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Ultra Gauge

Diesel

By Diesel
in 3rd Generation Dodge

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AH64ID

AH64ID

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EGT gauge is "THE MOST IMPORTANT" gauge you can install on your 3rd gen truck.....................then LP or lift pump IMHO!!

 

Only if tuned, if stock I wouldn't bother... it's a scary sight to see those OE EGT's.

 

But on a tuned motor I agree 100%...

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Mopar1973Man

Mopar1973Man

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Just wondering if the Ultra Gauge can be used for a Boost and EGT gauge?

 

 

Boost yes, Pyro no.

 

I still say EGT's gauge is a safe bet to have. No UG doesn't support anything that doesn't already exist on the truck. So if the pyrometer isn't there and readable by the ECM then the UG isn't going to see it. UG/SG can only see what the engine sees including the errors created by poor wiring and bad sensors.

 

Even on my fully stock 2002 I've seen 1,400*F completely stock (absolutely no mods) climbing a 6-7% grade towing a flatbed trailer with a Chevy truck on the back. No boost leaks either. Typically this is the cause of most exhaust manifold crack problem is excessive exhaust temps cause from a driver without a EGT gauge. Yes this does happen on stock trucks too.

 

Boost is seen because the MAP sensor is already supplied with the engine. But be warned MAP/Boost reading typically are not accurate on the upper end of the scale above about 20-25 PSI. Some have seen where the SG/UG will vary from a mechanical gauge on the upper scale.

 

I personally suggest full mechanical gauge to be the safest choice. UG/SG is OK for daily driver for boost gauge. But as for EGT's the only solution is a separate gauge. I do suggest a EGT's gauge if you plan on towing or hauling heavy at all. You'll be surprised what a true stock engine can produce for EGT's.

 

(Yeah I know this is 3rd Gen but I'm like Dorkweed rather error toward the side of safety!)

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AH64ID

AH64ID

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The boost issue, I forgot since I don't watch it so thanks Michael, is that OBDII isn't capable of communicating full boost. I can only transmit ~37psia, which at sea level is 23 psig. The stock 06 makes ~32.

The ultra gauge is still a great, and cheap, gauge to have will all of its OBDII sensor read puts and is probably the most reliable rail pressure gauge.

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AH64ID

AH64ID

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Confirmed on the boost...

 

Your MAP sensor is broken. It was reading 28.3psig with the engine off, or 15.1psi of boost at 3,000 feet on a standard day.

 

The high boost reading with the engine off is indicative of a failed pressure sensor, the 37 psi limit on the upper end is the OBDII limit as you know.

 

I am not sure how much the boost reading effects fueling on a VP motor, but on a HPCR it's huge. What you have there is about a 1/2 smoke switch.

 

Can you read requested rail pressure? Or does it only read sensors? I just picked up a 06 megacab and I am thinking about the gauge for tracking my mileage

 

No you cannot. I have been thinking about asking them for that, but I don't think it's an OBDII readout but a Dodge specific code.

 

The mileage may not be accurate on an 06, as the OBDII mileage readout isn't very accurate or correct on that generation diesel. My 05 included.

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Mopar1973Man

Mopar1973Man

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Your MAP sensor is broken. It was reading 28.3psig with the engine off, or 15.1psi of boost at 3,000 feet on a standard day.

 

Nope its not broken the 24V engines have a voltage offset that creates this issue. The early versions  have a different voltage span vs the later versions witch now have a different span. So the numbers on scan tools are skewed out. I've got 2 sensors with the same numbers. No error codes. Best I can say is look at the series of different MAP sensors on the 24V. There was like 3 different ones but the 01 and 02 are the same and interchangeable with each other as long as you used a adapter cable. (Pins where different).

 

The high boost reading with the engine off is indicative of a failed pressure sensor, the 37 psi limit on the upper end is the OBDII limit as you know.

 

Just a modified MAP sensor voltage. This is only a 24V issue. Corrected after 03...

 

 

I am not sure how much the boost reading effects fueling on a VP motor, but on a HPCR it's huge. What you have there is about a 1/2 smoke switch.

 

LOL... Smoke switch. I've played with that and it just buried the SG to 37.3 PSIa and stopped. But now look at my Version of SG vs. the new version of SG (software wise) they do have a valid boost gauge now vs. mine which had this skewed MAP reading.

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AH64ID

AH64ID

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Hmmm..

 

The upper limit is certainly a OBDII limit, and still holds true on new trucks.

 

OBDII was designed around sending 256 characters, 256 kPa is 37.2 psi.

 

I am not sure the skewing makes sense, why would the ECM want to read 15.1 psig off?

 

There are several connectors for MAP sensors over the years, but all the data I can find shows they are all standard 5V pressure transducers where 0.5V is 0 psi.

 

 

EDIT: I just had a thought, is that inches of Mercury? and not psi...

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AH64ID

AH64ID

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Not sure why. But the SGII works just fine one all other vehicles. Just the 98.5 to 02 Dodge Cummins is skewed in value. I've not figured out why yet.

It would be a ECM issue, not a SGII issue as they don't read or even have access to the actual signal from the map sensor.

Do products like a edge attitude read boost correctly?

Did you see my question about inches of mercury? That figure is very close to the proper level of ambient pressure in inches.

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Mopar1973Man

Mopar1973Man

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Do products like a edge attitude read boost correctly?

 

Yes and no. From 0 to about 20 PSI its correct then slow there is a offset as you run outside the designed range of the sensor. As for SGII the newer software on the SGII does have boost gauge and do show correctly but again also has the same loss of accuracy as the Edge Juice. Outside the designed realm of the sensor.

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AH64ID

AH64ID

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If other products read correctly then the ECM is putting out the correct MAP pressure, as there is no output for boost only MAP and ambient pressure (IAT).

 

For a SG or Attitude to read boost it does math, it takes the MAP pressure and subtracts ambient. This is also why digital boost gauges will show 1-2 psi more than analog, or even more, since they reference boost from the intake restriction to max pressure.

 

So if others read the MAP sensor correctly why doesn't the SGII? I am not talking about the above 20 psi, as the sensor is beyond limits, but why does it show 15.1 psi at idle? That's not a skewed signal, because if it was nothing would read boost correctly at the low end.

 

Still haven't answered my question about inches of mercury.

 

Why not send the SGII off for an update? They never charged me and I have had it updated twice.

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AH64ID

AH64ID

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The SGII should have the option to change the units.

It's weird for sure, but it's a SGII issue and not a 24V issue... Or none of the other readers would work.

I bet if you call SGII they would have an answer for you, and probably a free software upgrade.

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