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Flat Spots In Rb25De Neo


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Sounds like a vacum leak. Check all your signalling hoses/vacum lines for splits and cracks. Also brake booster and variable length intake actuator diaphram for breakage/busted seal.

Edited by iseekool
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Yeah I've tried a different afm also a different tps sensor hoping that that would solve the issue but no luck. I would have gone the cheaper plugs but yeah as Neil said just getting to the plugs is a bitch the whole intake pretty much has to be unhooked and taken out. Which isn't a fun job at all. Hopefully this afternoon when I get the car back they will have found out the issue.

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So turns out the plugs were causing timing issues with both my tps sensor and my ignition timing which was throwing out my timing in general, causing flat spots. But in all that with a dyno run a tune and new plugs cost me a bit but it the car runs completely different to what it did before hand. Gained and extra 60kw atw from the run they did this morning. Pretty happy with these guys but it still feels like its missing while cruising which is driving me insane... Going to give what iseekool said ago on the weekend to see if that makes it runs 100% :)

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60kw gain? It must've been running like an absolute slug before it went in, since that's about half the stock power output. My guess is today they dodged the dyno results somehow. But as long as it drives better then that's a bonus.

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Yeah well it was running like crap mums gt 86 was beating me in a straight line which was just embarrassing to be honest.

A GT86 is quicker than an n/a R34. I don't see what you are getting at here. LOL :P

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I'd put in a fresh o2 sensor in too, helps during cruise and for fuel economy.

Old injectors can cause issues too with slight misses at light throttle inputs. A friend and I have experienced that. Cleaning them usually won't help due to age/wear and tear.

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  • 1 month later...

So for future reference if anyone has this issue. It ended up being my "tps sensor". It was tested by an auto electrician and everything was working as it should right voltage etc. I managed to get one off a car someone was wrecking and car runs fine now.

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Im just curious, how much rwkw you running now in total? Cause a standard N/a skyline is roughly 90 - 100rwkw, gaining 60rwkw would mean you were running 40rwkw before? Unless you are putting out more than factory?

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  • 3 weeks later...

Total is 163.4 from memory. Made a massive difference after the tune when it was done. It was like driving a completely different car power wise. When I chnaged the Tps sensor over I put the connection as far down as I could as the further I moved it up the more the car reved and it hasn't played up once since I've done so. And its a manual transmission :-) couldn't make myself get an auto:-P

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  • 4 weeks later...

Hello I'm new to skylines Australia. I have a very similar problem atm with my rb25de neo

When in get up in the rpm say at 3500rpm there is a flat spot for a second then after the flat spot it picks up again

It's kinda like it's not getting enough fuel but i have a few things I got to look over but I just need someone else's input to help me. Ty

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