Loss of power high rpms & leaning out (searched)

[onr240sxse]

Hello,

I have searched and searched and as always when someone starts a thread and finds a solution they never state what the fix was.

So here we go,

Redtop Sr20, Gt2860rs, SAFC, Z32 MAF, walbro 255, and all the regular stuff.

I am hitting a wall of loss power at 5k rpms. Wideband gauge says that it is running around 14:1 AFR. I haven't checked the timing yet to see if that is the problem. I recently repaired the KS wire and I am wondering if this might be the culprit. Since the KS is working if there might be too much timing on the motor. It's not breaking up like the plugs are bad.

Let me know if you have had the same problems or any suggestions.

[onr240sxse]

Checked the timing and it is at 15*. I also replaced the fuel filter (z32) and nothing has changed. Fuel pressure is good (43psi). No boost leaks either.

It almost feels like a NA car when the timing is advance too far.

Anyone?


Thanks in advance.

[onr240sxse]

I also pulled the fuel pump and checked the sock and all is good. Good voltage at the fuel pump as well.


Anyone have any ideas?

[keepingitreal87]

are you running stock injectors?

[keepingitreal87]

also stock coils have been known to misfire under high boost at higher rpms

[USMCgetsome]

is your fuel pressure rising when you throttle your engine?

[onr240sxse]

Yes, they are stock injectors.

I've had a misfire under high boost and this is not the same feeling.

I will have to check the fuel pressure when throttled.

To check to see if the FPR was not functioning, I clamped off the return line and it still did not help.

I will have to check the injectors i believe. Any suggestions for cleaning the injectors?

[onr240sxse]

I don't believe it is an ignition problem b/c it is leaning out instead of fattening up under WOT.

[keepingitreal87]

good point about it running lean. a gt2860rs is capable of going beyond the fueling capacity of stock injectors. If you noticed this after raising boost im guessing its time for some bigger injectors. How much boost are you running?

[onr240sxse]

14 psi. The car has been tuned and have never had a problem with it leaning out like it is. I'm thinking that when I repaired the KS that something happened in the wiring. It's either that or clogged injectors.

[onr240sxse]

Bump bump bump

[rc1honda]

Dude the injectors are bad. If you weren't leaning out before you still were running well into and probably over 100% duty cycle on stock 370's. You are going to go through injectors like oil filters.

You are pushing a considerably more air then stock both with the turbo and boost pressure. I am surprised your motor is even still running. You really are playing with fire. A SAFC and running 100% duty cycle all the time? I mean people already told you the problem. Who do you wanna hear? Buy bigger injectors or buy a new motor it's your choice.

Even if the injectors are not the solution to your current problem you should change them anyway. It's only a matter of time until you fry your rings.

BTW what is a KS wire anyway? And how would a wire make your motor lean out?

[onr240sxse]

KS=Knock Sensor.

I have 550 injectors to put in. When I dyno'd my car it was running 12:1 AFR.

I find it odd that all of the sudden it would start this when I fixed the KS since it doesn't read past 5k anyway.

[rc1honda]

Well this might sound crazy but maybe youre having a lot of knock lol. Knock due to Improper air fuel mixture and to advanced timing. The ecu is going Into safe mode and pulling timing to save your motor from blowing up. It might going lean due to the SAFC saying there is less air then there really is and ur ECU is using the stock safe mode map assuming there is less air then is actually being metered. Hence lean fuel mixture.

I swear what's is so complicated about this. You are doing stupid s***. I mean c'mon man what r u thinking. And btw any tuner who tunes full boost at 12:1 a/f ratio is moron and should be fired.

[onr240sxse]

My SAFC is not showing abnormal knock.

The car has ran perfectly for the past 3 years like it is. I am also not some young punk that drives around like a bat outta hell everywhere he goes bouncing it off the rev limiter.

I know that 12:1 is leaner than what is optimal but that is the leanest it went on the dyno. Otherwise it stayed around 11.2:1 until 6500 (that's as high as I went after we saw the 12:1 in the upper rpms). Before this issue it would stay below 11.5:1. Then I pull it in the garage, fix the KS wire and BAM! It feels like a fuel cut @ 5k everytime no matter if I am at 30% throttle or WOT.

My original question was why it would all of the sudden run lean like that after fixing one wire. I know that 14 psi on stock injectors will wear them out quickly. I might drive the car 1000 miles a year otherwise it just sits in my garage collecting dust. And when I do drive it I might hit 6k once or twice.


I see your from Chicago, Cubs or Sox?

[rc1honda]

Sox all day. I am not trying to be d!ck and don't think ur are dumb punk I just don't see why u would take a chance with ur motor. U have a nice setup and it would be nice to see it last.

The stock knock sensor is kinda retarded though and anything near the harmonic range is sometimes misidentified as knock. Like valve or lifter tap can be read as knock from the sensor. Ask me how I know. So barring anything really audible the knock sensor may be bad and sending a high lock signal to the ecu making it pull timing and then u would lose power. The leaness might be do to the safc.

Replace the knock sensor and the injector that was bad. Maybe have a friend with a PFC or stand alone hook it up to ur car and it will give u a numerical knock reading. If it's high then something maybe be mimicking the knock frequency when it's not really knock.

[onr240sxse]

Get this,

It was the spark plugs! I was roaming around on some other forums and came across a thread about an Ls1 having some of the same issues as I was. Come to find out, if there is enough unspent fuel in the exhaust it could cause the wideband to "malfunction" and read lean. I though "no way". I replaced and gapped my plugs and BAM! Low 11's AFR.

I guess when I repaired my KS and was actually running correctly it fouled my plugs bad enough to cause this. Plugs that I pulled out were nice and black.

Thanks for everyones help!

Oh, and Go Cubs!