Charles Bradley

No the mechanic didn't replace them, even though I said to, bc he didn't want to throw parts at the problem without knowing what the actual problem was, and since both had tested out fine and when he pulled them, so he gave up and trucked it to Porsche.

Car was fine since returning to me, And here we go again today. Had 1/4 tank this morning, no issues and filled up. Few hours later, I am driving through the mountains of NC, tank down to about 1/4, and I have to pass a slower 18 wheeler. No power to make the pass, had to get back on right, then power surges back. Few miles later, same. On a hunch I pull off to get gas, engine dies as i pull up, but I fill up and she gets me to my destination without a hiccup. That's a fuel pump. Must have sucked one side dry and the other is basically dead. This after both the shop and the Dealer said both sides are good. So after I chew out the Service manager for giving me a huge bill, a pump problem that remains and a car that's still likely to strand me, he says they're paying to fix it right, and I guarantee they will. But I still have to get back to Alabama, can the only pump get me 5-6 hours back home so long as I keep it over 1/4 tank?

Question, can I sell the old DME, or repair and sell, and recoup some expense or is it not really worth my trouble.

Is this the correct part that I need for the Bosch sensor, and is this a fair price?

Oh I'm going to ask them to swap the old DME back in there and prove that it does not run with the old one and a new MAF. Question is, would a MAF failure exhibit the symptoms I was having before with the fueling? Would it make the car run 5-7 seconds and die repeatedly? On my other vehicles, it would not, it would cause stumbling/hesitation and possibly some rough running, but I don't know enough of the Porsche electronics to say for sure.

So the car is running again, the faulty DME was causing the FP#1 to not run, but it won't stay running now because one MAF is bad. So did the MAF kill the DME or the DME failure kill the MAF? Since it happened at the same time and there were zero issues with performance beforehand. So I get to add 1 new MAF to the bill to drive it out of the dealership. I'm getting the 2nd one aftermarket. Recommendations? This sounds very fishy to me.

Dealership diagnosed it as DME failure, no spares in Atlanta and I have to wait a week for it from Germany.

Apparently it passed all the continuity tests, I'm having it towed to a stealership to see if they can figure it out.

During my ownership of the car nothing has touched the DME. I have never felt the need to modify this car.

He said he had searched on his own Porsche mechanics forums for examples of actual DME failure, found none, and his buddy who worked at Brumos said he had never encountered one. I'm hopeful its not a DME, since that will add to an already high replacement cost for the pumps and related. Is there a wiring diagram available for your checks Brett, he may have it but I'd like to see it. Where is the chassis ground located for this circuit?

Both pumps passed volume and pressure testing, both nipples on the rail (L&R) are measuring between 62-65psi from prime to shutdown and holding after shutdown. DME still throwing a code for fuel relay and cutting spark to engine within 7ish seconds. New relays are in for both, no difference, code still sets. Both pumps had resistance measured and compared to spare pump from Porsche, matched within 0.01. Right within specs. Amperage draw from first pump was 9.7ish, 2nd was 7.x (adds to 15). Scanner shows no spiking, fuses are not blowing. So if something is wrong with the pumps then its not something he can find. Absolutely nothing is off spec. No broken hoses/lines in the tank. No water or trash in the tank. Yes he's using Porsche scanning equipment. I think its a wiring issue, possibly connection to DME or ground, since absolutely nothing else seems off about the car or has been off for quite some time, but I directed he change the two pumps anyway since its good maintenance, and maybe the computer is seeing something the scanner is not.

YES I do not know if he relieved pressure, all I know is that he said it read 65 psi during prime, run, and after failure.

It identifies relays 19 and 1/6, as well as Fuse 14, I found 13 was the other one by pulling off other diagrams. He told me both pumps hold 65psi throughout

As stated in the first post, I tried the fuses. Same behavior. This is actually the thread I was using as reference for the diagrams as to which to pull.

The tank is about 3/4 full actually, I had filled up before getting on the road. As I recall it was a little above 3/4 when I was on the side of the road.

Well we can't drive the car, the engine won't stay running more than 10 seconds before the computer cuts the spark and kills it. He's been pushing it in and out of his shop as he has had other cars prescheduled for service dropoffs. It will fire and run 10 seconds ad infinitum, I tried it at least 15 times as I was trying to figure out on the side of the road what it was doing. He has seen the same. It always fired right up immediately, and didn't drag any as I kept going, but I did stop just to ensure no further wear to the battery. I do not know if mine has a battery in the trunk, I thought they all did, but I know I have not replaced that battery. I did have the problem after getting gas, but 1.5 hours after getting gas. I had filled the tank up before heading out of town. No sputtering or other symptoms of water/trash in gas.

He's a Porsche owner and works on several, I know he has the Porsche testers. I replaced the battery under the seat myself a couple years ago, voltage has been perfect otherwise.

If they are maintaining 65psi from engine prime until engine shutdown, then how is that not telling me that they are putting out adequate volume

Output as in the pressure? Both put out 65psi

Tank was completely filled up.

Own an 06 Cayenne S since it crossed 98K. Its now at 170K. Has been serviced routinely by the stealership, except for a few things I've figured out myself. This one has me and my mechanic stumped however. Driving along at 50mph, I had to pass a slower car on the right. I pull out, give it gas, and engine just freaks out. Revs go up, seems to act like it was out of gear or the TC just crapped out immediately. Had just enough power to make the pass. I got a quarter mile further and limped off the road, put it in P, and the engine died. Car will fire, run 10 seconds, and die. This suggested to me that it was a fuel pump issue. Gauges all read fine, no CEL at the time. I had a small scanner with me. Since I was 2 hours from home, I researched on my phone and saw that a fuel pump failure happens on these cars and you could pull the fuses and trick it into running on the secondary pump. I tried this, and the same behavior resulted. 10 seconds and dead. Had it towed to a local mechanic I trust, an import guy who works on a lot of Germans. He looked at the pumps, both put out 65psi. He read the Ohms and compared to a new spare he had handy, checks out fine. He tried replacing relays, same behavior. Basically you have fuel to start the motor, fuel pressure holds, and then the computer is killing the engine. So we're at a wiring issue now. What would cause the engine computer to let the engine fire and cut it off within 10 seconds? Its not seeing some reading from a sensor or some pin issue. He did look at the crankshaft position and that was correct, and the computer is seeing it correctly. Has anyone run into this bug before? As of today, he said the codes it was showing were 907 (load mgmt.), a 1049, a Fuel pump no signal (set when I pulled the fuse we think), and a Check Brake light error (one of my 3rd bulbs is out).