Super high AFR please help

[Breakbeat93]

I just got my s14 sr in and running. Feels strong, and I hear no detonation, but my afr is at 16-18 at wot until about 4500 rpm. Then it comes down to about 13.5 and goes down to about 12 by redline. The o2 is mounted right under the shifter. Walbro pump, z32 filter, 3 inch catless exhaust, front mount, s14 mafs, stock ecu tune. I have a cheap pos fuel pressure gauge showing about 50lbs at idle and jumps to 60 when I pull the throttle. I don't wanna pop my engine before I even get to use it. PLEASE HELP!


EDIT: I'm reading up to about 6 psi at the manifold while my afr is still buried in the red

[ESone3]

Check timing. You could be too advanced causing a little lean.

[Breakbeat93]

Thank you for the reply. Anyone have any other ideas? Im running an 18 on my aem uego at wot! Could it be the placement of the gauge? Any ideas would be helpful.

[xpinoyxmk]

Have you recalibrated the o2 sensor? Does it feel like its not pulling as hard? Whats your afr at idle? 12 is still a little high in boost.

Btw, your fuel pressure is suppose to be 43 without vacuum and 34 with.

[rcdad123]

move the a/f sensor as close to the turbine as you can, i like mine between 6-8 inches away from the exhaust housing. also, check your spark plugs. if the ceramic part is really white, it`s running lean, if it`s caramel color, you`re good to go. if it`s got tiny spots, you`re detonating. and if it`s powder black, you`re running rich.

[Breakbeat93]

Have you recalibrated the o2 sensor? Does it feel like its not pulling as hard? Whats your afr at idle? 12 is still a little high in boost.

Btw, your fuel pressure is suppose to be 43 without vacuum and 34 with.

How do you calibrate an o2 sensor? It pulls as hard as it ever has. But this is my first 240 w sr so I really have no basis for comparison as it's only been running for a few days and I just put the a/f on it.

I put an aftermarket pos fpr in there in an attempt to richen it up. And even at50-60 psi I saw no change

Afr at idle is good. 14-16. About 15.5 most of the time

[Breakbeat93]

move the a/f sensor as close to the turbine as you can, i like mine between 6-8 inches away from the exhaust housing. also, check your spark plugs. if the ceramic part is really white, it`s running lean, if it`s caramel color, you`re good to go. if it`s got tiny spots, you`re detonating. and if it`s powder black, you`re running rich.

Aem says 36 inches from exhaust port...would this cause it to show a leaner condition than is actually occurring?

[ghettohatch]

thats where i mounted mine as well, when my sr was bone stock afrs were dead on just for reference. i believe they have you mount it there because the heat of the turbo will shorten the life of the sensor, someone correct me if im wrong

like others were saying, check timing, check for leaks after the maf also. if you have an aftermarket fpr, switch for a stocker and see if it improves (i had this problem when tuning, fpr kept causing fuel pressure to drop slowly only under load so i couldnt tell when watching the guage under the hood).

[Breakbeat93]

thats where i mounted mine as well, when my sr was bone stock afrs were dead on just for reference. i believe they have you mount it there because the heat of the turbo will shorten the life of the sensor, someone correct me if im wrong.

What do you mean by dead on?

[sr20sean]

thats where i mounted mine as well, when my sr was bone stock afrs were dead on just for reference. i believe they have you mount it there because the heat of the turbo will shorten the life of the sensor, someone correct me if im wrong

like others were saying, check timing, check for leaks after the maf also. if you have an aftermarket fpr, switch for a stocker and see if it improves (i had this problem when tuning, fpr kept causing fuel pressure to drop slowly only under load so i couldnt tell when watching the guage under the hood).

thats right.

get an adjustable FPR. it seems like you didnt adjust it after the walbro pump was installed.

[Breakbeat93]

thats right.

get an adjustable FPR. it seems like you didnt adjust it after the walbro pump was installed.

I ran the stock fpr first. When I saw the problem I did and aftermarket fpr gauge on it says 50-60 off-on throttle. Still the same afrs. Wouldn't higher pressure drop the afr?

[EsChassisLove]

How do you calibrate an o2 sensor? It pulls as hard as it ever has. But this is my first 240 w sr so I really have no basis for comparison as it's only been running for a few days and I just put the a/f on it.

I put an aftermarket pos fpr in there in an attempt to richen it up. And even at50-60 psi I saw no change

Afr at idle is good. 14-16. About 15.5 most of the time

Idle should be 14.7-15.2 ideally. If its 15.5 most of the time, then most of the time your just a tiny bit lean. Turn the fuel pressure down.

Aem says 36 inches from exhaust port...would this cause it to show a leaner condition than is actually occurring?

No it wouldnt, if you have a good gauge/sensor. Mines about 36" from the turbine, and read spot on with a dynos afr gauge that was in my tail pipe.


I ran the stock fpr first. When I saw the problem I did and aftermarket fpr gauge on it says 50-60 off-on throttle. Still the same afrs. Wouldn't higher pressure drop the afr?

Not necessarily. Your ECU can compensate for a little bit of extra fuel and trim it down.

Read your plugs. AND, I tell this to everyone when they have AFR issues judging by just their gauge. If its an AEM UEGO, make sure NONE of the wires are any where near the exhaust or any high heat source. When the wires to either my wideband or the factory 02 sensor get too close to the block or exhaust it will send my readings all over the place.

Sometimes it will run rich, sometimes it will lean out. And when I move the wire, bam everythings back to running perfect like nothing was ever wrong. Yea, its weird.

[Breakbeat93]

Turning the fuel pressure down will drop my afr? That sounds opposite of what I would think