narcotix Posted March 24, 2010 Share Posted March 24, 2010 Sorry if this is a dumb question but why would the flywheel cause that to happen? Quote Link to comment Share on other sites More sharing options...
andlid Posted March 24, 2010 Share Posted March 24, 2010 Sorry if this is a dumb question but why would the flywheel cause that to happen? I dunno just a guess... The heavier mass the slower drop of RPM (and increase) with a lighter flywheel you get quicker response... not sure why that would happen at low revs as your example (and mine) maybe just post a video request up to people to sit in there car giving it a bit of rev? Does your car shudder sometimes taking off if you dont give it enough RPM's? a Quote Link to comment Share on other sites More sharing options...
Valveman Posted March 24, 2010 Share Posted March 24, 2010 We do all have the same problem. Its something in the engine mapping - nothing else. Its a lot better once the UpRev map is installed but its not completely perfect. It is suspected that it is something to do with the anti stall map. Mark at Abbey is going to data log my car and see if the UpRev team can find out what is going on in this area. I would also like to know why the bloody engine needs to rev so high on start up. Mine starts and runs at about 1800rpm until the engine warms up before it drops to below 1000rpm. No wonder these cars are so thirsty and why >2006 cars are in the highest road tax/emissons bracket - they appear to waste so much fuel. Quote Link to comment Share on other sites More sharing options...
andlid Posted March 24, 2010 Share Posted March 24, 2010 We do all have the same problem.Its something in the engine mapping - nothing else. Its a lot better once the UpRev map is installed but its not completely perfect. It is suspected that it is something to do with the anti stall map. Mark at Abbey is going to data log my car and see if the UpRev team can find out what is going on in this area. I would also like to know why the bloody engine needs to rev so high on start up. Mine starts and runs at about 1800rpm until the engine warms up before it drops to below 1000rpm. No wonder these cars are so thirsty and why >2006 cars are in the highest road tax/emissons bracket - they appear to waste so much fuel. Cool keep us posted so... 1800rpm though! Mine does 1500 from cold thank god, otherwise the neighbours would KILL me... litterly... Quote Link to comment Share on other sites More sharing options...
Valveman Posted March 24, 2010 Share Posted March 24, 2010 Does your car shudder sometimes taking off if you dont give it enough RPM's? a Yes - this is down to the V engine configuration and the amount of revs the engine is doing (the imbalance of the engine at low revs). You don't get this so much on a flat 6 or straight 6 cylinder engine. It is similar to riding a V twin or V4 motorcycle, if any of you have you will know what I am talking about. Once past a certain number of revs the engine smooths out and revs really cleanly. Quote Link to comment Share on other sites More sharing options...
Valveman Posted March 24, 2010 Share Posted March 24, 2010 We do all have the same problem.Its something in the engine mapping - nothing else. Its a lot better once the UpRev map is installed but its not completely perfect. It is suspected that it is something to do with the anti stall map. Mark at Abbey is going to data log my car and see if the UpRev team can find out what is going on in this area. I would also like to know why the bloody engine needs to rev so high on start up. Mine starts and runs at about 1800rpm until the engine warms up before it drops to below 1000rpm. No wonder these cars are so thirsty and why >2006 cars are in the highest road tax/emissons bracket - they appear to waste so much fuel. Cool keep us posted so... 1800rpm though! Mine does 1500 from cold thank god, otherwise the neighbours would KILL me... litterly... If its like mine it starts off briefly at 1800-1900rpm and then drops slightly to around 1500rpm for the rest of the warm up period. Pity Nissan didn't get to Porsche to map their engine as you wouldn't have any of these issues if they had done it, plus you would probably get another 6-8 mpg better fuel consumption. Just recently drove a Cayman S round the new Porsche test facility at Silverstone and their new 3.4ltr direct injection engine was sublime, as was the handling but some of this can be attributed to the superb PCCB brakes as these are 50% lighter then the normal steel ones. Must get to drive a 370Z one of these days Quote Link to comment Share on other sites More sharing options...
