any danger if AFR is as low as 9 ?

[flyby]

I have a AUTO UK TT BPU+ running 1,2 bar.

I got a new AEM failsafe 5 cm after the orginal lambd sonde.

It shows im gooing as low as 9 AFR.

My EGT says max 600degress, plased right beside the AFR.

[Rummy]

That's running really rich. Should be ideally around 10-12 cold and 14-15 warm

[ManwithSupra]

Too rich, you will be getting Bore wash with that level..

[flyby]

but I have no way of controlling this right ?

whit out a piggybag ECU upgrade.

[Kaan W]

More boost

[Shane]

I seem to remember reading that the stock ecu does overfuel above stock boost,, that's why some people use a safc or piggy back to lean it out a bit, but that does sound very rich

[Scott]

That's running really rich. Should be ideally around 10-12 cold and 14-15 warm

 

[wile e coyote]

That on idle ?

Mine runs at 14 to 15 on idle

[Scott]

That on idle ?

Mine runs at 14 to 15 on idle

 

Yeah that's normal. This is at 1.2bar though. Should be 11-ish, mid-high 10s is what I used to see, when up the top end of the boost.

[Pulley]

10.5 -11 max at 1.2 bar

I always try and run 11s under high boost

Sometimes spike a 9

[Rummy]

That on idle ?

Mine runs at 14 to 15 on idle

 

Same

 

To the OP, Ah, just looked at the pic, I see you meant on boost, not idle. My bad

Edited May 23, 2014 by Rummy (see edit history)

[gaijin]

You could have a vac leak somewhere Have a pressure test done to see if there is a leak It might only show up when the system is under pressure

[Ian C]

That graph shows normal BPU operation before anyone panics. It hits 9.5:1 AFRs just before 1bar of boost, which is when the stock ECU is going 100% duty as it thinks you're in an overboost situation. This is just before fuel cut kicks in to protect the engine. When you stop fuel cut and go past 1bar of boost you are simply changing the AFRs by adding more air rather than controlling the fuel. Running 1.2bar leans off the mix but it still has to progress through the pre-fuel cut stage where you run 100% duty at 1bar. Hence, the 9.5:1 AFRs.

 

What the graph doesn't show is how long it stays at that condition. Yes, maintaining 9.5:1 would cause borewash. Zipping through it momentarily under full throttle conditions though clearly doesn't, else half the Supras here would now have bad compression

[Bossco]

As above. It's not doing anything out of the ordinary. When the car hits full boost the ecu throws in all the fuel but as the revs rise (staying on boost) it will leans it's self off. When you change gear and the revs drop more fuel is thrown in and the cycle starts over.

 

Before we can see if there is a problem we need to see the continuous AFR's compared to RPM up to the red line.

 

I'll post one of my old graphs up if I can find it. It explains it well. The car was on the dyno with a bit of an unknown problem. AFR's would drop just below 10 when the came on to full boost, but as the revs were rising it was leaning out to quickly and going up to 13s just above 5k. The problem was fixed with a new pressure regulator and fuel filter but the graph showing the problem displays how the AFR's should dip and rise.

[flyby]

That graph shows normal BPU operation before anyone panics. It hits 9.5:1 AFRs just before 1bar of boost, which is when the stock ECU is going 100% duty as it thinks you're in an overboost situation. This is just before fuel cut kicks in to protect the engine. When you stop fuel cut and go past 1bar of boost you are simply changing the AFRs by adding more air rather than controlling the fuel. Running 1.2bar leans off the mix but it still has to progress through the pre-fuel cut stage where you run 100% duty at 1bar. Hence, the 9.5:1 AFRs.

 

What the graph doesn't show is how long it stays at that condition. Yes, maintaining 9.5:1 would cause borewash. Zipping through it momentarily under full throttle conditions though clearly doesn't, else half the Supras here would now have bad compression

 

Thanks, I only did some test runs like 1/4 mile, and the result is the same as shown.

As I understand yours post, if this continues on boost over at longer time, it would be good, to get a piggyback ECU.

[Bossco]

I'd say if they stay down in the 9s then you might have a problem you should fix first before running a piggyback.

[flyby]

As above. It's not doing anything out of the ordinary. When the car hits full boost the ecu throws in all the fuel but as the revs rise (staying on boost) it will leans it's self off. When you change gear and the revs drop more fuel is thrown in and the cycle starts over.

 

Before we can see if there is a problem we need to see the continuous AFR's compared to RPM up to the red line.

 

I'll post one of my old graphs up if I can find it. It explains it well. The car was on the dyno with a bit of an unknown problem. AFR's would drop just below 10 when the came on to full boost, but as the revs were rising it was leaning out to quickly and going up to 13s just above 5k. The problem was fixed with a new pressure regulator and fuel filter but the graph showing the problem displays how the AFR's should dip and rise.

 

I try som more runs, and import the log into AEM program to compare RPM/Boost/AFR, and post it.

[Ian C]

I try som more runs, and import the log into AEM program to compare RPM/Boost/AFR, and post it.

 

That'll do the trick. My bet is that it hits 9.5:1 at 1bar of boost and leans off to around 11:1 by 1.2bar. I don't think RPMs come into it, it's all about what boost you are achieving at the time - if you feathered the throttle to hold 1bar of boost you'd run 9.5:1 AFRs all the way up the rev range

[flyby]

That'll do the trick. My bet is that it hits 9.5:1 at 1bar of boost and leans off to around 11:1 by 1.2bar. I don't think RPMs come into it, it's all about what boost you are achieving at the time - if you feathered the throttle to hold 1bar of boost you'd run 9.5:1 AFRs all the way up the rev range

 

OK here we go, but, something is wrong whit the RPM, it never goes over 7000rpm. I bay have connected the RPM wire wrong...

But is the result as expected?

 

I cant find the reson for only hitting 1,2 bar, i want 1,4 bar.