930 spits out of the blue

  • Hello everyone

    I have a 930 that doesn't really feel like it anymore after the winter.

    Error picture :

    It starts up well and runs perfectly up to 3000 rpm, from 3200 it spits, smokes black and the boost pressure goes to 0.8 without the car accelerating.

    From 4000 when the 2nd fuel pump kicks in it runs again as it should.

    New parts that I have replaced:

    Front fuel pump, fuel filter, fuel pressure regulator, flow divider, piston of the baffle plate removed and made smooth.

    This didn't change anything except after changing the pump, the car ran perfectly one evening and the next day too early, same problem.

    Today I disconnected the nozzle from the cold start hose and removed the plug from the cold start controller

    I thought exhaust black smoke - too much fuel

    That didn't help either

    Unfortunately my trusted garage is not available until October

    I don't have any special tools to measure pressures or anything like that.

    Does anyone else have any tips?

    I have run out of ideas;(

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    • How old is the fuel?
    • Which fuel is in it? SP 98 or v-power/ultimate?
    • How long has it been standing?
    • It doesn't accelerate at all despite boost pressure???
    • Details about the car? YEAR OF MANUFACTURE? US model? Tuning?

    Greetings, Thomas

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    81er ex-US 911 SC Coupé, platinmet., eSSD, K-Leder sw., Turboheckflügel & -frontspoiler, NSW, Maxilite 7/8J, Bilstein Fw("SpoStra" - noch...), 915/61, 930/16 o.Kat, WebCam 20/21 NW, hydr.KS, Dansk 92.502SD, 123 Ignition, orig. Porsche SWV, Seine Systems Gate Shift Kit, Momo Prototipo m.Nabenerhöhung


    „Nicht das Auto verdirbt den Charakter, aber wer keinen Charakter hat, sollte nicht Auto fahren.“

    Ferdinand Porsche

  • It has new fuel in it 95octane which he also liked last year 😂

    It only stood over the winter and last year it didn't make any trouble

    Between the revs of 3-4 it doesn't accelerate only the boost pressure goes up when I downshift and the revs are above 4 it accelerates as usual.

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  • From 4000 when the 2nd fuel pump kicks in, it runs again as it should.

    There is "no 2nd pump starting" -- the pumps are connected in series and BOTH MUST ALWAYS be running.

    There is new fuel in it 95octane which he also liked last year 😂

    95 octane?

    For the turbo???X(:kdash::kdash::kdash:k:scare:k:scare:k:scare:


    Lars

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    Nur wenn du schwarze Striche vom Kurvenausgang bis zum nächsten Bremspunkt ziehen kannst, hast du wirklich genug Leistung(Mark Donohue).

    Im Alter wird man immer knackiger -- da knackt es und da knackt es...

    Sechs 964er bisher mit abgerissenen Dilas --- 14(!!!) Ventilfederbrüche bei den letzten 5 Motoren! 4:3:3:1:3

    Porsche 911 -- der Volkssportwagen...

    "Hoffnung -- ist immer ein Mangel an Information!"

    Wer restauriert -- verliert...

  • Have you checked the ignition timing? I'm not familiar with the turbo, and this is just a suggestion, but I once had something similar with my SC. The car started well, but always jerked at 2000 rpm in partial load operation, but when I accelerated it accelerated normally. We also tried a lot with a colleague who has the same model and swapped everything from the timing system to the pressure accumulator etc. and in the end it had too much pre-ignition. We then adjusted it correctly and it ran perfectly again. But as I said, I have no idea about the 930 Turbo, but you can flash the ignition anyway. You just need a strobe light to do it though.


    :wink:

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    Porsche 911 SC / 930.10 Motor / Bj.1982 Pazifikblaumet.

  • I thought the 2nd only switches on at a certain speed

    Ok, that was wrong then. In any case, I had installed 2 new bosch pumps.

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  • Quote

    Hi,

    please check the two red pump rails and the bases.

    Best regards

    Ralf

    In my case (also 930) it was the pump relay or the socket that had a loose contact.

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  • Quote

    Hi,

    please check the two red pump rails and the bases.

    Best regards

    Ralf

    In my case (also 930) it was the pump relay or the socket that had a loose contact.

    Ok, I already had the two relays out and in my hand but I'll have a look at the plug connections tomorrow 👍

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  • Also swap the relays for each other.... :old:

    Wouldn't be the first time that one is still defective...

    What doesn't hurt in such cases with the K-Jetronic ... to put an additive in the tank to clean the injection system and take it for a brisk country road trip or two...

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    81er ex-US 911 SC Coupé, platinmet., eSSD, K-Leder sw., Turboheckflügel & -frontspoiler, NSW, Maxilite 7/8J, Bilstein Fw("SpoStra" - noch...), 915/61, 930/16 o.Kat, WebCam 20/21 NW, hydr.KS, Dansk 92.502SD, 123 Ignition, orig. Porsche SWV, Seine Systems Gate Shift Kit, Momo Prototipo m.Nabenerhöhung


    „Nicht das Auto verdirbt den Charakter, aber wer keinen Charakter hat, sollte nicht Auto fahren.“

    Ferdinand Porsche