AutoMeter Accuracy?

[DEFYANT]

Has anyone else noticed a discrepency in the readings shown on the Autometer Pro-Comp guages?

I am running the Boost, Fuel Press, Oil, Volts, and Trans Temp guages. Sometimes I data log the car with the Xcal2. Here are my findings:

The Fuel Pressure guage is off by 10 psi. Ever since I changed the sender for the oil pressure, it reads 100 psi when cold. Used to be around 75psi. The Trans temps are slow to react. I've had the trans temps way up but the guage does not reflect the same degree as the data logger. The volt guage reads about 14.5, the data logger showes 13.8. No big deal there.

For the money I spent, I would have expected alittle more accuracy from these guages. Is there a way to calabrate them? Perhaps I missed something.

[Vortech347]

If you saved your receipt they have a great service department and will trade you if your gauges are bad.

The Sport-Comps in my stang are all dead on. They're all electric.

[DEFYANT]

I agree the service so far has been good. This really was not ment to be a rant, just a simple observation.

I'll call them.

[Rider90]

Sharing my insight: My ScanGauge reads 14.3 at cold start (900-1000 RPM) and similar readings in traffic. My OEM voltmeter seems to read the same, above 14, depending on the accessories.

Comparing your results to mine, your Voltmeter gauge seems right. But like I said, this is at cold start. My volts range from 11.7 to 14.3 depending on the song :D

Oh and [/insight]

[JMan]

Has anyone else noticed a discrepency in the readings shown on the Autometer Pro-Comp guages?

I am running the Boost, Fuel Press, Oil, Volts, and Trans Temp guages. Sometimes I data log the car with the Xcal2. Here are my findings:

The Fuel Pressure guage is off by 10 psi. Ever since I changed the sender for the oil pressure, it reads 100 psi when cold. Used to be around 75psi. The Trans temps are slow to react. I've had the trans temps way up but the guage does not reflect the same degree as the data logger. The volt guage reads about 14.5, the data logger showes 13.8. No big deal there.

For the money I spent, I would have expected alittle more accuracy from these guages. Is there a way to calabrate them? Perhaps I missed something.

For what it's worth, here's my two cents -
The data you're reading on the logger is coming from the PCM. For one thing, that data is being computated and is not live. It is what the PCM sees. Secondly, items like fuel rail pressure, system voltage and trans fluid temperature are certainly being read at a different location than your live gauges and may be buffered. For instance, rail pressure is read on the rail not before it. It also sees the pressure drop of the injectors firing. Trans fluid is measured in the tranny not in a cooling line and has conduction included from the metal it is mounted in. The PCM voltage may be buffered or dropped slightly to maintain a constant level so as not to interfere with critical functions.

I'm not saying your gauges are accurate but they may never be equivalent the logged data from the PCM. As far as your oil pressure gauge goes, 100psi in Florida at start-up would make me very suspicious. Maybe a local repair facility can use an external gauge on a 'tee' to verify the accuracy of your sender. An infra-red temp gun can be used also at the point of your trans temp measurement to gauge its accuracy. That would at least provide some peace of mind!

:twocents:

Good luck,

J

[Marauderjack]

My fuel pressure gauge is 10 PSI low like yours but I think it is because the OEM sender is at the entrance of the fuel rail and the Autometer sender is at the far end.....Maybe a 10 PSI drop over 8 injectors??:confused:

Marauderjack:cool:

[TooManyFords]

My nexus gauges seem to be dead on too depending on compatible pickup locations. As mentioned above, you'd have to have your gauge sending units in identical positions to really compare.

What you should look for are identical dips and spikes between the two. Averaging your readings gives you far more information than any split-second comparisons.

And that's why I like my Nexus gauges. It has a computer with a SD memory card that can record whole runs (up to two hours worth if I really wanted) and be able to play it back on the gauges themselves or on the laptop from the SD card.

They're not cheap, but were worth it in my humble opinion.

