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Hi guys 

 

im new to the forum, I have introduced myself and have only owned my Z a few days. I have looked on here and can find one thread relating to my question but it seems to say it’s normal.

my 2007 350z HR has a horrible flat spot when you let the revs drop. Say turning a bend change down into second and when you put the gas in it coughs which if you put the gas down harder to start turns into a kangaroo effect. I’m driving it gently and trying to stop it but I’m hoping this is just an servicing or sensor issue. I’m finding it’s spoling the drive for me.

does anyone else experience this? Is it normal. 

 

any help appreciated 

 

Darren 

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Not quite sure if this is the same, but the HRs are known for their kick at the low rev range. It's easy to trigger this behaviour, let the car pull you along in 1st on idle, then try to accelerate as gently as you can. You should find somewhere between 1K and 2K it will kick like a mule, as if it went full throttle for a split second, after that it's nice and smooth. So getting stuck in stop start traffic on the motorway is a common situation to really bring the problem to the front. In higher gears it's a lot less noticeable and the exact spot it kicks at varies so maybe you are letting the revs dip low enough for it to do this when you get back on the power after a corner?

 

The common fix for this is an ECU remap as the stock map has bad figures for the exhaust cam timings. There are some other fixes reported too but the remap seems to be the most common fix. Check out this thread for a good collection of info:

 

 

I had my HR remapped and the kick faded into a much smoother lump (for a comparison it used to hurt my partners back before the remap). It has since returned but I've been chasing down some other gremlins in my ageing zed so I don't think mine is a good example of the norm and given it's not hurting my partner I don't think it's as bad as when I first got the car.

 

As for the remap, the bulk of the cost in that is getting an uprev licence for your engine, once that is purchased you're then just paying for the tuners time. So if you get the bad behaviour fixed now, and later decide you want to mod the car it will be a lot cheaper to get it on the dyno for a 2nd time :)

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I really appreciate the info. It’s really taken the edge off it for me. I’ve only owned it a few days and if I can’t sort that out I won’t be able to live with it. I’m in two minds what to do now. Spend some money trying to sort it or just put it up for sale. Not really what I expected from a Nissan. 

 

D

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Noting your location, consider a little trip along the M4 to Horsham Developments for a diagnosis/tune.  They are a respected trader on here with an excellent reputation for sorting out issues on Zeds (see their appreciation thread).  I'm sure Jez will be able to resolve your issue to enable you to fully enjoy your car.

 

https://h-dev.co.uk/?v=79cba1185463

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I agree with Ebized, take a trip to Horsham and get them to take a look.

 

My HR used to 'bog down' at low revs. There is a right turn junction close to work that is on a bit of an incline which gave me a couple of brown trouser moments when it would bog down half way across and in the way of oncoming traffic. Always had to remember to give it some gas. I just lived with it but in hindsight I should have got it sorted properly.

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Thanks, I have booked it in for diagnostics. Seems to think it’s cam position sensor related (I think that’s what he said) if so £1500 or a remap for £400 should sort it. See how I get on. 

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1 hour ago, Outline1 said:

Thanks, I have booked it in for diagnostics. Seems to think it’s cam position sensor related (I think that’s what he said) if so £1500 or a remap for £400 should sort it. See how I get on. 

Ouch!

Did you get the car from a dealer? I'd be getting them to stump up the cost if you have only had the car a few days.

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6 hours ago, Outline1 said:

Unfortunately not I bought I private. :-(

It's not that much of a problem really, UpRev remapping has other benefits apart from sorting out your flat spot.  

 

It's one of the first things listed on Horshams tuning guide for the 350z: https://h-dev.co.uk/350z-tuning-guide/?v=79cba1185463

 

Only problem is if you have any plans to fit an aftermarket exhaust (including hfc) it's recommended you do this prior to the remap to get the most out of the mod.

 

Sucks you have to spend the money, but look on the brightside - possibly 10-15 more HP :)

Edited by Kryptek49

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I don’t mind spending the money if it makes it better. I find I can’t drive it how I want to drive as I’m consciously thinking about it. What I don’t get is if the parts are worn as the guys says they probably are, how does a remap make up for worm parts.

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Best to take it to the experts and let them decide, however it appears most people who have had this issue have confirmed that an UpRev sorts it out.

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do the throttle idle relearn first since that costs nothing but 5 minutes of your time (you're unlikely to get it correctly first attempt :D

 

  

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