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Re: Rb20 won't run

Posted: Fri Apr 09, 2010 1:56 pm
by Hotrodstu77
So I'm almost positive it's something to do with the maf. Cause when a maf is unplugged it sets to limp mode and hits a fuel cut just above 2200 whiCh mine is doing. Am I wrong? If that's the case maybe it has something to do with the read exception Error message I keep getting. And it's not uploading the right maf ino to the ecu. But then if I loaded up the other bin that matt said was ok it should remedy the problem. But it doesn't. I tried adjusting the k constant and setting my fuel map to 0 around the idle zone and it would lean up but then drop right down to below 10 again. And this is only possible by me dropping my fuel presure down to like 5 psi. I'm racking my brains on this guys. Anyone have ideas? I pulled my ecu apart to make sure the dealer that installed it didn't miss and solder points or something it's totally fine though. Fml.


I have no idea what is going on. The motor ran fine before all this. What should I do now?

Re: Rb20 won't run

Posted: Fri Apr 09, 2010 1:59 pm
by BlueRB240
Yeah if u unplug the maf it should limp it and limit the rpm to like 2200-2500ish. If u still have the stock maf why not solder the plug behind the new maf plug so that way you can switch easy.

Re: Rb20 won't run

Posted: Fri Apr 09, 2010 3:12 pm
by Hotrodstu77
i did try the ol maf and it didnt change anything

Re: Rb20 won't run

Posted: Sat Apr 10, 2010 8:25 pm
by louiswun
Your ECU might be in limp mode.
Is there any blinking red light on ECU ?
If your ECU running in normal mode, if your enigne and ECU harness connected properly.
And when you turn off the key, you will hear the relay inside the ecu cut off the power delay in 2-3 seconds.
(you will hear the sound "tick" after 2-3 seconds after turning off the key)
If your ECU running in limp mode, the ECU will cut off the power at the same time you turn off your key.
What resistance is the new injectors ? If it is low resistance injectors, did you connect the injector resistor pack?
Doube check all 28 pin and 4 pin soldering.

Re: Rb20 won't run

Posted: Sun Apr 11, 2010 12:28 am
by STATUS
Hotrodstu77 wrote:Hey guys just finished getting it back together.

Rb20det from an r32 skyline
z32 maf
deastchwork 550cc injectors

so the problem is it is getting so much fuel I can't start it. I've been tryig to go off the basemap but it won't do anythig. My afrs are 10.0 or less when I can actually get it to fire for 2 seconds and all I can smell is raw fuel. Does anyone have a map that i can try that should get me idling properly at a decent fuel ratio?

Thanks in advance. Nothig I do is working an it's very frustrating.
check your maf voltage i reckon you have wired it backwards, if it reads more than 0.4-0.6volts with the key on its wrong. i bet its reading 3.5volts...

The diagrams for maf wiring are looking at the BACK of the plug NOT the front.

Re: Rb20 won't run

Posted: Sun Apr 11, 2010 2:45 am
by Hotrodstu77
ok thanks. ill try that and get back to you.

Re: Rb20 won't run

Posted: Tue Apr 13, 2010 10:04 am
by Hotrodstu77
maf voltage is sitting at .5 with key on and it still run like crap.

Re: Rb20 won't run

Posted: Tue Apr 13, 2010 10:09 am
by Hotrodstu77
just tried running it an the maf voltage stays at .5 no matter what the rpms. we reved it till it spit flames and still only stays at .5. so now time to inspect the maf wiring an he maf itself.

Re: Rb20 won't run

Posted: Tue Apr 13, 2010 10:23 am
by TM_S13
something is in fact wrong with the wiring or the maf...
track that down and the problem should disappear... I think... lol... I'm sleepy now so appologize for some mistakes :P :roll:

Re: Rb20 won't run

Posted: Tue Apr 13, 2010 2:05 pm
by Hotrodstu77
ok so i swapped back to the stock maf an redid some messed wiring an long tory short was able to drive it own the street. so now i have that problem figure out. thanks for the help. see my new thread about it stalling out........

Re: Rb20 won't run

Posted: Thu Apr 15, 2010 1:05 am
by Matt
please post here your current BIN file from the ECU and a log file of you starting idling and then trying to run. We can have a look through and see if anything is wrong

Re: Rb20 won't run

Posted: Thu Apr 15, 2010 4:31 am
by Hotrodstu77
It was the maf. I wired it in back asswards. My bad!

Re: Rb20 won't run

Posted: Sat Oct 30, 2010 11:48 pm
by Hawaiisr20det
Hey, I'm having the same issue with nistune crashing when I try to change the maf, but my car run's and can be driven around...can boost...etc but that's with a stock base map and my Safc hooked up, as soon as I disconnect my Safc, my car can't rev passed 2200 and has a hard time with idle...what do y'all think...matt?

Re: Rb20 won't run

Posted: Sun Oct 31, 2010 1:01 pm
by Matt
which MAF are you changing to? was hoping i sorted out the bugs with maf change. Cant repeat it here :(

Re: Rb20 won't run

Posted: Sun Oct 31, 2010 8:17 pm
by Hawaiisr20det
Well here's the run down,

I have a sr20der and trying to change to the z32 maf. Car runs and is drivable but seems sluggish...when I try to change the maf nistune crash's. The maf is hooked up cause I can run my Safc (apexi) and the car is fine, when I run the nistune and wire the maf back to stock is goes limp mode I think. I'm so frustrated with this and can't seem to figure things out. Please matt I really need your help. Thanks