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