Just installed AEM failsafe Wideband gauge & Datalogger

[IUP99snake]

I've been in the market for a wideband gauge for years. But I always put it off. Now that I've been trying to determine if my car needs a new tune, I've been trying to learn as much as possible about the car's actual performance by reading live PID data from a code reader, and now, I am able to read the actual air fuel ratio, not to mention, boost and RPM.

My car has been throwing lean codes because it has high long term fuel trims for both banks. As a result, the computer is overcompensating and adding fuel. I'm not sure why it thinks it's running lean. It may have to do with the way the MAF signal is intercepted by the computer, and I think that might need to be tweaked with a new tune.

Anyway, I was able to gather some data last night with the new AEM wideband failsafe gauge.

Here is a quick video of my gauge setup at idle, including the new AEM gauge at the bottom.
[youtube_browser]y0_8UmLVHTs&hd=1[/youtube_browser]

This first picture is a live readout from the AEM gauge software that plots all the AFR and Boost readings on an XY axis. It's important to note that this is not spread out over time, it's a cumulative set of readings for the entire time the car was running, which included a mix of start and stop driving (which is why there is a lot of yellow plots when the engine is under vacuum), plus a couple full throttle runs. You can see that both full throttle runs are pretty consistent when graphed together.

After exporting the datalogs from the gauge software, I opened up the log file in the AEMdata program that shows the data in greater detail over a specific timeline.

This graph shows a timeline of about 5 minutes and 35 seconds to show normal driving conditions before and after a full throttle run.

The top graph shows the widband air fuel ratio. The pink like is the actual AFR, while the white and yellow lines on top and bottom of the air fuel ratio are the failsafe limits I had previously programmed into the system. I'm still tweaking it, but for the most part, the air fuel ratio should stay within the white and yellow lines.

The bottom graph is the boost and RPM as an overlay. Those little RPM spikes before the full pull may be short partial runs before I went "all out" just to make sure I wasn't going to blow anything. Also, keep in mind that I tapped into an injector wire for the tach signal and programmed the gauge to read .5 pulses per revolution. So, it may also be an additional injector pulse for whatever reason.

The vertical line is to select at which point in the time line to show data in the chart legend and the gauges for boost and AFR in the corner.

The third picture above shows the same exact data except it is spread out over about 11 seconds instead of 5 minutes to show the full pull in greater detail.

This picture shows the same exact data above, except it is zoomed in only on the graph instead of showing the whole window so you can see the numbers on the legend better.

Overall, the information I'm getting from this is that during cruising I have a nice healthy A/F ratio that hardly goes below 14.0.

But looking at the data from the full pull, you can see that the A/F drops almost immediately down to about 11.5 until 6,000 rpm and gradually rises to about 12.5 because the fuel system is reaching it's limits toward the higher RPM and boost range.

The boost rises steadily as the RPM increases up to a max of 6759 RPM and 10.40245 LBS of peak boost. Notice how the boost slope is almost perfectly linear throughout the entire pull, especially in the upper RPM range. That tells me belt slip is minimal. If it had flattened out towards the end, I would know the belt may be slipping.

I'm really happy with this gauge and the information I have learned. This gauge is such a great bang for the buck. No one else makes a gauge that displays both boost and AFR in the same unit, plus built in datalogging capabilities of boost, AFR, and RPM. And the killer feature is the failsafe function. If the AFR goes outside the paramers you set, it will not only flash the gauge, but it will trigger an output wire that can be used to control a timing retard box, wastegate (for turbo people), a warning light, siren, or anything else you can think of. Since I don't have a wastegate or an aftermarket ignition box, my options are pretty much limited. I saw a similar install in an 03 cobra where the failsafe wire was wired into relays that simply cut power to the ECU. I was also thinking of a way to use a solenoid to manipulate the boost signal going to the bypass valve so I can electronically force it to dump boost. Either that or a second bleeder valve. Who knows.


If anyone could provide me with some thoughts about this data...What might you change? Why are my fuel trims are high at idle (the car thinks it's running lean), but the actual AFR is pretty close to being spot on? Or how to best wire up the failsafe wire.

Any thoughts or opinions would be greatly appreciated

 

[iggster]

edit

 

[Brutal Metal]

Did you take any installation pics? I'm getting ready to install the same gauge in mine in the next couple weeks, already bought it just waiting for spare time..
Did you ground it right to the negative on the battery? I heard it the best spot for accurate readings..

 

[Smacked_in_ATL]

Those gauges are pretty sweet but expensive. I think I prefer a standard wideband then connected to an Xcal3 via firewire for logging purposes.

