I'm running rTek 2.1 with a 255 walbro, SX performance AFPR, Rising RPM fuel rails, RC 750/1200 injectors, FMIC, Greddy RS bov (not sure if its tight enough or not) and an HT-18 Turbo. I've been running fine until the other day it seems like the car after about 20 minutes will start leaning out hardcore even though the car is at operating temp 180-200 degree's F (a little under 1/4th-just about 1/2 sometimes around the 200f mark) and has been running fine. It happens around 2nd or 3rd gear under load about 1/2 Throttle 12-18inhg i get 15.5-16.8's or so. Tried tuning around and giving more fuel, but it wont respond much - will only be SUPER rich the next drive cycle until that 20ish minutes has passed and it runs lean again. Have checked fuel pressure and its 45-50psi, Idle pump voltage is 8.5-9.5volts. I'm running a fuel pump rewire and battery relocate. I've Smoked the motor and the only place its leaking is the acv block off plate where the bolt gap is.

i've done lots of reading and still cant find out what's going on, if its obvious - please go easy on me - i've just been staying out of load when it does that to get it home keeping under safe afr's. Any info you may have would be awesome help! if you need any more info ask away!

Ps. i think i have my wideband analog output into closed loop however it shows 0 on the Rtek AFR so i may not, i also have a Code 5 which is 02. If anyone can point me to the rtek closed loop AFr install for the analog narrowband that'd be great i've searched and searched and cannot find the article i used to install it. i have an AEM uego

thanks in advance :/

 

This seems to be a kind of common issue. I'm pretty sure it's related to the o2 sensor.

https://www.rx7club.com/rtek-forum-1...-827389/page9/

I have a similar issue and I was going to try a new o2 sensor, but my car is down (for quite some time now) with a leaking lower intake manifold o ring...

Good luck, maybe just try a new stock o2 sensor...

 

Not sure what you are talking about as far as the "closed loop" you talk about. If you are looking to use the wideband as the naarrowband for the ECU, you just need to connect the narrowband output form the AEM to the o2 input on the ECU. Wiring diagrams for the ECU are easily obtained online. Just be sure to disconnect the OEM o2 sensor.

If you have a code for o2, I'd definitely start there.

 

Awesome, i don't even have a stock 02 sensor so that might be an issue
i was reading since the stock 02 would help it make some small calculations still. but i'll likely do what Turbo2ltr mentioned and hook up wideband to the ECU.

sorry to hear your car is down. get some new orings and replace it the world needs more rotaries! I'll update once i get it done and find out what the issue is. Ready to drive it and finish tuning - since cold weather

okay awesome, i think my friend who hooked up the wideband for me/Rtek did the connecting to the ECU, but we're not sure and going to double check now that it looks like we're getting 0 on the AFR. willdo, the OEM isnt there at all, and is plugged. Thanks for your suggestion!

 

FWIW, I connected my PLX narrowband output to the ecu and still had minor lean issues, like it just isn't reacting fast enough, maybe because it's farther down the exhaust at the end of the downpipe and not in the stock location. I was/am going to try a new o2 sensor when I get there. Might also try WB in the stock location with a heatsink...

 

i thought about running a stock one also, i had mine in the stock location for awhile just because i didnt have my 02 bung welded yet. it worked fine for some tuning sessions and some time. i have another Wide band i was toying with the idea of hooking it up in the stock location. some stuff i was reading said they dont react the same voltage i guess even if they have a narrowband output so you wont get a true narrowband reading from them. idk

 

Soooo doesn't look like its the o2 sensor, had the analog from Wideband hooked up to the input for the 02 on the ECU. I've been skeptical just because I've been driving and tuning just fine until like 2 weeks ago and the **** just started leaning out all of the sudden after i parked and went to Walmart one night. started back up and was Way lean, idk. I'm going to take it up to the shop Script7 works @ and have him scope the AFM & TPS to see if i have deadspots/eff'd up spots. also going to check my map sensor and start narrowing **** down.

its turbo weather, i want to boost!

Edit: Also its not 20minutes now, it leans out randomly - i dont get it. Drives fine, and then i'll step a little harder and its lean. If i ease into it slowly it seems like its not leaning as bad. stops around 14.5ish under normal load while easing into it. So we're thinking AFM/tps issues with that flapper/plunger

 

You can do this with the stage 2 pretty easily.

I have seen a TPS that only fails after it warms up...it would get stuck and drivability would drop drastically.

