leeroy_25

Come on guy's someone must have fixed the issue and got some answers?

I have had issues with my car starting from hot pretty much since it was first built. Seemed to be fine after one mapping session and then another mapping session later it was back. Tuner is quite a way from me so I have not had a chance to take it back.. SoI was trying a bit of self help! With the assistance of some experienced guys on here hopefully! I was googling the other day and found an old thread on here describing the same problem with some suggestions but no final post of the end result. Basically if I go for a drive and the car is warmed up then say stop for petrol.. fill up.. go pay.. when I come back to start the car sometimes it keys over a long time before it fires and when it does the rpm is real low and you have to give it a blip to clear it.. then it's fine. Rarely it will fire and then stall.. Then key over and nothing.. then key over and fire instantly and with a blip as before it's fine? First of all I was wondering if the heat soak was setting messing the air temp settings up? as it does get hot under the bonnet quite quickly if its a warm day. And it is definitely worse on warm days. I pulled the air temp sensor plug off to try and test the theory and it didn't seem to help? i.e it did the same thing. I did notice that if you stop and then start the car straight back up it's perfectly fine. I am guessing it is lack of fuel or lack of spark? just not sure why and then how to fix it.. One suggestion was a faulty FPR. not sure why this would only effect if on hot start? I have played with the cranking settings in the ECU a bit but don't think these would normally need changing and I am not 100% sure which way to move them in honesty.. but they don't seem to make a lot of difference with what I did try. Leaky injector was also mentioned in a post? However I would imagine this would only effect 1 cylinder an the car would start ine but run lumpy for a second? Anyway if anyone could give me some advice I would really appreciate it! its sounds like quite a few people have had this issue but cannot find anyone posted and answer to it! Thank you Lee

Hi There, Only just seen this reply! Tanks for the feedback.. I would agree with you I have some kind of flow issue! Strange how it holds boost fine on the road but not on the dyno is the weird thing? I can only assume it is the lack of airflow in the dyno cell? I am running a stock intercooler and may well look for a larger one in due course. For now I redid the exhaust and put a stiffer wastegate spring in and went back for another run. Gained 1 bhp top end! But was still getting the same boost drop and also wheel spin problems. I did make quite a big gain in the low down power and torque though which was nice 30ftlbs of torque and I think similar in the power. My cams are set to maximise low down power and torque and not top end so I guess it depends how you set yours as to the power difference? in our setup? You also mentioned fuelling.. As I am I don't think I can support much more power as the duty hits 90's top end.. not sure if that is pump not keep up or the 600cc injectors are too small? I don't have a FPR/gauge inline to check at present. You say you are running an old HX40?? As in an H1E? What size turbine housing is it? What rpm do you hit full boost out of interest and what are you rev limited to? interested to know someone else experiences with a holset! I ended up setting my boost to 1.3bar.. (18.8psi). I didn't fancy going any higher especially as I cannot hold that on the dyno to map the top end properly!

Thanks for the info/confirmation. I am running a Holset turbo.. HX40.. The intake temps on the commander are generally fine.. Gets a bit warm under the bonnet in summer when you stop! but I am fitting a vented bonnet soon!

Thanks for the reply.. I have FCedit but no datalogit connection for my car sadly!.. When it was on the dyno previously the high odd numbers were around column 12-15 on the bottom couple of rows.

Just for reference here is a screenshot of my current ign map vs a more std one? What you guy's reckon? is the 40+ values okay up in the low load section? My map: Standard Map: Cheers Lee

Assuming the CAS was set correctly by me! Then it is at about 20degs. Idle is a bit lumpy so not easy to get a definite reading! Engine warm, idle at 950rpm.. Strobe on the front pullie? I presume there is no way that reading can be wrong? I don't imagine a degree or two is going to make a huge impact on power is it? And yes that is through the top end range. Thank you Lee

I had a look in the map and spoke to my tuner and decided to take a degree out of the high load/rpm end of the chart in my apexi commander.. They are around 21-23degs at that end which looking at the basemap is possibly a degree or two high anyway? I will monitor the result and if need be take another degree out. The weather has just cooled down here after getting it mapped so I expect the cool dense air is not helping in as much as I am getting to the point of maxxing the fuel system anyway as well! So to be sure I might kick back the boost ever so slightly too if need be, only 1psi! I think better safe than sorry!

