SR problem guys please help

[S13FASTBACKSR]

Alright I just uprgraded my maf, fuel injectors and had my ECU retuned. The problem is when I hit about 2500 rpms my car is very very hesitant, it misfires very badly and continues to do so throughout the midrange rpms and finally runs fine when it hits about 6000rpms. I tried checking the timing but the light on my timing gun wouldnt come on, so I used the same gun on another car and it worked fine. I figured maybe I didnt have any power going to my coilpacks so I checked them all with a volt meter and they all had 12volts going to them. Also I am positive I do not have any boost leaks. This is not my question but I cannot figure why my timing gun did not work on my car but did on another. I am 100% sure I had it connected good. But my question is what do you guys think could be causing the misfiring and the richness? Another thing also is the guy who tuned my ECU tested it on his car and said it worked fine so I dont believe its my computer. Im also running NGK iridium heat range 7 spark plugs on a pretty basic setup. FMIC, T28, 3" exhaust, 255lph fp 550cc injectors and z32 maf.

[lv kaotic]

sounds like a bad tune to me... im guessing you have no type of piggyback..(i.e. safc)

[S13FASTBACKSR]

No I dont have any type of piggyback but I dont think that is the problem. I think though that I am onto something, my fuel injectors are not sealing into place which is causing too much fuel to be dumped in. The middle o-ring on my after market injectors (sard) was too thick causing it not to pop into place. (anyone ever heard or had this problem) And that same o-ring made a rather large gap at the top of my injector before i screwed it into place, and it shouldnt have been like that. so i switched it with the o-ring that came off of my 370's and it seems to pop into place how it should but that is without the collar and the top o-ring on. so when i put those on as well it just barely doesnt reach. so what i have to do is put 2 o-rings on the middle part of my injector and i think it should work. Its kind of hard to explain hopefully i did not confuse anyone. I will keep you guys updated. And if anyone else has anymore input on what the problem could be just incase this is not the problem i would greatly appreciate it. thanks

[lv kaotic]

could be a faulty mafs.. is it wired properly? i still think its a bad tune, thats why when you hit a certain RPM range it bogs down, then once you reach a higher RPM it smooths out..

how was it tuned? im guessing its just a generic tune?

this is why im getting a stand alone..

my three cents.. good luck dude..

[S13FASTBACKSR]

yes my maf is wired correctly. I unplugged it and tried to rev past 2500 rpms and it wouldnt. also i took off the fuel rail and stuck a hose on the bottom of the fuel rail where it connects to the intake manifold and blew on it but no air passed through so i guess my injectors are sealing fine. I want to try other things before I send off my ecu and have it checked out so if anybody else has any suggestions i'd appreciate it. Im going to try to get my hands on another maf and see if thats the problem. thanks guys

[FAST-DATSUN]

read maf voltage at the computer to see if its working, What MAF and Computer tuning do you have????????????????????????????

[spider_slayer]

i'd also make sure your spark plugs are gapped correctly....other then that sounds like the tune...

[S13FASTBACKSR]

just a question..how would reading the maf voltage at the ecu differ from reading it at the maf itself. I read it at the maf and got a 12v and a 5v reading. Im just wondering how it would differ though from reading it at the ECU. And also as far as what maf and computer tuning I have, if you mean what is it tuned for..then I have no idea because I am also starting to believe it is a bad tune myself. i dont know what the guy did. It is SUPPOSED to be tuned for a z32 maf 550cc injectors 255lph fuel pump pretty much the basics. but i dont know what this guy did. and i also gapped my spark plugs at 30 before installing them. thanks for the help guys. im going to try to get another ecu that is already tuned for what i have because the way this thing is running, i dont think anything but the ecu could make it run that bad.

[goldollar]

The reason you would want to check the the signal at the PCM (ECU) is because the maf sensor sends a sigbal back to the PCM and then the computer can make the adjustments for enigine load. That 5v signal you have at the maf sensor is just a reference voltage and will actually change depending on driving conditions, i.e. engine under load(boost), or crusing. If your voltage is 4.9v at W.O.T then there is something wrong and will make the car run like ****, thats why you want to check the signal aft the maf. I would also double check your pluggs because its not hard to foul out a set of plugs.

[lv kaotic]

power fc ftw..

my advice is.. save for a complete stand alone ecu.. find a dyno.. tune that **** yourself...

the djetro is like what.. $1200 or so??

[S13FASTBACKSR]

well guys im about 95% positive that the problem is my ecu. I tested my maf with a volt meter again and it has power going to it and it hits about 3volts at wot but when unplugged it revs past 2500rpms. I think the computer is just not reading limp mode because I do have my maf wired correctly. I dont know if its a bad tune or if its shorted out. the light on the ecu comes on when i turn my key on and stays on when my engine is running. this right here means that my ecu is bad does it not? but i dont know how it could be bad i dont know of anyways i could have shorted it out. It kind of confuses me but i guess im going to send it to enthalpy now

[lv kaotic]

get a power fc...

[S13FASTBACKSR]

lol thanks lv kaotic i get your drift ...i'll keep you guys updated