Ranfurly

Hi Everyone

This more of a vent than a query about a possible cause or fix. I posted yesterday about getting my new to me S4 with low mileage. 1990 MY.

In getting the car I knew there was some risk as it had very low use for a number of years, gremlins likely to come out. I'm very unlikely to not use this car, so no doubt I'll find them one by one.

I'd taken the car to work as I wanted to organise a time to get it into a very good indie workshop here for a couple of things to be looked at. Got that sorted for next Monday. Got the wheels rebalanced and outside weights changed to inside at a local tyre shop, feeling good driving well, sunny day, life is good.

Finished work went to the gym and then looking forward to my first night time drive in the 928 jumped in and started it. It caught and idled for a few seconds then died. Restarted and it'd catch but not fire up. Tried a few more times would crank strongly but not fire.

I'm not a home mechanic so it'll be into the workshop tomorrow a few days early, pita as it's in a tight carpark. My limited knowledge has me suspecting fueling as the issue either fuse, relay for pump? Or fuel pump gone wrong, just seems like it ran on what fuel was in the line, then had nothing. No doubt I'll find out in due course and at what cost, hopefully nothing major.

The Forgotten On

Put the horn relay in where the fuel pump relay was to check to see if the pump works. Or you could jump the contacts and test that way.

Most of the time it is the relay from what I have seen. Your LH could be on its way out too.

Ranfurly

I hope it isn't the LH, trying not to think about that possibility. Will try your horn relay suggestion in the morning. Thanks Richard

siscogts

Relay is the first, I suggest deoxit for electric panel, fuses, ground points.... Saturday deoxit pack arrived home, used everywhere and "smooth idle" took a new meaning for me. Also sunroof is faster during open/close operations,mirrors move up and down (so I will not search for chafed wires)....

Hilton

Things to try:

First, go round each lock and use the key to lock then unlock the car, then try starting it again. If it still has the factory immobiliser, it could be something as simple as a stuck contact on a lock.

Does it have an aftermarket alarm? That can be an issue too - my first 928 (my 89) had no-start issues the first few times I drove it to the hardware store just after getting it. After reading "relay relay relay" here, I disconnected the battery and swapped the fuel pump relay, and the car magically started. Took three occasions on the first weekend of ownership for me to realise that I probably didn't have 3 dodgy spare relays, and that the problem was the alarm, and was being "fixed" with a battery disconnect and reconnect followed by siren noises I'm sure my neighbours didn't like.

Second, check the fuel pump fuse (38 on a 1990 model apparently)

Third, swap the horn relay into each of these vital relay positions trying to start it each time

XXVI - fuel pump relay
X - ignition relay
XXV - LH relay
XXII - EZ-K relay

Then jump the fuel pump position and go check you can hear the pump running. If not, give it a gentle tap while energised (remove the rear cover over the fuel pump - two 10mm nuts you can see behind the rear bumper if you stick your head under there). You need to make a short, insulated jumper lead with a spade on each end to keep in the car for this test.. you'll use it in the future too

If it still hasn't started, after the above things, then get it towed home and prepare to check out the alarm wiring, crank position sensor & wiring, LH ecu etc.

928Myles

Ranfurly,
I have a spare LH I could send to you to try if you have no luck with other items.

PM me if needed.

Myles

Ranfurly

Thanks Myles! Going into Motorscience this morning to have a chat with Peter first and work up a plan from there. Will look at Hilton's suggestions and do the initial checks, but will talk with Peter first.

Thank you very much for the offer.

Richard

Ranfurly

Quick update. I thought I'd nailed it as I found the fuel pump fuse had gone. Got another but still no start. Off to the workshop as someone with an experienced eye who knows what they're doing needs look at it.

f3nr15

Did you have a PPI done? Peter Booth did a very good PPI on my GTS.

Keep us posted...

SteveG

The question then is what caused the fuse to blow.

Ranfurly

Hi

The answer to my issue was a seized fuel pump with the other one described as 'iffy' so 2 new pumps ordered and to be installed next week. Seized pump caused a voltage spike which blew the fuse.

The car I brought has low mileage and as I've described has had low use. It appears the fuel tank has crud in it which caused the issue with the pump. I got a range of things done before taking the car, it crossed my mind re having the fuel tank flushed but didn't happen, lesson learnt. You live and learn. I've owned a 928 before and understand the risks, thought I'd mitigated the major ones.

f3nr15 - no he didn't as it was brought down the line so not possible. He now has it, Peter told me I should have waited to have brought a GTS like yours as they are last of the line which equals better, but this is the car I wanted so no matter. Despite the fuel pump issue I'm really pleased with the car.

928Myles

Glad it was a easy issue to diagnose.

Some people take this opportunity to replace the in-tank pump with a strainer (either stock or an upgraded one). Worth some thought.

Myles

potdog

Google John Speak /JDSPorsche Chambridge U.K