check engine light after long tube install

tomazzzo · 02-16-2001, 03:01 PM

I installed bbk ceramic long tubes and the shorty off road h pipe in my 93 GT. I had to extend the wiring for the o2 sensors by splicing in wire to my original units. H had to run around with no mufflers for a few days because the h pipe was defective and needed to be fixed(strike 2 for bbk). It seemed that once the car got to full operating temp, the check engine light would come on and not go off.

once I got my hpipe fixed, and put on mufflers, the check engine light seemed to stay off for 3 days, but today it poured down rain, and it went on again.

I thought that the o2 sensors would not throw a check engine light. I believe the way the o2s work, is that the car runs lean until they heat up, then the computer includes their input in the mix of fuel.

Is there any way to strap the o2s and eliminate them all together?

thoughts anyone?

Thanks in advance

------------------
93Reef Blue GT
BBK Ceramic Long Tubes
Flowmaster 2ch
Pro 5.0 Shifter

Forcedpower · 02-16-2001, 03:39 PM

My check engine light has never came on. I installed the same longtubes as you only I used an x-pipe. I don't like the idea of cutting the 02 wires to make them longer all you had to do was re route the wires for the 02's to reach.

------------------
'93 LX 425rwhp/410rwtq

84_GT350 · 02-17-2001, 03:27 AM

That's just one of those Mustang mysteries. Same reason some cars have problems after springs....some don't. It's weird. In any event, my guess is that the O2 sensors aren't heating up enough since the longtubes are placing them too far downstream in the exhaust.

------------------
1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s

SaleenGTS · 02-17-2001, 10:17 AM

My bud bought the BBK's...loved them.

He had to totally disconnect all ov his emissions(the pipe behind the motor too)since the BBK h-pipe doesn't have a smog pipe going back up to the motor. Did you do this?

------------------
Dustin
1993 Cobra #1926

Bassani Full lengths,Bassani short X-pipe, American thunder Cat back, 3.55's. More to come...

2FastLX · 02-17-2001, 10:27 AM

I have the MAC L/T's and mine just started doing the same thing lately. It was fine for a few weeks after the install and just started doing it recently. How old are your O2 sensors? I was thinking mine was doing it because I used the old O2's and one of them was ready to come apart.

And BTW, I've heard that Auto Zone and Pep Boys are selling O2 sensors with longer wires for long tube headers now.

------------------

tomazzzo · 02-19-2001, 10:03 AM

Yes, I disconected the smog pump, and plugged the vaccuum lines that go to the two diafragms on the smog plumming.

I tried the long wiring o2s from auto zone, and they were short by about 3-5 inches. I keep hearing different things about cutting the wiring loose from the harness, but I think I need to get the extensions from Downs ford, and get new sensors.

I gather that the 02s will trip the check engine light then?

Thanks,

Thomas

------------------
Thomas Monahan
Shreveport, La.

93Reef Blue GT
BBK Ceramic Long Tubes
Flowmaster 2ch system
Pro 5.0 Shifter

Capri306 · 02-19-2001, 10:45 AM

Just a thought, guys. I think it was Rebel who gave us that little 'tech info' on off-road H-pipes and how they affect HEGO sensors. I welded in the 'stops' he showed us how to make, and it REALLY made a difference on the low and high ends for me. They're basically dome shaped pieces of 16ga sheet metal welded into the H-pipe three inches after the HEGOs to create just enough backpressure for the sensors to get a reading. Mebbe this is what we need on the full lengths??? I want to know, too, since I'm going to be putting BBK full lengths on my Notch with the rest of my planned mods this spring. Oh, if your wiring is even a little messy, or not connected completely, yes it will throw a code. I had a little corrosion in one plug and it threw some bad signals. Hope this helps.

------------------
Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch

S Howard · 02-19-2001, 05:23 PM

If the light came on during rain sounds like the splice was not weatherproof/spliced properly. Additionally, the length of the wire could effect the temperature reading.

tomazzzo · 02-19-2001, 05:49 PM

Thanks guys,

I just ordered some o2 extensions from downs ford today...I will get 2 new sensors, and replace the old 02s and see what happens.

------------------
Thomas Monahan
Shreveport, La.

