likely common problem, "runs" odd wont rev

[insanitykouki]

info: 1998 nissan 240sx SE KA24DET. t3/t4 50trim 63a/r turbo, 550cc deutchwerk injectors, walbro pump, EFI ECU, z32 maf.

Car will not under any circumstances rev/drive over 3000rpm. Initially I thought this was a MAF issue (and still may be) However i triple checked the maf wiring is perfect, a friend double checked and the z32 maf is wired correctly. So i thought maybe the ECU program was wrong... sent the ECU back for reprogramming and it came back but the vehicle is doing the same thing...

I guess im at my wits end... I need some input on possible solutions before i take it to a performance shop and just give them my headache. Please help me, me love you long time :S

edit: forgot to add some more info (long night at work sorry) i have two z32 mafs and swapped just in case one was bad and both make the car run the same. I cleaned both with approved maf cleaner and still nothing. I checked my o2 sensors and they are fine. im def getting fuel lol it flooded once. If you guys need any more info just ask ill post!

[cronux]

have you tried a different MAFS? like, wire up a stock mafs. because 3000 is the standard ECU cutoff for no mafs, so its either wired incorrectly( you say its not, but just checking ) or its a bad mafs.

[98s14inaz]

Z32 mafs needs to have one of the grounds going directly to the chasis and the other one needs to go to the harness. If you put both of them together you will get a similar result. Go to autozone/checker and use the code reader. Just because there isn't a cel on doesn't mean there isn't a code.

[insanitykouki]

I have not tried a different mafs (non z32). I sold my old s14 one to a friend so ill see if he will come over and swap temp. The odd thing is that if i unplug the maf it still caps but the car runs like junk (obviously the maf is unplugged lol) so its just strange that it would even alter.

[Z U L8R]

i'm not a fan of generic "these are my mods, tune my ecu for em" type tunes. every motor is different. if you take 10 brand new cars off the showroom floor and dyno each one, they'll all make different power. i personally think your ecu's still not tuned for the maf, but just to aleviate (sp) wiring as a possibility. could you take a picture of how you wired in your maf and and label what each wire does on the plug pinout.

Dave @ Lethal Injection Motorsports www.lethalmotorsports.com

[insanitykouki]

Yeah I will do that here in a bit, I have quite a bit of homework to do tonight.

And I am almost 100% gaurenteed its the ECU. Ill get pics but i am absolutely positive it is wired up right. ECu came and did that i KNEW it was that right then and there. I actually have an SAFC-II to use, I am going to try and get my hands on a stock s14 MAFS and use my stock ECU and tinker with that first then I may as well sell the other ECU and save up for a freakin standalone so i dont have to DICk with this kind of thing lol.

[1QUICK4]

Try the SAFC 2.

2 in 6 out is for z32 without ecu being tuned for it

2 in 2 out is for z32 with the ecu being tuned for it

[deuceforty]

be careful with the mafs, i know its easy for me to sit here and tell you what to do behind a computer, but make sure you have the wiring right.. as simple as the wiring diagrams are, i actually reversed the wires on my maf and my car did the same thing yours did. i switched out 3 other mafs before someone told me to switch the outside wires around. fixed all my problems

heres the diagram, when your looking at the plug, make sure you not the positions of the little square locks, make sure when you read the output that your looking from the back where the wires are coming out, and there are 2 squares on the top and 3 on the bottom

http://nissaninfiniticlub.net/photopost/data/500/17500z32diagram-correct.jpg

[ILoveMyRHS13]

I had the exact same problem a few weeks ago after I changed the valve cover gasket... I just kept starting it up and trying to keep it running. When it did actually start running, I drove it around and it sounded like a shitty WRX and wouldn't have any throttle response at all... I was driving home and mashed the gas again and it somehow worked fine ever since...

Yeah... Unhelpful... I just told you to wait it out to see if helps any; Fucker.

[insanitykouki]

Assuming my homework allows me today (didnt yesterday, college sucks) ill go double check to that diagram as when i wired it with the diagram i had i wired it by looking AT the plug not how the wires were coming out so maybe it IS wrong, ill check!

at that time i will get pictures of my wiring IF it is right, if not ill switch her around.

