I've seen a few of you guys with boost gauges mounted, I'm curious as too where you plumbed in the line/sensor.

Has anyone referenced the TMAP sensor voltage wire for a reading?
As I'm planning to possible run form the TMAP Volt into my data acquisition unit and just write a formula to convert back to a pressure reading.

Assuming something like Boost= (slope)(volts)- atmosphere pressure


Additionally, what kind of readings are you seeing at max boost? Specify year model with replies.

Seems:
The AJ26/27 setups see max 11.6 lbs (0.8 Bar) ? Pulled from the training manual

The AJ33 setups see 13 lbs (0.896 Bar)? Is this accurate?


Thank in advance

D. Fricke

 

Just a thought but is it not available via the OBD port?

 

Can't measure boost via OBD on the 4.0 or 4.2, the map is in the wrong place. You can on the 5.0 though.

 

Exactly. Good thought though JagV8.

If I can find the the volt/pressure relationship, I'd like to read off the TMAP rather than install an additional sensor if possible. Was curious is any has tried this. I might be able to contact the sensor manufacturer for the conversion if its not in the jag manuals. I located the older MAP sensor chart, but not the TMAP.

Regards,
D. Fricke

 

Why can't you read TMAP via OBD? (I guess non-standard OBD.)

I used Search but failed to find what TMAP is on this engine variant
Do tell....

 

2008 XKR has the AJ34S engine, there is no pressure sensor in the boosted part of the engine, only temperature. The MAP is located between the throttle body and the supercharger, so it only reads vacuum.

TMAP is on the 5.0L only. (Temperature-Manifold-Absolute-Pressure) sensor located in the outlet of one of the charge coolers.

 

Also, there is a boost line which runs from the outlet of the supercharger to the fuel pressure sensor, if you don't want to drill/tap a hole, you could probably just put a little tee in that rubber line.

 

That's what I did.

The stock Eaton (at least on my X100) would make 13-15psi depending on ambient temperature and whether I turned on the water/meth injection.

 

That's what I did.

The stock Eaton (at least on my X100) would make 13-15psi depending on ambient temperature and whether I turned on the water/meth injection.

 

Good thinking Cameron. That's probably what I'll setup for a manual reading, then see what that coverts to with the volts coming out the TMAP.

Per the shop manual for 2006-2009 4.2 actually does list a TMAP, or MAPT rather that is plumbed in on the front of the RH engine bank intercooler. (See attached)

Thanks for the help.

Regards,
D. Fricke

 

If it exists I expect OBD can read it.

 

Well I learnt something today.

Have you got the PID for the sensor & can you see it via obd?

 

I would guess the difference comes between the AJ33 and AJ34. In addition to the VVT, they added the pressure sensor.

Did the XJ ever get the VVT version of the supercharged engine?

 

The later XJR's and S-Type R's also got VVT, from 2006MY onwards.

My understanding was the AJ33S is with the STR/XJR (and XF SV8) charge cooler & intake setup, and the AJ34S is the XKR charge cooler & intake setup. Could be wrong though...

You have an AJ34S in your X103 XKR right Charlie?

 

I have a 2008 XKR 4.2 and I see boost pressure readings using Torque app for Android and a OBD to Bluetooth adapter.

 

I have not attempted to view the PID via OBD yet. I will look into it.

Are the Jaguar specific Paramter ID's listed anywhere with the Formula conversions?
Seems MAP and MAPT will be Jaguar specific PID and formulae.

The standard PID's are listed Wiki, anyone know of a creditable source that has standards with formulas published?

Regards,

D. Fricke

 

Most car makers deliberately choose non-standard PIDs with inconsistent formulae as part of their vendor lock-in strategy so don't expect to find anything published, let alone openly. It's time the authorities put an end to this anti-competitive nonsense but for now about all you can do is snoop the wires or just use IDS/SDD.

 

I thought that the AJ33S was the earlier 4.2L, independent of the charge cooler arrangement and the AJ34S was the minor update that got VVT, etc.

I don't really know that for sure though, I was just making an assumption (and going by what is listed in Wikipedia).

 

8 bit Im using the same app and am seeing 11psi max with 1.5lb. What is your max?

 

Alex, I asked a question about this on another thread about 2.5 years ago. The thread is here, my post is #5 and there's a potentially useful (to you) reply from Cambo immediately following - https://www.jaguarforums.com/forum/x...r-boost-62599/