93Reef Blue GT
BBK Ceramic Long Tubes
Flowmaster 2ch system
Pro 5.0 Shifter

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02-16-2001, 03:01 PM	#1
tomazzzo Registered Member Join Date: Feb 2001 Location: shreveport, La. USA Posts: 27	check engine light after long tube install I installed bbk ceramic long tubes and the shorty off road h pipe in my 93 GT. I had to extend the wiring for the o2 sensors by splicing in wire to my original units. H had to run around with no mufflers for a few days because the h pipe was defective and needed to be fixed(strike 2 for bbk). It seemed that once the car got to full operating temp, the check engine light would come on and not go off. once I got my hpipe fixed, and put on mufflers, the check engine light seemed to stay off for 3 days, but today it poured down rain, and it went on again. I thought that the o2 sensors would not throw a check engine light. I believe the way the o2s work, is that the car runs lean until they heat up, then the computer includes their input in the mix of fuel. Is there any way to strap the o2s and eliminate them all together? thoughts anyone? Thanks in advance ------------------ 93Reef Blue GT BBK Ceramic Long Tubes Flowmaster 2ch Pro 5.0 Shifter

02-16-2001, 03:39 PM	#2
Forcedpower Registered Member Join Date: Aug 1999 Location: Charlottesville, Va, USA Posts: 328	My check engine light has never came on. I installed the same longtubes as you only I used an x-pipe. I don't like the idea of cutting the 02 wires to make them longer all you had to do was re route the wires for the 02's to reach. ------------------ '93 LX 425rwhp/410rwtq

02-17-2001, 03:27 AM	#3
84_GT350 Registered Member Join Date: Apr 1999 Location: Overland Park, KS, USA Posts: 1,631	That's just one of those Mustang mysteries. Same reason some cars have problems after springs....some don't. It's weird. In any event, my guess is that the O2 sensors aren't heating up enough since the longtubes are placing them too far downstream in the exhaust. ------------------ 1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s

02-17-2001, 10:17 AM	#4
SaleenGTS RICE taste like Chicken Join Date: Jun 2000 Location: Edmond, OK Posts: 687	My bud bought the BBK's...loved them. He had to totally disconnect all ov his emissions(the pipe behind the motor too)since the BBK h-pipe doesn't have a smog pipe going back up to the motor. Did you do this? ------------------ Dustin 1993 Cobra #1926 Bassani Full lengths,Bassani short X-pipe, American thunder Cat back, 3.55's. More to come...

02-17-2001, 10:27 AM	#5
2FastLX The Photoshop Guru Join Date: Feb 2001 Location: Mecca, Indiana Posts: 1,419	I have the MAC L/T's and mine just started doing the same thing lately. It was fine for a few weeks after the install and just started doing it recently. How old are your O2 sensors? I was thinking mine was doing it because I used the old O2's and one of them was ready to come apart. And BTW, I've heard that Auto Zone and Pep Boys are selling O2 sensors with longer wires for long tube headers now. ------------------

02-19-2001, 10:03 AM	#6
tomazzzo Registered Member Join Date: Feb 2001 Location: shreveport, La. USA Posts: 27	Yes, I disconected the smog pump, and plugged the vaccuum lines that go to the two diafragms on the smog plumming. I tried the long wiring o2s from auto zone, and they were short by about 3-5 inches. I keep hearing different things about cutting the wiring loose from the harness, but I think I need to get the extensions from Downs ford, and get new sensors. I gather that the 02s will trip the check engine light then? Thanks, Thomas ------------------ Thomas Monahan Shreveport, La. 93Reef Blue GT BBK Ceramic Long Tubes Flowmaster 2ch system Pro 5.0 Shifter

02-19-2001, 10:45 AM	#7
Capri306 Moderator Join Date: Sep 1998 Location: Grand Rapids, Michigan, USA Posts: 1,001	Just a thought, guys. I think it was Rebel who gave us that little 'tech info' on off-road H-pipes and how they affect HEGO sensors. I welded in the 'stops' he showed us how to make, and it REALLY made a difference on the low and high ends for me. They're basically dome shaped pieces of 16ga sheet metal welded into the H-pipe three inches after the HEGOs to create just enough backpressure for the sensors to get a reading. Mebbe this is what we need on the full lengths??? I want to know, too, since I'm going to be putting BBK full lengths on my Notch with the rest of my planned mods this spring. Oh, if your wiring is even a little messy, or not connected completely, yes it will throw a code. I had a little corrosion in one plug and it threw some bad signals. Hope this helps. ------------------ Capri306, Moderator, The Mustang Works Online 1979 Mercury Capri, 5.0L -- C4 -- 2.73 1987 Mustang LX Notch

02-19-2001, 05:23 PM	#8
S Howard Registered Member Join Date: Jun 2000 Location: Orlando, FL Posts: 195	If the light came on during rain sounds like the splice was not weatherproof/spliced properly. Additionally, the length of the wire could effect the temperature reading.

02-19-2001, 05:49 PM	#9
tomazzzo Registered Member Join Date: Feb 2001 Location: shreveport, La. USA Posts: 27	Thanks guys, I just ordered some o2 extensions from downs ford today...I will get 2 new sensors, and replace the old 02s and see what happens. ------------------ Thomas Monahan Shreveport, La. 93Reef Blue GT BBK Ceramic Long Tubes Flowmaster 2ch system Pro 5.0 Shifter