andlid Posted March 24, 2010 Share Posted March 24, 2010 Does your car shudder sometimes taking off if you dont give it enough RPM's? a Yes - this is down to the V engine configuration and the amount of revs the engine is doing (the imbalance of the engine at low revs). You don't get this so much on a flat 6 or straight 6 cylinder engine. It is similar to riding a V twin or V4 motorcycle, if any of you have you will know what I am talking about. Once past a certain number of revs the engine smooths out and revs really cleanly. hmm my SV650S V Twin doens't suffer from that... thought that had more to do with the clutch/flywheel... Quote Link to comment Share on other sites More sharing options...
kazman Posted March 24, 2010 Share Posted March 24, 2010 My car is pre up rev (55 plate uk) (not nessesarily relevant but are all the other occurences of this on this thread on rev up engines)? and i have never noticed the revs climb when the clutch is depressed untill this morning, so i dont believe its the map.... Quote Link to comment Share on other sites More sharing options...
narcotix Posted March 24, 2010 Share Posted March 24, 2010 I have an 04 Zed ... I'm quite interested in the fly wheel theory ... what possible flywheel/clutch issues could cause this type of behaviour? Quote Link to comment Share on other sites More sharing options...
Valveman Posted March 24, 2010 Share Posted March 24, 2010 Does your car shudder sometimes taking off if you dont give it enough RPM's? a Yes - this is down to the V engine configuration and the amount of revs the engine is doing (the imbalance of the engine at low revs). You don't get this so much on a flat 6 or straight 6 cylinder engine. It is similar to riding a V twin or V4 motorcycle, if any of you have you will know what I am talking about. Once past a certain number of revs the engine smooths out and revs really cleanly. hmm my SV650S V Twin doens't suffer from that... thought that had more to do with the clutch/flywheel... All V engines vibrate especially at low revs - that is inherent in the design of the V. Take a look at a 1640cc Harley (Road King, or Dyna range) where the engine is rubber mounted and you will see it vibrate about a inch either side. This is what happens to all V engines at low revs - however the greater the number of cylinders the less the effect. Quote Link to comment Share on other sites More sharing options...
kazman Posted March 24, 2010 Share Posted March 24, 2010 On the way home I noticed that it only occurs when the revs are below 2k. To be fair I suppose it may have always done it and therefore be down to the map as it only happens if: 1 I am below 2k Rpms and 2 I have been on the throttle aggresively before hand and 3 I press the clutch very shortly after coming off throttle my rpms when cold are 1500 btw. About 700 when warm. Quote Link to comment Share on other sites More sharing options...
andlid Posted March 24, 2010 Share Posted March 24, 2010 On the way home I noticed that it only occurs when the revs are below 2k. To be fair I suppose it may have always done it and therefore be down to the map as it only happens if: 1 I am below 2k Rpms and 2 I have been on the throttle aggresively before hand and 3 I press the clutch very shortly after coming off throttle my rpms when cold are 1500 btw. About 700 when warm. 3 I press the clutch very shortly after coming off throttle Sounds like you're not giving the engine enough time to react after you've pushed petrol into the cylinders? ^ all that sounds like normal behaviour to me... Quote Link to comment Share on other sites More sharing options...
kazman Posted March 24, 2010 Share Posted March 24, 2010 I suppose it could be.... Never noticed it on my other cars and don't understand why it does not happen at higher revs though.... Quote Link to comment Share on other sites More sharing options...
Valveman Posted March 24, 2010 Share Posted March 24, 2010 My car is pre up rev (55 plate uk) (not nessesarily relevant but are all the other occurences of this on this thread on rev up engines)? and i have never noticed the revs climb when the clutch is depressed untill this morning, so i dont believe its the map.... Why not? The map controls everything.............. Remember there is no direct connection between your right foot (accelerator) and the butterfly in the throttle body - The butterfly is controlled electronically by a stepper motor which is controlled by the map. When you remove your foot off the accelerator pedal the engine management software (or map) is controlling the throttle - this is why the engine revs rise - the map is fueling the engine not you! It can detect when the engine is about to stall and then tries to increase the throttle opening to keep the engine running. This problem has got nothing to do with the clutch or the flywheel. Quote Link to comment Share on other sites More sharing options...
