Another car off to Redtek
#47
Three Wheelin'
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#48
Instructor
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Location: Crawley, West Sussex, UK
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I think the fluctuation in oil pressure is due to the speed fluctuation when it's trying to idle. If it was anything to do with a loose sender or wires, you'd see it occasionally when the speed rose. ISV and coils test would want to be eliminated. You're welcome to pop over my way when you get it running and we can swap over some bits...
#49
Nordschleife Master
I had a bouncing needle when I first got the car. Changed it for a similar aftermarket part which was no better. Then changed it for a porsche original and the needle is now rock steady.
Original bouncy one on the left. Similar rubbish aftermarket one in the middle and Porsche original on the right.
Original bouncy one on the left. Similar rubbish aftermarket one in the middle and Porsche original on the right.
#50
Three Wheelin'
Definitely running rougher than mine at idle but it almost feels as if all it needs for the idle speed to be raised slightly.. Have you dropped it back at nicks yet? I'm not having a great time with my interior and made a few mistakes..let me know when you do yours so I can let you know what NOT to do...
#51
Three Wheelin'
Thread Starter
Thanks guys I really appreciate the input
The oil pressure gauge has always been rock solid until the engine rebuild. Same with the idle.
The fear when the bottom end has been apart and you get that sort of oil pressure bounce is that the clearances weren't done correctly. That is worst case though, so trying not to go there. You'll notice in the video the pressure is at least bouncing "up" from a safe minimum point.
Its hard to know if the sensor is accurately reflecting fluctuating pressure or if there's a fault with the sensor wiring. The fact that its in sync with the idle bump could lead either way.
The idle; my thoughts are:
1)the chip hasn't been tuned for the combination of cam, option 150, my exhaust, my oddball one year only midweight flywheel.
2)the isv needs dialing back in for this cam or has coincedentally gone bad at the same tine as the rebuild.
3)something hasn't gine back together properly and I have airleaks or similar meaning the isv isnt effective
4)or ...
Some good news! I rebuilt my pedal box, cleaned up and white greased everything and the brakes and clutch are now smooth as butter. Wow, big big difference.
The oil pressure gauge has always been rock solid until the engine rebuild. Same with the idle.
The fear when the bottom end has been apart and you get that sort of oil pressure bounce is that the clearances weren't done correctly. That is worst case though, so trying not to go there. You'll notice in the video the pressure is at least bouncing "up" from a safe minimum point.
Its hard to know if the sensor is accurately reflecting fluctuating pressure or if there's a fault with the sensor wiring. The fact that its in sync with the idle bump could lead either way.
The idle; my thoughts are:
1)the chip hasn't been tuned for the combination of cam, option 150, my exhaust, my oddball one year only midweight flywheel.
2)the isv needs dialing back in for this cam or has coincedentally gone bad at the same tine as the rebuild.
3)something hasn't gine back together properly and I have airleaks or similar meaning the isv isnt effective
4)or ...
Some good news! I rebuilt my pedal box, cleaned up and white greased everything and the brakes and clutch are now smooth as butter. Wow, big big difference.
#52
Three Wheelin'
Thread Starter
Another video, the car was visibly rocking but due to my hands not being steady you can't really see it.
Jack, its good to know I'm not going mad, I was sure yours was better but my memory of Spa is vague enough now that if Nick insisted yours was the same I couldn't really argue.
Thanks for the offer of assistance Dan, coils is a good thought. I'd see of you were about this afternoon but I'm holding the baby while the wife goes out spending all my money
Thanks Boxsey if I go that way I will make sure I get a genuine Porsche Oeldruckgeber!
Jack, its good to know I'm not going mad, I was sure yours was better but my memory of Spa is vague enough now that if Nick insisted yours was the same I couldn't really argue.
Thanks for the offer of assistance Dan, coils is a good thought. I'd see of you were about this afternoon but I'm holding the baby while the wife goes out spending all my money
Thanks Boxsey if I go that way I will make sure I get a genuine Porsche Oeldruckgeber!
