justinsrx7

I took my 3.2 out today for the first ride of the season today. I drove it to work (20 minutes), drove to the Porsche dealership and then to lunch (40 minutes). After lunch, I tried to start the car and the trouble began. The car started but ran very rough and then died after a few seconds. Pressing the gas pedal had zero effect (except maybe to kill the engine a bit quicker). I tried to start the car 10 times, and 10 times it ran rough and then died after a few seconds.

It is a beautiful day today in Toronto, and I just bought a Porsche cap so that I could take the roof down on my way home and not get sunburnt. How disappointing. Now the problem diagnosis begins. Any ideas?

imcarthur

The DME relay is the 1st culprit to check. You should always carry a spare because they are prone to failure. It's a small black relay on the front of the DME under the passenger seat - assuming your 3.2 was installed normally.

Ian

Mike Murphy

Well, you could just have bad fuel. I would consider replacing the fuel filter if it hasn't been done already. Also, check for moisture in the distributor cap.

imcarthur

I should have said driver's seat . . .

But a good point from murphyslaw1978. Did you treat the gas before storage?

Ian

scarceller

Could be the Air Flow Meter carbon track. The symptom you descripe is what happens when the AFM signal is not correct. You can find full detailed spec on the AFM and howto test it at my site here:
http://members.***.net/widebody/
at the bottom of the page is the link to the AFM doc I have been working on. If you read through it you'll learn how to quickly test it.

Basically you are looking to be sure you get 0-5 volt signal on the signal line. The voltage will start at 0v or so with the barn door fully closed. Then with your finger or a pencil (eraser end) push the door open slowly and verify the voltage goes from 0v to about 5v when the door is fully opened. You are looking for dead spots in the voltage. Really test the 1v to 3v section as this is where the car runs most of the time.

imcarthur

Wow, scarceller. Great AFM doc. Another project for the summer.

Ian

justinsrx7

When I put the car away in November, I filled the gas tank full and put in fuel stabilizer, so I doubt it is a bad fuel issue.

If the DME relay is bad, what would the symptoms be. When I drove the car before the issue, it started fine and ran fine, so I wonder if the DME decided to fail which is why it wouldn't start. How do you know if the DME relay is gone, or do you just start be replacing it and see if the engine runs?

I will check the AFM next. It could be as simple as fouled spark plugs or a bad cap or rotor, but it's just weird that it happened so suddenly.

dshepp806

They all seem sudden when they happen...first things first,..DME relay changeout. With that spare it should be "bada' bing, bada' bang"...?

then:

fire, fuel or air.

How old is the dist. cap/rotor? Have a look underneath...


Reseat all sensor connectors (reachable ones), spark plug wires, coil wire, etc.

Then it's real T/S time!!

Best,

imcarthur

I had my fuel pump fail while I was driving. It was like a switch turned off. I flat-bedded the car home & went to the Porsche dealer for the DME relay which brought me no relief. A new fuel pump did. There is an easy fuel pump test in the Bentley.

The DME relay hangs cantilevered in front of the DME & it plugs into the harness. The way it is mounted allows it to absorb every bump. I think cold solder joints are its demon but they are cheap to replace.

Ian

justinsrx7

When the fuel pump went, did the car just stop running or did it just run rough and then die like mine. I don't have a Bentley manual yet, so if you could tell me what the easy test is, that would be great. - Side note, did you talk to Vicky about a 19A?

justinsrx7

This is really useful stuff. Thanks!

imcarthur

No faltering. It just stopped as I was accellerating on to the 404 southbound.

I am playing phone tag with Vicky but I have an appraisal update in the works. Bruce Farrow also told me that Chubb offers 19As & gave me a broker lead so I'll get quotes from both.

PM your email & I'll pdf the pump/relay checks.

Ian

dshepp806

Justinsrx7,

That's one helluva shine you' have on that baby!!! Looks killer!!!


Best,

justinsrx7

Thanks. It's funny but it gives off almost no shine sitting on top of a hoist at the mechanics shop...LOL.

It looks like the issue is the electric part of the ignition switch. I ordered one which should be here on Friday, so we will know for sure at that point.

Oh yeah, I have downloaded the manual, Thanks.

Rotten Robby

While it is good advice to keep a DME relay in the glovebox, my experience has been that when they go you can crank until the battery dies and it will not fire. I would chase the AFM or an electrical connection being loose first.