o2 voltage drop mid pull help

[hardcorandy]

Trying to tune a friends car. His mods are the same as mine except he has an LC2 simulated through link and has stock cams. I have the idle and cruise tune spot on. The o2 does cycle. During WOT the car is a little lean from my target (still dialing in the maf and such) with the o2 at .8. At about 3500-4000rpm the o2 drops to .2 and the car goes leaner and leaner as the rpms go up. Im talking like 16/1 AFR. Anyone have the same issue?

Im to the point of putting the factory o2 back in and just use the gauge to log and see if that fixes it.

 

[Phantom DSM]

There is a Battery value that can be logged from the displayed items menu F9 that you can add, you can watch if battery voltage dips below 13.5...fuel pump can be getting lower voltage, flowing weaker.
Verify its a voltage issue before you swap o2 sensors. Ihave seen o2 sensors fail this way at higher rpms. They stop cycling at weird times cruising as well,etc.

 

[hardcorandy]

Here is a log. Battery voltage doesnt drop below 13.5. The car never does hit target AFR. On my car i dont run an adjustable FPR as i dont have the high pressure pump. My Pump has a high pitch whine. My friend bought the same kit but ive noticed his pump has a very low pitch whine to it. Like the voltage is lower going to the pump then what mine is. We both dont have a rewire. Just trying to figure out why this thing is so lean and dropping o2 voltage.

 

[edged1g]

Here is a log. Battery voltage doesnt drop below 13.5. The car never does hit target AFR. On my car i dont run an adjustable FPR as i dont have the high pressure pump. My Pump has a high pitch whine. My friend bought the same kit but ive noticed his pump has a very low pitch whine to it. Like the voltage is lower going to the pump then what mine is. We both dont have a rewire. Just trying to figure out why this thing is so lean and dropping o2 voltage.

This log came from a 1G and you have 2g selected as base MAF type. You most likely need to to some more MAF tuning at the higher Hz values assuming your fuel settings are correct.

Battery voltage doesn't necessarily indicate fuel pump voltage. This could still be a fuel pump issue. I would do a rewire to rule it out. Its a good thing to have more voltage at the pump.

 

[silvreclips]

Dont forget about the fuel filter. If it hasnt been replaced in a while that could be a problem.

 

[hardcorandy]

I have 2g maf selected because it does have a 2g maf. Like i said, same mods as my car except the front o2 sim and has stock cams. Ill ask about the fuel filter and I should do the rewire to it.

Changed fuel filter. Did make a different but Still goes leaner as RPMs go up under WOT. Checked the voltage at the pump. Double checked maf wiring. Tested the FPR. Plugs are coming up brown. They show no lean issue. Also not seeing any knock.

 

[hardcorandy]

Last night I redid the ground on his wideband. Made sure it was a solid chassis ground. Also recalibrated the o2 to Inovatives specs again. Still no change. The problem from the start was he had all these parts saved up. Went from stock to not in one night. But who knows, Bought the car with a blown motor and i built a fresh block and head. Everything else was put back in the car as it was. Could be anything.

I almost feel like i need to try and put the stock injectors back in to rule that out. His PTE's do not have a size stamped on them. Looked up the serial number and they do come up 880 but his dead times are close to a 680.

Pump was checked, fuel filter changed, maf checked. Plugs are still showing no signs of lean condition. Max knock we are seeing is .4 and that doesnt happen often.

 

[gofer]

How is the wideband wired into the front o2, is it tapped into the harness or did you CUT the o2 sensor wire when you wired it up?

Have you checked for any exhaust leaks before the WB sensor?

 

[hardcorandy]

No exhaust leaks. Wideband is in the front o2 and being simulated. I cut pin 4 to the ecu, capped off the harness side and soldered the ecu side. Should there be a ground to ecu? The ground from the DB gauge and Lc2 got tied together and put to a chassis ground. Im running the 5v line to the ecu and gauge. Which is the yellow on the Lc2 model. I wired via Snowboarders writeup.

