rb20 idles at 2k then dies

[the_momo]

just like the title says. it starts and is smooth at 2k (really high i know) and then it stumbles and dies after about the same amount of time (10-15 sec) i think its like a start up cycle then it dies.

some things1. it has a gm 3 inch maf. there is also a mystery black box controlling it.2. i didnt do the wiring or initial swap. (there are a lot of deamons in the car, but it does start.)3. there isnt a serial number on the ecu.4. there are a lot of open plugs on the harness, but no where for them to go on the motor or chassis.5. the car did run before it was torn apart (i bought it disassembled)6. the ecu has a dial on the back, and lots of japanese.7. the car was run without the iac valve. (throttle was left open slightly..i know ghetto.)

it gets good fuel pressure (around 43psi) and the ignition and timing are functional and correct, respectively. i thought it might be the tps so i pulled them and cleaned the contacts, no change. it has the aftermarket big plenum intake manifold and a q45 tb, has the two connectors (one on the tps and one on a wire lead from the tps).

ive tried things that i could think of, but just wondering if anyone had a similar problem or know what could be the issue. thanks for the input in advance!

[Pogi240]

hrmm, thats really weird. I would have guess the TPS as well, but its shutting off, I would imagine it just being at 2k all the time, if it was stuck open. but it eventualy closes. the Throttle body that is.

Ide check the wiring,

[the_momo]

yeah, i was for a good...oh id say 3 hours. im not one to fiddle with other peoples work for long periods of time, and since i was going to do a stand alone soon, ill prob just rip it all out and do a megasquirt. just sooner than i imagined.

[digzsublime]

Not an expert but, my freinds RB20 was having similar issues and it ended up being the wiring for the MAF. In your case I think wiring combined with GM MAF my be double trouble. I'd check MAF wiring first.

[the_momo]

yeah, i was really nervous when i saw that, im gonna change to a draw through z32 maf (its blow throught now) i might just end up going to a map sensor when i go megasquirt, since nissan mafs have like a 10 minute life span. i wont see teh flexibility of a maf, but ill never go over 300whp and im pretty sure the map will give me enough flexibility to make it reliable. i dunno.

[the_momo]

ok so i did some more work and i figured out how to check the ecu codes (+1 for the search, thank you nico ) and i got a code....12. maf circuitry. so i checked all the wiring and such (black box adaptor for gm maf) and all checked out (from what i could see, stupid non english speaking electrons) and i had a broken wire at the maf connector. so i fixed it, and....nothing. same. and i still have the code. gonna give it another try tomorrow, and see if i cant find anything about the gm maf adaptor. supposed to be here somewhere....thats what i was told from the previous owner. itll prob be megasquirted by the end of the week. this is not a good setup by any means at all.

[Pogi240]

ok so i did some more work and i figured out how to check the ecu codes (+1 for the search, thank you nico ) and i got a code....12. maf circuitry. so i checked all the wiring and such (black box adaptor for gm maf) and all checked out (from what i could see, stupid non english speaking electrons) and i had a broken wire at the maf connector. so i fixed it, and....nothing. same. and i still have the code. gonna give it another try tomorrow, and see if i cant find anything about the gm maf adaptor. supposed to be here somewhere....thats what i was told from the previous owner. itll prob be megasquirted by the end of the week. this is not a good setup by any means at all.

Did you reset the ECU after? pulling the pos terminal off the batt for a few secs. try that. restart, and see if it pulls the code agian.

[the_momo]

yeah i did. i actually dotn ahve a battery for it (my odyssey batt died and i couldnt get it to hold a charge, big one wont fit anymore) so i am jumping it from a battery on the floor. i had reset it after every time i changed something. i thing maybe it still doesnt have a very good connection at the maf connector. just gonna go through every thing i can think of before i start changing parts.

[the_momo]

ok so i found my problem. my mystery black box was the cluprit. i put a maxima maf (blue label, same pn as stock rb20, yay!) and it works just fine now. well kind of. i have 550 cc injectors (fc rx7) and its reaaaalllllyyy rich (11.8 at idle) so im gonna get a fpr to lower the pressure to compensate for now. then power fc! (i fixed all of the wiring crap and now...its not too bad.) so insted of doing the megasquirt, the fc will be a lot easier, epsecially since i dont have to do anymore wiring!! yay.

so yeah if your car idles really high, then sputters and dies, its your maf.