Strange problem: K11 expert required

[ELA]

Ok guys, I have finished installing my new engine today and whilst the engine was out I decided to do a little tuning to make it a little more interesting; basically along the lines of the "EBB Mirco Micra" thread as per the following.

New engine going in:

Cut up old HT leads to use some connectors:

To make new leads from copper core cable:

Bashed out the first cat:

Chopped up the suspension

Fitted new Bosch super 4, gapped at 2x OEM setting

Throttle grind

Lightened the flywheel

Made a new induction system removing the filter but using 2 x throttle wire mesh; one on the throttle in the normal place and one at the other end where the air is drawn in as per the pictures

Treated to a full service including top Ester based racing oil from Motul, new fuel and oil filter et cetera

Removed jacks and happy to see her sit about right

A quick blast up the road to test

A now here comes the question; the handling has been massively improved with reduced body roll and great turn-in. Under WOT the car pulls very well however under partial throttle at around 2-3000rpm (guess as no tacho yet) there is awful juddering like under or over fuelling, especially up hill. I don't think it is AFM or other sensor related, as I used the same throttle assembly, which was working fine with the other engine. I mentioned all the worked I have done on the car the last few days as someone may know if this has caused the problem. My guess is Nissan map the car at 15:1 AFR in the midrange stock and now I have added lots of air in the equation, with the mods, the car may not like it. There are 2 other things that may be causing the problem; the rocker cover to airfilter box hose is now left sucking in atmosperic air, as is the little hose (around 2-3mm internal diameter) that came from a sensor which attaches to the air filter box. Any help much appreciated guys.

 

[SuluR]

Ok guys, I have finished installing my new engine today and whilst the engine was out I decided to do a little tuning to make it a little more interesting; basically along the lines of the "EBB Mirco Micra" thread as per the following.

New engine going in:

Cut up old HT leads to use some connectors:

To make new leads from copper core cable:

Bashed out the first cat:

Chopped up the suspension

Fitted new Bosch super 4, gapped at 2x OEM setting

Throttle grind

Lightened the flywheel

Made a new induction system removing the filter but using 2 x throttle wire mesh; one on the throttle in the normal place and one at the other end where the air is drawn in as per the pictures

Treated to a full service including top Ester based racing oil from Motul, new fuel and oil filter et cetera

Removed jacks and happy to see her sit about right

A quick blast up the road to test

A now here comes the question; the handling has been massively improved with reduced body roll and great turn-in. Under WOT the car pulls very well however under partial throttle at around 2-3000rpm (guess as no tacho yet) there is awful juddering like under or over fuelling, especially up hill. I don't think it is AFM or other sensor related, as I used the same throttle assembly, which was working fine with the other engine. I mentioned all the worked I have done on the car the last few days as someone may know if this has caused the problem. My guess is Nissan map the car at 15:1 AFR in the midrange stock and now I have added lots of air in the equation, with the mods, the car may not like it. There are 2 other things that may be causing the problem; the rocker cover to airfilter box hose is now left sucking in atmosperic air, as is the little hose (around 2-3mm internal diameter) that came from a sensor which attaches to the air filter box. Any help much appreciated guys.

Is it anything like this video? Need help with kinda the same problem

VIdeo: http://s655.beta.photobucket.com/user/sulur/media/A7D2C52C-B073-41C6-8213-FB25B14D843E-1190-00000132C294781D.html

 

[frank]

have you disconnected the speed sensor wire ELA ?

 

[ELA]

I don't think so Frank, the speedo still reads correctly, if this is what you are refering to? I have also connected the OEM loom up exactely as it was before

 

[frank]

i removed the screw on mine mate, it should run better then (it wont effect the speedo btw)

 

[ELA]

Forgot to add it idles perfectly and under full throttle all seems well apart from this 2-3k rpm spot. SulaR it is difficult to tell from your video (I don't have a rev counter to be totally sure when it is happening with my car). Mine doesn't seem as pronounced as the problem in the video.
Frank I will try to remove the screw you mention; will the speedo still work?

