/oil filter change, and new spark plugs and valve cover gaskets earlier this week but I've driven the car about 150-200 miles since then and everything has been fine. No abnormal leaks... nothing. Also, the spark plug wires were in good condition when I inspected them last Tuesday while doing that valve adj., et cetera.

Here are the play-by-play details of what just happened:

--Started the car (cold start), and it started right up; no problem.
--The car idled normally for about 60 seconds while I took my time to plug my iPod in and find a certain track
--Car continued to 'act' normal as I left the parking spot (in reverse gear)
--I then put the car in 1st... it drove fine for about 30 feet then started bucking violently...
--RPM's dropped to 600, then 400... the car continued bucking violently until it finally stalled out after another 20 feet (for a total drive of about 50 feet)
--I soiled myself (not really, but close)
--I let the car sit for a minute or so while I thought about what just happened; trying to get a grip on what it could be...
--Decided to try to start it again... It started right up just as it normally does, then after about 5 seconds is stalled out again...
--All lights were on. Every light in the xmas tree including the master... But I think that's because the ignition was in the 'on' position after the car stalled out the second time.


What could this be and where do I start? What ever it is, I know it's gonna suck to fix.




Thnx,
Harry

Euromagination

so i've been out there for about a half hour just checking the car out. all the connections, making sure the coils are plugged in (top ones anyway; i didn't drop to the ground to look at the lower ones), et cetera. i swapped the DME relay with both of my spares but there was no positive result.

i tried starting the car 4 times... it got close to starting every time, and 1 out of those 4 times it even ran for about 3 seconds. i didn't depress the throttle pedal any of those times since i'm kinda cautious of doing that with a fuel injected car.

after trying and failing to start it those few times, i decided it would be beating a dead horse so here i am.

i'm still not sure where to continue with this, but i want to. i wonder if i should go back out there and get on the ground to see if it's one of the lower coils that may have popped out of the valve cover somehow?

this car is crazy.

ttAmerica RoadsterAWD

Harry, take it a step at a time. Check these:
1. Electricity at the spark plug
2. Fuel in the fuel rail
3. correct timing



1. Take the closest accessible spark plug boot and pull it out......take a phillips screwdriver and gently place the tip into the boot so that it touches the metal binding loop. Now, place the screwdriver's shaft next to any metal, allowing for about 2-3mm space. ask girlfriend to crank the engine. You should see an arc of electricity clearly without any problems. If you don't, check the coil...don't know exactly how to check the coil, but if it's ok, then you go upstream from there.

2. I *think* you should have a fuel rail similar to mine, on the driver side in the engine compartment, look for the rail that feeds the injectors. Somewhere on this rail you will see a nipple with a cap that looks like a tire cap. unscrew it, get some rags under it and while the ignition is on, push the center metal to see if you get pressurized gas. It look identical to a tire/wheel valve with the inside metal being "pushable".

Not sure exactly how to check timing.....maybe somebody will chime in....

Jaime

Marc Shaw

I'd suggest a look at the fuel filter and/or fuel pump as it sounds like it stalled as it was starved.

Marc

Richard Curtis

I'd suggest checking something even more simple: Remove the negative battery cable, clean the battery post and BOTH ends of the cable plus clean (wire brush) the negative battery cable connection to the car BODY. Reinstall and see if the car runs normally.

If you do check for spark at the spark plug, the color of the spark has to be blue (good coil). If it's any other color (red, orange, yellow), the coil is BAD. Hope this helps.

Euromagination

if fuel is present in the fuel rail, and i'd like to test the pump... would pulling the fuel pump relay produce the same results as a dead fuel pump?? i was thinking of pulling R41, then trying to start the car--just to see if it acts the same--but i'm not sure what other electronic effects this will have?? i'm not sure of any other way to test the fuel pump other than just pulling the R41 relay...

damn thing just keeps starting then immediately stalling, or just not starting at all as if it's starved of fuel... i can't find a problem and the coils are good.

also... if i feel that it's on the edge of starting, should i or should i not give it just a little bit of throttle?

Peter Badore

For definitive results you should test the fuel pressure with a gauge at the fuel rail test port. In addition to a clogged filter in the engine compartment there is another location for a clog to develop. In the fuel system there is a the nylon fuel stainer in the fuel tank opening that feeds the fuel pump. And, of course, there always the suspect DME relay which is easy to access and change. The DME relay failure usually is complete not permitting any fuel pump operation but not always ( the DME failures in my cars were 100%).

