3.6 Died

Rouxzy · 10-06-2006, 07:30 AM

I was driving down the road and then all of a sudden nothing. It was almost as if someone shut the car off. I coasted to the side of the road and tried to start it. The engine turned but would not start. A few minutes later I tried it again and it started to start but then the engine would just keep rolling over with nothing. I understand that the motronic has a DME relay up to '89. Mine is a '90. Would that have something similar?
Tom

Bill Verburg · Bill Verburg's Garage

yes, the DME relay would be the most likely suspect, on a 993 it is located in the main electric panel in the left rear corner of the luggage compartment, look for a large black relay left/front

I would expect 964 to be similar

Jack Olsen · 10-06-2006, 08:42 AM

In my car, the DME relay is under the seat, near the DME itself.

jevvy · 10-06-2006, 08:50 AM

Same here, you can probably get to it wihtout pulling the seat if you are prepared to feel about a bit, heres what you are looking for:

Bill Verburg · Bill Verburg's Garage

oops, I thought the chassis was a '91 964

Rouxzy · 10-07-2006, 04:13 PM

Jevvy,
That is exactly what I found under the seat, but when I opened up the box to the new relay I got it didn't have the round connector post like that, it had spade connectors. The part in the picture is numbered, 89 8247 000, but the supply house sent me, 89 8892 000. I'm thinking they sold me the wrong part. The part on the box said it is for 911's 89 and on. I'll have to find out on Tuesday because of the holiday.
Tom

jevvy · 10-08-2006, 01:37 AM

Yup, I think the earlier ones have spade connectors like this:

What a bummer you got the wrong part - I remove this part as an extra anti-theft device if I have to leave my car somewhere dodgy.

htron435 · htron435's Garage

I've always been told that it's a good idea to keep a spare in the glovebox with the rest of the fuses, as it is the usual cause of no-start and running problems with the DME cars. Just a friendly suggestion.

Rouxzy · 10-11-2006, 01:52 PM

Well,
I got the right DME relay and put it in with no good results. The engine just turns over without starting. The question I have is this. If I continue to crank the engine over and over, will I eventually be able to smell fuel if the fuel pump is pumping fuel?
Tom

jevvy · 10-11-2006, 02:11 PM

Hmmm, how strange.

As I remember the fuel pump only kicks in once the flywheel sensor detects a certain RPM is reached but cant remember what that was.

Are you getting a spark?

htron435 · htron435's Garage

If you're getting spark, check the fuel pump itself. I had a similar no start issue with an 88 carrera. I tried the DME relay and then the cylinder head temp sensor to no avail. It turned out to be a bad fuel pump -- no fuel pressure, no start. Good luck with the diagnosis.

Rouxzy · 10-11-2006, 04:37 PM

What is the easiest and safest way to find out if I'm getting spark?
Tom

DW SD · 10-11-2006, 04:55 PM

Quote:

Originally posted by Rouxzy
What is the easiest and safest way to find out if I'm getting spark?
Tom

Take a spare spark plug, ground the electrode with a test lead (test lead = wire with alligator clip connectors on both ends). One end to the spark plug electrode, one to a good clean ground.

Remove one wire from a spark plug and attach the plug wire to your new test plug.

Crank and look for the spark.

Doug

DW SD · 10-11-2006, 04:59 PM

Quote:

Originally posted by Rouxzy
Well,
I got the right DME relay and put it in with no good results. The engine just turns over without starting. The question I have is this. If I continue to crank the engine over and over, will I eventually be able to smell fuel if the fuel pump is pumping fuel?
Tom

Find your +12V lead to your fuel pump. Mine has its own fuse in the fuse box.

Remove that fuse and apply 12V with your same test lead (this time with one end to 12v+ on the battery or other source. Check 12V w/ the test light or voltmeter.

You can also apply the same 12V to the 12V+ post on the fuel pump itself. The brown wire is ground.

Apply 12V to the pump w/ no cranking. You'll hear the pump buzz as long as the engine isn't cranking.

No buzzing = crapped out pump.

Doug

Duckworth · Duckworth's Garage

One thing about the pumps I never liked was having them covered or blocked off by sheetmetal shrouds. Some think it's unwise to have them exposed because they can get hit by a stone or get some salt on them. But I want to able to 'see' the pump in about 30 seconds of using the floorjack. I'll never forget a trip across Nebraska at 105 degrees F. and the 'wailing' the pump made seemed louder than the engine - sheesh !

Anyway, a spare 12 V source under the car (with jackstands) is a nice way to get the pump buzzing by by-passing the wire loom, relays, and fuses. I like it unshrouded for this reason as the car raises up. You can leave the 12 Volts on it for 5-6 seconds and then try to start it.

_____________

Duckworth · Duckworth's Garage

.... just wondering if it started up.

..........

_______________

'82 Targa - sold
'80 928

Rouxzy · 10-12-2006, 02:58 PM

Unfortuneately, I'm not going to be able to get to it again until Friday morning. I work at a nuke plant and we are in a refueling outage right now which means I'm working 15 hour days for the next 6 weeks. So, my plan is on Friday morning I'm going to check to see if I'm getting a signal from the speed sensor by checking for a signal across the 47 and 48 pin at the DME. If that works out then I'm going to jump pins 87a and 30 to send power to the fuel pump to see if it works. I have a feeling that it may be the fuel pump seeing that the pump is going on 30 years old.
Tom

Rouxzy · 10-14-2006, 06:39 PM

Here's the latest. Checked to make sure I was getting power to the fuel pump thru the DME relay, which I was. Then I crawled under the car and put 12V straight to the pump and nothing. My 30 year old fuel pump is siezed. Ordered a new one from our host and will be putting it in. Now I'm wondering if it has been on the outs for a while and I haven't been gettting the full benefit from it for my 3.6. If not I'll probably realize another jump in hp.
Tom

DW SD · 10-15-2006, 08:02 AM

When my fuel filter was plugged, the 3.6 would actually die under WOT after a few seconds. Then it would come back on when the fuel pump would catch up. Unless your engine was actually shutting down, I don't think you'll be losing HP. Maybe, though. We'll see.

Let us know.

Doug

Rouxzy · 10-23-2006, 02:30 AM

Got the new fuel pump back in and after priming it the ole girl fired right up. I have noticed a little better pedal response. So, I would suspect that the pump has been on its way out, but now its running great and a Steve Wong chip is on order. Too bad I'll have to put her to bed in the next couple of weeks for the winter.
Tom