3.3 turbo trouble during first drive of season.

[puddy]

My car is a 1975 911 with a 3.3 turbo motor, dual plug and CIS system using Tec 1 electromotive ignition system. The PO did a little security feature, he said, by wiring the fuel pump so that the car won't start unless the key is in the RUN position, then pull the turn signal back, which triggers the fuel pumps, then turn over the engine and VROOM.

I did a little work on the car over the winter. Installed a new steering wheel so i'm not sure if this would have changed anything with this "security feature". I also installed an Auxilliary Air Bypass valve that the PO gave me, he said he couldn't get the car running right with it. He had blocked off the intercooler port and intake port where the AABV is normally installed between. So last fall the car would have to be warmed up before it would idle and drive without stalling. Once warmed up it would be fine, idle nice and never stall. SO over the winter I tested the AABV and it seemed to work and would slowly close over a few minutes, so I reinstalled it. Once reinstalled, the car would start great fast idle then slowly idle down to a nice 6 or 700 rpm. But last night was the first night I actually drove the car after putting it away over the winter, aside from a few time I started it over the winter.

So heres what happened last night. I took the car for a drive around the neighbor hood, slowly, trying to bed in new front brakes, after a couple minutes it just died slowing down for a turn. I pull over restart is but took some pumping of gas to get it started. Drive a little further not thinking I have a problem other than its been sitting all winter and only run a few times. Dies on me again. After trying a few times to restart it and killing the battery in the process, I see one of the hoses for the AABV came off (forgot the put clamp on). So I walk home, get my truck, charger and some fresh gas, thinking maybe I had run out of gas and my gauge wasn't functioning properly or the gas over the winter was bad? A nice guy lets me charge the car in his driveway, I add gas, reattach hose on AABV, car fires up nice, he follows me home in the car, then drives me back to my truck, great guy, i'll make it up to him.

So i'm home now, reattach the hose that came off permanently with hose clamps, thinking this caused my problems. I get brave and decide to drive further to the gas station to top up the tank with fresh fuel. Well theres a long stretch to the gas station, so I'm in 2nd going to boost and it falls on its face, no boost or power but still running, I shift to 3rd, running fine, accelerate to boost again falls on its face no boost, coming up to intersection she dies on me again, but I have enough momentum to wheel into the gas station and fill the tank. try to restart, kill battery again in the process. Get a boost off another nice lady, has a hard time wanting to stay running but I keep idle high and get almost home, onto my street she dies again. I push it home a block with help of an awesome neighbour who happened to be walking by. At this point i'm thinking about just throwing a match into her and watching her burn, but instead I get it into the garage, put charger on it, and remove the AABV and put it back to the way the PO had it with the holes blocked off. Try to restart with battery charging, no luck doesn't' seem to want to fire. Frustrated its getting late and i'm supposed to be in an IDS with the Porsche club this morning. This probelm is bigger than me I think. I let it trickle charge all night. In the morning I try to start agin, fries but after a few second it dies, won't stay running, did this over and over again, even adding throttle it just dies. Both fuel pumps are running fine. So my plans for IDS today are officially off.

So i'm thinking could there just be a problem with bad gas or something in a fuel line? Do the Auxilliary Air Bypass Valve contribute to problems or just coincidence? I'm going to have a local Porsche expert look at it soon when he has time but i'm wondering what I can try to do myself with limited tools. Any advise is appreciated. I have two weeks ot sort it our before the next IDS session. If I miss that one I won't be doing any DE days with the PCA this year

Another note I have new spark plugs but have not installed yet and will be installing new plug wires soon too. I don't know if they are contributing to the problem but it all ran fine last fall as it was.

[gsxrken]

Often times running but stalling stumbling and barely taking gas is fuel pump or delivery related. These car run richer when there isn't enough pressure, basically the opposite of EFI.
I'd suggest you get a CIS pressure test gauge kit and verify your warm and cold pressures. It may save you untold $$ at a shop, this time and in the future.

[puddy]

My father thinks its an intermittent electrical issue, since it keep stalling after the initial fire up. If I leave the key turned to the start position the car runs until i let it go. He was wondering if it would have a ballast resistor that is bad?

[quattrorunner]

I've had bad gas do this but also I've had boost leaks act like that. I would think you need to check every intake connection for loose clamps or bad o-ring if you use a regular 930 turbo and intercooler. It doesn't seem to big to me. Maybe use some fuel system cleaner and let it run only driving around you'r home once you've checked all hoses and intake lines etc. Anything that sees vacuum and boost need checked.
Not a big deal. You'll get it.

[ersatzS2]

I will be very curious to hear if the cause is bad gas. Seems like an escalation in complaints just in the last 12 mos. regarding gas going bad after only 4-5 mos. A friend who is a Lotus mechanic says he has rebuilt two CIS units when the innards became a gooey mess. Jay Leno just did an article (not sure where; sports car market? Octane?) complaining about new gas formulations and the grief they bring to his collection. So let us know.

[full quack]

To me, if it stays running with the key held in the "start" position, then instantly dies when you let the ignition switch return to the "run" position....I would say faulty ignition switch or corresponding wiring from the switch to the engine.

Intermittent short/ground while driving, also sounds like a faulty electrical circuit, with a bump here or there leading to a short/ground condition.

I'm still thinking your ignition switch has gone south on you.

My .02 worth.

Mark

[puddy]

Well gentlemen, I found the problem this afternoon and I do feel a quite dumb for not noticing this sooner but the negative battery terminal was loose. I tightened it up and everything worked perfectly! I just got the car last fall and never did anything to the battery other than charge it but I never noticed the clamp was loose! So I took it for a drive and it seems to work as It did last fall, and I reinstalled the AABV which is very nice to have. I hope this fix isn't too good to be true!

[mark houghton]

Turns out your dad's lame advice (electrical) was correct after all (sans the ballast resistors anyway). Give him a welcome and warm invite to join our forum!
I was about to join Mark-the-Quack's advice re: ignition switch, but now I see you've found the issue on your own! Damn, doesn't that feel gooood??? Now go out and drive the holy crap outa her.

[puddy]

Thanks Mark, my dad is an old school hot rodder and admits he knows nothing of my car but he loves it and the power surprises him!

Another question, the hose between my Auxillary air bypass valve and intake collapses to almost flat when the engine is running, is that normal?

[mark houghton]

Originally Posted by puddy

Thanks Mark, my dad is an old school hot rodder and admits he knows nothing of my car but he loves it and the power surprises him!

Another question, the hose between my Auxillary air bypass valve and intake collapses to almost flat when the engine is running, is that normal?

No it's not...the hose is shot. By collapsing, it will not let the air from the open AAR into the manifold and will not sustain high idle when cold as a result. That happens to be a simple diagnostic tool to see if your AAR is open or not at cold idle; pinch the hose closed and watch the idle speed drop.
Get a new hose from your local auto store, unless you're a purist and absolutely must have one made in the Mother Country. It's a freakin' hose, for Christ's sake! (but make sure it has the proper bend and is stout enough not to collapse again).

[Das Schnell Ei]

Originally Posted by JFairman

Ballast resistors havn't been used on ignition coils since the days of points and condensor ignitions. Lame advice and it shows he knows nothing about your car.

.......... classy