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[Mk2] [Turbo] What AFR does a stock Rev 3 run at (Idle/Cruis/WOT)

 
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Danbob




Joined: 14 Nov 2011
Posts: 780
Location: Wellingborough
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1993 Toyota MR2 Mk2 Turbo Rev2

PostPosted: Tue May 02, 2017 7:43 pm    Post subject: [Mk2] [Turbo] What AFR does a stock Rev 3 run at (Idle/Cruis/WOT) Reply with quote Reply with quote including images

Been monitoring my AFR's as engine break in is just about done and boost will be raised shortly.

Seems a little rich, so want to know if anybody has a wideband fitted to a stock Rev 3 to compare.

Car is running stock Rev3 ECU (for break in) currently on 10PSI boost. HKS 264 cams.

Cold Start Idle AFR ~ 10:1
Warm Idle AFR ~ 12.7:1
Cruise/part throttle ~ 14.6:1
WOT High revs 10PSI ~ 12:1 --> ~ 11:1


Idle AFR's seem rich. and it doesn't idle great, it needs more air than usual but I thought that was just due to the cams.

Does anybody have some data for stock Rev 3 Idle AFR?

Thanks
Dan
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jon
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1994 Toyota MR2 Mk2 Turbo Rev3

PostPosted: Tue May 02, 2017 8:32 pm    Post subject: Reply with quote Reply with quote including images

Warm Idle AFR should on average be 14.7:1, it will oscillate around from 14.3:1 to 15.0:1 due to feedback from O2 sensor.

Cold Start Idle AFR can be anywhere from 10:1 to 14.1 depending on coolant temp.

Cruise/part throttle should be around 14.7:1. Again it will be oscillating due to O2 sensor feedback.
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Danbob




Joined: 14 Nov 2011
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1993 Toyota MR2 Mk2 Turbo Rev2

PostPosted: Tue May 02, 2017 8:36 pm    Post subject: Reply with quote Reply with quote including images

Yeah cruise and wot seem about right to me and the car feels right under those conditions aswell, just idle seems too rich and idle is also where the car struggles.

Wonder if it's due to the fuel pump resistor not being used, that would explain it only running rich at idle. Maybe the stock fuel pressure regulator can't handle the full flow from the walbro pump at idle to keep the pressure down...
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jon
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1994 Toyota MR2 Mk2 Turbo Rev3

PostPosted: Wed May 03, 2017 7:24 am    Post subject: Reply with quote Reply with quote including images

Could be due to the fuel pump resistor not being used, or it could be that the 264 cams are pushing the volumetric efficiency at idle so far out that the ECU can't compensate.

If you raise the idle a bit do the AFRs go to 14.7:1?
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jimGTS
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1997 Toyota MR2 Mk2 Turbo Rev4

PostPosted: Thu May 04, 2017 9:40 am    Post subject: Reply with quote Reply with quote including images

i dont run a fuel pump relay or resistor.

afrs at warm idle should still be in the 14.3-15.0 range.

and ive ran all manor of fuel pressures, from 33psi to 46psi base pressures.
granted most of that was on the stock pump, but my walbro its still fine.
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simpson_eh
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1993 Toyota MR2 Mk2 Turbo Rev3

PostPosted: Fri May 05, 2017 1:02 am    Post subject: Reply with quote Reply with quote including images

looking at mine today 2.2 gt3076 264 always in 13 drops to 12 maybe 14 now and again boost drops into 9 time for a remap i think:(




but i have added a frp at 41 psi to set no vacuum and high flow pump swirl pot etc so injectors prob getting a throat full
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