04 MSM: car has 3 o2 sensors, which is hydra?

Thread Tools
 
Search this Thread
 
Old 05-01-2013, 02:24 PM
  #1  
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 10,917
Total Cats: 2,201
Default 04 MSM: car has 3 o2 sensors, which is hydra?

Like it says...

I could just try and trace everything, but that might be a problem since it seems the wiring from two of the sensors goes to the same drilled hole in the body that's been filled/sealed with a bunch of silicone goop of some sort.

I'm fairly certain it's not the one post-cat.

Sooo.... o2 housing? Or pre-cat?

Just hoping someone might know off the top of their head.


My next question is: Do i even need any of these o2 sensors? (Besides the Hydra wideband, of course.) I can't fathom why this car has 3 friggin o2 sensors.
concealer404 is offline  
Old 05-01-2013, 02:31 PM
  #2  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

1 pre cat, one post precat, one post second cat.
Braineack is offline  
Old 05-01-2013, 02:32 PM
  #3  
Elite Member
iTrader: (2)
 
thenuge26's Avatar
 
Join Date: Aug 2012
Location: Indianapolis
Posts: 3,267
Total Cats: 239
Default

1 for the hydra, 1 for the gauge, and the original post-cat sensor to make sure the cat is still working? I assume that is what the post-cat one is at least.
thenuge26 is offline  
Old 05-01-2013, 02:40 PM
  #4  
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 10,917
Total Cats: 2,201
Default

Originally Posted by Braineack
1 pre cat, one post precat, one post second cat.

......

Right... but on a Hydra car do i A) need all 3, and B) which one should be the wideband?

Originally Posted by thenuge26
1 for the hydra, 1 for the gauge, and the original post-cat sensor to make sure the cat is still working? I assume that is what the post-cat one is at least.

No gauge. Hydra can't output to a gauge because HERP DERP. One of the 3 is Hydra's wideband (At least i think...), and the other two are stock things that likely aren't doing a damn thing anymore.


Or... there IS an un-used bung on the exhaust, and there's a sensor of some sort in the trunk of the car that was there when i bought it. Maybe that's a something? I don't ******* know. I'd think with a standalone i'd only need 1 sensor, not 3, 4, or 5.
concealer404 is offline  
Old 05-01-2013, 04:40 PM
  #5  
Elite Member
iTrader: (2)
 
thenuge26's Avatar
 
Join Date: Aug 2012
Location: Indianapolis
Posts: 3,267
Total Cats: 239
Default

Originally Posted by concealer404
No gauge. Hydra can't output to a gauge because HERP DERP. One of the 3 is Hydra's wideband (At least i think...), and the other two are stock things that likely aren't doing a damn thing anymore.
Did it ever have a gauge? Because if it did, then it would have needed a second wideband. That would at least explain one of the extras.
thenuge26 is offline  
Old 05-01-2013, 07:14 PM
  #6  
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 10,917
Total Cats: 2,201
Default

Never had a gauge. I called Jeremy and he said it's the one after the o2 housing in the downpipe, pre-cat.

Seems I gotta pin the plug and run it to the ecu.

Suppose I should have asked him if I can get rid of the others.
concealer404 is offline  
Old 05-02-2013, 01:03 AM
  #7  
Junior Member
 
Canyonfive's Avatar
 
Join Date: Oct 2012
Posts: 68
Total Cats: 4
Default

My understanding is that pre 2.7 its just the front and pre-cat (Wideband) but that the 2.7 uses all 3?
Canyonfive is offline  
Old 05-05-2013, 11:29 PM
  #8  
Newb
 
cbaylis77's Avatar
 
Join Date: Feb 2012
Location: Clinton MA
Posts: 5
Total Cats: -1
Default

I'm also figuring this out as I bought my car already running a Hydra 2.5 and I just "upgraded" to 2.7. Now I find out my wideband is missing!
Concealer: of your two front O2s one should be a 5 wire wideband for the Hydra and one the stock 4 wire narrow band.The after cat O2 does nothing. My guess is that the previous owner left both stock O2s incase they had to switch back for emissions.
cbaylis77 is offline  
Old 05-06-2013, 04:53 PM
  #9  
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 10,917
Total Cats: 2,201
Default

Originally Posted by cbaylis77
I'm also figuring this out as I bought my car already running a Hydra 2.5 and I just "upgraded" to 2.7. Now I find out my wideband is missing!
Concealer: of your two front O2s one should be a 5 wire wideband for the Hydra and one the stock 4 wire narrow band.The after cat O2 does nothing. My guess is that the previous owner left both stock O2s incase they had to switch back for emissions.
Yeah, sorry i should have updated.

I called Jeremy and the Hydra wideband is the one after the one in the o2 housing.

I'm pretty sure you're right as to what the previous owner was doing. The stock ECU is still mounted in the car, and he had the MAF hooked up as well when i bought the car, stock injectors in the trunk.
concealer404 is offline  
Old 05-06-2013, 10:46 PM
  #10  
Newb
 
cbaylis77's Avatar
 
Join Date: Feb 2012
Location: Clinton MA
Posts: 5
Total Cats: -1
Default

It's always fun when you're trying to figure out what the previous owner was doing. Better to have too many sensors than not enough! I never got the Hydra O2 with the car. I thought I could switch my AEM wideband to the Hydra but it's a different plug.
cbaylis77 is offline  
Old 05-07-2013, 01:57 AM
  #11  
Junior Member
 
Canyonfive's Avatar
 
Join Date: Oct 2012
Posts: 68
Total Cats: 4
Default

Originally Posted by cbaylis77
It's always fun when you're trying to figure out what the previous owner was doing. Better to have too many sensors than not enough! I never got the Hydra O2 with the car. I thought I could switch my AEM wideband to the Hydra but it's a different plug.

I put on the stock WB connector with my WB perhaps its a compatible WB?
Canyonfive is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
satisfied
MEGAsquirt
144
11-05-2018 04:05 PM
StratoBlue1109
Miata parts for sale/trade
21
09-30-2018 01:09 PM
Greasyman
General Miata Chat
2
09-28-2015 10:44 AM
AlwaysBroken
Engine Performance
4
09-04-2015 01:35 PM



Quick Reply: 04 MSM: car has 3 o2 sensors, which is hydra?



All times are GMT -4. The time now is 12:35 PM.