rb25 crazy problem!!

[camo240]

Dropped in a rb25det s2 into my s13. S1 ecu (everything but vct should work fine) I have a wiring specialties harness. Everything hooked up. No boost leaks. Tips is set closed at .45 wide open is 4.11 and input is 5.12 fish lol. Mac is a s1 on it. I tried s2 that I believe is bad And a z32 but I have no way to tune for it unless I wire in a vafc I have but I don't ha e a diagram for it.

What happens is when I start car it runs normal with air fuel at 14.6-7.. when t warms up enough or I hit throttle it gets really rich and pegs out AFR gauge to rich. And the idle bounces a little bit slowly. After searching my ass off and trying parts from my buddys car I know my tps is good BC he swapped and actually drove home with my sensor and I have his.. I tried bypassing IAC and same results.. I disconnected the purple plug under the intake for the boost sensor? I was told to do it to flow more boost without cut. I tried plunging it in and unplugged for every thing I changed and no help.

I have a walbro 255 and no fuel filter ATM. Idk if the for is bad or how to check that.. any ideas let me know.,. Also I don't have my ign timing set yet BC of bad idle. Also I'm in Scranton pa if or local with a s2 Mac or ecu or wanna lend a hand let me know lol I have a hks 3071r with a 2861r cold side although I don't think its causing this problem thought I would add the info.

Thanks for any help and please don't say search I have so have my friends I am lost ATM so much bouncing around in my head lol

[camo240]

Sorry typing on girlfriends tablet lol lots of auto corrects and misspelled words haha

[Sileighty_85]

pull codes from ECU.

Could be dirty MAFS or bad ECU Coolant Temp Senor

[sx_danny]

firstly get a fuel filter in there and also set the ignition timing that will give you a lumpy idle and will make it sound/look like its missing, plus you could be predetting

[camo240]

Only code is auto tran code 54 and that shouldn't effect the way it runs at all from my research. And I'll be putting a filter on today I hope.

I tried timing it multiple times to time it but it jumps around so much I can't get it exact at all

[camo240]

Checked coolant temp sensor And seems to be reading any way to know for sure its good any tests I can do?

[mhalez]

Are you 100% positive you have no boost leaks? Definitely put a fuel filter in it they are cheap... like ten bucks. Secondly to test the maf simply unplug it, ECU goes into failsafe mode and that can rule out your maf right there if it improves.

[OBEEWON]

You have an auto ECU?

[mhalez]

Auto ecu shouldn't cause an issue like that. I can't say for sure on an s2 ecu but I know for an s1 it will run a manual transmission car fine, just wont have a rev limiter or fuel cut since that's controlled by the auto transmissions ecu.

[camo240]

Got a filter today but since my gas gauge don't work due to previous owner I ran out of gas so to,orriw will be the test on that seemed to stop pulsing from the little bit of time I had it running. Killing myself about running out of gas lol thanks for the tips and advice keep it coming just in case I missed something stupid.

Also I'm going to bypass intercooler And make sure I'm not getting boost leak from a crack or shitty weld. Its new but still no name shit so I'm not gonna trust it till it proves its self. Anyone know his to tell if my turbo is leaking from the cold side?

[mhalez]

only way to test for boost leaks properly is to make a fitting from a pvc pipe end that hooks up to your turbo inlet and compress it to just a bout whatever psi you plan on running. boost leaks come from the most rediculous places and can be near impossible to hear with a motor running. using a bottle of soapy water and squirting it around any hissing areas will show if you have issues.

[aga]

you can take your intercooler and pipes off, and test them by capping their ends off, run some pressurised air in them (2 bar max,especially if your intercooler is of the chinese disposition) and putting them in water to check for bubbles. i was chasing some boost problems in the past and the only thing i hadnt checked was the intercooler, turned out it was leaking in 5 places.

also, about the idle, have you checked/ cleaned up the idle valve?

also i dont know how cold start is managed on Rb's but if there's a cold start valve, check that too.

[camo240]

Haven't made it to get a cap for boost test yet but now fuel filter is on and I have has I cleaned plugs bc they were soaked in gas and then fired it up it doesn't seem to bounce the idle as bad but I tried to drive it and it leans out when it revs up but at idle its still rich as hell any ideas? Also the screw on the iac?? Where should it be set I found one post saying a half turn out?? Thanks for all the help I will try and get a cap to do boost leak test.

[camo240]

Bump I'm so lost on what to do. Anyone find a vafc wiring diagram or how to for the rb25? Thanks for any help in advance I really appreciate it.

[camo240]

Car starts out idling normal and normal afr until I hit the gas or it warms up just thought I would add this and bump it up!! Using a s 1 Ecu with s2 Ecu should I disconnect the vct plug? It don't seem to change anything

[camo240]

OK moved my maff farther from the turbo and now its not rich at idle now but its still leaning out under throttle it goes from 14.6-8 at idle sometimes up to 18.9 or so depending g on the gear and how much throttle. Sometimes if u ease it up in rpms I can get it going pretty good with AFR around 15-16 back and forth. But I'm so afraid I'm gonna burn it up I'm not driving it home just around the shop on a nice long industrial road. Now my question is my turbo the problem or what is it making to lean. I'm running the internal gate around 6lbs (my eyes are glued to the AFR lol) which should be fine from what I figure with the guesstimate dyno in my head.

Its a 3071r hks with a 2871r housing I have pics in my older post. I figure its about the same size cold side with a bigger prop so its pushing more cfms but at only 6lbs I figured it should be fine. Plus I lean out when I'm not even under boost so idk what it is. A friend told me about a purple plug under the intake Mani that controlls stock boost? I tried it with it plugged in and unplugged same result from what I noticed

[aga]

obviously if you have a bigger turbo you need more fuel, but at idle and cruising there shouldnt be a difference. something's wrong. you gotta get all the sensors checked. get a consult cable to run diagnostics...

[camo240]

Still having trouble. Now my idle is good 14.5 to 14.7 average. And idles smooth but under throttle I lean out up to 18.5 to 19.0 when car is cold when it warms up completely it goes up to 15.5 ish under throttle inbboost. I have a plx devices AFR gauge and its mounted far enough away and at the recommended 15° angle away from flow so I should be good on that. I tried disconnecting my O2 and it seemed to drop my AFR at idle but not to noticeable under throttle when driving. Is there anything else I can try to see if I can fix or adjust before I find a fpr and turn up pressure? BC I'd like to drive it while I come up with cash and buy a fpr thanks for any ideas and help.

Also trying to figure out this consult cable with my wiring specialties harness so any help there will be great too.