#53
Three Wheelin'
Thread Starter
Also to answer Jack's q; no its not been back to Nicks yet, I need to put 300 or so more miles on it then I'll drop it back for post run-in service, repaint the bumper and look at the idle and oil pressure issue.
#54
Three Wheelin'
Alex, mine does have a lumpy idle but yours just seems a lot more extreme... I think that the chip is just not suited to your particular set up.. Would be surprised though if the rebuild has any inherent big problem. Nick does these all the time and seems pretty thorough to me
#55
Three Wheelin'
Thread Starter
Alex, mine does have a lumpy idle but yours just seems a lot more extreme... I think that the chip is just not suited to your particular set up.. Would be surprised though if the rebuild has any inherent big problem. Nick does these all the time and seems pretty thorough to me
#56
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Alex, I can raise you the idle rpm target on one of those chip files you sent. It could just get the cam out of the lumpy region. Though you're best off doing the disconnect coil-pack thing first, to see if you have an ignition issue...
#57
Three Wheelin'
Thread Starter
Right, I disconnected the Coil HT lead from each of the dizzys, just at idle, removing the top one actually made the car run slightly smoother, removing the bottom one made no difference.
I also tried unplugging the ISV (with the car warm) and the idle dropped about 100rpm or so but was much more stable.
I am now confused.
I also tried unplugging the ISV (with the car warm) and the idle dropped about 100rpm or so but was much more stable.
I am now confused.
#58
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When you disconnect the ISV, the ecu can't control the idle speed, and hence there isn't the fluctation in speed you had before. If you disconnected one coild and there was no difference, then it's broke...
#59
Three Wheelin'
>If you disconnected one coild and there was no difference, then it's broke...
Is it? If this were the case then surely the engine would have stopped when the top coil was disconnected?
Is it? If this were the case then surely the engine would have stopped when the top coil was disconnected?
#60
Three Wheelin'
Thread Starter
overdue update:
Towards the end of the summer Nick took the car back to sort the low rpm issues and perform the post run in service.
The car was with him a while, my work was busy so I wasn't really in a hurry. I picked it up a few weeks ago, drove great - idle much better, pulled great from 4000rpm (wasn't allowed to use all the revs while running in). Got it home and booked a dyno session to check afr, knock, and see what difference the cams made to the power.
Didn't drive it until the morning of the dyno session, it coughed on start up and ran rough as hell, hoped it would clear when the car got warm, but no, cancelled dyno, called Nick, ran through a few things on the phone but no obvious cause, he picked the car the next day I think and returned it the day ofter that (must be a 2-3hr drive both ways with the trailer - great service). Luckily just a air hose popped off so it wasn't sucking through the AFM, phew.
Booked on the dyno again today.
Before rebuild on the stock chip, decat, factory primary and secondary, it was 176.9 bhp at the hubs ... now it's 198.7bhp - I'm pretty happy with that gain.
Much more power now after 4000rpm with a torque curve that's wider - obviously you can really feel this on the road, and gains a few hp before 4000 too.
Towards the end of the summer Nick took the car back to sort the low rpm issues and perform the post run in service.
The car was with him a while, my work was busy so I wasn't really in a hurry. I picked it up a few weeks ago, drove great - idle much better, pulled great from 4000rpm (wasn't allowed to use all the revs while running in). Got it home and booked a dyno session to check afr, knock, and see what difference the cams made to the power.
Didn't drive it until the morning of the dyno session, it coughed on start up and ran rough as hell, hoped it would clear when the car got warm, but no, cancelled dyno, called Nick, ran through a few things on the phone but no obvious cause, he picked the car the next day I think and returned it the day ofter that (must be a 2-3hr drive both ways with the trailer - great service). Luckily just a air hose popped off so it wasn't sucking through the AFM, phew.
Booked on the dyno again today.
Before rebuild on the stock chip, decat, factory primary and secondary, it was 176.9 bhp at the hubs ... now it's 198.7bhp - I'm pretty happy with that gain.
Much more power now after 4000rpm with a torque curve that's wider - obviously you can really feel this on the road, and gains a few hp before 4000 too.
Last edited by alexjc4; 10-20-2014 at 09:09 AM.