jeffswav

Anyone out there using EGT gauge or Oxygen sensors to adjust their Carb or EFI? What works best for detecting engine problems?

Wobble

I use 2 egt probes and plug readings. Works well to avoid over lean situation at WOT and partial throttle. In my boat I look for 1150-1200 max, which seems to be good safe temp for a boat motor with iron heads.

RumRunner

O2 is going to be more accurate than EGT. You can have a high EGT being rich or lean. With Lambda it's giving you accurate A/F ratio.

Mike Paula

Be careful there, a dual stage lambda sensor is only accurate from lambda= .9 to 1.0 out of that range it falls off. Now a wide band sensor (controlled sensor) it is very accurate for monitoring Air fuel mixtures. There is a lot of companies out there making stand alone systems with the wide band o2’s
Mike

RumRunner

If you use O2 you need to go Wide Band.

Wobble

I have bungs for o2 sensors in both headers in dry jacketed area, but the sensors corrode and fail in short order.

Mr Gadgets

I was just looking at the LC-1 from Inovative Motorsports today. It is a controller in a cable and puts out an analog or digital signal. Pretty cool! I think I will have to have one for the new fuel injection I am building..

Anyway, there is a video clip on that model and it says that the Bosch 4.2 is good for 1300* gas temp and 900* pipe temp. If you have more than that.. they sell an insulator that prevents eat from eating them up.. I know that leaded gas and oil and other things can contaminate them, but I didnt realize they had heat limits. You would think something in the exhaust pipe would handle what ever you could throw at it.. So I learned something today.. It was a good day!!

I ran thermocouples a few years back and drill a hole right at the exhaust flange. I would see some pretty high temps, but I know placement was an issue. If it runs too rich it can go hot and lean well the pistons tell you that after they go mush... But it is all relative! If you gauge tells you the upper limit accurately then you can go by that..

Best way to figure it all out is burn down a couple of motors and then you will know the limits.. *S*.. just kidding.. I am hoping the WB O2 is the way to go. Problem I might have is CMI welded the bung in the colletor right next to the four incoming pipes, instead of down steam a bit. I have no idea how that may effect the readings. I have been running narrow band sensors, one in each pipe and with Cutler self tunning EFI would see one side go lean a bit every now and then. But never burned a piston.. We'll see what happens when I get the laptop out and try it myself...

Good luck with your project Jeff.. I think the O2 is the easier way to go..

Dick

jeffswav

I currently have Eddie Marine Exhaust with the long stainless risers. I had them put oxygen sensor bungs 19mm right before the elbow in the risers. I have a Holley MPI kit with their laptop programmable ECU. I have never been able to calibrate it correctly with the O2 sensor. They have always read low. Before switching to the EMI's I had a oxygen sensor mounted about 3 inches away from an exhaust port on the stock manifolds. Could this have damaged the sensors? This was the location Holley recommended to put them on the stock manifolds. When I called to inquire about my O2 readings not reading correctly they wanted to sell me the wide band kit for additional $$. I was thinking about installing EGT's and setting it off of the gauge. Any suggestions?
Thanks,
Jeff

phughes69

Regular O2 sensors are only accurate at 14.7, past that their readings are NOT very accurate. Wide band is the way to go. At my work we sometimes dyno motors with a wide band sensor in each header tube. (try tuning that)

Mr Gadgets

jeff.
I would imagine that you could have damaged your NB sensor, but I dont know that for sure. But Phughes is right.. the NB acts as a switch that turns off and on at the 14.7 point. I used analog gauges and considered them as not accurate and not the best indicator of what is going on. The WB is much more accurate if the contoroller maintains the proper heat and is calibrated, at least that is what Inovative implies and their unit does this. How much did Holley want for the WB conversion? The LC-1 is $200 and includes the sensor and will connect to various inputs on ECU's.. I think Holley is on thier list.. Take a look at it.. http://www.innovatemotorsports.com/products.php
They have a wide range of products used to get a handle on whats happening in the motor.. I am leaning toward the LC-1 to add to my Megasquirt ECU, where I have the option to run in closed loop or not. I think I may tune it and either leave it in and keep an eye on it with my guages or use it to tune my buddies boats..
Another route to go, is a thermocouple and a hand held meter. I have seen the two input hand held meters as cheep as $90.. So if you did want to check your temps, that would give you some idea of temp, but I think the money is better spent on the WB O2...
Hope this helps...

Dick