Oil Pressure Gauge and wideband A/F

Post by **jtp** » 03 May 2012, 00:03

I wasn't going to fool with these right now until I found out you need the intake mani off to do oil pressure. Not a huge deal but I will have it off anyway in a few weeks so I might as well do oil pressure then, and if I'm gonna do that I might as well fill out a three-gauge pod with the A/F as I was planning on doing that eventually anyway. Combined with my scangauge obsession I'll have everything monitored and can start modding with a better conscience.

Anyway, here is what I've found for oil pressure. The metric kit on that page includes the M12x1.5 adapter I have read I will need. I'm not sure if it will allow me to retain the CEL connection but I'm fine with that.

Here's what I'm leaning toward for wideband A/F. Looks like they just replace your front O2 sensor I guess.

I have zero experience installing either of these types of gauges so is it really as easy as ordering these kits and going from there are am I missing some huge complication?

Post by **jblackburn** » 03 May 2012, 08:16

I foresee one thing you're overlooking.

A wideband O2 sensor is a great device, but it talks to the computer in a different way than the Volvo is set up for [with a narrowband sensor].

A narrowband sensor tells the computer whether the air/fuel mix is above a certain threshold (usually 14.7) by signaling back on a single wire (+ or -). It does that quickly, but it's dumb in the way that it ONLY does that. (Because it can't tell what the mix is, at wide-open throttle, the car defaults to a value that does not take the O2 sensor into account for air/fuel mix calculations anymore. This is why you will see cars blow out black smoke under hard acceleration sometimes)

A wideband sensor can tell the computer exactly HOW MUCH it's above or below some pre-determined threshold. This is great for tuning or maximizing fuel economy, but two wires report back to the computer, and it reads the values in a different way.

To my knowledge, there's no way to get the computer in these cars to interpret those values.

Post by **jtp** » 03 May 2012, 09:12

So if you install a wideband O2 sensor you basically take the front O2 sensor calculation totally away from the ECU whereas at least with the narrowbond the ECU is incorporating that info most of the time (when your not @ WOT)?

I'm assuming that means you throw a CEL with a wide-band sensor?

I would rather my computer have some good info and me have none than the other way around. Plus, I can't live with a CEL on permanently. I think I will just do the oil pressure sensor for now and leave a spot in the three-pod gauge as a project for a later time.

As an added bonus, the oil pressure sensor is way cheaper than the wideband A/F so this will make the bank account a little happier.

Thanks jblackburn, I would have been pretty upset to have found this out after spending the money and doing the work to install the wideband A/F.

Post by **jtp** » 03 May 2012, 09:23

Maybe I could custom install the wideband into a downpipe by having a machine shop drill in an extra hole and add the appropriate thread size. That way I would be adding the sensor without taking the narrowband away. I could just wire the wideband to the gauge so the ECU would be in the same situation it was always in and I would get my readout.

The downpipe is definitely not happening right now ($$$) so I've got some time to learn more.

Post by **jblackburn** » 03 May 2012, 09:26

If you want to custom map the tables in the ECU to adjust your power and air/fuel mix characteristics, that would make sense.

However, a good tuning company (like ARD that you're looking at getting) will have already done all of these measurements and tweaks with their tune.

Post by **jtp** » 03 May 2012, 09:42

No custom mapping for me. I learn by getting in over my head but not with things that would kill my car in the mean time.

If I would have already payed someone to take the A/F into account I won't bother with the gauge.

Post by **tjts1** » 03 May 2012, 10:20

You need a wide band controller not just gauge. Almost all wide band controllers have 2 outputs. One is for the wide band gauge or ECU which is a generally 0-5v output. Then theres a second output that mimics your current narrow band sensor. This output switches between 0 or 1 volt at lambda or in gasoline terms 14.7afr. This second output can be used to fool your existing ECU into thinking that it still has the same narrow band sensor.

Typical narrow band O2 sensor output

Typical wide band output.

I have used this controller on 2 megasquirt cars so far without any problems. This controller has both outputs.
http://14point7.com/Products.php

jtp wrote:Maybe I could custom install the wideband into a downpipe by having a machine shop drill in an extra hole and add the appropriate thread size. That way I would be adding the sensor without taking the narrowband away. I could just wire the wideband to the gauge so the ECU would be in the same situation it was always in and I would get my readout.

The downpipe is definitely not happening right now ($$$) so I've got some time to learn more.

I had an exhaust shop add a extra O2 sensor bung on my exhaust for $20. It took them 10 minutes.

Post by **jtp** » 03 May 2012, 19:19

Wow. So how does it control the A/F ratio? You add a chip to the ECU?

The first product on your link looks sweet since I could add sensors over time if I wanted to.

Post by **tjts1** » 03 May 2012, 20:50

I use the wide band controller in conjunction with a Megasquirt 2 EFI system on my Mercedes. WBO2 outputs 0-5v to MSQ and MSQ uses that data to adjust the air fuel ratio in real time. It also uses it auto tune fuel maps, cold start enrichment and a few other parameters. Basically MSQ would be impossible without a wide band sensor and controller. The MB left the factory with mechanical Kjet fuel injection which was less than ideal. I wouldn't recommend going this route with your OBD2 car but the wide band controller would be very useful to monitor AFR, EGT, MAP etc if you make any other changes to your car like chip, intake, exhaust, injectors. EGT would be especially interesting. It can even datalog as you drive all on its own. Its a powerful bit of kit for a good price.

I separated the display from the WB controller with an extension chord and built it into the dash. Its quite handy on the MB. I only use for AFR but I would be even nicer if you took advantage of it full functionality.

After assembling the DIY kit but before separating the display.

Post by **jtp** » 03 May 2012, 22:24

That is ridiculously sweet.

Best part is that every sensor it works with is one I don't have, except for boost.

One more question, and I'm sorry it's such a stupid question, on their site they have like 6 or so sensors that can plug into that thing. Where do the plugs go?

Are we talking about little wires that go into ports, like plugging in speakers?