Bringing the GT500 Cluster Boost Gauge back to life!

[19COBRA93]

You're wasting your time. As I've mentioned, and shown, the EGR does NOT in any way see a boost signal. There is no vacuum line or boost source running to the EGR. You may as well try to take a boost reading off your seat headrest. You'll get the same result.

You can choose to ignore what I'm trying to tell you, but feel free to pursue what you're pursuing, but don't expect it to work. Sorry.

 

[Alfiedagr8]

You're wasting your time. As I've mentioned, and shown, the EGR does NOT in any way see a boost signal. There is no vacuum line or boost source running to the EGR. You may as well try to take a boost reading off your seat headrest. You'll get the same result.

You can choose to ignore what I'm trying to tell you, but feel free to pursue what you're pursuing, but don't expect it to work. Sorry.

Agree. !!!!


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[crownaviation]

So... why the hell did the engineers make this so freggin difficult? Oh... engineers.

 

[19COBRA93]

So... why the hell did the engineers make this so freggin difficult? Oh... engineers.

That's a good question. A boost gauge should be a very simple thing. Like in the '03 cobras. There was a nipple on the back of the cluster that fed the gauge itself.

 

[08Eleanor]

To the engineer(s) who designed it, I'm sure they felt it was better doing it over the communications protocol that already exists in the car.

Why do something mechanically with a vac hose when the data can easily be sent over the same wires as the rest of the sensors etc.

Besides, all clusters these days are controlled by microprocessors so it would actually have been more difficult to put in a mech gauge instead of a stepper like the other gauges use.

 

[crownaviation]

Well, I have not looked at the back of one but I assume the gauge is a part of the pcb. Could a guy bypass the pcb to retain continuity and then just make a sending unit for the damn boost gauge? I know it sounds complicated but I am sure someone could do it. Unless I totally do not get how the damn thing works (most likely lol)

I would really like to do this and free up one of my holes in my pod

 

[08Eleanor]

Hmm well I suppose one could desolder the stepper from the PCB to isolate it then get a stepper motor controller and wire up a circuit to convert pressure to voltage/current.

That would involve hacking into the cluster so I'm trying to avoid that at all costs.

I don't see how an egr valve doesn't see boost.

The egr recirculates the exhaust fumes into the intake. If the egr is funneling that into the intake it HAS to see boost I would think, as the intake will.

 

[19COBRA93]

Hmm well I suppose one could desolder the stepper from the PCB to isolate it then get a stepper motor controller and wire up a circuit to convert pressure to voltage/current.

That would involve hacking into the cluster so I'm trying to avoid that at all costs.

I don't see how an egr valve doesn't see boost.

The egr recirculates the exhaust fumes into the intake. If the egr is funneling that into the intake it HAS to see boost I would think, as the intake will.

The part of the intake the EGR has anything to do with is the "intake" part of the blower which is pre rotors, and pure vacuum. Only the discharge part of the blower (after the rotors) see's pressure, and the only vacuum line post blower is the single line that runs to the fuel rail pressure sensor from a single port off the lower intake manifold at the front (as I explained, and showed in pics on the prior page).

Look at the pics I posted on the previous page. The pic of the bare blower, there are several ports shown toward the rear of the blower housing, those are all vacuum only. No boost.

 

[19COBRA93]

Here:

 

[19COBRA93]

This is the inside of an M122 (stock GT500 blower), and you can clearly see the ports all lead to the inlet side of the blower, not the pressure side.

 

[lito]

This bird will never fly as expected, this is a SIP sensor, to measure vacuum at inlet and for EGR and DBW in the calibration, anyone that works on GT500 calibrations should know this.

As 19COBRA93 said, it never sees MAP, only SIP. MAP is inferred in the GT500 as it is in a GT.

So... why the hell did the engineers make this so freggin difficult? Oh... engineers.

If you can save a sensor, connector, harness and calculate its value thru the logic efficiently, what you think would they choose?

 

[dmhines]

Probably be simpler to install a GT500 PCM tuned to run the GT engine. I had a GT500 cluster in both my 2006 and 2010 Mustang. The 2006 wasn't too bad .. just a non-moving needle. The 2010+ cluster consider lack of signal as an ERROR and light up the gauge RED when headlights are on ...

 

[08Eleanor]

So then the only way would be to reprogram the PCM so that it sends that inferred reading to the cluster.

I was about to buy a ford ids vcm for various reasons I wonder if it could allow the necessary programming.

 

[Alfiedagr8]

So then the only way would be to reprogram the PCM so that it sends that inferred reading to the cluster.

I was about to buy a ford ids vcm for various reasons I wonder if it could allow the necessary programming.

No it will not. IDS can only program factory stuff you cannot change a thing. You can mix and match either. I have one. Trust me.


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[sportinawoody]

why couldnt the egr measure boost thru the exhaust side of the egr ? its all math and im sure the added pressure thru the exhaust can be measured thru logic. im way behind you guys but it seems a relevant question

 

[19COBRA93]

why couldnt the egr measure boost thru the exhaust side of the egr ? its all math and im sure the added pressure thru the exhaust can be measured thru logic. im way behind you guys but it seems a relevant question

There are too many variables that would effect exhaust pressure. Mufflers, cats, pipe diameter, boost level/air flow, timing, exhaust temps, etc. Those would all have an effect on exhaust pressure. There would be no way to accurately calculate boost level based on exhaust pressure, unless the variables were all fixed and known. Unfortunately you would need a team of sensors to continually read and calculate it.

The most accurate way to read boost pressure would be to simply T off the single vacuum line between the intake and the FRPS.

 

[TexasBlownV8]

If the issue is simply a matter of providing a boost-controlled voltage, use of a simple boost sensor would provide that, maybe along with some minor supporting circuitry for proper calibration.
But if the pcm can't provide the signal to the instrument cluster, it doesn't matter what the sensor-side is all about.