kazman Posted March 24, 2010 Share Posted March 24, 2010 Never said it was the clutch.... My point was that I did not believe it was an inherently poor map because it has only just started doing it. I will concede that I could be wrong on this point for the reason I stated a couple of posts back. Quote Link to comment Share on other sites More sharing options...
narcotix Posted March 24, 2010 Share Posted March 24, 2010 It's defintely not normal behaviour as I recently drove a friends Zed and his doesn't do it ... I'm not too sure about the map theory either as my car is completely standard and therefore must have the original maps loaded ... They can't just start playing up for no reason can they? I've done a few ECU resets since and also the other been through the other various reset procedures and there was no change ... I'm now thinking it's down to something like a faulty sensor (maybe throttle position) ... Quote Link to comment Share on other sites More sharing options...
Valveman Posted March 25, 2010 Share Posted March 25, 2010 It's defintely not normal behaviour as I recently drove a friends Zed and his doesn't do it ... I'm not too sure about the map theory either as my car is completely standard and therefore must have the original maps loaded ... They can't just start playing up for no reason can they? I've done a few ECU resets since and also the other been through the other various reset procedures and there was no change ... I'm now thinking it's down to something like a faulty sensor (maybe throttle position) ... This is a possibility although this would normally throw up an ECU fault. I only bought my Z last November and noticed the same thing on a lot of 350Z's that I drove, mostly from main Nissan dealers. When you drive the car on a regular basis you do get used to the way the car behaves and you compensate for this yourself (you slow the gear changes down to make smooth shifts) and its not until you drive something else that the holding of the revs is noticeable. I am going to drive a 370Z very soon and will check if the same thing is apparent on that car. Quote Link to comment Share on other sites More sharing options...
narcotix Posted March 25, 2010 Share Posted March 25, 2010 I've checked for any error codes and there were none reported ... Would it still throw up a code if the sensor was being sluggish ... by that I mean it's not completely failed but just not working as well as it could ... I have changed the way I drive to compensate for this but I still think it definitely shouldn't be like this ... being a sports car it's designed to be driven fast and a big part of that is being able to change gears quickly ... Let me know how the 370z compares, but as I said before I drove a friends Zed 2 weeks ago and it didn't have this problem ... Quote Link to comment Share on other sites More sharing options...
andlid Posted March 25, 2010 Share Posted March 25, 2010 I've checked for any error codes and there were none reported ... Would it still throw up a code if the sensor was being sluggish ... by that I mean it's not completely failed but just not working as well as it could ... I have changed the way I drive to compensate for this but I still think it definitely shouldn't be like this ... being a sports car it's designed to be driven fast and a big part of that is being able to change gears quickly ... Let me know how the 370z compares, but as I said before I drove a friends Zed 2 weeks ago and it didn't have this problem ... Mine has NO problem changing fast... it's working REAL well shifting fast actually so not sure why you see a problem there... still think it could be the flywheel thats out of balance or worn down. I can't see it's fueling in my application since I'm not using the standard ECU for that and got a full retune... Quote Link to comment Share on other sites More sharing options...
Valveman Posted March 25, 2010 Share Posted March 25, 2010 I've checked for any error codes and there were none reported ... Would it still throw up a code if the sensor was being sluggish ... by that I mean it's not completely failed but just not working as well as it could ... I have changed the way I drive to compensate for this but I still think it definitely shouldn't be like this ... being a sports car it's designed to be driven fast and a big part of that is being able to change gears quickly ... Let me know how the 370z compares, but as I said before I drove a friends Zed 2 weeks ago and it didn't have this problem ... Mine has NO problem changing fast... it's working REAL well shifting fast actually so not sure why you see a problem there... still think it could be the flywheel thats out of balance or worn down. I can't see it's fueling in my application since I'm not using the standard ECU for that and got a full retune... If you don't have the stock ECU then you won't see this problem. I have driven about 25 Zeds leading up to buying mine and they all exhibited this problem to some degree - some more than others. I have a friend who worked for Bosch and was in charge of ECU mapping a number of UK made cars (admittedly diesel) Range Rover, Freelander, Mini and the new ford V6, and he used to tell me stories of how some manufacturers would spend an enormous amount of time getting the mapping absolutely perfect, and some manufacturers would not. He used to go all over the world in different climates testing and refining the car and fine tuning the maps. This is an extremely complicated subject as the ECU is switching in different maps and juggling settings all the time to optimise the correct fueling for the vehicle and the conditions. Here I think is the problem. Nissan have optimised the maps to make the car safe and run right assuming that 95% of drivers will be happy with the car as is. They have mapped the car for "safe" running. We "experienced" drivers (probably) represent less than 5% of drivers who would notice and complain about such things. Quote Link to comment Share on other sites More sharing options...