Just trying to get some view points and maybe piece of mind as it seems to vary who you speak to! I have an RB26/30 motor with a stock RB30 bottom end. I am running about 1.2 bar boost and limited to 7000rpm.. I have an Apexi ECU for info. When I am driving hard on full load, 3rd, 4th gear the knock levels hit around 38 most of the time which I am not too worried about. However every now and then I get a low 40/41 recorded and very rarely I get a mid to high 45-48 pop up? Should I be worried about this and looking to put a bit more fuel in or dial out some ignition somewhere? The fact it is not consistent implies maybe it is one or two slightly rogue cells which I may be able to find if I investigate the map? But just wanted some thoughts before I get all carried away! Thank you Lee

Okay guy's so I went back to the dyno at the weekend. Had no time to get a new wastegate spring. So I tried to put some pre-load on it. I had made a new MAF table for the Q45's and raised the airtemp correction value and also increase the warm water correction temp as the car never seems to get over 70deg and this seemed to solve the random problem of the car getting richer every run! My tuner then trimmed up the fuel some more (still running very safe) and did a few runs but still the boost was dropping off as the revs increased. In the end in a effort to try and get a representative run my tuner held half throttle to build the rpm up to around 5000rpm and then hit the throttle to try and get the boost to hold out for redline. Still no joy! Anyway. In the end I came away with 451bhp at the rear wheels. with the boost dropping off below 1.1bar! So would estimate at least another 10-15bhp if I could hold boost on the dyno. Annoying because it holds boost on the road fine! Another graph and video below! I am pleased enough to call it a day now unless I have good reason to go back later! Essentially I am just chasing proof of a big number on the dyno! The whacky graph is from where we tried slamming the throttle at the end of the run! A quick little video clip too.. Not that great. But hey!

Thanks for all the tips guy's had a second go at the dyno this weekend.. I recalculated my MAF table and found that my previous calculation I had used an inverse multiplication by accident.. it didn't solve the stall issue on it's own but my tuner watched the map while I did some typical driving on the dyno and he found the cells that it drops into as it stalls.. He then kept leaning them out until it didn't stall any more. Sorted! Cells are not used any other time so that should not be an issue! Cheers Lee

Come on guy's. I only have a few day until I am at the dyno and I want to get my MAF table setup as best as I can. I cannot afford to go back to the dyno again! Only after a few key values along the way so I can try and fill in the blank between! Thanks in advance. Lee

Would still be great if someone could give me some of the first few and last few numbers in the MAF table for a pair of Q45 MAF's on an RB26 ECU. I went through and altered all my current chart by the corresponding % for each voltage band.. I assume I did it right?? I just multiplied each table value by the relevant %? Just to confirm I did this and checked the graph mode and the graph looks nice and smooth just like it was before I changed the values!? I have one more shot at the dyno next weekend and really want to get the car as smooth as I can this time. Really appreciate any pointers please. Thank you Lee

Hi Jono, Saw your rey on my other thread.. Thank you. The fuel cut at the mo is set at 1200rpm and 1300rpm. Would raising this help my MAF related tendency to stall do you think?? Slight aside.. I need my cold running setup.. When the car is cold does it run on the same map load cells and just use watertemp compensation to control it? Mine idles pretty fine but if you touch the gas a bit to hard it really struggles.. Hard to say if it's lean or rich.. I would guess lean? Once it's warmed up it's perfect. Thanks Lee

Thanks for the reply again.. Surely a single Z32 is not good for that power?? From an earlier reply you simply splice the two MAF wires together to convert to single set-up? A little tempting but I am just concerned about physically flowing enough air? I have after-market front wings and the crap shields didn't fit! I am sure I could fix something up if needed though. Just another thought.. Which I have started a new thread on.. but would (I guess) raising the fuel cut value in the rpm screen help sort the problem at all? From what I can tell monitoring the hand commander. When you lift of the fuel is cut? so injector duty is 0%. Then when it falls far enough.. presumably to the F/C value the fuel then starts injecting again to catch and control the idle? If that is right.. If I was to increase the fuel cut rpm would that help the stalling issue at all? Would it have any other negative effects? Thank you Lee

Okay guy's wondering if anyone could assist me with a few little questions I have. 1st I have always noticed my car rev counter does not read the same as the power FC hand commander. It is about 200rpm out? Is this normal for a start or is there some way to get the car better in sink with the ECU. Also which is actually correct!? I did try re-learning the idle which did not seem to help. next is the idle.. I don't know if this is actually a faulty idle control valve or related to the above but in the RPM settings you can set idle1 and idle2. Mine are set to 900 and 950rpm respectively. However the car idles has to be set by the air bleed screw in the idle control valve. It seems the ECU does not control it? It starts col and idles around 1200-1500rpm then when warm idles at around 1000-1050 although since my re-map that has dropped to around 850-900 to be honest but I am not convinced the settings for ide 1 and 2 have any effect on that? Can I test by raising or dropping them? Also I noticed when hot if the car is sat idling, after a while the rpm slowly increases? Would this air temp correction if the air inlet temp is going over 40degs? Which is very possible. Just to point out if you put the a/c or other load on the rpm value does rise up as it should. Lastly What exactly is the effect of changing the Fuel Cut values in the rpm setting screen.. i.e if I raise them up or down? Thank you Lee

Hi There Guilt toy. Thank you for the option. At the moment the MAF's are as far away from the turbo in the engine bay as possible. But that is not a great distance! If I can find somewhere to mount two MAF's and filters sensibly outside the engine bay I might go for that as it would also help keep inlet temps down! Not convinced I have space though? Also I don;t want the filters where they are likely to get covered in crap from the road or brake dust etc.. So that kind of rules out most places! And if they cannot be in direct airflow which I can see why.. limited even more! Can you post a pic of where yours is mounted? And are you on twin MAF's or a single? Thank you Lee