 

[IUP99snake]

It was only $100 bucks more expensive than the standard Wideband gauges. $300 is a lot of money, but it's nowhere near the cost of the more intricate dataloggers. I don't have a handheld tuner such as an x-cal 2 or anything like that, so this was my best option for the money, plus the features were right in the ballpark for my setup. Wideband, boost, RPM, live datalogging, plus a failsafe output?! Sweet. Sure, I'd like to have the capability to integrate it with other electronics such as an OBD II datalogger which other gauges from PLX and other manufacturers do, but I don't want to buy all sorts of add on modules. I'm not buying an AEM standalone computer anytime soon, so I don't see that happening. There are tons of options, this isnt the best for everyone, but this just happened to be right for me.

I didn't take any installation pics, but I will take a few pics of some important things to consider when installing it.

I have a triple a pillar gauge pod that had a fuel pressure and boost and oil pressure gauges already installed. When I originallt installed those gauges, I used a common wiring harness for the power wires and a common harness for all the wires that needed to be run into the engine compartment to the sending units. I accessed the switched 12V, ground, and dash illumination from the radio wiring harness and daisy chained all the gauges together for the power,
Ground, and illumination.

Since I couldn't find anywhere else to mount the AEM gauge, I decided I would sacrifice my oil pressure gauge for now until I can find a new place for it to go. (Im thinking of hiding it in the center console or putting it in a cupholder. I dont want to buy any more gauge pods. By sacrificing the oil pressure gauge, I already had a power source, ground, dash illumination (for the dimmer feature), and for the RPM input, I used the existing oil pressure sender wire that was already wired in the cluster through the firewall. I just connected it to a fuel injector wire instead of the oil pressure sender (so I took the easy way out and repurposed the oil pressure wire so I didn't have to run a new wire through the firewall. I didn't need a tach adapter because it has a programmable tach input. If you hook it up to an injector, set it for .5 pulses per revolution (that's 1 pulse for every two revolutions on a 4 stroke engine).

Since I already have a mechanical boost gauge, I just T'd into the hard plastic like using the included T adapter and vacuum tubing. Fortunately the outside diameter of the hard plastic line is the same size as the inside diameter of the vacuum hose included with the gauge. I just slid on a couple inches of hose over the hard plastic line on both sides until it wouldn't go any further to make sure it wouldn't leak.

Since the rear 02 sensors are disabled in my tune, I just took out one of the factory 02 sensors and installed the Wideband sensor in its place. Before I weld a dedicated bung closer to the engine, I want to see if I'm getting the same readings from both sides. So, I'll run it for another week or so to get a good idea of how it's reading now, then switch it over to the other side and see if there are any differences. I'll also take the datalogs from both sides during idle, part throttle, and a full throttle run and overlay the data to see if one bank is reading different from the other. If both banks are within the margin of error for the sensor, I'll then find a better location closer to the manifold knowing that it didn't matter which side the sensor is reading from.

But in the meantime, the connector at the end Wideband sensor pigtail even has a factory style push plug that snapped right in to the existing holes in my transmission crossmember just like the original narrow band rear 02 sensor I was replacing. I plugged in the extension harness and ran it toward the front of the car next to an existing wiring harness near the transmission for about a foot where I ran it up through the shifter opening. There is a little hole in front of the shifter opening just big enough to fit the small connector that connects with the gauge through. I ran the 02 sensor harness under the radio and next to my existing power harness that I had previously made that taps in behind the radio. There is about 2 feet of slack, so I coiled about a foot of it under the shifter boot, and I coiled the rest of the slack under the dash near the fuse panel.

I didn't need the 3 analog signal output wires, so I trimmed them down and taped them up in the harness.

I ran the USB wire from the gauge back down the same exact way I had run the 02 sensor harness, under the dash, coming out under the radio and center console, with the plug coming out of the side of the center console right in front of the passenger seat. That way, I can just pull out the slack from under the console and hook it up to a laptop sitting on the seat. The problem is that it's a male plug, so it's not like you can just terminate it with a USB input jack.

Since I haven't figured out what to do with the failsafe wire yet, that was the only wire in the gauge harness I didn't cut or tap into an existing source in my cluster. For now, I ran it down to the bottom of the dash with the rest of the wires, but I coiled it up and hid it behind the driver side kick panel for now.

Ive been experimenting with the failsafe limits and it's touchy! I'll trigger it when I'm downshifting most of the time. So, I've still got some tweaking to do. I only want the failsafe upper and lower limits to take effect when there is boost. I was half tempted to wire up some relays to get it to shut off the ECU, but to do that, I'll need to have the limits "finely tuned". I don't want it shutting off the motor by accident when Im downshifting or blipping the gas.

