phil996cab99

Hey Torque Pro app users,

What are normal values for the things this app tracks, and/or which things do you track using this app? Thanks.

I'm using this app to monitor my engine health, but I have no idea what the "normal" values should be.

I'm graphing stuff against RPM to provide some context. The list of things available to log seems to be growing daily, which seems odd. Anyway, here's what I logged yesterday:
Engine Coolant Temperature(°F),
Intake Air Temperature(°F),
Mass Air Flow Rate(cfm),
Timing Advance(°),
Turbo Boost & Vacuum Gauge(psi)
Voltage (OBD Adapter)(V) ,
Acceleration Sensor(Total)(g),
Engine RPM(rpm),
Engine Load(%),
Fuel trim bank 1 sensor 1(%),
Fuel trim bank 2 sensor 1(%),
O2 Volts Bank 1 sensor 2(V),
O2 Volts Bank 2 sensor 1(V),
O2 Volts Bank 2 sensor 2(V),
Throttle Position(Manifold)(%),
Volumetric Efficiency (Calculated)(%)

Macster

What is normal varies considerably.

For instance, timing advance. This varies constantly as the DME adjusts timing as engine conditions change from well in the worst case from combustion cycle to combustion cycle (the appearance of detonation).

Nominally advance can be 0 to 5 or 6 degs. at idle, to maybe 35 degs. advanced under steady state cruising at moderate speeds. It can retard some under hard acceleration to around 25 degs. maybe less.

Load is a calculated value. At idle it can just a few percent (your Porsche is using about as much HP to idle as a lawnmower engine produces) to around 20% or so (whatever when multiplied by the engine's total HP comes to around 40hp) at steady speed cruising on a level road (this approx. 40hp number is pretty consistent between my various cars, from my VW Golf TDi (90hp) to my 03 Turbo (420hp) -- IOWs, it takes about the same HP to move the VW down the road as the Turbo, but for the VW the engine was operating at around 50% load while the Turbo at around 10%) to well 100% under some conditions.

Coolant temperature starts out at around ambient -- if the engine has been off long enough and in a temperature stable environment long enough -- and climbs 1 to 2 degs. per second as the engine idles. With the A/C off -- so the radiator fans aren't running -- coolant temperature can reach -- based on my observation -- around 180F to 196F (the lower temperature on colder days) under steady highway cruising. It will go up if the car is stopped like at a light and it will really go up if the engine is worked hard. Higher ambient temperatures also affect coolant temperature. It can climb to 212F and then begin to fall as the fans come on. (They shut off -- in my Boxster anyhow -- at 205F. On really hot days coolant temperature can reach 226F (observed).

Intake air température generally reflects ambient temperature though offset by some few degrees. For instance with my Boxster the best I found was intake air temperature running 10 to 12F above ambient. The Boxster's engine air intake pulls in some heated air from the radiator's exhaust air. The 911 engine air intake is located at a cooler place. If the car is parked up with the engine hot upon hot start the intake air temperature can be quite high as the heat soak has warmed the intake system.

Mass air flow rate depends upon throttle.

RPMs, ditto.

Boost and vacuum also are throttle dependent though boost can be modified by the DME to limit or reduce boost under some conditions. (My 03 Turbo's boost can climb to 0.7 bar under hard acceleration (or even higher at higher elevations) but begins to drop off as RPMs rise, falling to IIRC 0.4 or even 0.3 bar at redline.

I haven't looked at vacuum with my Porsches but from my memory of observing vacuum readings of other engines vacuum is high at idle and can become nearly atmospheric pressure under WOT.

Short term fuel trims can vary quite a bit -- a few percent on either side of 0% -- to sometimes around 10% under some conditions, though under most cases if the adjustment gets 10% on either side of 0% this reflects a problem. Generally though these do not want to vary too much but I can't recall how much though. These are very dynamic readings, that I do recall.

02 sensor readings… the pre-converter sensors -- when up to temperature -- should have a voltage swing of between 0.1v to 0.7v as the DME constantly varies the fuel mixture from a bit too rich to a bit too lean than ideal. At idle the DME can vary fueling at a 1Hz rate while at higher RPMs it can vary it at several times or more per second.

The post-converter sensors want to read above 0.6V as there should be no oxygen in the post-converter exhaust. The oxygen should be retained and consumed in the converter. If oxygen makes it through the converter this is a sign the converter is not working properly.


By observing the various engine sensor readings, and derived/calculated values, what you will see is the engine and its inputs and sensor outputs are very dynamic and there can be a good range of readings that are normal.

If you want, if you can, log some data under various operating conditions: cold start, idle, hot idle, steady cruise, hard acceleration, etc. and bank these to have some baseline data in case.

Generally though if something's amiss readings will indicate this without having to refer back to the historical data. One benefit is these engines have two banks. Often times a problem is confined to one bank so one has the other bank and its sensors to compare to those of the other suspected bad bank. There can be one or more error codes too which helps pinpoint where the problem is and observing related readings one can see something's not right.

The only time I can recall using the data to trouble shoot a problem for when there was no error code but some symptoms -- I forget the symptoms now -- was with my VW Golf TDi. I found the coolant sensor was not operating properly and had this replaced.

Even with an error code, as was the case with my Boxster once with what proved to be a bad O2 sensor, I tried to observe the actual sensor misbehavior. It was tough to catch this. But after awhile I had a good feel for when the error was about to appear and could watch the sensor readings and observe the bad readings concurrent with the CEL coming on. What I also noticed was shutting off the engine even for a moment and then restarting it had the bad sensor acting normally again.

phil996cab99

Macster thanks for writing that up.

Within a week or so I'll start posting my graphs and maybe start a Torque Pro for 996 quick start thread to save others the learning curve.

kj217

ia torque app able to calculate AFR and knock retard?

Third-Reef

What blue tooth done are you all using? The cheap one I have worked on my honda but will not work on the Porsche or BMW.

bal

I use with my iPhone running DashCmd. It uses WiFi rather than Bluetooth (apparently this is a requirement for iOS, not so for Android but should work with Android too). The only change I needed to make after connecting to the WiFi AP created by the dongle was to manually set the IP address and remove the gateway address. This forces it to use cellular data for Internet access, which the phone would otherwise not have through the dongle.

phil996cab99

BAFX PIC18F2480 works fine. I've hit it a few times w/my knee, so next time I'd get a smaller one or L-shaped or DIY extension cord. on/off switch would be good.