O2 sensor issue

Topic: O2 sensor issue (Read 3329 times) previous topic - next topic

O2 sensor issue

April 17, 2012, 06:16:57 PM

'88 Sport, '89 5.0HO from a Stang, speed density, T5...

The issue is that since I installed the new BBK X pipe yesterday, and slapped in a couple of used O2's I had laying around, the car won't run, or barely even start with them connected. If I unhook them, it runs great, idles great, but of course smells like it's a little rich.

I know I need to pull codes, but would bad O2 sensors cause this?

When I had the Stang's H pipe in there, it never ran like that with the sensors connected. (one of the O2's in the x pipe is one from that Stang H pipe..)

O2 sensor issue

Reply #1 – April 17, 2012, 11:15:27 PM

If one's real dirty and the other one is new there could be an issue, but the old one would have to be fouled REALLY bad....I HIGHLY doubt it would cause a condition where it won't run at all though.

How is the car on a cold start after sitting overnight?
Also, is there a point once it's warmed up where it will even out and run fine again?
How long can you keep it running with the o2's hooked up?

O2 sensor issue

Reply #2 – April 21, 2012, 01:25:33 PM

Any update?

O2 sensor issue

Reply #3 – April 22, 2012, 01:02:35 PM

I still haven't gotten codes from it...it seems to run pretty fine with the O2's disconnected. One of them was on the car's original Y pipe (err, what was left when I bought it) and the other was in a box in my bin 'o Bird parts, so who knows what shape it's in.

To answer your questions:
How is the car on a cold start after sitting overnight?
Also, is there a point once it's warmed up where it will even out and run fine again?
How long can you keep it running with the o2's hooked up?

Starts great...IF the O2's aren't hooked up.
Same as above
Not at all....IF it will even start.

Will pull codes later today, or tomorrow and reply back.
I've got 3 vehicles sitting here, one won't start, one will only self-propel in the first 2 gears, and one runs fine. (Hint: it's got a 5.0 under the hood..)

Got to pull the Opti Spark off the family car, it's apparently went bad now. I have much love for GM's LT1 engine. Not.
Also the Chevy truck has a bad transmission. FML.

Anyhow, I'll get codes sometime soon, but right now, it runs as long as they're both not hooked up. Weird. Runs great w/o them, surprisingly.

O2 sensor issue

Reply #4 – April 22, 2012, 09:26:42 PM

Without them it's going into fmem mode. It should do that under most cirspoogestances if they were hooked up and had an issue. It's very odd that it gives you a cold start issue with them hooked up too. Something's funky in the harness is my guess. Do you have another on hand you could swap it with?

O2 sensor issue

Reply #5 – April 22, 2012, 11:03:28 PM

Yeah, I have another engine harness. FWIW, I had one of these O2 sensors in my cut-up Stang H pipe when I first put the HO engine in the 'Bird. NO issues then. It wasn't till I changed the dash harness, then put in the BBK X pipe and the O2 sensors that the issue came up. One was in the car before, the other came from a Ford truck. (5.0)

The only things that have changed has been the dash harness and the exhaust pipe. Surely neither of those would affect an oxygen sensor..?

I know it's weird that with them hooked up, a cold start issue is had. At idle and WOT it should go in closed loop, right?

O2 sensor issue

Reply #6 – April 23, 2012, 12:22:25 AM

Quote from: ThunderbirdSport302;387540

Yeah, I have another engine harness. FWIW, I had one of these O2 sensors in my cut-up Stang H pipe when I first put the HO engine in the 'Bird. NO issues then. It wasn't till I changed the dash harness, then put in the BBK X pipe and the O2 sensors that the issue came up. One was in the car before, the other came from a Ford truck. (5.0)

The only things that have changed has been the dash harness and the exhaust pipe. Surely neither of those would affect an oxygen sensor..?

I know it's weird that with them hooked up, a cold start issue is had. At idle and WOT it should go in closed loop, right?

Here's a page describing all the different EEC-IV strategies. I see they renamed the website. http://oldfuelinjection.com/?p=64

Also:

And an old thread that may steer you in the right direction.... http://www.foxtbirdcougarforums.com/showthread.php?21560-White-10-pin-connector...

O2 sensor issue

Reply #7 – April 23, 2012, 03:23:25 AM

That old thread you linked has been most valuable. I suppose I should mention my car seems to be running rich. The exhaust burns my eyes, but doesn't seem gassy, like it's not burning all the fuel.

it, I AM going to pull codes once it's daylight.

Paul, it's a shame your pics in the old thread don't show up. I feel those would rather helpful, since my Sport WAS an auto, but now has a Mustang 5.0 and T5. I also run a DA1 EEC.

I don't recall any ring terminals for grounds on the back of either head, but I'll give everything a good look tomorrow to see if I've missed anything. Definitely has me wondering now..

O2 sensor issue

Reply #8 – April 23, 2012, 06:33:39 AM

The O2 sensors should not cause a NO START???? I have changed many defective ones that illuminated the SES light but the customers still drove the vehicles. The ECM should substitute a limp in reference. just saying. Are you sure the O2 sensors are pinned out the same??? Also pin 49 should be grounded. Normally on the V8 it is near the DIZZY. I am assuming you have 3 wire units. Are they wired correctly. Clearly you have a wiring issue. As the O2 sensors dont work until they light off. Good luck and i would check wiring and the O2 sensors for crossed battery or ground internally or externally. Sounds like the O2 sensors are killing the 5 VOLT REFERENCE. That is a simple thing to check. I am thinking you have a cross between and signal lead. I would assume the no start trouble shooting should be checked as a no spark or no injector pulse for starters. If in fact the O2 are shorted to battery that would indicate a very rich condition and a no start. Fascinating trouble . Once again good luck.

Note their are kits to eliminate the OPTI SPARK SYSTEM.

O2 sensor issue

Reply #9 – April 27, 2012, 01:35:38 AM

Most of the pics were simply moved/deleted from my photobucket account. I believe they ALL came from http://www.veryuseful.com. They have a wiring section.
I going to quote one of my old posts and throw the photos in with it.

Quote

Here's the main harness and engine harness as it sits in a MUSTANG

Now here's the MUSTANG HEGO harness:

That HEGO harness has some differences compared to the one in my car......

1) I have ground wires on each o2 connector. That one does not.
2) The wire colors in the picture do not correspond to what I see under my hood
3) That wire harness has a part # beginning with E8......

My hypothesis:

There are TWO (2) different HEGO harnesses......
Depending on which one was installed -- which was most likely through the vehicle type -- foretold whether or not the orange ground in the main engine harness was cut or hooked to the block. I realize there are different part #'s for auto and manual cars, but from what I understand, the difference is the main connector -- it varies from auto to manual cars.....

See here:

Take note of the black connector -- the one I have. The only one with a HEGO ground wire provision

I suppose my original post should read that there are THREE different HEGO harnesses and TWO different engine harnesses. IIRC -- the HEGO harness green connector was for Automatic Mustangs and the brown was manual....

Now I ask....Which engine harness/main underhood harness/HEGO harness do you have?

Quote

Note their are kits to eliminate the OPTI SPARK SYSTEM.

Have any links or info on that? I have a friend who would be most grateful.