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Rb20 won't run

Posted: Wed Apr 07, 2010 12:10 pm
by Hotrodstu77
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.

Re: Rb20 won't run

Posted: Wed Apr 07, 2010 12:21 pm
by Hotrodstu77
there are no present codes on the ecu. consult cable connects. when i can finally get it to idle for a brief period it will show the data changing but it wont go any better then 10.0:1 or less. i tried using a basemap that someone else had posted for a similar motor with 555 injectors and that didnt change anything either.

Re: Rb20 won't run

Posted: Wed Apr 07, 2010 12:29 pm
by Hotrodstu77
this is the map i tried running off of.

Re: Rb20 won't run

Posted: Wed Apr 07, 2010 1:19 pm
by Hotrodstu77
here is the exact bin i just pulled from the ecu

Re: Rb20 won't run

Posted: Wed Apr 07, 2010 3:39 pm
by BlueRB240
adjust the Kconstant. make sure it's on Auto and start sliding it to the left till it fires up.

Re: Rb20 won't run

Posted: Thu Apr 08, 2010 12:03 am
by Matt
hcr32_rb20det_04U12_z32_555.bin

That file looks fine for starting from and shouldnt flood unless your injectors are bigger than expected or your AFM isnt the Z32 AFM you think it is or has problems

K constant of 208 seems about a good starting point, and pulling it lower should make it run leaner

Now was the Nistune board in before doing these modifications?

The best way to do things is usually the Nistune board, then test, then change injectors, then test, then change AFM and then test

That way you know what exactly is going on. Right now I dont know if its the injectors or AFM so pick which one you want to swap back to factory first and then try again unfortuantely.

you can try pulling your K constant down lower but it wont assist if there is a physical issue you dont know about (ie tuning around a problem)

Re: Rb20 won't run

Posted: Thu Apr 08, 2010 1:53 am
by Hotrodstu77
thanks guys illl try that. i wont be able to get around to it till thursday now. im really hoping im not off a tooth of timing. ill check the wiring on my afm.

Re: Rb20 won't run

Posted: Thu Apr 08, 2010 12:02 pm
by Hotrodstu77
still wont run. maf wiring and injectors are all fine. my plugs are probably fouled by now but even still when we had it running for a couple min before my plugs failed when ever we tried to change things on nistune it didnt change anything on the car, i dont wanna have to keep putting 12 dollar plugs in every couple hours just to watch it run rich for 10 min and then foul ot cause its not changing anything.

as well as when ever i change the maf settings it says the system is trunctiating and then the program crashes. and when ever i try to change anything else it says read failed. anyon else had this problem?

Re: Rb20 won't run

Posted: Thu Apr 08, 2010 12:07 pm
by BlueRB240
you can try and unplug the major vacuum line from the intake manifold. That should lean it out enough, I had the same problem with my RB20 when I changed the injectors. It would start with the vacuum leak caused it leaned it out enough. I had to adjust the Kvalue till it leaned out enough.

Re: Rb20 won't run

Posted: Thu Apr 08, 2010 1:08 pm
by Hotrodstu77
ok......... so everthing poeple have told me dosent work....... I can get it to run if i drop the fuel pressure right down to nothing.... but that dosent help me...... I cant adjust the Kconstent..... it doesent change anything.... AT ALL....


every time i try to change the maf it still says the program has encountered a problem and crashes. any insight on this matt?

Re: Rb20 won't run

Posted: Thu Apr 08, 2010 6:10 pm
by Eric
what happens if you unplug the AFM (while the engine is running) ?

if the engine stalls, the AFM is probably ok...if it keeps running then the AFM is the problem.

Re: Rb20 won't run

Posted: Fri Apr 09, 2010 2:14 am
by Hotrodstu77
i tried changing the maf back to stock. didnt change anything. put another ignitor box on it. didnt change anything. even put a stock ecu back in an it still runs like crap. unplugged the 02, no change. the only thing that will allow it to run is if i back fuel pressure off to almost nothing,

Re: Rb20 won't run

Posted: Fri Apr 09, 2010 5:55 am
by Hotrodstu77
Is it my computer tht is the problem as to why it encounters a problem everything I change te mad and it crashes the program?

Re: Rb20 won't run

Posted: Fri Apr 09, 2010 6:06 am
by Hotrodstu77
Also when I change injector sizes it does the same thing.

I'm using windows 7 on a laptop bought brand new in December. Just wondering if this info helps.

Re: Rb20 won't run

Posted: Fri Apr 09, 2010 12:49 pm
by Hotrodstu77
We tried swapping back to stock maf stock ecu and stok fuel pressure regulator and still nothing changed. Runs at 10:1 or less and won't hardly start. It so rich that I held a torch to my muffler and my exhaust gases literally lit on fire. I kid you not. So we tried uninstalling nistune and the Tom packs and uploading them again. Still nothing. Matt are you able to send me a bone stock rb20 map please. My main concern is the error message I get saying read error caught exception everytime I change the maf or change the injector size.