Porsche Enthusiasts Club Forum

Hi All,

I just typed this out and it disappeared when submitting it. Apologies if it appears twice.

Looking at the link my car matches and has the same empty holes.

Therefore question I have is there any way of testing the relays are working correctly without replacing?

I plan to replace all relays relating to the fuelling first and then the ECUs, fuel pump etc if I have no luck.

The car was working when parked up in Feb. (To add I have never seen it run myself. Just bought the car)

Now when I start it the whole car vibrates and there is a smell of petrol from the lower rear of the car.

I have not had it started at all and it does not seem to want to start at all.

Anyone who has any comment to make on my approach please do!

Regards
Paul

Update on getting her running:

I have cleaned out the boot and put on the new Varta battery.

Previously I had tried to start the car connecting jump leads to the battery outside the car. This had resulted in the car vibrating, but not much else.

Good news is having attached the battery this morning there is a very strong turn over and it feels like it wants to start. However I am not getting ignition that I can tell. By that I mean no bang or smoke of any type if you know what I mean.

I am thinking fuel pump perhaps? However - It was allegedly running fine until it was parked up in Feb.

Taking suggestings on what to do next?

I have bought a whole load of used relays (all being well as price not yet confirmed) and will change the fuel ones over. I might also buy new relays just in case. Found a cheap US site that looks good value.

One other questions for anyone who might know - Would petrol in the tank since Feb be ok?

Thanks
Regards
Paul

You need to be methodical, start down checking one track otehrwise you'll be there months.
When you turn the key does the fuel pump run briefly? etc. Only when you're sure you have fuel check for a spark & again be methodical.
One hint is a tin of easistart can be useful when fault finding like this.

Thanks Jim,

How do I know if the fuel pump is running? I would guess I listen for a noise?

Will look into the easystart stuff as well.

Thanks
Regards
Paul

Yup put finger on it & feel for slight vibration, other option useful if fault finding is to connect a sidelight bulb across it.

Easistart useful for starting stuff that has been standing, spray it into the intake & if it has a spark you should get a burst of life.

Ok, thanks for that. Will try that.

Also - out of interest can you start the engine in Neutral normally?

Thanks!
Regards
Paul

Hi Paul

Yes Neutral or PARK for starting....

All the best Brett

The most common place for the fuel lines to leak is the driver's rear wheel arch where they are most exposed to the elements, at least one well-loved 928 has expired in flames due to this so most owners are cautious about this - some carry a fire extinguisher.

Regarding diagnosing the fuel pump relay, if you are confident in what you're doing it's possible to "jump" the terminals which will result in the pump running even with the ignition off; if you get this wrong, however, you could damage the ECU, so swapping with a known good one is safer. In fact I believe the relay is non-Porsche-specific and used in several locations so, as it's only a few pounds, you might buy a new one and swap it round all the positions you want to test.

Jumping the fuel relay is useful - just make sure you bridge the 30 and 87 terminals (marked on panel but in any case parallel to long side of electrical panel).

If pump works the noise will be obvious.

Fuel pressure gauge on test point will confirm whether pump actually pumping fuel.

Check for spark with inline tester (a few quid - flashes when energised) or simply grounding plug after removing. Careful high voltages!

If you have fuel and spark next step is to check whether injectors are firing.

Fuel pump relay (and several others on 928 depending on model year) is the simple and widely available '53' relay.

Same as horn relay among others. So swap the horn relay in first if you suspect pump relay problem (if pump runs when relay socket jumpered, relay suspect)

Great advice guys, Thanks!!!

Will pop to Halfords and get one of the inline testers now. Going to pick up the easy start as well.

Will try the horn, swap the relay and see what happens. Funny you should mention fuel in wheel well. I did smell some there they other day, but nothing since. I will check it out.

Thanks, will update later once back from picking up wheels from Brett!

Have a good one,

Regards
Paul

Hi All,

An update ...

Tried starting with a can of easy start but no luck.

Then have changed the distributor caps and rotor arms (they were actually in good condition when I took them off) ... still nothing.

I then put an in line flashing thing that shows if spark plus are working ..... Interestingly no flash!

When I turn the key it sounds like it wants to start, but no actual ignition. Now it looks like this is because spark plugs are actually not getting any power.

Battery is brand new.

My thoughts are change the coil?

Or is there something else I should do first?

Thanks
Regards
Paul

Well, you've probably considered this, but I haven't seen anyone else ask - are you sure that there's no old alarm/immobiliser that may have gone bad? If there is an old immobiliser you might be best off getting that removed, even if you think it's working OK.

After that all I can do is point you again at http://www.jdsporsche.com/fault%20find.html, looks like you're currently at step 2 or 3:



It could be the coils but it's more likely to be the coil leads if they're the originals - if all the leads are original then they could probably all do with replacement (expensive!), the amplifiers are also known to fail without warning but I believe these were also used in some other makes of car (Saab/Citroen? - not sure, you'd have to ask around) so can be found secondhand.

Sorry sometimes there's no obvious answer until you find the faulty part, at which point you wonder "Why didn't I try that earlier!"

Thanks for that. Will start eliminating things.

The EZK relay is the 53 relay I can switch for the horn one?

Regards
Paul

I believe they should be the same type - as the "man on the ground" it's up to you to make the final ID. Also, don't forget to disconnect the battery whilst you're fiddling with the relays.