sr20det leaning air/fuel

[negrosx13]

Sr20det redtop Mods are (FMIC,FULL EXHAUST,STOCK INJECTOR,MAF AND TURBO) and i was pushing 13-14psi using XS turbo mbc then i switched to Hallman es(used) and turned it down to 12-13,the xs turbo was a loaner. After that the car started to feel weird and notice i was dropping from 13 to little under 10psi. But i figured there the new used controller or boost leak was the blame,i searched found loose clamp and changed it but it didnt make a difference. Note the car idles and drives perfect and no smoke at anytime other than cold start smoke. Only thing it feels weak on top end but could be the boost drop.

I was able to get around to hooking up the wideband a few weeks ago,And the sucker is leaning on idle17.6-18.1/driving normal high 14s to mid 17s and didnt even dare get into boost. I pinched the return and saw the idle go to normal 14.0-14.7. So Figured out some problems with the exhaust and leaky fuel line clamps. Now im at 16.8-17.5..driving normal 13-16s full boost when the boost drop 12.1-12.3 after 5k.


Things that happen in the time span
*Found one my injectors to have little too much resistance( swap out for one in spec)
*cleaned the maf sensor( car felt a little better )
*My o2 sensor was unplugged and my gas mileage was crap for like 3days.i havent checked the plugs since
*After i found leaky clamp,Im still having raw fuel smell at times.

I did some research and nothing 100% that matches my issues
*fuel pump o-ring leaking making lean mix??
*fouled out plugs causing lean mix??
*leaky injector lean mix??
*loose behind the steering wheel is overthinking crap


Thanks for your time:bow::bow::bow::bow::boink::boink::boink::boin k::boink::boink::boink:

[KaminaSan]

Sr20det redtop Mods are (FMIC,FULL EXHAUST,STOCK INJECTOR,MAF AND TURBO) and i was pushing 13-14psi using XS turbo mbc then i switched to Hallman es(used) and turned it down to 12-13,the xs turbo was a loaner. After that the car started to feel weird and notice i was dropping from 13 to little under 10psi. But i figured there the new used controller or boost leak was the blame,i searched found loose clamp and changed it but it didnt make a difference. Note the car idles and drives perfect and no smoke at anytime other than cold start smoke. Only thing it feels weak on top end but could be the boost drop.

I was able to get around to hooking up the wideband a few weeks ago,And the sucker is leaning on idle17.6-18.1/driving normal high 14s to mid 17s and didnt even dare get into boost. I pinched the return and saw the idle go to normal 14.0-14.7. So Figured out some problems with the exhaust and leaky fuel line clamps. Now im at 16.8-17.5..driving normal 13-16s full boost when the boost drop 12.1-12.3 after 5k.


Things that happen in the time span
*Found one my injectors to have little too much resistance( swap out for one in spec)
*cleaned the maf sensor( car felt a little better )
*My o2 sensor was unplugged and my gas mileage was crap for like 3days.i havent checked the plugs since
*After i found leaky clamp,Im still having raw fuel smell at times.

I did some research and nothing 100% that matches my issues
*fuel pump o-ring leaking making lean mix??
*fouled out plugs causing lean mix??
*leaky injector lean mix??
*loose behind the steering wheel is overthinking crap


Thanks for your time:bow::bow::bow::bow::boink::boink::boink::boin k::boink::boink::boink:

First of all, when you have a problem, put it back to the basics.

Go back to 7 pounds of boost. Recheck your AFRs. Most people will tell you not to push anything past 11-12 pounds on stock injectors, because they will be supposedly close to maxing out.

Second... judging by the way you cheaped out by getting a MBC, and you didn't list it under mods, I'm assuming you don't have an upgraded pump/walbro?

I would go this route:
1.)Back to stock boost
2.) Check for vacuum leaks/exhaust leaks
3.)Walbro Fuel pump
4.)Check Fuel pressure to see if your FPR is working.

Have you calibrated your wideband?

[negrosx13]

First of all, when you have a problem, put it back to the basics.

Go back to 7 pounds of boost. Recheck your AFRs. Most people will tell you not to push anything past 11-12 pounds on stock injectors, because they will be supposedly close to maxing out.

Only i havent is try stock boost and yes I know whole blah BS of maxing the injectors.. I know a bunch of people that pushed there injectors to the max and there motor lived to see 300-420+whp for another year plus.


Second... judging by the way you cheaped out by getting a MBC, and you didn't list it under mods, I'm assuming you don't have an upgraded pump/walbro?