showtime1 Posted April 22, 2010 Share Posted April 22, 2010 i get it when i let my foot of the gas it takes a second for the revs to drop im gonna get some cleaner to clean the throttle body i did it on my tt Quote Link to comment Share on other sites More sharing options...
Valveman Posted April 23, 2010 Share Posted April 23, 2010 i get it when i let my foot of the gas it takes a second for the revs to drop im gonna get some cleaner to clean the throttle body i did it on my tt Don't bother, cleaning it will not fix this problem. It's an ECU or ECU to throttle body control problem. Remapping the ECU has helped but not completely fixed the problem. It would also appear that some who use non standard ECU's do not see this problem. Quote Link to comment Share on other sites More sharing options...
pernickerty Posted October 19, 2010 Share Posted October 19, 2010 I have a similar issue that's recently occurred. I went away for 2 weeks and when I came back the engine wouldn't run. It would fire up but die instantly. After about 5 goes at this I left it for a bit and came back. It started up but with the malfunction indicator on. I manually read the code which gave a 122 which is the Throttle Position Sensor (low). I reset the ECU and the car would start so I took it for a drive. About 5 miles in it went to limp mode. No error code this time so I restarted and since then (a week and a bit) it's been running without going to limp mode. HOWEVER, it's not running how it should. When warm the engine idles high at about 1100rpm. As other people have mentioned on here, when driving along when the accelerator is released it actually revs higher for a second before falling back and the fallback itself seems a bit lumpy. It did not do these things before I went on holiday. I'm relating this as some of the symptoms sound like other peoples (although obviously I've had an error code) so may have some relevance. The car will most likely be going into Abbey soon for other work but before I take it I'm going to clean the TB as suggested above and see if it makes any difference. I'll report back if I find out anything.... Quote Link to comment Share on other sites More sharing options...
Valveman Posted October 19, 2010 Share Posted October 19, 2010 I have a similar issue that's recently occurred. I went away for 2 weeks and when I came back the engine wouldn't run. It would fire up but die instantly. After about 5 goes at this I left it for a bit and came back. It started up but with the malfunction indicator on. I manually read the code which gave a 122 which is the Throttle Position Sensor (low). I reset the ECU and the car would start so I took it for a drive. About 5 miles in it went to limp mode. No error code this time so I restarted and since then (a week and a bit) it's been running without going to limp mode. HOWEVER, it's not running how it should. When warm the engine idles high at about 1100rpm. As other people have mentioned on here, when driving along when the accelerator is released it actually revs higher for a second before falling back and the fallback itself seems a bit lumpy. It did not do these things before I went on holiday. I'm relating this as some of the symptoms sound like other peoples (although obviously I've had an error code) so may have some relevance. The car will most likely be going into Abbey soon for other work but before I take it I'm going to clean the TB as suggested above and see if it makes any difference. I'll report back if I find out anything.... Cleaning the TB won't make any difference. Best to take it to a Nissan garage or a 350Z specialist like Abbey Motorsport and get them to sort it out as there may be a chance some damage might be done to your engine if the fault is left unchecked. Engines today run withing very tight limits and if these are exceeded for extended periods potential damage may occur. At the very least you should get the throttle position sensor checked and adjusted if necessary. Quote Link to comment Share on other sites More sharing options...
Z-Boy Posted February 17, 2011 Share Posted February 17, 2011 Hi all Did anybody find a resolution to this issue as mine now has the same problem! It very frustrating. Quote Link to comment Share on other sites More sharing options...
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