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New member with a 930


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Hi to all. I am not sure why it took me so long to find this forum, but I've been on the lookout for a more active 911/930 UK community for a while. My name is Adi and I live in West Yorkshire. I bought my 1989 Turbo last year, which is the youngest classic I've had, unless you count my also current 997 Turbo as one, being 15 years old. I've had quite an eventful time with the 930 as what I thought was a simple hot starting problem became a 5 month saga including damage, lots of K-jet issues, new windscreens, repainted wheels, and so on, which is finally nearing the end. The car is everything I wanted it to be and having had classic cars for the last 20 years, sorting out issues is just a part of the process. My car is GP white over Marine Blue/Linen, G50 5-speed. It's entirely original except for the cup mirrors (I have the originals) and the Porsche PCCM unit, fitted by the previous owner. At first I disliked the cup mirrors, but have to say I love them now.

 

porsche-911-turbo-g50-1989-3-a7306170-3.
 

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Welcome Adi. That's a lovely looking car. Tell us more about your starting and K-Jet woes, we love technical stuff here.

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Posted (edited)

Thank you all!

The K-Jetronic issues I've had have been really interesting (if you're into that kind of stuff) as it's required quite a bit of detective work. Please let me know if this should be posted in a more technical section.

My car has only 25.5k miles and the previous owner, not counting the dealer I got it from, bought it at auction in 2016 with only 24k miles. I have extensive records on the car all from either OPCs or known specialists. The car seems to have had starting and electrical issues for a number of years and the previous owner had all of the above do investigations and threw a lot of money at it, but for some reason an OPC and a specialist replaced three CDI units, another place replaced the starter motor and yet another determined there was an air leak, etc. But no one looked at the K-Jet, or at least the records don't show it. It's possible those parts needed to be replaced, but it's odd that none fixed the problem.

The issue the car came to me with was the typical hot starting problem. Fine if you restart within 15-20 minutes, but then tough for the next 20-25, and after that fine again. I took it to one specialist who replaced the non-return valve on the fuel pump, but admitted their team was too young, so I took it to an OPC who didn't know and sent it to a carb specialist, who replaced the fuel accumulator. Neither part helped, but what came to light was that the yellow overboost relay was malfunctioning if disturbed, which was originally thought not to be related. If moved in a certain direction it would cut the fuel pumps.

Long story short, after I finally found someone willing and knowledgeable to properly get into it, I supplied a new yellow relay which wouldn't allow the car to run at all. It turned out that the only reason car ran was because the original yellow relay wasn't working properly due to dry connections, and only if you moved it so it connected, it would do its job and cut the pumps as there was an issue further up. This was confirmed as they repaired the original relay and it now also wouldn't allow the car to run. This prompted investigation of the green switch on the metering unit, upon which it was discovered that (and forgive me, I don't know the correct names for these parts) the contact plate on the air flap was making contact with the pin and without the relay to cut it off was arching so much that it burned a hole in the metal plate and melted the plastic spacer on the pin. Someone has then pushed the pin too far in in order to give the flap more space to move and the faulty relay was allowing the pumps to keep running, which is why the car ran at all.

What we suspect happened is at some point the yellow relay malfunctioned (or someone replaced it with a regular one), which allowed the pin to get so hot and cause the damage, move out of position, then for someone to bodge it, and ever since everyone else has been chasing their tails.

The car is still away, but should be done on Tuesday and I have everything crossed that this will have fixed it. It actually ran fantastically even with this issue, but I am so glad we have discovered that there was actual damage, so no matter what it was very important to have found it and to repair it.

Edited by adigra
Typo
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It's great when a bodge is discovered and corrected, with the added bonus of fixing something that wasn't working. Who was the willing and knowledgeable person?

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3 hours ago, Phill said:

It's great when a bodge is discovered and corrected, with the added bonus of fixing something that wasn't working. Who was the willing and knowledgeable person?

Sam Lander in Malton, North Yorks. Nothing is ever a problem, he just gets on with the job and really loves old Porsches.

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5 hours ago, GimmeShelter said:

Lovely looking car, and I enjoyed the technical detective work.  Fingers crossed for a job well done!

Thank you. Had an update and a video of the K-jet today operating as it should now. They manufactured a new spacer for the airflap pin and it looks as new. I am very impressed.


Rereading my post above I realise I made it a bit confusing by mixing up two different contact points, but I hope to those who are familiar with K-jet it made sense. I'm sure there are specific names for these things, but even my K-jet workshop manual skims over it.

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Very good choice of car, well done. Almost impossible to find a G 50 930 down here, the last official 930s delivered down under was in 85 until the 964 Turbos arrived.
Very pleasing to sort out issues others couldn't quite get their brains around or nipped in the butt properly right at the start, makes things difficult sometimes for those that follow later. Will be interesting to hear how it is once you get her back.

 

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1 hour ago, Bugs 77 said:

Very good choice of car, well done. Almost impossible to find a G 50 930 down here, the last official 930s delivered down under was in 85 until the 964 Turbos arrived.
Very pleasing to sort out issues others couldn't quite get their brains around or nipped in the butt properly right at the start, makes things difficult sometimes for those that follow later. Will be interesting to hear how it is once you get her back.

 

Thank you! I didn't know that about OZ. Was it because of emissions?

Just had an update from the specialist. The car running as it should, starting on the button hot or cold, no problems at all. He's going to check all of the fuel pressures to make sure they are within spec. I am very relieved! After I got the car I really wanted to have someone good go through the fuelling system to make sure everything was as it should be, but it was really hard finding anyone willing to do more than fit new parts, so to finally have a proper report on every detail is really satisfying. I am also very grateful to understand the car a lot better now. Having come from dealing with Webers, K-jet has been a brave new world for me.

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In OZ it was because of the introduction of unleaded fuel and I guess the powers that be were not sure if the new fuel would suit the tune of the 930s or lead to engine damage. Aussie delivered 3.2 Carreras 86 and on are detuned (I think slightly lower compression) but were still sold, 84 and 85 cars are the full Euro spec 231hp. Today it matters not and most rebuilds are wound back up so don't see what all the fuss was about, don't think the fuel has changed and we have 91, 95 and 98 RON to choose from.
Good to get to know your car, in a way gives you much more confidence in it or what to expect from it. Just about to put another car together so will be nice to know a few major things will be sorted, funnily enough will be moving from K-jet to carbs.

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  • 2 weeks later...
On 13/06/2021 at 11:06, World Citizen said:

Welcome, great looking car, hope you enjoy driving it as much as I enjoyed mine

Hello mate can you pm me or call me if like my 964 quarter back please. 07834315640

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