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Discussion Starter · #1 ·
Hey everyone! I just hooked up a 4 wire 02 sensor to my 1986 dodge charger. When it heats up enough for the 02 sensor to kick in it doesnt seen to be working. B4 i intalled this 4 wire, the pervious owner broke off the 1 wire on the original 1 wire 02 sensor...so when it heated up to go off the 02 to the rpms would drop to around 700..and it would idle rough and stumble.. Now that I have replaced to 02 sensor with a 4 wire...it seems to be doing the same thing...right when she heated up the idle dropped and it was stumbing running rough around 700 rpm...the after a few seconds it kicked off and smooth out at 1000 rpms.

heres how I hooked it up:

The soldered the black signal wire from the 02 sensor to the cars 02 black signal wire that goes to the computer.

then I tapped in to the dg/blk 12v ignition coil wire to the white wire off the 4 wire 02 sensor and it solderd those together. (12v heater)

I just used crimp connecters for the last two wires (grounds) (grey and white) and ran them straigt to battery ground.

thats about it really...can anyone out there tell me why the 02sensor doesnt seem to be working? would be most appreciated! thks all!

-ryan
 

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never use crimps unless you solder them. in time they will fail. have you disconnected the - battery cable to reset your lm.
 

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Discussion Starter · #5 ·
yes. actually right after i hooked up the wires I installed a new optima battery.. so i had it disconnected for around 20 mins.
 

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Discussion Starter · #7 ·
Nope. No lights are on. Its doesn't hurt it soldering the signal wirer does it? Seems like how I hooked it up earier in the post is right? Idk
 

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shouldn't though when I converted my cars to 4 wire I grabbed a 4 wire plug setup from the J-yard and soldered the 4 wire plug to the stock O2 signal wire, then ran the heater and grounds to the appropriate places. You need to solder the grey wire at it's connections all the way to the battery connector. The sensors operate on just a 0-1v scale so every little bit of voltage loss affects how rich or lean the car runs.

Though it doesn't sound much like an O2 issue, more like base idle isn't set properly, but hard to diagnose without hearing the car.
 

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any smoke coming out of the tail pipe. and does it run ok off of idle. if theres no smoke and runs ok off of idle , i would run it and see if it smooths out. give the lm a chance to recalabrate. heres a good sight to go to if you want to no how these things work . MiniMopar Resources
 

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Discussion Starter · #10 ·
Well the car runs perfect. But like I said when the 02s heated up. It drops to the base idle. Its right around 600 to 800.. its runs rough only when its in base idle..and that's ran by the 02. Right. What else do u think it could b?
 

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Discussion Starter · #12 ·
Timings good on her. She runs fantastic. It'll start up perfect around 1200 rpm smooth idle while she's warming. Then it'll gradually idle down smooth to 1000 rpms. Then a lil while later when its heated up the rpms drop to 600 to 800 with a rough idle. Which would seem when the o2 should be working. Like I said b4 when I got the car. The previous owner broke the 1 wire off the original o2 sensor. So I installed a new 4 wire o2. Just like I describer above. Its idling the same as when the 02 wasn't hooked up. Idk.. if the ignition timing was off would it idle perfect at 1000 rpms but rough at 800?
 

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The O2 is a fuel trimmer.
Once the car is goes into closed loop(Time and Temp) the controller is paying attention to the O2 and makes minor fuel corrections.
The Map sensor is dominant fuel control and the O2 brings the fuel calculations into a tighter range for fuel economy and emissions.
The reason HO2S are used is to keep the O2 hot so the vehicle does not constantly go in and out of closed loop operation when exhaust flow slows down and O2 temp drops.

First off it sounds as if your idle speed is low which can be caused by base idle being incorrect or because of another issue.
Have you checked all of your basics, Engine Vacuum, Ignition System, Cam/Ignition Timing, PCV/Vacuum system, etc.
If you want to know what is going on in your engine as far as rich/lean tap into the O2 signal line with a digital voltmeter.
When the vehicle is warm voltage should be constantly crossing above/below .450 volts.
The crosscounts should get faster as rpm is increased.
If voltage....
Stays at .450 volts there is a problem with the O2.
Is latched or hangs above .450 volts you are lean.
Is latched or hangs below .450 volts you are rich.

Again all basics must be right before you can expect the fuel control system to operate correctly.
 

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Discussion Starter · #14 ·
alrite ill check the ignition timing first... on this one is that with just a timing light hooked to the #1 cylinder? what degrees is it supose to be at. also ill check the cam timing soon to. my timing best is covered in oil. idea where the leak could be?
 

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Actually the cam timing should be checked before checking ignition timing.
Let me know when you are ready to check cam timing and I will show you a foolproof way to be sure you are at centerline of the head.

Yes the timing light gets connected as you normally would.
The procedure is different.
Warm engine to normal operating temp.
With the engine running disconnect the coolant temp sensor connector.
The power loss/check engine lamp will illuminate and the cooling fan will cycle on.
Now the vehicle is in failure mode and the controller stops spark advance and puts timing at base.
Shine the light at the timing marker on the bellhousing.
Timing should be 12 degrees BTDC +/- 2 degrees.
If timing is incorrect loosen the distributor hold down and turn the distributor until timing is in specs.
Tighten the distributor, shut the engine off and then reconnect the CTS.

As far as the oil leak.
Remove the upper timing cover and inspect the front cam seal, valve cover and cylinder head for a leak.
The oil could also be coming from the bottom from the front crank seal.
If there is a lot of oil present clean the area's with brake cleaner so you can see where it is coming from.

 

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Discussion Starter · #16 ·
Ok will do. I checked the head cam and valve cover and they r dry. It looks to me like its the front main leaking. Wuts the correct proceedure to replace that front main.? Thks!
 
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