If anyone has any ideas on how to use the failsafe feature without having to buy anything more expensive than an couple relays or solenoids, let me know. I was trying to think of a way of using a couple solenoids and check valves to electronically actuate the blowoff valve under boost by closing off the boost reference signal to the valve and opening up a vacuum reference from a small vacuum reserve tank that uses check valves to keep a vacuum stored up in it for when the failsafe solenoid opens up. That will bleed off boost temporarily. What do you think?

Ideally, I'd rather have a two step, or ignition box that engages a rev limiter or timing retard. That's the safest way to prevent detonation in the event of something such as a fuel system failure without shutting off the engine completely and having to restart it for false alarms.

Regardless of how I connect the failsafe, I'm going to wire in an "override" switch for daily driving. I don't have to worry about catastrophically destroying anything during normal driving. It's just for dyno pulls and drag races where I really need the failsafe feature. Maybe I'll wire it into the traction control switch, so when the TC is off, the failsafe is active.

Anyway, I'll post up some more pics and videos when I get around to it later this weekend. Please share some ideas or thoughts! I installed it one way out out of hundreds of right ways to install it..

 

[Brutal Metal]

I have my fuel pressure mounted on the auto meter steering column pod and a triple gauge holder in the spare Din stereo opening. Gonna mount the wideband in a single pillar pod, no real other spot don't want it on the dash or under the cluster..

 

[IUP99snake]

I have my fuel pressure mounted on the auto meter steering column pod and a triple gauge holder in the spare Din stereo opening. Gonna mount the wideband in a single pillar pod, no real other spot don't want it on the dash or under the cluster..

That's cool! I thought about mounting a gauge (or two) in one of the extra DIN slots.

The separate DIN openings for the 94-00 cars vs. the double DIN for the 01-04 cars both have their pros and cons. With the earlier cars, you can do things like mount a CD player without an install kit and have a whole extra space to mount gauges. You can even swap spaces and mount the CD player on the bottom and the gauges on top, or vise versa. If you install an aftermarket CD player with an install kit on the later cars, there isn't enough room to mount gauges. But, if you're a fan of an aftermarket navigation system, it looks real nice in that double DIN opening.

I found a single DIN gauge mounting plate that fits 3 gauges but the cool thing is that it tilts them toward the driver.

GlowShift Universal Triple Gauge Single Din Radio Face Pod : Amazon.com : Automotive

But I'm not gonna buy two more gauges in addition to my oil pressure gauge. Having 6 aftermarket gauges would be ridiculous. Maybe one more gauge, such as a pyrometer or an intake air temp gauge. So, I'll make my own plate with two gauge openings. But that's way in the future. In the meantime, with my motor getting older and older, I have a feeling that oil pressure gauge I just removed will be more important than it was in the past. I think I'm gonna try and fab up a cupholder mount. Maybe I'll make it out of the factory "cupholder ashtray" that came in the 99 cars. That way, I can just flip the lid closed to hide the gauge when I don't want people asking me stupid questions about it.

I hate it when non-car enthusiasts ask me "did your car come with those, or did you install them?". Because they don't know what they're for and they probably think they're tacky and stupid. I don't know what they're thinking. But at least I made them think it looks factory. Whatever, I don't care what anyone thinks.

Homer

 

[ruthless]

I bought the same gauge and its working great except for the RPM. I also wired the analog outs and connected them to my SCT X3 for datalogging A/F and boost. Remember our cars do not have a boost PID in the computer.

Since I have a turbo and an AMS-500 boost controller I have the failsafe setup as a constant ground to triger the second stage of boost that kicks in when I let off my transmission brake (Runing a th400 transmission). If at any time my failsafe settings are triped it turns the trigger off and I am back to wastegate spring boost.

Edit: I see you connected you RPM input into an injector and not a coil. Is it reading on the money wired this way? I have mine connected to the same coil my raptor shiftlight is connected to and the RPM reading is all over the place. I even called AEm and was told that it should work but I think they are full of crap and if I want to use the coil signal I will need a tach adaptor because of the type of signal the gauge is looking for but dont hold me to that.

 

[ruthless]

Those gauges are pretty sweet but expensive. I think I prefer a standard wideband then connected to an Xcal3 via firewire for logging purposes.

Its cheap next to other options. Plus this gauge recordes from key on and keeps a total of 3 hours. So no need to keep a laptop connected to your car to log RPM, A/F and Boost.

 

[Brutal Metal]

That's cool! I thought about mounting a gauge (or two) in one of the extra DIN slots.

