Ed Hughes

She at least let me down for the first time ever, though. I sent some company on their way this morning and started Ruby up for a romp up the mountain. I got a few miles away, and up to a decent temp and ran her to 5K a few times, then once at 5.5K, and I was headed for 6 when she lost power like a switch was thrown. Deader than a nail.

The one thing I did notice when it happened, is that when I let off the throttle when it happened, it seemed to want to run, then when I tried to go back on the gas, there was nothing. She cranked on the starter no problem, but not a gasp.

No loud clangs, no explosions, no nothing, she just shut down at about 5800rpm. So, I went and got my trailer and got her home off of a turnout on a very narrow two lane mountain road-that was fun.

A quick check shows there is fuel in the system. That is all I know; I don't know the pressure. I suppose that since I felt what I did for the fleeting instant when it happened, I'm going to key in on this to see if something in the tank may've clogged the pickup or something. Maybe the fuel pump went lame?

I'd still think that if I had SOME fuel pressure as shown when I crack the fuel rail line, it would at least try to run? One thing that does stick in my mind is that when I cracked the nut on the fuel line that connects the rails, right opposite the test port on #1, I didn't have real high pressure fuel squirting out. It more or less dribbled. I then cranked the engine without being able to look at that line, and fuel had certainly pumped out into a rag I put under the line. Again, "some" fuel, but whether it is at the 2.3-2.7 bar pressure I should have, I don't know. Would "some" fuel allow it to at least turn over and then die, or sputter? I have no signs of life as it cranks over.

A second quick check with a grounded spark plug shows spark. I also swapped in a new DME relay.

I really hope it is something in the fuel, the injection system or DME. I'd think if something got hosed up internally, I'd have had notice, and it might even run. Heck, even when I did my money shift a few years ago, the engine actually still ran.

So, this will be playing in my mind for my trip to Le Mans. The reality is I'm not going to have any more time to play with it until we return in a couple of weeks.

With the quick check of fuel and spark, the other big component to make an engine run is compression. But again, even if something catastrophic happened in one or two or three cylinders, I'd have some sign of life, no matter how poor it may run. So, I'll remain optimistic that it is something simple.

RJT

I think she was just sad that you were leaving her for a while, that's all.... Or maybe a little jealous.

I hope it's something simple.

whalebird

I don't know Ed. I need to think, but what about the belt inside the 964 dizzy. Usually they will still run on 6 of the 12, but... You got me thinking ignition because of the sudden "off", fuel usually gives something of a warning, but anything can happen.
This will be a simple deal so don't sweat it on your trip.

I am curious about the splitter set up for the ignition. I've never set one of those up, so I naturally ask what, if any, load it puts on the DME. Is the signal, being split, have a lower signal voltage? Just questions I have and possibly unrelated.

Sorry. I know that sinking feeling.

whalebird

Ed if it were a mechanical grenade you would know. Nothing you did inside the motor would do what your describing...I just can't see it based on your description.

Ed Hughes

That's what my wife said. We all know that women can be moody.

I agree WB. Of course, the aspect of a mechanical issue is at the top of my fears. Unless I lost compression in all 6 cylinders somehow, I can't see my work being the problem.

If the dizzy belt broke, it would still have a bank of plugs firing, the danger being detonation. But, it would run.

The splitter doesn't put and load on the DME, which is why it exists. Of course, it could be the problem, but a quick check of spark in two cyls tells me it would at least sputter.

So, when I get back:

1. Check fuel pump operation.
2. Check fuel pressure.
3. Check power to injectors.
4. Check speed, reference sensors.
5. Check splitter connections.
6. Inspection of dizzy to make sure all is well there.
7. Compression check.
8. Full DME troubleshoot, if necessary.

ivangene

sorry Ed - good luck getting the fire back in her. Maybe something super simple (loose wire)

w00tPORSCHE

I'm sure it is a testing time for you Ed. Please take a much needed break at LeMan's; you've worked hard on Ruby...She will reward you handsomely when you return. I promise.

Rouxzy

Ed, the exact same thing happened to me. Running great and then someone hit the switch. It turns out my 30 year old fuel pump quit without any warning at all. I feel your pain. It just didn't look right seeing her being pulled onto the ramp truck.
Tom

Ed Hughes

Thanks guys. I'm convincing myself this is only going to be $500 worth of new fuel system parts! I'm really leaning in that direction.

Tom, I thank you for at least giving me a glimmer of hope in that regard.

When I popped my rails off to remove the injectors for cleaning, I got a very pressurized spray of fuel with removal of the first fitting. I did not get anywhere close to that today. It was a liquid "dribble". My thought is that the high pressure is absolutely needed to get fuel to spray thru the injector when it energizes. 2.3-2.7bar is 33-40psi! There is no way I had that. I'll start with fuel pump and go thru the pressure system on the intake: regulators, etc.

My first instinct was fuel starvation, so, go with the first iimpression....right?

I'll probably have time to squirt some starting fluid in the ICV hose tomorrow. If she fires, that will give me confirmation that I'm on the right track, I believe.

I need to get all the negative thoughts on me screwing something up during the build out of my brain. I have a couple of hundred miles on her now, I'd like to think I'd have seen a mechanical failure right off the bat. I did take it to 6K the other day once, with no issue.

2specs

Hope it's just a quick fix. I would send you my existing fuel pump to test but it's only good till an 83.

rusnak

It sounds almost surely fuel pressure related, probably minor. If you have a simple fuel pressure gauge, it would be a quick test to jumper the dme socket.

Ed Hughes

Thanks for the offer Sammy. I'll work it out.

I need to order a new one actually, my last one was never returned. I'll get one of the CIS kits with the proper adapter. I think its a 12mm X 1.5mm thread at the test port. You can jumper the DME socket or the 6/7 fuse terminals, IIRC.

rusnak

Yes, according to the neat-o dme test plan that Lou Parrota posted in the "coasted to a stop" thread. The Bosch master test kit is nice. HF sells a cheapo one, actually only the gauge itself is cheapo.


Edit: Oops, it's fuse #16 and #17.

lparrotta

How many of us we hit by fuel pump gremlins this week? I'm troubleshooting the same thing.

Ed Hughes

That's what I was thinking, the Carrera flu bug.....ice's buddy up in Canada too.