Basicly what it looks like is Wideband reads lean when the car kicks into open loop WOT. The Engine itself isnt showing any signs of that though.

 

[codym]

Snowborder714's write up is for the LC-1 wideband, the LC-2 is slightly different; there is no wire for ECU sensor ground.

I had some confusion with mine, and this is what I got for the end result.

LC-2
Red-12v
Black-Chassis ground w/ DB Gauge ground
Yellow-DB Gauge white wire
Brown-ECU Pin 4

DB Gauge
Red-12v
Black-Chassis ground w/ LC-2
White-LC-2 yellow wire
Yellow- Headlight power source (This will dim the gauge when headlights are flipped)


From your post it seems as if you have the yellow wire split between the ECU and the DB Gauge.

 

[hardcorandy]

Ive PM'ed snowboarder about the wiring a few days ago. He said I can just use the 5v for both gauge and ECU, that i can tape the 1v wire. True? Or do i still need to run the 1v to the ecu?

 

[gofer]

The 1v wire is to simulate the narrowband sensor from the gauge, ECMLink provides the simulation so it isn't necessary to wire it up.

Looking at that log it seems you haven't even tuned your idle or cruise FT's so how can you expect to go WOT and have your WB AFR's even come close to what you're targeting?

Tune your MAFComp table idle first, cruise second, WOT third...

 

[hardcorandy]

CombFT is near zero % at idle and cruise. I dont know what more i have to do. Airflowperrev and idle is .25, then i adjust the deadtime. Mafcomp is actually too high. Its not matching the boost est at 5500. Should i then play with injector size? Serial numbers come up 880s which are actually 840s i know. but from what im seeing on link is they could be flowing about 680s. Deadtime is way off from an 880 too. My 880s have a deadtime of 370. Ive searched other threads for people with 880s and they have deadtimes of 370 or higher.

I can get you an idle log if youd like.

EDIT I just looked at the log again that i posted. I do see the cruise needs to be adjusted a bit now. Sorry, I thought i had it.

 

[gofer]

To target AFR's in WOT you also need to adjust the MAFComp table at those Hz points, i.e., your WB is logging 12.5:1 and your AFREst is targeting 10.8:1 @ 1500Hz and the sliders already at +6%. That means you need to increase that 1500Hz slider another 15.7% to get target AFRs lined up to your WB.

You're not logging boost but if you were that's another way to tune the MAFComp sliders, I prefer using the WB logs to the AFREst to tune the MAFcomp sliders.

Looking at your log you say you're leaning out at WOT, that could be because NONE of your MAFComp sliders have been touched that would account for additional airflow to richen up AFR's in open loop.

 

[hardcorandy]

Decided to mess with the car a bit today. Gofer, I adjusted the maf up down and to the moon. Cant get the AFR to change above 1200hz is what its looking like. No matter what i do to this thing I get the same result pull after pull. Even tried changing injector sizes just because.

Changed out the maf and FPR with mine and no change. I also checked for a kinked fuel line. Plugs are still coming out brown right after a 15-1 AF.

 

[gofer]

Check your fuel pressure, it should be rising 1:1 with boost pressure, so if you're running 37psi it looks like the AFR's start leaning out when fuel pressure would be reaching 60psi (23psi of boost).

To test a 1:1 rise you'll need to do a modified BLT. Just hook up the laptop and manually activate the fuel pump in Link, then perform a BLT and watch the fuel pressure gauge as you increase boost pressure and verify it's rising 1:1 like it should.

 

[hardcorandy]

I think you are on to something. I have been noticing his car taking longer and longer to start. When i activate the fuel pump it does seem to take some time for the pump to sound like it has allot of pressure behind it. Way more then mine.

Im not gonna be able to do a test till next weekend. So i will keep you posted. What would cause fuel pressure loss? Has new 255 pump and filter. Made sure we didnt get the high pressure model. Voltage has been verified to the pump. His regulator is good.

I know people say run a AFPR on a 255 but seems to be untrue. You just need to not run the high pressure pump. Never had issues.

I cant thank you enough for your time thus far.