The separate DIN openings for the 94-00 cars vs. the double DIN for the 01-04 cars both have their pros and cons. With the earlier cars, you can do things like mount a CD player without an install kit and have a whole extra space to mount gauges. You can even swap spaces and mount the CD player on the bottom and the gauges on top, or vise versa. If you install an aftermarket CD player with an install kit on the later cars, there isn't enough room to mount gauges. But, if you're a fan of an aftermarket navigation system, it looks real nice in that double DIN opening.

I found a single DIN gauge mounting plate that fits 3 gauges but the cool thing is that it tilts them toward the driver.

GlowShift Universal Triple Gauge Single Din Radio Face Pod : Amazon.com : Automotive

But I'm not gonna buy two more gauges in addition to my oil pressure gauge. Having 6 aftermarket gauges would be ridiculous. Maybe one more gauge, such as a pyrometer or an intake air temp gauge. So, I'll make my own plate with two gauge openings. But that's way in the future. In the meantime, with my motor getting older and older, I have a feeling that oil pressure gauge I just removed will be more important than it was in the past. I think I'm gonna try and fab up a cupholder mount. Maybe I'll make it out of the factory "cupholder ashtray" that came in the 99 cars. That way, I can just flip the lid closed to hide the gauge when I don't want people asking me stupid questions about it.

I hate it when non-car enthusiasts ask me "did your car come with those, or did you install them?". Because they don't know what they're for and they probably think they're tacky and stupid. I don't know what they're thinking. But at least I made them think it looks factory. Whatever, I don't care what anyone thinks.

Homer

Yeah I have the 99 double Din..here's mine..

 

[IUP99snake]

I bought the same gauge and its working great except for the RPM. I also wired the analog outs and connected them to my SCT X3 for datalogging A/F and boost. Remember our cars do not have a boost PID in the computer.

Since I have a turbo and an AMS-500 boost controller I have the failsafe setup as a constant ground to triger the second stage of boost that kicks in when I let off my transmission brake (Runing a th400 transmission). If at any time my failsafe settings are triped it turns the trigger off and I am back to wastegate spring boost.

Edit: I see you connected you RPM input into an injector and not a coil. Is it reading on the money wired this way? I have mine connected to the same coil my raptor shiftlight is connected to and the RPM reading is all over the place. I even called AEm and was told that it should work but I think they are full of crap and if I want to use the coil signal I will need a tach adaptor because of the type of signal the gauge is looking for but dont hold me to that.

You bring up an important point about the RPM input. I first tried connecting it to a coil as well, with the same results as you. Your shift light might work because it only activates at high rpm when there's only one spark (pulse) per firing revolution (.5 pulses per RPM). However, at idle and low RPM, the computer will fire the plugs multiple times during the firing stroke (Multiple Spark Discharge). That's what is throwing off your RPM readings.

When I hooked it up to an injector, I didn't think it would be a good source for the RPM input because I'm not too familiar with how they fire in relation to the crank position, engine speed, load, etc. All I knew was that they might also have .5 pulses per revolution.

Sure as shit, it was pretty accurate. And it doesn't matter which injector you use either. To double check the accuracy, I enabled the "dealer test" feature in the digital readout for the odometer to show a digital RPM readout in the dash cluster. I then compared that to the readout on the AEM program. Although the computer readout from the gauge had a "little" lag, it was pretty accurate.

Also, note some RPM spikes during the beginning of a pull. (See pictures 2, 3, and 4 in the beginning of this thread) I'm still trying to figure those out. Maybe the injector duty cycle is changing or something.

Nevertheless, you DONT need a tach adapter. Just find anything that has a pulse that's correlated with RPM and program it to the computer. Hook it up to an injector and tell me if you think it's pretty accurate. Even better, tell me if you see the same "RPM spikes" in your datalogs.

However, I am finding that the boost function is reading a little lower than my mechanical boost gauge is reading. My auto meter gauge will read 12-13 lbs of boost, but the datalog only says 10.4 LBS. They are both connected to the same exact hard line. Maybe the flexible line running to the AEM gauge got partially kinked when the A pillar cluster was snapped into place. However, at idle, they both read an identical amount for vacuum... 20 inches. So, maybe my mechanical boost gauge is reading a little high.

I'll have to look at it more. Maybe I'll record video of it during a pull and compare it to the datalogs.

 

[ruthless]

Thanks for the information. I will try changing my RPM pickup to an injector wire and see how that works.

My boost gauge and AEM read very close to one another.

 

[IUP99snake]

Yeah I have the 99 double Din..here's mine..

