Update: once motor builds boost it doesn't want to accelerate

[silviasgp06]

UPDATE:

the other night it got really cool here in Texas and the car ran like it did before all this mess. and when it was that cool i want to guess 60* it ran fine all the way past engine warn up and everything. Fast as balls, and i remembered what ive been missing about my car.

its something heat related, like the motor is pulling timing to warn off detonation. ive noticed the "raw" knock sensor numbers on the safc2 to be considerably higher -at idle- when the motor is acting up.

since the MAF is on the hotter side of the motor, has anyone had issues with the turbo heat messing with the MAF?

something heat related......

and i checked the MAF,i swapped in a friends z32 MAF and changed the IN/OUT safc setting numbers to the correct values, and at first it ran fine but still warmer weather temps make the car bog.[ 04in 04out is stock s2 rb25, the correction code is 02in for a z32 maf]

link to original thread with symptoms zerothread/332138

[onepuff]

If you have a pod filter try to isolate it from the hot engine bay. There's some good examples here.

http://www.skylinesaustralia.c....html

[s13_240_rb20]

Just for a goof: Try to unplug your o2 sensor for a while and take it for a test drive. My rb20det was choking/bogging out on me if I barely touched the gas pedal too hard, and I think unplugging my o2 sensor fixed it (whatever "it" is...)

--TJ

[silviasgp06]

tried it for a little bit, didnt seem to do anything, but cooler air temps make most of the issue go away.

i got to thinking about the heat related thing and forgot that is might be a coil issue. only thing is its more of a loss of power than a break up cause when it happens the motor doest sound like its loosing spark, but spark loss would account for the rich fuel burning cause the it to ignite in my exhaust and pop every now and then

any ideas? i might just have to do a coil retrofit sooner than i wanted to.

[WhatsADSM]

Do you have a UEGO? What is it doing under boost when you are having the problems?

[gawdzilla]

check your timing with a timing light first.

check your AF with a wideband. if you can't afford a wideband, stop using the safc.

it probably isnt your ignition system. you would feel missing for sure.. it jerks the car

[silviasgp06]

trust me i really want a wide band, but as for the SAFC its only there for reading knock, rpm, volts and such. the fuel correction graph is all zero'd out. trying to save for a Apexi PFC. hmm man i guess ill cut into that and get the wideband asap.

[gawdzilla]

trust me i really want a wide band, but as for the SAFC its only there for reading knock, rpm, volts and such. the fuel correction graph is all zero'd out. trying to save for a Apexi PFC. hmm man i guess ill cut into that and get the wideband asap.

half the leet safc users out there install it wrong anyway, so thats why i suggested removing it

[silviasgp06]

hmm i see, well its only 2 wires that you can possibly mess up lol, and i even called apexi for the correct in/out rb maf codes, but i guess since the MAF signal is going through it i should disconnect it just in case the safc is messing up the signal somehow.

fun update: car was a blast today thanks to the weather, took the motor past 105mph for the first time since the swap. rocketed up to 120mph, felt good creeped to .7bar, no hickups but soon after the run, it started the gayness.

i wonder if the ecu is actually the issue, like its doing intermittent R&R, or is just going bad. i know i know, i wont know til i slap a wideband on.

[gawdzilla]

maybe bad coolant temp sensor causing the timing to retard significantly?

[silviasgp06]

you know i was actually thinking about that today, i remembered someone saying that the temp sensor will do that when it goes bad.

looking up what senors are compatible now..