Scary low O2 #'s at WOT

[cathan]

Anyone else had problems with Denso heated O2 sensors?

I bought three for a "good deal", the first on fried out after 3 months, and now I am getting 3-4 degrees of retard on shifts with audible knock.

When I push recall on the scanmaster the low O2 reading is like 10-50.......that cannot be right!?

Don't want to kill this machine.....is there a quality heated sensor out there?

 

[dpasadena]

Anyone else had problems with Denso heated O2 sensors?

I bought three for a "good deal", the first on fried out after 3 months, and now I am getting 3-4 degrees of retard on shifts with audible knock.

When I push recall on the scanmaster the low O2 reading is like 10-50.......that cannot be right!?

Don't want to kill this machine.....is there a quality heated sensor out there?

Switch to the regular Denso sensor. They seem to last a long time

 

[Chuck Leeper]

When all this is going on, what's the fuel psi doing??
Using any coolant?

 

[cathan]

When all this is going on, what's the fuel psi doing??
Using any coolant?

Let me first state for clarity that the very low O2 #'s I mentioned are when I push both buttons on the scanmaster to get the lowest O2 with the MPH.

I have a FP gauge on the hood, it is reading the steady 1 psi increase per lb of boost as it should.

Not using any coolant......

The other change I made which could be a factor: I changed the spark plugs from 42's to 44's to pass emissions. Could this be causing knock?

Other ideas: lousy pump gas, bad O2 sensor, or are the 50# injectors possibly just not enough for this motor at WOT?

 

[The Darkside]

I was experiencing the same symptoms & it was a bad o2.... Installed a new o2(reg denso) & everything is great again.

 

[~JM~]

Switch to the regular Denso sensor. They seem to last a long time

X2!

I just replaced mine & now my readings are much more stable.

Good luck
~JM~

 

[Mr.Spool]

lower the boost if you dont want to hurt it,knock is no good.switch the o2 sensor,should be logging things and not guessing.a wideband o2 is great for tuning.

 

[cathan]

X2!

I just replaced mine & now my readings are much more stable.

Good luck
~JM~

Thanks.....and final question. The 4 wire heated has been in so long ......how do I switch back to the stock wiring? Do I simply remove the Casper "plug and play" wiring and what I need is still there?

 

[jimmymack87gn]

probably a good idea to switch back to 42's also

 

[cathan]

probably a good idea to switch back to 42's also

Why?

 

[Ttype6]

Why?

Your o2 is probably bad,however it isn't the cause of your audible knock and installing a new one won't fix your knock problem. You either have a fuel supply problem,too much boost for your octane,or too much timing.
The hotter 44 plugs are a hot spot in the combustion chamber. A cooler plug won't absorb as much heat.

Thanks.....and final question. The 4 wire heated has been in so long ......how do I switch back to the stock wiring? Do I simply remove the Casper "plug and play" wiring and what I need is still there?

Correct.

 

[cathan]

Your o2 is probably bad,however it isn't the cause of your audible knock and installing a new one won't fix your knock problem. You either have a fuel supply problem,too much boost for your octane,or too much timing.
The hotter 44 plugs are a hot spot in the combustion chamber. A cooler plug won't absorb as much heat.


Correct.

Thanks guys.

Jimmymack87, sorry, I thought you were referring to injectors, but I see you meant the plugs. That is why I asked "why"? Duh.....

T-type 6,

I understand and agree with you that the o2 is not the sole culprit.

I have had this car long enough to know heat and octane are a factor as well.

She always starts to act up when it gets warm outside, and I'll bet if I put some race gas in it would go away.

Thanks for the tip on switching back to the colder plugs. I had 42's in it before.

Any opinion as to which is better for my combo.....42's or 43's?

 

[Ttype6]

Thanks guys.

Jimmymack87, sorry, I thought you were referring to injectors, but I see you meant the plugs. That is why I asked "why"? Duh.....

T-type 6,

I understand and agree with you that the o2 is not the sole culprit.

I have had this car long enough to know heat and octane are a factor as well.

She always starts to act up when it gets warm outside, and I'll bet if I put some race gas in it would go away.

Thanks for the tip on switching back to the colder plugs. I had 42's in it before.

Any opinion as to which is better for my combo.....42's or 43's?

How much boost are you running?

 

[cathan]

How much boost are you running?

The TT street chip is set for 16-18 psi, but I turn it down to 15 usually for street use. (especially if I see retard......) But it would be nice to use a bit more.


And I did put the regular O2 sensor in ........what a difference!!!!!

Stable O2 readings up at ~800, where before I could not get more than 750-760 at WOT no mater what I did with the FP.

Not sure if the wiring on the heated O2 had a problem or what......it was old.

 

[cougarmtr]

when you put in the regular o2 sensor did you just take the casper 4 wire heated adapter off? was any other wiring adapters needed for the non heated sensor? having the same issue you had. thanks.

 

[Ttype6]

The TT street chip is set for 16-18 psi, but I turn it down to 15 usually for street use. (especially if I see retard......) But it would be nice to use a bit more.


And I did put the regular O2 sensor in ........what a difference!!!!!

Stable O2 readings up at ~800, where before I could not get more than 750-760 at WOT no mater what I did with the FP.

Not sure if the wiring on the heated O2 had a problem or what......it was old.

You shouldn't be seeing retard at that boost level. Have you tried adding fuel. I would suggest an additional 4%.

 

[cathan]

when you put in the regular o2 sensor did you just take the casper 4 wire heated adapter off? was any other wiring adapters needed for the non heated sensor? having the same issue you had. thanks.

Yes, if you remove the plug and play harness, you will find the proper connectors to replace the stock one with out cutting any wires.

Check out the casper electronics page , it has a diagram on a pdf which I printed up , it was quite helpful.

The only extra wire I found in the conduit was a green one which I think connects through the firewall to draw the current for the heated part.
I left that one alone....

Hope that helps....

 

[cathan]

You shouldn't be seeing retard at that boost level. Have you tried adding fuel. I would suggest an additional 4%.

Thanks, I'll try that.

But I think first switch to the colder plugs again.

Again, any thoughts on 43's vs. 42's? I haven't raced the car in years, and if it makes a difference I an in colorado at 5300 feet.....less air to mix with fuel!

 

[Ttype6]

Thanks, I'll try that.

But I think first switch to the colder plugs again.

Again, any thoughts on 43's vs. 42's? I haven't raced the car in years, and if it makes a difference I an in colorado at 5300 feet.....less air to mix with fuel!

I've never used anything other than 43s.