I like that DIN triple gauge cluster. I was thinking of doing a similar install with the CD player on the bottom and the gauges on the top. Things like fuel pressure, oil pressure, and maybe intake air temp. While the more important gauges to look at while doing a full throttle blast like boost, air/fuel, and maybe a pyrometer can stay in my line of sight in the a pillar pod.

You have a parchment interior like mine. You should paint that steering column gauge cluster using interior paint. They'll mix you up a can using your interior paint code over at NAPA or any body shop supply store. That way it matches the rest of the interior and looks like it was supposed to be there. The interior paint is quite good. It matches perfectly and it doesn't easily flake or chip off. Trust me, it'll look sooo much better.

Homer

 

[Co-brat]

i like your posts they are very detailed. I am cosidering geting this guage as well so hopefully tou will post your results when you swap the sensor from side to side and then further up the head pipe, which where I think you are supposed to have it for the most accurate readings.

 

[Abilor]

Fantastic information. Thanks for documenting well; this will help me immensely down the road.

 

[IUP99snake]

A littLe update: although I haven't had a chance to change around the sensor location, I have been experimenting around with the gauge configuration. It has a center OLED screen and a ring of LED's around the outside of the gauge as you can see in the pics. The center display (which is super sharp...much nicer than a LED clock style display) can read AFR, lambda (which is AFR displayed like in a different scale where 0 represents 14.7) Boost/vac in PSI-in/hg, vacuum only (for n/a cars) or BAR. The outer LED ring can also be configured with all of those same parameters and you can use different faceplates that have various labels/scales for whatever choice you make.

I experimented around with boost/vac on the LED ring and AFR on the center display and vise versa. But the LED ring is nowhere near as accurate as an analog boost gauge. And I didn't really like reading boost/vac as a numerical readout on the center display either. So I just set it up to read AFR on both the display and LED ring. Another note about the LED ring is that you can configure the colors, green, orange, and red wherever you want based on the target conditions for AFR or boost.

One last thing. I've noticed that sometimes the gauge hasn't been turning on at startup. I'll have to cycle the ignition on and off to get it to come on. Maybe it's a power source, but all my other gauges are connected to a common switched 12v source and they work fine. If it gets worse, I'll call AEM.

 

[chevysRslow]

Brutal Metal - where did you buy the triple gauge panel? Looks much better than the one that I made. Need to get one of those.

 

[ruthless]

Guys I know this was from way back when but I got the car out of storage and to my "new to me" house where I now have garage space. I LOVE it!! :banana: So I finaly got back to correcting the RPM input for the gauge. The tick is like the OP said... Hook this up to a fuel injector wire and NOT a coil pack. I used injector #1 that is pin 75 (Tan wire). After that I started the failsafe software and connected up the gauge. I went to the pulses per revolution drop down and then I had a WTF look on my face. My option only went to 1 and the RPMs where reading low. I then tried 2 just as a test and they where even farther off. So I needed a .5 option. I was about to smash stuff but since I work in the IT field I gathered myself up. I hit the update button in the software that took me to the web where I down loaded the latest software and firmware for the gauge. Wouldn't you know it... They added a .5 to the list. I selected that baby and my RPMs read spot on! These where just quick revs in the garage but I have races Sunday so I will report back.

The gauge works slick even without the RPM but now its going to be even better. I have mine teamed with an AMS-500 boost controller in a turbo setup. I use the output signal to always trigger high boost and if the failsafe see a lean condition it grounds the trigger and that cuts boost. You have got to love that!!

 

[ruthless]

Had the car to the races and I am afraid that the injector signal is not 100% correct. Looks like I am going to need to figure something else out. I am sure it will be ok for street use but using it to log racing, launch RPM, tire spin ect. just isnt working out 100%.

 

[IUP99snake]

Yea, it needs to be set on .5 pulses per revolution because there is 1 firing stroke every 2 revolutions (on a 4 stroke engine).

I can't think of any reason why a fuel injector wouldn't be an accurate tach signal for the gauge...

I've checked the tach display on the software compared to the diagnostic tach feature on my odometer and it's pretty damn close. The only discrepancy I can notice is with the software.

If anyone can tell me a better place to hook up the tach input, I'm all ears.

You could always get a standard tach adapter and use that..

Or get an MSD box with timing retard and a tach output and that would kill two birds with one stone.. You'd get the most accurate RPM input and you'd be able to use the failsafe wire to pull timing.

I've been having problems with the CCRM powering my fuel pump lately... I think I'm gonna use the failsafe wire to power a relay in order to supply extra power to the fuel pump if the pressure gets too low. (I know, a new CCRM would also fix the problem).