Some of you may have followed my attempts to resolve a P0159 code that has plagued my car. I thought it was related to not having cats, so I bought a tune. I would still get the code every 300-500 miles. I replaced my O2 sensor, replaced the exhaust gasket... still getting a code. I traced the O2 sensor wire, and all looked stock.

I checked with RR Racing, and they helped me figure it out. Apparently some of the older O2 simulators wired directly into the ECU. Look at this ugly mess...



Now I just need to figure out how to return this to stock. Any advice?

Major thanks to RR for helping me diagnose this 1.5 year problem, which I didn’t even pay them for. In return, I shall buy Penskes and their oil cooler. Their a great vendor that helped me out.

 

Wow, that's quite a mess. Since the the stock wires are color coded it shouldn't be that difficult to match them up. I would splice in 2"-3" pieces (to give working room), solder & heat shrink. I know some oppose soldering, however I've never had a problem.

 

Glad you figured it out! Usually when guys have had a similar issue it ended up being the O2 sims with prior vehicles that had headers before the tune was available through RR Racing. Bet you felt better after narrowing it down to the real issue.

 

I knew I was onto something when I suggested a conditioner being installed in your other thread

 

Looks like Sikky unit, you should be able to remove it and just re-connect the wires by their colors.
There should be few cut off wires that are not connected to anything.

 

(Im)Patiently waiting to hear the results. Have had my F for a little over a month, went ~2000km worry free, and then threw a P0156 (O2, Bank 2 Sensor 2), have thrown it 4 times since then at intervals ranging from 50km to 600km. Has Sikky headers, if I read/researched correctly, last owner got the O2 simulator/conditioner from RR. Had the intake apart today to clean the throttle body, MAF, intake tube and cone filter, so also took off the driver-side shield/panel and opened the same fuse box, and found almost identical setup. Only difference was the style that the wiring was spliced in.

Before spotting this thread, next step was to go get the O2 sensor checked (might just do this anyway, my mechanic for the past 20 years told me he isn't interested in helping me maintain this car, so have to make a new friend/mechanic).

EDIT: Forgot to say setup sounds similar; Sikky headers, primary cat delete, Borla everything else.

 

thank god ppe came out with a plug and play one

 

I worked on WC-135Bs in the Air Force. They were built with solder cup cannon plugs in the wiring harnesses. The wires would stress fracture underneath the insulation right where the flux ran up the wire when it was being tinned before being soldered into the plug. I will never ever solder a harness again. The Air Force spent $1.5B rewiring the entire 135 fleet because of this. I'd use bare crimp connectors with a decent tool (like a Daniels unit) and put shrink tubing over the joint if I intended to just put it back together. If I thought I might need to plug something in those wires at some point, I'd put a connector with crimped pins in and call it a day.

 

I know you're anti solder, I understand and even agree with your reasons. However in 45 yrs I've never encountered a problem.

 

Got another tool suggestion that doesn't start at 300 dollars for the bare tool?

 

That is big bux. I'm sure that if you shop around you could find a more reasonably priced tool. We're not working on an aircraft here, so MIL spec or top of the line is overkill IMO.

 

Personally I hate all the normal crimp tools (though, admittedly I've never used a $300 one)... I never feel like I'm getting it tight enough. So I bought a hydraulic one from Harbor Freight for like $50 or $60. Works really well and gets super tight crimps. Its so powerful you can probably overdo it and damage some stuff so you just have to make sure you're using the correct die and take it slow.

I know a lot of people look down on the HF stuff but its served me well for all the hobby mechanic stuff I've done. Only broken a couple things and even then they will replace it in most instances.

Anyways, here is the one I have... obviously can be had cheaper if you use a coupon or wait for it to go on sale: https://www.harborfreight.com/hydrau...ool-66150.html

 

Could be a good tool, but not for the size wires we're talking about here.

 

Agreed. MIL Spec is overblown in most cases anyway. I'd shop around for a decent used head and buy new dies if I planned to do any significant wiring work. Otherwise, I just use bare metal butt connectors with a manual (very low cost) tool and put shrink wrap over when I am done. But I do everything possible to NOT cut wires in the first place. I hate having a hacked up harness, and truthfully it's one of the reasons I buy new cars. No surprise wiring crap from a previous owner who "put it back to stock" by twisting wires and wrapping with vinyl tape. That's way worse than soldering.

 

I’m with you guys on tool cost. Any idea what gauge those wires are? I’ll shop around for an affordable tool. I hate wiring and don’t ever cut wires. This and resisters for race seats are the only wiring mods I will do (and this is a repair).