Cheers Cubes.. I know ideally Holsets for more efficiently at higher boost. but this is my first build with all stock internals so I don't want to push my luck! The HKS Step1 cams I think are 9.1mm lift off the top of my head. not sure on the other specs. Do I really need a spring?! Why does pre-load not work? If I want to run 11-12psi low boost I don't think the spring is more than a few psi off? I will check though. I want it so hold good solid 18psi though.. maybe 19 for the most! AFR wise we were aiming for the mid 11's as it happens.. Just the sudden change messed us up at the end of the day and then we ran out of time. Hopefully I have the answer to that but wont know until I go to the dyno again now! If air temp correction is not the answer then it will be a wasted trip! While we are talking AFR's and boost.. What is a good sensible knock value to be hitting? i.e if I am hitting 40-41 every now and then am I safe?? Generally a heavy squirt gets you in the mid to high 30's?? Obviously the lower the better but what is considered dangerous for my stock internals? Thank you Lee

Just saw your reply there cubes! I am not too worried about it as it is pretty hard to stall it to be honest.. Just it would be nice to get over it if possible! if not then so be it.. I could fit a BOV I guess but prefer it without as well! How did you wire a single MAF with an RB26 Power FC?? Cheers Lee

Thanks for the replies again. First off Rob.. I see the graph is an exponential curve and non linear. Not sure why that matters on a percentage change? Surely that just moves the curve up or down generally. Or maybe where the percentages are not the same that gives jumps between each voltage range? Next I am not sure what you mean about the commanded fuel map? My tuner has adjusted the fuelling to suit the current setup using datalogit? Please elaborate and I will try and reply with a useful answer! Jono, I will set the global adjustment back to 100% and go through altering the 32 table values by the appropriate % for the voltage. Then I can lock the x values and smooth out the curve? Sounds good so far? Would be very nice to know a starting and maybe ending value so I can work out inbetween though. Please can someone give me this info? I chose to put it in Airflow 3 as I know I will never use that. Left the VG30 (Airflow 5) slot in case I ever got Z32's! I assume the line you choose to alter is erelevant? I am pretty sure that you cannot just use the RB25 values as if you look at the other common MAF's between RB26 and RB25 in FC edit you will note they are not the same from one to the other.. This was how I determined a scale factor to work out the Q45 values in the first place.. Clearly the scaling is not a linear factor though and hasn't quite worked out! It definitely needs some kind of multiple but it is not 2 or as I said I don't think it is indeed linear full stop. I guess you would have to work out the difference in airflow volumes and it might be something related to that? This may or may not be related but I noticed while monitoring injector duty that when you are driving along normally and lift off the throttle to change gear otr stop the duty falls completely to 0.0%? Is that normal as that implies the injectors are not putitng any fuel in? If you are going really slow then it maintains a low %? Just wanted to get that clarified as normal or not!! Please keep the info coming Thank you Lee

I see.. Someone else told me it was a pulse dampner? I thought that was more likely the bit on the OEM pump itself? So in fact I could take the one way valve out of the Bosch pump if I leave this inline one there?? I presume that might give a little extra flow from the pump? Or is it not worth it?? I actually think the pump is not the issue now but preparing myself with all the options just incase! Thank you for your answers Lee

I missed some points to reply to earlier.. Water temp and oil temp wise I know there is no problem! That is actually the first thing my tuner asked.. is the oil cooler getting hot? It was perfectly fine and the water temp and oil temp struggle to reach 80degs! However air temp is a different story. I did not think to check that at the time and I am not sure if my tuner did. Just checking the Power FC settings you start getting air temp correction after 40degs. I know from driving my car yesterday and checking that is reaches 40-42deg in generally slow moving traffic so stuck on a dyno with limited airflow I guess it is a strong possibility it would go higher? I reckon it would only need 50degs to get the sort of correction I am seeing on the printout. And the fact it seems over the entire map kind of fits? but then that said .. Will the correction change the exhaust gas AFR like this as I would assume the correction is to try and keep the burn the same and prevent knock? warm air gives less effective combustion right? So actually if you add fuel to make it safer??! then you would get richer exhaust readings for sure?! Have I got that about right? Not sure how the more fuel for less burn works though? What you all think.. have I maybe cracked it!? Wonder if I can get a logged max air temp from those dyno runs to check? Cheers Lee

Pretty please!

I am running a Power FC ECU.. standard MAF type. I am aware the turbo comes from a large diesel motor! I think for the engine CC the HX40 is the right compressor housing.. I think the HX35 would not cope top end. I think it is a case of needing a 16cm turbine housing over the 19cm I currently have ideally. If I find one great but for now I have what I have! Thank you Lee

I Just upgrade my in tank pump on my R33 GTR.. When I was doing it I noticed there is some kind of regulator in line inside the tank? Should I remove this regulator or is it fine to stay? I am currently running the standard external FPR if that makes any difference. That said I may need an upgrade! Thank you Lee