 

yeah, that's Jeff (Script7) said. i don't have a scope but he has one at the shop we're gonna do some searching. Then i might just breakdown and buy a NEW both unfortunately i hate spending that much money on OE parts =( but the TPS i have is a used one from some guy up north because i lost mine when i had my T-body off for like 3/4ths a year. We'll see how that goes, probably do that this weekend.

 

okay so this weekend got to swap out afm's, not the issue but more sood afm now. tested map with a known good, still going crazy lean. foun out my prosport evo fuel pressure gaugw is ~10psi off (wtf!!!) so low fuel pressure was adding to the issue. not the whole time but sice this friday when i turned down from "53" psi.
so now we are thinking injectors. my primarys are 2.7ohms from connector to ecu not through resister and secondary are 13. im pretty sure all are high resistance and i think thats got something to do with it. as soon as i find out whats going on (which is soon... narrowing down) its on!! =)

happy rotoring!

 

2.7 at the ECU sounds like low impedance without resistors. The injectors should always be 12-13 at the ECU no matter the type of injectors.

 

yeah just had that realization I think have the wrong ones going thro the resister now... will fix tomorrow hopefully. I hope injectors are all good and I didn't blow a transistor in the ecu :/

 

Apparently they sent me or i ordered the wrong injectors. I guess the Primaries were only like 2ohms. so i guess something was giving out under a 20 minute load. its just so weird that it worked fine for like 5 months. Anywayz, now working fine. just got a few leaks to fix (damn silicone hoses on the Oil injector vacuum ports, need to ziptie). then a bit more tuning.

can do some highway tuning once i get my "new" tires on, should be much easier than VROOMStoplight VROOOOOOOOMPSHSTOPlight lol.

 

you should check both of the fuel filters, if you haven't already. i had one car with an after market filter, and it rusted out internally and would do exactly what you describe, it would run great on startup, and then performance would gradually drop to the point where it would hardly make it over an overpass.

the injector thing is also bad, but easy to fix

 

did you ever solve this problem? mine was running great for about 2 yrs now and just yesterday started going super lean in mid throttle and up and in boost?

suspecting possible fuel pressure problem, going to install a guage and see if filter or pumps on its way out

rtek 2.1 with 720 primary 1200 secondarys

 

Mine ended up being injector resistance (also fuel pressure - i got a prosport evo and the sender it came with is like 10psi low.. i think, the gauge might be but i doubt it. although i did drop the sender once haha) - i don't know why it took months to show itself, i'm thinking that the ECU was just under so much load and took it for so long then just started showing signs?

BUT you might check MAP sensor, AFM. Maybe reload the tune... sometimes i swear to jeeebus my tune changes by itself and i reload the tune and its fine?

 

i replaced the dead battery in my palm so i just got to be able to use it again and notice my tps is maxing out at only 93% i kind of have suspicions around this being the culprit, af seem ok until around 1/3rd throttle then they get real lean ...

 

yeah TPS too. i got another from someone in IN i think. Yeah that was kinda happening to me too. would be fine until around 2500/3000ish and then lean WAY the EFFF out. made me almost **** myself a few times. yeah i cant wait for them to finish the android/bluetooth port so i can kick my palm off a cliff loll

 

hmm well it wasn't the tps, need to get ahold of a fuel pressure gauge, might replace filter, then try swaping fuel pumps from a known good one

 

hmm. go down the line testing happy hunting. lemme know when you find it!

 

well I hooked up a fuel pressure gauge,
at idle 900 rpm -14, pressure it about 35 psi

getting on it brining it up to around 0-2 psi, it seems to raise to slightly over 40 psi,

then when getting into boost it seemed to steadily rize to 50 psi or so, was pretty hard to watch this guage taped to the side door mirror, and my other gauges at the same time... max boost is around 12 or so, didn't go quite that high I don't think

a/f used to be mid 12's rolling into boost, then 10-low 11's when above 2 psi or more

now they seem to jump up into the low 14s rolling into it and in boost


I have a walbro pump and it is not rewired, it is seeing about 11.3 volts at all times( same voltage its seen since day one)
pump was purchased new in 2005 I believe

 

hmm I put this fuel gauge on my other t2 which is running normally, and it seems to get about the same pressures vs boost and idle...

 

swaped pumps seems about the same.. perhaps slightly better, filter comes in tommarow ill swap it then

 

no change with filter, I did swap tps and the result seems about the same... found it odd this other tps onl reads up t 97%

 

I had this problem. the turbo inlet coupler was a little loose throwing off everything. Check all your sensors like the coolant temp sensor behind the water neck.