Oh, and just so everyone is aware, the best gauges in the world cannot tell you if you're going to break a rod or not. I know. Trust me!

:D

john

[snowbird]

"Has anyone else noticed a discrepency in the readings shown on the Autometer Pro-Comp guages?"

Defyant,

For the oil, i also have 90-100 PSI on startup but we're still in winter. I don't think they are off.

Fuel, I've got 30-40 PSI readings for idle and light loads. My reading was installed at the front, driver side, the nearest from, say MAF. What are your FP gauge reading ?

As for the trans, i hooked it with the manifold option from Autometer. It barely move before 15-20 miles, but again, at this time of the year, it doesn't surprise me.

[metroplex]

Re-evaluate the sensors that are transmitting the data/signal to your Pro-Comp gauges. If the sensors are quality, the connections are good, and the gauges aren't crappy gauges, I would trust those readings over the X-Cal 2 DMR/PID readings taken from the PCM/data bus network.

[KillJoy]

My Real Oil Pressure Gauge reads almost 100PSI Cold at Idle. 25PSI Warmed Up at Idle.

KillJoy

[DEFYANT]

Ok, it seems we have similar experiances here.

I am reading the Fuel Pressure at the end of the fuel rail also. Is there a more acurate location to tie into?


Mods, can you adjust the "down thumb" in the thread title?

[RF Overlord]

My Real Oil Pressure Gauge reads almost 100PSI Cold at Idle. 25PSI Warmed Up at Idle.Mine, too...and many others I've heard from as well.
Mods, can you adjust the "down thumb" in the thread title? Done.

[JMan]

Ok, it seems we have similar experiances here.

I am reading the Fuel Pressure at the end of the fuel rail also. Is there a more acurate location to tie into?

No need. You're simply looking for variations, particularly loss, in fuel pressure. I don't know what pump(s) you are using but establish a baseline on your set-up and monitor for variations from that baseline. If your logged data stream says 39psi and the gauge reads 47psi - so be it. The gauges are probably accurate within x.x% (As stated in the paperwork that came with them.) as are the sensors for the PCM. Don't worry about the calibration of the gauges but moreso the readings themselves. Hope that helps!

Best of Luck - See you at Sebring :burnout:

J

[Marauderjack]

I found out a little more about the FP difference between the OEM sender (OBDII) and the Autometer one!!:beer:

OEM sender deals with "Absolute" pressure to the EEC which is the fuel pressure plus atmospheric (25# FP plus 14.7# at sea level = 39.7# total) which is why the OBDII pressure is always higher than the Autometer pressure. The "Absolute" varies with altitude changes and the EEC compensates for it.:cool:

Thus the Autometer gauge reads actual or "Delta" pressure which is "Absolute" minus atmospheric at any given altitude........Make sense??:rolleyes:

Thanks to Dave Lamberson for clearing this up for me!!:beer:

Marauderjack:burnout:

[MENINBLK]

Has anyone else noticed a discrepency in the readings shown on the Autometer Pro-Comp guages?

I am running the Boost, Fuel Press, Oil, Volts, and Trans Temp guages. Sometimes I data log the car with the Xcal2. Here are my findings:

The Fuel Pressure guage is off by 10 psi. Ever since I changed the sender for the oil pressure, it reads 100 psi when cold. Used to be around 75psi. The Trans temps are slow to react. I've had the trans temps way up but the guage does not reflect the same degree as the data logger. The volt guage reads about 14.5, the data logger showes 13.8. No big deal there.

For the money I spent, I would have expected alittle more accuracy from these guages. Is there a way to calabrate them? Perhaps I missed something.

How can you be so sure that the Data Logger is accurage ?
After all it is getting its data from FORD sensors.....

[DEFYANT]

How can you be so sure that the Data Logger is accurage ?
After all it is getting its data from FORD sensors.....


I hear ya.

I figured since Lidio tuned the car off the same sensors, they were more reliable
:help: