air fuel ratio while warming up. normal?

[Quiksilver]

Hi all. 2002 stage 1 turbo 17k miles. I was messing with the bike the other day and noticed the a/f was around 12.5 on start up after warming up the bike is around 13.5 to 14.5. I did a compression test and two cylinders were 120psi while the other two were 118 and 119 psi with .080 spacer. Is this normal? I live in south louisiana and the temp was 70-80 degrees with the bike cold. s this normal or should I be looking at a engine rebuild sooner than later? Thanks.

 

[Boosted Cycle Perf]

Compression readings are fine.

It does seem to be pretty lean for Ideling. I'm willing to bet you hear a lot of popping coming from the exhaust once it's gets around 14.0 afr. However that doesn't mean you're engine needs a rebuild, it does tell me that your fueling is off a touch.

 

[BA BUSA]

A engine rebuild won't do anything for your a/f
ratio, but getting it mapped correctly will.

 

[Quiksilver]

Compression readings are fine.

It does seem to be pretty lean for Ideling. I'm willing to bet you hear a lot of popping coming from the exhaust once it's gets around 14.0 afr. However that doesn't mean you're engine needs a rebuild, it does tell me that your fueling is off a touch.

Yes sir sure does. Just checking don't wanna be riding if something was wrong. It rides soso nothing major but it's about little things right?

 

[Dscahill]

Quiksilver: The signature..is awesome! I'll have to use that when my install is done!

-D

 

[Boosted Cycle Perf]

Yes sir sure does. Just checking don't wanna be riding if something was wrong. It rides soso nothing major but it's about little things right?

What's the afr under boost?

Yes that's lean, but at idle since the engine isn't under load that isn't the worst thing in the world.

 

[cwalker2]

An engine will idle on a wide range of air fuel ratios. It will idle fine from the factory at 14.5:1 to 14.7:1. That said, what the AFR is at idle, is no indication of what it is doing at all other throttle positions and rpm and boost levels. Your engine should warm up with a rich AFR. Since it is EFI the engine goes rich to crank and start, then lessens the fueling over time/engine rotations. Additionally it will run richer while coolant temps are low until reaching normal operating temps.

A lot of Dynojet trained tuners tune to an air fuel ratio and tune everything to 13:1 Idle to WOT at all RPM. It won't hurt anything, but that's not technically the best for every engine.

As others posted above, and I am in full agreement, an engine rebuild will have little to do with the AFR as seen from an exhaust gas sensor. The other thing to remember s that a lot of the several hundred dollar AFR meters are just hobbyist meters. They can be a a full AFR unit off from actual. One of the most popular units on the market is one of the worst.

 

[Quiksilver]

Quiksilver: The signature..is awesome! I'll have to use that when my install is done!

-D

Thanks! Had to come up with something to tell people lol. Small town here so turbo bikes are insane to people here.

 

[Quiksilver]

What's the afr under boost?

Yes that's lean, but at idle since the engine isn't under load that isn't the worst thing in the world.

At full boost I measured mid 15 ' s (I know). I'm surprised the motor hasn't grenaded yet. One I seen it was that high I stopped running her hard. I know it needs to get dyno ed by someone who knows turbo. I'm no professional by any means but it seems to me my bike was tuned backwards. Afr as low as 9 mid boost and as high as 15.5 just seems weird to me.

 

[Quiksilver]

An engine will idle on a wide range of air fuel ratios. It will idle fine from the factory at 14.5:1 to 14.7:1. That said, what the AFR is at idle, is no indication of what it is doing at all other throttle positions and rpm and boost levels. Your engine should warm up with a rich AFR. Since it is EFI the engine goes rich to crank and start, then lessens the fueling over time/engine rotations. Additionally it will run richer while coolant temps are low until reaching normal operating temps.

A lot of Dynojet trained tuners tune to an air fuel ratio and tune everything to 13:1 Idle to WOT at all RPM. It won't hurt anything, but that's not technically the best for every engine.

As others posted above, and I am in full agreement, an engine rebuild will have little to do with the AFR as seen from an exhaust gas sensor. The other thing to remember s that a lot of the several hundred dollar AFR meters are just hobbyist meters. They can be a a full AFR unit off from actual. One of the most popular units on the market is one of the worst.

My afr meter is aem failsafe. Bought it for the basic datalog and boost/afr setup. Never thought about it not being as accurate as a dyno, makes sense.

 

[Quiksilver]

I noticed the other day when I cranked it I seen what looked like gas or oil on my house. Once the bike gets to operating temp it stops. I thought it might be rings. Did compression check which was ok. Haven't done a leak down and don't have access to one right now.

 

[Boosted Cycle Perf]

It's usual to get a little moisture to come out of the dumps when warming up, specially in cooler weather.

However I would check your oil level. If it's over full it could be backing up in to the turbo when it's not running and most of the oil returns to the pan.

 

[Quiksilver]

It's usual to get a little moisture to come out of the dumps when warming up, specially in cooler weather.

However I would check your oil level. If it's over full it could be backing up in to the turbo when it's not running and most of the oil returns to the pan.

The oil level is below max. I have the big cc scavenge pump with the check valve that should help with oil draining after stopping? I have the full system so maybe that could collect more water I suppose.