 

[frank]

will the speedo still work?

yes mate, my engine holds back bigtime if i leave it connected, and goes mental when its disconnected (albeit a different setup to yours)

 

[ELA]

Hopefully it is that simple (can't see why this works though). I was starting to think that I need an adjustable FPR to up the fuel pressure slightly or something along those lines, as this was done in the EBB project.

 

[frank]

the ecu is forced into closed loop in 3rd, 4th and 5th by that sensor ELA, and you may well need some fueling adjustments

 

[ELA]

Many thanks for all your help Frank, how simple is the fueling adjustment?

 

[frank]

i,ve got a few threads on cisco,s of my ghetto fueling mods mate, here,s 1 http://micra.com.au/community/message.php?messageid=75745 but i,m running a proper Ed/fusion nistune ecu now tho

 

[ELA]

Ok the little speed sensor wire made no difference. It is pretty unbearable to drive normally, outside of this rev range: idle, WOT and under very light throttle the car behaves normally making me think it is not ignition related. At 20-80 throttle, especially uphill, the car kangaroo's and almost feels like it will cut out up steep hills. Any other ideas?

 

[frank]

those huge plug gaps maybe ?

 

[Ed]

Bosch super 4 plugs are terrible in my experience. Swap them to normal plugs and gap them to OEM. Try a different AFM too.

The speed sensor doesn't force it into closed loop. It just has some speed fuel compensation that leans out the higher rpm. Shouldn't be a problem for most people. Only becomes a big problem with turbos. I first discovered the behaviour on a dyno.

 

[r-reg-sr]

i got them big 3mm gaps,with no probs, standard leads though

could try the throttle body "FULL" service.

 

[Ed]

There is no benefit to doing so. When I'm running engines that are making well over 130bhp/cyl and using 0.8mm gaps, I can't see why people thing big gaps help?

 

[r-reg-sr]

my theory ,,,,,,,,,,,,,,,,,,,,,,,, have i even got one?

slightly bigger gap, time up the distributor to the sweet spot by ear hole and see how he feels on the rd.

 

[r-reg-sr]

my theory ,,,,,,,,,,,,,,,,,,,,,,,, have i even got one?

slightly bigger gap, time up the distributor to the sweet spot by ear hole and see how he feels on the rd.

only other modage are larger air intake, light flywheel, 1.0 gear box

 

[ELA]

Many thanks for all the advise guys. I tried re-gapping the super 4 to no avail. I will try the stock plugs and see how that goes. The throttle assembly was working perfectly before (by this I mean that the AFM should still be ok, or are you suggesting that degregationof of the AFM is instantaneous as opposed to gradual? I'm surprised no body is suggesting the adjustable FPR route; or are the mods detailed not likely to affect the AFR to that greater extent and the stock setup should cope with these mods?
Once again many thanks for all the help thus far

 

[Ed]

I dont know your full setup, but FPR should be the last thing on your list if the OEM one has tested fine.

If seen what appear to be working maf sensors only to be reading slightly wrong causing all kinds of issues,.

 

[ELA]

Once again many thanks Ed. I will have to find a diagnostic tool somewhere to see if any error codes have been registered.
I have just read another thread and it mentioned that a faulty O2 sensor can cause running problems. Is this likely to cause the type of issue that I am having? The thread also mentioned disconnecting the O2 sensor to see if this was causing the problem; if I disconnect the O2 sensor what should I expect to happen?

 

[Ed]

If its a slightly off AFM, now codes will be present. However lambda feedback compensation if it has the stock lambda sensor will be way out - thats a good clue

 

[ELA]

It seems the car has improved by about 60-70% by itself; is the ECU self learning? I still have an annoying flatspot between 2000 and 3000rpm is this a typical trait with the 1.0l? There is also the odd judder every now and then but overall there is a massive improvement compared to how it was previously

 

[Ed]

The ecu learns nothing.

 

[ELA]

Many thanks Ed, do you suffer from insomnia 03:27hrs and you are up posting on here. Either that or you have a incurable Micra fetish I'm guessing you are in some way associated with Fusion MS, judging by your knowledge with these cars. Many thanks for all the advice you are providing on this website.