March 23, 2019, 04:48:14 PM

Author Topic: Lean a WOT. Didn't used to be like this  (Read 792 times)

Offline Exidous

Re: Lean a WOT. Didn't used to be like this
« Reply #30 on: March 01, 2019, 04:26:26 PM »
My WOT MAP reading is almost identical from 2017 to now. The MAP is a 4bar unit internal to the ECU case. I had thought about running an aftermarket 1bar MAP in an effort for better reolution but the 4bar wasn't causing me any issues.

I will note that when I was running the GM ECU and 1bar map I'd usually get about 101-102kPa but this was at sea level in Hawaii. This was back in 2013.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Too loud, need bigger muffler....

Offline Exidous

Re: Lean a WOT. Didn't used to be like this
« Reply #31 on: March 11, 2019, 01:58:36 AM »
Bit more testing.

Pressurized flow at the rail is 214lph. This is a little lower than I would have expected for a 340lph pump but it is after the orifice in the FPR. I kept the voltage constant using my running Jeep.

I've also tested the flow again out of each injector. The results were as expected. Avg of 608cc/min. The calculated flow in MLV(MegalogViewer HD) maxed out at 150lph. So, flow to the rails and out of the injectors are not the issue. All that I have left is the ECU or something with the O2's that's only showing up at heavy loads. Only issue being, if there was a leak making it show lean I should be running super rich now with the VE peaking at 118%. The plugs are telling a different story though. They look slightly hot. Just a touch of brown/red on the ceramic. No carbon deposits at all.

The O2's are in very close agreement for each bank. Almost too close if that's even a thing. It seems unlikely that each bank would have the same size leak.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Too loud, need bigger muffler....

Offline shainiac

Re: Lean a WOT. Didn't used to be like this
« Reply #32 on: March 11, 2019, 08:31:03 AM »
Might be a dumb idea, but is EGO correction doing anything funny in your logs?
'88 TII - 13BT, MS3X , EFR 9180 IWG, A2W Intercooled
539whp/407wtq @ 25.5psi

Soon to be Alum 5.3 GenIV LS, Twin EFR 6758s, T56 Magnum, Ronin 8.8" IRS, MS3Pro Ultimate

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Offline Exidous

Re: Lean a WOT. Didn't used to be like this
« Reply #33 on: March 11, 2019, 07:23:25 PM »
Nup, have never used it aside from turning it on for a min to see if it worked.

There was a leak on the driver's side header vband. Fixed it. No change. All that is left is the O2's(that are both equally wrong?), the ECU and engine itself.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Too loud, need bigger muffler....

Offline jwvand02

Re: Lean a WOT. Didn't used to be like this
« Reply #34 on: March 12, 2019, 12:31:11 PM »
Have you checked previous logs at not WOT to see if the car is flowing more fuel to hit those commanded AFRs in closed loop?

Here's a theory that may be super duper wrong since I am NOT a tuner - in the US maybe you're getting fuel with Ethanol in it, which requires more volume to hit stoich. If you're in open loop at WOT, it may still be fueling based on 100% gasoline and not 10% ethanol or some other blend.

Offline Exidous

Re: Lean a WOT. Didn't used to be like this
« Reply #35 on: March 12, 2019, 01:03:16 PM »
I've pretty much only ever run in open loop. The only thing I have closed loop is the idle timing after the idle without it was nailed down.

The odd part is that inj PW is about the same from old logs to new logs. As an example: My injectors range from 10.2ms to 11.4ms(due to individual inj trims) at WOT. This is about the same from the old and new logs however the AFR output has changed(by ~2 full AFR points). It changed enough to where adding 16% on the VE wasn't enough. One more test I could do is simulate 6000RPM at 10ms PW and verify that all injectors are flowing what they should. It should be around 310cc/min or about 50% duty cycle. I did static flow testing already and everything came back normal.

An E10 blend would show lean everywhere but it's all dead on except at heavy load. Screams flow issue but I've fully checked out the fuel supply.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Too loud, need bigger muffler....