Red Line

After trying to crank your engine over several times you should start to smell gas. Pull out a spark plug and see if it's wet with fuel. If it is you might want to look @ your Mass Air Flow Sensor. Don't 4 get about the O2. Your engine needs fuel,spark ,and O2 to start. It's a long shot but give it a go.
You can take the MAF out of the car and hook it up to a volt meter and test for dead spots on the board. If the MAF is bad it will make your car act just like you talked about above.


Good luck..........

Peter Badore

Also, you should look at the clamps securing the hoses between the air flow meter and the throttle body. A loose clamp or an improperly seated duct/hose will give a false air reading and cause a problem similar to the one you are describing. I had three different 944s have this type of problem.

Indycam

Got spark ?
Got starter fluid ?

ttAmerica RoadsterAWD

So, Harry, What's up? did you try the above??

BGLeduc

This sounds like the airflow meter wiring harness issue. With all the work you did, I am guessing the harness was moved around a bit.,,,now you have a new problem Search around, there is a TSB for it....I had that problem and it scared the crap out of me when it happenned.

"Violent" does not do justice to the way the car behaves when this happens.

The good news.....its a very cheap fix.

Brian

Euromagination

So here are today's happenings...

--I went out to the C2, tested for spark... I have spark.
--I then unhooked the battery again, then cleaned the posts, tried to start it and it started right up like a champion!!
--So I'm like "WTF? How did this thing just start up? I'm not complaining though so I'll drive it...
--My GF was with me so I asked her to get in her car and follow me around for a little drive. (good thing i did...)

--I drove it about 5 miles (everything was perfect), when I decided to pull into a gas station to fuel up. There was a line, however, so I had to wait...
--While I was waiting (and the car was idling), suddenly as it idled it started to lose power again. Not all of a sudden, but gradually...
--Soon it just stalled out... (DAMN IT!!!)

--I then had the station attendant put some fuel in the car, and I started it again... It started right up again!!!
--I leave the gas station, get two blocks and it dies again!!! (This time for good.)

It's now parked in front of a fellow Porsche owner's house, by chance. He's quite a nice gentleman who who has a couple Porsches of his own so he walked out to see what the problem was when he saw my dead Porsche in front of his house. I guess my car chose a good spot to stall out.

SO...

--I have spark...(as I said)
--The car is being staved of fuel somehow; I'm sure of this. The car tries its best to start but just doesn't get fuel.
--It's not a clogged fuel filter (I checked; AND anyway it's brand new)
--I'm guessing it's the fuel pump.

The reason why I think it's the fuel pump is because when I had my girlfriend try to turn the engine over, I heard no whining from the fuel pump at all, but I heard tons of clicking from the relays.

Knowing that the DME/fuel pump relay (R41) has a dual role as the DME's relay as well as the fuel pump's relay, I pulled it out and had my girlfriend try to turn the engine over (knowing it wouldn't work)... I just wanted to see if it would act the same without the relay as it did with the relay.... and since it *did* act the same with/without it, that's how I came to the conclusion that it's probably my fuel pump, since I hear no whining from it.

Punchline: My car is acting like it doesn't have a DME relay, but it does. In fact it has three and I've swapped all of them in/out. LOL

So with this said... if I buy starter fluid tomorrow (didn't have a chance today) and give the car a couple squirts while trying to start it, and it runs better while spraying the fluid, should I go on ahead and order that new fuel pump??? Or is my scientific method in this case flawed???

Also, if it's the fuel pump, why was it good at first, then after about ten minutes it started to mess up?

Thnx for the help.


-Harry

Bearclaw

Don't go crazy with the starting fluid. That is wicked sh*t. A couple little shots maybe to diagose for a "yes-or-no", but it's too violent to keep loading up a combustion chamber with.

ttAmerica RoadsterAWD

If you have an ohmeter, go under the car and check for voltages at the wires that supply the fuel pump. If you turn the ignition "on", but don't hear or feel the fuel pump run, it's gotta be either the fuel pump (internal problem),or wire/connector problem to it. Start at the fuel pump to check for live electrical connections, then follow up back to the fuel cell. You can even use one of those pointy screwdriver-like deals with a little light bulb that glow when you touch a live wire.

Check it out and report to us with results.

Jaime