[insanitykouki]

update: according to deuceforty's diagram, my wires were backwards. The diagram i had was from JWT, however, the diagram did not specify which way to look at the plug.

further update: car wont start, low on premium and bad plugs so I cant conclude whether or not the issue is resolved! D'oh!

[jinesz32]

kinda funny, my friend with a z32 tt. has the same problem, he can't rev past 3000 rpm.

[insanitykouki]

Got pictures of the mafs wiring, kind of hard to tell things, odd lighting. Car wont start right now though and i dunno why. I think it has to do with my oil level, i have a terrible leak that i cannot locate (odd enough with the oil leak i have should be super easy to find) and I think the low level is contributing to the car not starting. I realize some of the wires (specifically the chassis ground) is bare and not protected. The ground is fine, checked with a volt meter, and is only temp till i can get it running fine.

Here are the diagrams I used:
http://a13.ac-images.myspacecdn.com/images01/128/l_99a121521248e980df116266c48009ec.jpg
http://a435.ac-images.myspacecdn.com/images01/60/l_19843281e6fe970c498360875cc6e55a.jpg

Here is the plug (2 blocks on top, 3 on the bottom) from left white(0-5v), black (ground to chassis), orange (ground to mafs), black/white (12v)
http://a929.ac-images.myspacecdn.com/images01/97/l_e1d9252cf2275ee122073e39a4da1460.jpg

Black to chassis then another pic showing the ground itself
http://a235.ac-images.myspacecdn.com/images01/73/l_91efa36fdac5942fe90f71d0780c5a22.jpg
http://a170.ac-images.myspacecdn.com/images01/39/l_2f38ffed5726f9ef7441b3631560fc79.jpg

Next up, excuse the picture its hard to see anyway
Orange z32 MAFS ground to Black s14 MAFS ground
White z32 MAFS 0-5v to White s14 0-5v.
http://a750.ac-images.myspacecdn.com/images01/36/l_2ade67e75974ea086eedf0877278f9fd.jpg

Finally, black/white z32 mafs 12v to black/white s14 mafs 12v.
http://a391.ac-images.myspacecdn.com/images01/49/l_4616b868a9bf3a3faecb9dfb634fc0f6.jpg

[deuceforty]

so did you get it working??

i had originally wired mine wrong too, i had some weird ass n60 maf with the oddest pigtail ever O_O

http://i25.tinypic.com/24cio0n.jpg
the red and green wire is actually the 12v signal wire, i had wired it up that the 12v was the white wire, with the 0-5v maf signal being the red and green.


car ran like total dogshit and wouldnt go over 3k rpms :(

[insanitykouki]

The car wont start. However, I have a massive oil leak that i cannot locate (odd huh) 5qts of oil drains in a day but i cant locate it... i must be a fuckin retard.

Not sure WHY it wont start but im pretty sure it has to do with the oil as its doing the sa me thing last time i filled it up and the oil drained out and i tried to start it with low/empty oil lol just wont do it, thankfully.

[deuceforty]

The car wont start. However, I have a massive oil leak that i cannot locate (odd huh) 5qts of oil drains in a day but i cant locate it... i must be a fuckin retard.

Not sure WHY it wont start but im pretty sure it has to do with the oil as its doing the sa me thing last time i filled it up and the oil drained out and i tried to start it with low/empty oil lol just wont do it, thankfully.

drain plug in? ;)

in all seriousness, is it coming from the front or rear of the engine?

check your bung in your oil pan and all oil lines

if its all dirty take some carb/brake/whatever cleaner and clean everything up as much as possible.


and throw a pan under the car so your being environment friendly <3 and it wont be so hard on your wallet trying to find the leak :wavey: good luck buddy!

[insanitykouki]

Thanks. Its not the plug lol its not THAT hardcore. Im going to THOROUGHLY check soon.

HOWEVER, bad news everyone, today i found out some bad news... my department no longer exists as of friday. I am going to have to sell the car. The job market in michigan, as some may be able to attest to, is terrible and I may even be forced to relocate. However, I am still going to try my best to at LEAST find the oil leak and get her runnin as I am attempting to sell. I feel terrible but there are mouths to feed, least of importance mine... if you get my drift (which i wish someone would take over the drift)