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Thread: Wheezing, coughing, spluttering. Old age?

  1. #11

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    Not so fast young man...

    I replaced the offending pump, hoses and check valve, and during my travels under the inlet manifold discovered the little 4mm hose from the spigot under the mani that goes to the N249 valve (right next to the spigot that goes to the fuel pressure regulator) had split and fallen off since I last looked. This would not have improved the breathing at all...

    So I got all the new bits in and reconnected and tightened up and took her for a run. Worse! The boost was spiking straight up to 23 PSI and she was going into instant limp mode. Fortunately I can delete DTCs on my screen without even slowing down, but every time I applied more than a whiff of throttle she went straight to limp mode.

    Both car and weather are too hot to work any more but in the morning I'll go over all my connections again and see if something has gone adrift. Not impossible when you can barely see what you're doing most of the time.

    I'll get there eventually, but the one faint glimmer of satisfaction is the knowledge that I have removed all the one-time clamps from the system so doing it all over again will be a damned sight easier. One of the little suckers yesterday took me over half an hour to remove...
    Gittin' there: MY01 TT quattro 225 Roadster, BAM motor. FT-23, FT 'Phatty' TIP, Hi-flo downpipe and cat, 550 injectors, QMS flash. HPA Coilovers. Gauges by FIS-Control.
    Back on the road: MY00 A4tqm - GP Series with GTRS and a few bits and bobs. 420,000 km. Zeitronix monitors the Heat Demons
    Gone and almost forgotten: MY01 allroad - 2.7TT 6-speed, dual-range manual, GIAC St I. Beautiful motor and box, untameable handling

    * * * * * * * * * * * *
    Fanging since the 60s

  2. #12

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    So this morning I went over everything again, checked I'd replaced all hoses in the right places, all the electrical connectors connected up, and took her for another run. No change! With the slightest whiff of throttle (anything over about 10psi) the boost jumps immediately to 17 then 20 and upwards, there's a soft wheeze from the motor and she's in limp mode. What it has done is to get rid of nearly all the blow-off type noises and chattering which often (but not always) led to limp mode. Other times she would happily sustain 22-23 psi in bursts without any problems.

    One difference I have noticed however is that every few seconds the fuel trims were resetting themselves to zero and I don't think that's normal. After a bit the trims were stuck on zero and didn't move at all. By the time I got home Add was 0.0 and Mult likewise. What does this mean I ask myself?

    And whereas before I was getting a range of 4 or 5 codes, now I'm only getting one - 17963, charge pressure exceeded. Something is making the boost shoot up and the ecu spots this and shuts things down.

    Everything else seemed quite normal although AFR could have been a tad lean on boost - probably consistent with driving with a very light foot.

    Ever have the feeling you're not getting anywhere?
    Last edited by kermac; February 11th, 2018 at 12:51 PM.
    Gittin' there: MY01 TT quattro 225 Roadster, BAM motor. FT-23, FT 'Phatty' TIP, Hi-flo downpipe and cat, 550 injectors, QMS flash. HPA Coilovers. Gauges by FIS-Control.
    Back on the road: MY00 A4tqm - GP Series with GTRS and a few bits and bobs. 420,000 km. Zeitronix monitors the Heat Demons
    Gone and almost forgotten: MY01 allroad - 2.7TT 6-speed, dual-range manual, GIAC St I. Beautiful motor and box, untameable handling

    * * * * * * * * * * * *
    Fanging since the 60s

  3. #13

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    And around the same all the hundreds of emails in my Inbox just disappeared off my screen. Can't find them! Don't know where they've gone.

    Could there be a connection? Is it time to make up a little foil hat for myself?
    Gittin' there: MY01 TT quattro 225 Roadster, BAM motor. FT-23, FT 'Phatty' TIP, Hi-flo downpipe and cat, 550 injectors, QMS flash. HPA Coilovers. Gauges by FIS-Control.
    Back on the road: MY00 A4tqm - GP Series with GTRS and a few bits and bobs. 420,000 km. Zeitronix monitors the Heat Demons
    Gone and almost forgotten: MY01 allroad - 2.7TT 6-speed, dual-range manual, GIAC St I. Beautiful motor and box, untameable handling

    * * * * * * * * * * * *
    Fanging since the 60s

  4. #14

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    Quote Originally Posted by kermac View Post
    And around the same all the hundreds of emails in my Inbox just disappeared off my screen. Can't find them! Don't know where they've gone.

    Could there be a connection? Is it time to make up a little foil hat for myself?
    Back to basics, Kerry.

    N75 tested and working correctly? if disconnected will the car operate happily at wastegate pressure?
    Smoke tested?
    I'd be tempted to try out a stock ecu to see if it's tune related.

  5. #15
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    unplug the maf and see how it runs as well, just to check..

  6. #16

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    I've tried unplugging the MAF but this made no difference. I've just done a whole lot of logging with N75 disconnected for Ed which has satisfied him there's no problem with a sticky wastegate which we suspected for a while. Another few logs and he's going to be able to do another revision which will hopefully settle things down.

    In summary, the car is going extremely well under high boost conditions. Nearly as good as a BT but a whole lot less laggy, much more power low down. She probably won't pull so hard above 6000, but in the interests of longevity that's pretty much as far as I would go most days.

    The only remaining problem is the sudden spike in the (displayed) boost level under light throttle conditions, usually around 3000 rpm. It was no better with the stock ecu which was a bit odd. We'll see what Ed can come up with. I don't think there are any more leaks on either vacuum or pressure side.

    I'll report once I have the revision installed
    Gittin' there: MY01 TT quattro 225 Roadster, BAM motor. FT-23, FT 'Phatty' TIP, Hi-flo downpipe and cat, 550 injectors, QMS flash. HPA Coilovers. Gauges by FIS-Control.
    Back on the road: MY00 A4tqm - GP Series with GTRS and a few bits and bobs. 420,000 km. Zeitronix monitors the Heat Demons
    Gone and almost forgotten: MY01 allroad - 2.7TT 6-speed, dual-range manual, GIAC St I. Beautiful motor and box, untameable handling

    * * * * * * * * * * * *
    Fanging since the 60s

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