Sorry if i seem like i cheaped out by getting a MBC,But a blitz sbc i color is outa my reach for now..LMAO The fun knob isnt really under a mod? you're kidding?? By the way what kinda dummy swaps sr into there 240 then thinks stock fuel cause handle the motors needs???Be serious,thats given having walbro pump

I would go this route:
1.)Back to stock boost WILL GIVE THAT A TRY
2.) Check for vacuum leaks/exhaust leaks MOTOR READS PERFECT VACCUM 20+
3.)Walbro Fuel pump GOT ONE
4.)Check Fuel pressure to see if your FPR is working. I NEED GET GO

Have you calibrated your wideband? Its AEM Wideband and yes



Thanks for your input kamina:love:

[KaminaSan]

Only i havent is try stock boost and yes I know whole blah BS of maxing the injectors.. I know a bunch of people that pushed there injectors to the max and there motor lived to see 300-420+whp for another year plus.




Sorry if i seem like i cheaped out by getting a MBC,But a blitz sbc i color is outa my reach for now..LMAO The fun knob isnt really under a mod? you're kidding?? By the way what kinda dummy swaps sr into there 240 then thinks stock fuel cause handle the motors needs???Be serious,thats given having walbro pump



Have you calibrated your wideband? Its AEM Wideband and yes



Thanks for your input kamina:love:

You would be surprised how many people swap in SRs and don't upgrade their fuel pumps as they would rather spend money on some new jdm wheels, and wonder why they lean out.

The problem with a MBC is it can't control spiking, so your 13 psi might jump to 15-16, and thus lean out your motor pretty badly. You won't find many people using them for that reason. No need for an 800 dollar EBC. Even a 200 dollar AEM tru boost will prevent that.

The reason why I suggested vacuum leak/exhaust leak is that(and I have personally seen this on my car), I unplugged the vacuum hose on my FPR, and the AFRs at idle went from 13, to 19, so even a tiny vacuum leak could cause your motor to take in more air than you'd expect. Even when I had a vacuum leak, my boost gauge showed -19 in/hg.

Secondly, if you have an exhaust leak around your downpipe, the wideband might read the extra oxygen, and your reading will be leaner than it really is.

Take some carb cleaner, and start spraying it all around your motor. If your rpms rise, there is your issue.

I highly doubt that with a walbro, stock t25, etc you are running that lean, unless your pump is taking a shit on you (as mine did after 7k miles). Make sure to check your voltage at the pump.

[negrosx13]

True that

The xs turbo controller never spike ever,not the hallman is another story. So I got my first hand feel when that shit spikes..its scared Crap outa of me! I really like sbc and I just hate the greddy shit.

I'll give the ol carb cleaner trick a try,but I been trying to search for any exhaust leaks and I don't see find any but u can kinda hear like there is one.

Thanks again ill update with breaking news when it happens

[negrosx13]

So i pretty much cleared all thoughts on what it could be.
I reseal the fuel tank and now when i fuel up,when i open the cap i get pressure relieve hissssss. My MPG got alot better after this and nomore rawww fuel smell in the car. Then checked the lower o rings( no leaks there). Found a small vaccum leak the port under the TB,now im reading 20-21in of vaccum.

Now when checked the plugs They look more or less normal no real sign of lean they were medium-dark tan colored and gapped too small,i must have fucked up. now there at 31-32. Then check the fuel pump( its seeing battery 13.8 and white/purple wire has 11.8? and when i check voltage at the fuse it was 11.8 as well?). Another i found weird when i pulled the EGI pump relay that the coil side of the relay showed some overheat/burn marks and so did the relay itself. I swap in one i had laying around. I added a ground wire in the engine bay to see if it would a difference. Also played with the tps but when i checked..it was showing 55mv closed,4.8~ wot(ill recheck again).I set it back to 45 but it felt worst than ever and no difference on A/f ratio. Btw i removed the MBC and no change.

Finally i checked the ecu code and came up with 34 and 13. So ima be aiming focus on that. I did resistance on the KS and showed nothing,same thing on continuity test.
My drive to work the felt alot better then it has in a while,so im getting there. Next im gonna try is to wire the maf wire(The harness wasnt done by me other than 3 plugs that need to repined)


Thanks for time again:wiggle:

[negrosx13]

anyone help??? now im finally back to normal power,not dropping so much pressure like i was.After playing with the maf and wire etc etc; my are AR'S(12.1-12.5) at WOT.But i guess i fouled my plugs while playing the maf. i unplugged the maf while the car was running and rev'd a few times for w.e. reason. But now the wideband is saying super lean on idle(18+) and my vaccum is little off 18-19..