cal44

After reading some of the posts about their 911's not starting I thought.....that will never happen to me..... I don't work on it.

It's only when I touch wrench to a car do they stop running.

I had a fellow coming over to take a look at my beauty for sale.
Guess what?

I just ordered two DMEs and two fuel relays. I like two of everything.
I called the guy and asked if we could have a redo.
I hope one of the relays is the problem.

Damn

WPOZZZ

She doesn't want to be sold.

Ed Hughes

If the guy knows anything about DME's, he should forgive this incident.

cal44

The latest is I just recieved my DME relay, it didn't help. I also changed out the fuel relay. It still will not start..........darn it. The old DME states 15amp. The new one is 30amp. I will call the supplier and see whats up.
I will next check the fuel pump, to see if it is pumping. I suspect when I remove the plate covering the pump, I should, with the ignition on, be able to feel it vibrating. Is this correct? I am not mechanicly inclined.

dbryant61

You should be able to hear it without removing anything. The fuel pump on the 3.2 is different from an SC, but I can hear mine from the driver's seat.

old man neri

Doesn't the engine have to be cranking to for the fuel pump to engage?

cal44

You may be correct. Is there a way to test it if I am by myself? Thanks, Mike

old man neri

Do you have a bently? It probably has a procedure.

Peter Zimmermann

You need an assistant. Remove the skid plate under the pump, connect a test light to the power side of the pump and watch the light when a helper cranks the engine. You should have power while cranking...you might be able to do this yourself if you have a long jumper wire that you can bring into the trunk compartment from the pump, and connect the test light between that wire and the ground terminal of the battery.

WHATEVER YOU DO - MAKE SURE THAT THE CAR IS PROPERLY SUPPORTED ON A LEVEL FLOOR, AND IF THE REAR WHEELS ARE DOWN MAKE DARNED SURE THAT THE CAR IS IN NEUTRAL!!!

dbryant61

Neri: "Doesn't the engine have to be cranking to for the fuel pump to engage?"

EDIT BY AUTHOR:

I originally wrote:

"Nope. Not on an SC (or other CIS cars). You just turn the key to "ON" and the fuel pump comes on. Audible whining noise.

Does this not happen with a Motronic car? Peter?"

I have ben corrected. The whining apparently is the ignition module. The fuel pump does not engage until the starter is cranking."

Peter Zimmermann

SC and Motronic cars all have a built in safety circuit that shuts off the fuel pump(s) in the event of an accident that shuts off the engine, but the ignition stays on. This translates to a system that prevents a CIS or Motronic car's pump from running with only ignition.

The thought was to prevent pumping gallons of raw fuel out of a torn-open gas line. The system functions via a sensor plate/housing switch on CIS cars (including Turbos), and is handled through the electronics on 3.2 liter cars.

Over many years at the shop I saw some 911s that had been in horrific accidents (unfortunately some involved fatalities), and I can not recall a single car that caught on fire because of an accident. Pretty remarkable.

If your pump runs with the ignition on, I strongly urge you to diagnose the system and correct any problems!

cal44

Thank you Mr. Z. I would like a comment from you concerning the new DME relays a 30amps as opposed to the old 15amps. Mike

old man neri

I think it just means it is rated for more juice. In theory there should be less chance of it going than a 15amp model. A relay should not act as a fuse.

theiceman

Dbryant that is incorrect. You should edit your post. The whining is the ignition module. The pump comes on when you are cranking.

cal44

I was reading on the Pelican website tech section, where I can jumper from number 6 fuse and touch #5 or #7, on the bottom of the fuse terminal and it will bypass the safety and make the fuel pump run. Anyone done this and is there a downside?