Help with injector multiplier/trying to set up base map

revolutionz_s13 · Post by **revolutionz_s13** » Fri Aug 12, 2011 3:10 pm

Ok bear with me, still learning how to tune using a system this extensive.

What I have is a 95 240sx with a s14 sr20det. The motor consists of msd 96#(1008cc) injectors, z32 maf, and a pte 5857 turbo with BC stage 2 cams. I bought the car as it is, the person I bought from was trying to run e85. I have since put fresh 92 octane in, and started over from the basemap in the rom pack.

Here is what I've done to make this work, and I'm not sure if this seems right or not...
First, use injector resize tool, then maf change tool. This puts my K constant at 20951. Now following the ecu mapping guide, by turning off o2 feedback, to make it run relatively normal, I end up adjusting my K constant to almost 40000. By doing this, my idle afr sits a tad lean, and my cruising afrs are somewhat normal as long as I dont give the car too much throttle. With even a little bit of throttle, the wideband pegs lean, like at around -10 to -5 on the boost gauge. By using the target a/f map, I can get the a/f to be not quite so lean with a tad bit more throttle, but the numbers in the map as I get near/into the boost transition section are in the 8-9's, and it still seems a bit lean. So I'm thinking my K constant is off, or maybe my injector multiplier needs to be adjusted? I am sure there is something I'm missing here, as I've only tuned on a couple piggybacks previously and this is my first go round starting from scratch. Another point to note is to get the car to start, I have to increase the crank enrich and the crank offset by quite a bit. Any ideas on what I'm missing here? Sorry for the lenghty post, just trying to be detailed on what I've done thus far.

Thanks in advance.
-Nate

Matt · Post by **Matt** » Fri Aug 12, 2011 8:30 pm

Does Nistune show a Z32 MAF when you do the 'resize MAF' option? Just checking correct calibration curve

Also is the Z32 MAF genuine (see main discussion section about dodgy Z32 AFMs)

Reason why I ask is either there is a problem with the tune in there or MAF itself if its leaning out with some load on it

Also if you could post the maps from the ECU here we can check those

revolutionz_s13 · Post by **revolutionz_s13** » Sat Aug 13, 2011 1:38 am

Im pretty sure that the maf is genuine, i'll double check next time I go out there. there is a z32 option for the maf. If I remember right, the K constant drops to approximately 12,000 when i resize injectors, then goes to the 20951 when i change the maf. I will also post the whole tune, I may have something set up wrong. This is the one I've had the best luck with. As far as the crank enrich and crank offset tables, I'm not sure if I'm setting those up right, I have just been changing them until the car starts, usually based off of whatever cell its accessing when it wont start.

tune.jpg: (996.43 KiB) Downloaded 3976 times

EDIT
I think the MAF is genuine, here is a picture of the sticker on the maf

2011-08-10_09-58-46_636.jpg: (1.13 MiB) Downloaded 3970 times

johnus · Post by **johnus** » Sat Aug 13, 2011 7:50 am

Its probably your latency thats wrong ,580 is the standard for 370cc injectors ,stick with the settings nistune calculated for injection multiplier its usually not far off then adjust latency untill it idles properly .Hope this helps
Regards Paul

revolutionz_s13 · Post by **revolutionz_s13** » Sat Aug 13, 2011 11:17 am

I did actually play with the latency a little bit, and making it smaller did help on the idle. However, I'm still confused as to why I'm leaning out so much as I come into boost, or why I have to increase the crank enrich and crank offset to get the car to start. With injectors that big, I figured I would be taking away fuel in areas, not increasing it a crazy amount. I have the map as rich as it will go in the boost transition, and my wideband still pegs lean, along with the car acting like there is a fuel cut happening. I need to take my multimeter to my maf, injectors, and tps and make sure they are all good I think.

revolutionz_s13 · Post by **revolutionz_s13** » Sun Aug 14, 2011 12:51 pm

Well, I think I discovered my problem. I went for a cruise today just around town and logged it. I noticed the my MAF voltage never goes higher than 2.4v, which would be a problem. I attached my log if anyone wants to look at it, you can ignore the O2, its just a narrowband input. I havent figured out how to connect my wideband(AEM) to the ecu yet to datalog...

Matt · Post by **Matt** » Sun Aug 14, 2011 11:43 pm

you cant tell from the outside since even copies have the same sticker. need to check the elements on the inside

2.475v was the highest in the log file which seems like its getting capped. Time to try another MAF

revolutionz_s13 · Post by **revolutionz_s13** » Mon Aug 15, 2011 5:08 pm

Well, went through some wires and started over from the base tune again. I don't think it is the maf anymore. I pulled the maf out, it is genuine, and the element is clean. I did some more driving around, this time the maf voltage reached all the way to 3v. The only way I could achieve this though was slowly rolling into the throttle. It seems to me maybe I have something else weird going on. Before when it was cutting out the wideband would read very lean. After fixing some grounds and rewiring the fuel pump, now it is pegged all the way rich as it comes into boost. As soon as I get near 0 vaccum, I get something that feels like either a fuel cut or ignition cut. I dont know too much about timing, but I did another log, and maybe the timing is getting too advanced? Sometime in the next couple days I'm going to pressurize my system and see if there are any leaks anywhere. Im not sure what the best 4 to log for this problem are, but I logged rpm, maf, injection time, and ignition timing.

Thank you for all your help
-Nate

revolutionz_s13 · Post by **revolutionz_s13** » Tue Aug 16, 2011 6:39 am

Got it figured out thanks to nissangts. The problem was my injector latency was wrong. After setting it to 995 for my 96# injectors, I started running just fine, now just gotta figure out why my wastegate didn't hold at 15 psi. Thank you very much for all your help guys.

-Nate

BlueRB240 · Post by **BlueRB240** » Tue Aug 16, 2011 11:30 am

revolutionz_s13 wrote:Got it figured out thanks to nissangts. The problem was my injector latency was wrong. After setting it to 995 for my 96# injectors, I started running just fine, now just gotta figure out why my wastegate didn't hold at 15 psi. Thank you very much for all your help guys.

-Nate

I was just about to post that. Glad u got it figured out.

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Help with injector multiplier/trying to set up base map

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