John H

Turn the key to on, no fuel pump noise. I hear the relay kicking and I have checked the fuses. Every once in awhile I hear the pump try to start. I checked the fuel pump with a meter and with the key in the run position, there is no power. I am not sure what to check next. It did this to me yesterday and eventually started and ran. Once I turned it off, if I turned the key to the run position, the pump would kick on. I would normally think the pump was going bad except there is no power down there when I put the meter to it. What would cause this intermittent problem? TIA

Wachuko

I can only share my experience... try the easy stuff first...

The fuel pump relay(red one) was loose in the socket. Two ways of fixing it, close each socket receptacle or expand the relay pins. The pins on the relay are split, if you take a thin blade you can make them expand enough that they will go in and make good contact.

Clean the contacts on the fuel pump. Make sure the connections are clean and tight.

Check your grounds... clean them and validate those are tight.

Then you can start to worry about other stuff... I took apart the whole fuel system, cleaned each fuel line, replaced all 6 fuel injectors with new ones, replaced fuel filter in the tank and in the engine bay, new fuel pump, new fuel pump relay.... all for a frigging loose relay.

Pretty sure others will chime in with ideas.

MillenniumFalcon

Does the SC have the safety switch on the airflow meter? You should be able to raise the airflow metering plate a bit to hear the pump start up, right?

Wachuko

Correct... remove the cover to the air filter, remove air filter, push up on the plate and it will activate the pump (if the electricals are in good shape )

theiceman

ok everyone lets dial it back a bit ...

in the "run" or on position the fuel pump should not run if it is set to factory specs. It is absolutely correct that it should run when the air plate is lifted as pointed out above. as the safetly switch is well .. deactivated if you know what i mean.. you will definitely hear it..

Okay now here is the caveat.

Some SC's have had what i would call "an illegal mod" thats just a term we use in our business. Which means someone has rewired it to start the fuel pump in the on position as oppose to the start position ( usually done for an underlying start condition that could not be resolved otherwise ) . Wether that is a good idea or not is a debate for another time, point is your car may be one of these cars.

You may find your car has been rewired so any troubleshooting may differ with your car ...
All that said tho .. replace the red fuel relay

John H

Weird. I have been driving around with a black relay with a different part number. I just ordered two red ones. I'll give that a try and see what happens with the correct relay. I went out this morning and flipped the key and the pump kicked on for about a second and quit, never to make another noise despite repeated attempts. The correct relay will take care of the issue, I hope.

Thanks Wachuko!

John H

I did this ^ and the fuel pump kicked on....Tried the starter and it started. This is weird.

I'm going to put in the right relay (red one) and see if I have any issues. If the problems continue, then I'll move to thinking it is a fuel pump issue (although, it looks brand new). When I bought the car, I drove it 3 days at MidOhio and right on to the trailer. That was in August. Problem arose when I finally got around to unloading it two days ago.

Anyway, thank everyone so much for taking the time to respond.

Wachuko

Then make sure you get a feel for how the relay goes in... if too loose then you know the problem is not the relay but the contacts from the relay to the base/plug. Never hurts to have a new relay in there, but make sure it is going in tight.

MillenniumFalcon

bad airflow meter safety switch then?

theiceman

not sure .. those things are VERY robust .. and the fact he tells us he hears the pump run when he puts the inition on tells me that car may be jury rigged. i think eople rewire the relay socket for this . i wouldnt be surprised if that is what has gone wrong.

this thread has some good info

http://forums.pelicanparts.com/porsc...or-switch.html

Steam Driver

Yes it does (have good info). I'm logging this one for future reference when it gets to that point on my car.

John H

Thanks for that link. Maybe this weekend I will have the time to inspect it more. The red relays have a different part number than the black ones and the cost is different. Maybe i am paying extra for the red plastic?

Question. You said "jury rigged". I always thought it was "gerry rigged", i.e. a slap at Germanic fiscal conservatism. Jury rigged makes sense too. I always thought is was more a of a cultural thing a la "appalachian engineering" etc

theiceman

I am from the Uk and I think the correct Colloquialism is Jury Riggerd .. I think Jerry Rigged is an Americanism
But im sure its out there on the internet soemwhere .. and someone wil jump in and correct us both.

oh by the way the red ones are a little more robust with heavier components inside becuasse of the higher current required by the fuel pump that flows through it .. thats what they tell us anyway...

personaly if i were you id just swp it with another black one and see if the problem goes away or moves ...

I just like the red Bling in there ...

theiceman

wow everything is on the internet ..

http://en.wikipedia.org/wiki/Jury_rig