Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing TMAP sensor accuracy not great

Not really but it did successfully re-calibrated the sensor so the ecu received the actual air temp and that was my goal. I did leave the sensor biased a little in the other direction, maybe 5%. I wouldn’t say that I noticed any driving difference after fitting the filter or the resistor but then again I’m probably not the best driver for accessing that.

The sensor and air filter mod are all stripped out now anyway as I have returned my car to standard ready for sale, but it was a fun exercise….

My first thoughts were how accurate is your thermo couple measuring system, with 3 units all displaying a similar error?

Graham Bell in his book
Modern Engine Tuning
Has tested many potential upgrades and tweeks. He quotes actual measured differences.
Re IAT.....he quotes a rough estimate of power increase as

10degC gives about 1% increase.

On my Plus8 (Rover with Gems) my ODB reader shows IAT as sensed.
I did a check of engine heat effect.
At 15degC ambient the IAT measured by the sensor was 35degC and rising slowly. My intake trumpet points roughly towards the side louvres but the cast exhaust manufold is below it. Not the best!
I would like cooler air but routing it is not easy due to lack of room.
My first option is fitting the John Taylor bonnet rear catch extenders I just bought to see if better venting helps. I will try actual measurements, time permitting.
I have not had a rolling road test done so no idea of actual bhp so for the time being it will be simply IAT measurements.
Perhaps shielding the air intake is another fix to divert the hot air away.
Just an add on.....
I will use a thermometer to check the accuracy of the IAT readings I have a digital one and will stuff the probe into the air intake and set it to record/print the readings and compare.
No....I am not an alien with probe experience!

Reasonably accurate I would hope as the test equipment used is on 12 months routine calibration.

Any changes to my 1994 +8 to improve air flow or exhaust performance really do very little unless the ECU is rechipped. I have the Tornado chip installed and have improved the airflow by creating a cold air ram input behind the front wheel which takes air via tubing to the air box (modified trumpet) and a K&N cone filter. The exhaust is free flowing after the Cat. A noticeable increase in acceleration and performance in the mid range and overall smoother run with increased efficiency.

My aims are to reduce under bonnet temperatures generally. It gets damn warm under there. I have measured nearly 50degC on the air filter container (polished stainless).
A better airflow is the aim to help man@ge this plus aid rad airflow. No overheating issues but just want reduced heat.
The Tornado chip is a good route for performance but not interested (yet!).

Roger, respect to anyone with the capability to carry out this tech stuff 'in house'

Thanks Jon

My hare-brained plan was to break in over the back of the thermistor with a scalpel and 'hope' that I might get a pot in series. I got lucky…