1G can't get low fuel trims away from maxed

[93AWDDSM]

Wow, I feel as piece by piece the car is falling apart . Do I need the plug in part from the wiring harness to the o2 or can I bypass that completely and wire just the o2 up? I think my wires coming from harness side are messed up. I jiggled the plug and I saw random .01/.03 volts or it would shoot to 4.98v then back to either .00 or .01 volts. Also, when I do pulls the value doesn’t change much at all...?

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Edit/ just found 2nd picture reviewing log. Looks like this has to be due to wiring as these wires are bundled together (CTS and o2)

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[Vegas Smith]

I'm not aware of any need for the stock connector. If it helps, I have my wideband o2 wired directly into the ecu.

 

[93AWDDSM]

@Vegas smith
Yes, it does thanks. I’m going to rewire that and the coolant temp sensor after Work tomorrow and see what the new values are, as I’m hoping that fixes my low volt value at idle/cruise for o2.

 

[Turbo2g]

It will work, but make it a bi*** to replace when the sensor ever does fail. It can be done to at least test your theory. Thats the kind of stuff that has me swearing under my breath when a customer brings in a frankenstein car to diag. Consider fixing it right if you go to sell it one day.

 

[93AWDDSM]

Always staying in the family. This things never leaving and as of now it’s my only/daily so I need to fix stuff ASAP and your right it’s to test . Also, I have access to a donor, so I will use that oem “plug in connection” part and wire it up so it’s back to normal-ish

I’d be glad to find it being bad wiring then going and spending money on a working part :/

 

[93AWDDSM]

The rewire fixed voltage. It now cycles at idle. Found another slight issue with a partially collapsed in the middle Vacuum line from Intake manifold to BOV top.

Ideas for the high - low fuel trim and o2 fuel trim <- that one cycles pretty average but above 100%- —-
am I correct when reading this the logger is seeing the ecu trying to add fuel because I’m “lean” at idle?

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Thanks guys

edit: I think I've found the cause of the high Low fuel trim. I have a hacked maf (lower honeycomb removed and the "idle screw" in the MAF area backed out all the way) slightly leaner? I have a large PRE o2 leak at the turbo inlet gasket.

 

[93AWDDSM]

So with no luck, my LOW trim is still at 137%. I'm going to re-route the valve cover breather hose back into my Dejon intake today. I have a feeling though that the lower honeycomb removed is causing all this lean low trim (don't have the option now for swapping stock MAF anymore). My mids and highs are like 101-103% so not bad. I've checked and fixed exhaust leaks from Manifold/turbo inlet and o2 housing. No boost/vacuum leaks, vacuum @ idle is 20 inHg. I'm just dumbfounded on why it's so lean, the o2 cycles as it should.

 

[93AWDDSM]

Since I’m having a hard time tracking down this lean low fuel trim I’m going to purchase a Safc 2 in 2 weeks to help compensate for that (which I believe is the hacked maf).

I’ll update when I can.

I want to have a resolved thread regarding this, since a lot go problem unsolved or don’t return with a solution for the problem.

 

[pauleyman]

Since I’m having a hard time tracking down this lean low fuel trim I’m going to purchase a Safc 2 in 2 weeks to help compensate for that (which I believe is the hacked maf).

I’ll update when I can.

I want to have a resolved thread regarding this, since a lot go problem unsolved or don’t return with a solution for the problem.

Adding a bandaid isn't a solution. Fix all the leaks. Replace the hacked maf. At least screw the plug in. I had a lower honeycomb removed for years and it didn't cause idle fuel trim issues.

 

[pauleyman]

You should also list ALL mods in your profile. Anything that isn't stock. No hose from vc to intake....list it. Bov vented or not? List it. No mention of hacked mas in profile. These are potentially important details when the forum tries to help you.
Also...a 16g fmic and stock injectors? Better keep that boost low.

 

[93AWDDSM]

Adjustments today I'll be doing:
Adjusting the MAS "calbration" screw in to help potentially with the LEAN issue @ idle.
Drilling a hole for a 3/8 vacuum nipple for the valve cover breather hose.

I'll report back once those are completed and I have logged with a fresh ecu reset.

You are right. I’m going to edit my profile to the T right now with everything.

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While cruising to work today

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, I didn't notice how large the phone pictures come out while using a computer web browser!

Correct me if I’m wrong but doesn’t my coolant temp need to be above 190 for my ecu to get into learn mode? And if it doesn’t my trims won’t update right?

When cruising I can only get the temp to 182-186* with the heater on the first level. At idle I can get up to 192-203 but once I start moving it cools right back down to 176-186 sometimes 189*

THANKS!

 

[93AWDDSM]

Just rerouted the valve cover hose back to the intake pipe. Adjusted the MAS screw all the way in for less unmetered air. Can I make a block off plate for the unmetered air section on that MAS?

It’s 49* here now, got the car up to 199-203 while idling, fuel trims rapidly started towards lean until it stops at 137%. I applied gas at a steady 2k rpm and while that was happening I was able to lower my low fuel trim to about 122-123% and my FTo2 was more bouncing around 80-103%. After that I sat at idle 750 rpm my FTo2 was bouncing around 125-155% and my low trim went right back to 136%.

This seems like a boost leak but I have checked many times and it bleeds down very slowly. So I just attempt to keep finding even the smallest leak?

 

[93AWDDSM]

I’ve looked over the Downpipe and exhaust manifold. I noticed the grounding strap for the Downpipe is missing (read some threads about it helping ground o2 for correct readings?) and my manifold has a couple hairline cracks in it.

My main question is, is the grounding strap needed for the o2 or just for RFI stuff?

Thanks....