MainePorsche

Below is a pic of the 14 pin connector. It is under the cover where the jumper post is.

landsharklady

Fab picture-very helpful arrow! So I need to pop that off and check and clean it? Thanks so much for your help.

MainePorsche

DISCONNECT battery ground strap in the rear first.
Be careful - the pins in this connector are movable. This connector may never have been dealt with prior and so may be 'brittle'.

MainePorsche

Check for corrosion. Mine didn't have any when I dealt with it, but I did take a small file to it. Careful when re-seating it.

landsharklady

Are they easy to replace if i knacker it checking it?

MainePorsche

Well.. not really.

landsharklady

I'd better be careful then!

landsharklady

I just found this.. _what do you think? Worth setting this up incase new ground straps, relays, fuses, ignition and cleaning 14 pin connector don't solve it?
_______________________________________As an emergency measure: - Get six inches or so of 14 or 16 gage stranded insulated wire (standard automotive primary wire), and strip both ends about 1/2". - Carefully disconnect the 14-terminal connector located next to the jump start terminal on the right fender panel. Insert one stripped end into the female connector of the yellow wire in the corner of the connector. Push the connector back together. Be very careful during all of this to avoid letting the connectors escape from the body of the connection. - When you need to start the car in an emergency, make*certain*that the transmission is in neutral. Make*certain*that the transmission is in neutral.* - Turn the ignition switch on. Double-check the transmission to be sure that it is in neutral.* - Touch the bare end of the wire to the jump start terminal. The starter should immediately operate. - Be certain that the bare end of the wire can't touch any metal or electrical terminal afterward.

Hilton

There are two fuel pumps.

There is a pump inside the fuel tank, where the hose comes out of the tank to the main fuel pump by the filter.

The purpose of the one in the fuel tank is to feed the main fuel pump - however when they fail, they just act as a huge restriction.

If the pump in the tank fails, the main pump can still build pressure to start the car, but after that is starved of fuel causing running issues, and after running, it'll often cause a no-start as vapour lock occurs when the main fuel pump cavitates due to a lack of fed fuel.

It takes all of 5 minutes to go test the in-tank pump. Just these steps:

1. undo the two 10mm nuts on the cover at the rear of the fuel tank to expose your fuel filter and main pump
2. use a 7mm or 8mm spanner to undo one of the connections on the main fuel pump. wrap a bit of electrical tape around the disconnected contact to prevent shorting and blowing the fuel pump fuse in step 3.
3. jumper the terminals in the fuel pump relay position
4. go back to the rear of the car where you've removed the cover, and listen for the noise of the in-tank pump running

If you hear nothing, you'll need to deal with it regardless of the intermittent start issue.

As for replacing ground straps, I do't think its worth it until its proven to be causing an issue.

Instead, use a jumper lead to supplement the ground strap and see if it fixes the problem.. otherwise you're throwing money at the problem rather than figuring out what the issue it.. which will get expensive at Porsche prices.

If just testing in the garage, you can use a jump lead with the massive crocodile clips, although if planning on driving around, I'd crimp up some heavy gauge wire and bolt to the car and battery.

69gaugeman

Although your mechanic may already check for it, the power cable to the starter may be an issue as well. I didn't read if the starter has been rebuilt, but there are a lot of high current connections in the starter circuit. Bad electrical connection on any one of them will cause this very problem.

'I' would grab another battery, throw the car on the hoist and use jumper cables to see if the starter will turn over. The solenoid on the starter is a wear item and may need to be replaced. Although you have an intermittent problem which may make this hard to prove out.

If the clicking is coming from the starter area (right side bottom at the back of the engine) it is the starter solenoid moving the contacts but not making electrical contact to turn over the electrical motor to turn the engine.

landsharklady

I don't have any garage equipment- car won't even fit in my garage!
There is a click coming from somewhere in the engine when its doing its no start trick, but it seemed to be coming from the ignition coil area.
Car won't jump start via traditional methods when its doing its trick btw. Not tried jumping from the 14 pin connector though, be interesting to see if that works.

Randy V

Model year of your car?

Hilton

Its in the second line of the first post

1989 S4

69gaugeman

In order to better be able to diagnose this you are going to have to do some more detective work. Without it we are just using a shotgun approach to find the problem.

Yes the 14 pin trick will narrow down what the problem is. Like it has been said before, be very careful with that connector. It is made from bakelite a million years ago and is very brittle. That pin is the coil wire for the starter solenoid. If the car turns over when you apply voltage to it, there is something wrong upstream (relay and or wiring from the the CE panel). If there is nothing when you jump that wire, then the starter needs to be looked at (or the connections for power and ground to the starter)

Landseer

Do I need to use frequent flier miles to replace the battery ground strap for you?
That is first. We've seen 9 or 10 East Coast cars down because of these.

Then the rest, starting with what Hilton proposes.

The 14 pin can easily break apart in your hand, best to clean it, removing backing plates and resoldering if needed.
If it cracks, complete the job but get a new one on order.

And it that doesn't cure it, we will dissect some brain, electronic that is.