Anyone know if this part is legit?

 

Connector is wrong also , but I can be wrong as not having the supercharged Mass Air Flow

XKR is a V - 8

Genuine Air Box-air Flow Meter-4.0 Litre Supercharged (4.0 Litre Supercharged) For Jaguar Xj 1995 - 1997 (from 720125 To 812255) Classic | Jaguar Land Rover Classic Parts



LNE1600BB found here

LNE1620BB - Jaguar Air flow sensor | Jaguar Land Rover Classic Parts

 

https://www.autozone.com/engine-mana...271/178897_0_0

considering they are made of Unobtainium

 

The problem with the Autozone offering is by the time you get it it may be for the more common normally aspirated version and not be a proper match for your maps in the supercharged ECU as they are different.

As an example the flow rates on the fuel injectors ( as the injectors are different on the superchargerd engine ) are about twice the amount of fuel metering flow

So the injctor pulsewidth at idle should be about half the normally asperated

The current one that you have should read about 1.2 volts DC on X color wire as the return wire to the ECU at proper idle speed

Someone in New Zealand plotted the data points as he throttled up as you should be approaching 5 volts

This test would show that the MAF is alive and not a calibration

There was some people on other cars that was able to make a calibration flow plate and vacuum cleaner

The power to the MAF is from the large # 5 right ECU control relay as B + power and not a specific 5.0 reference voltage like on other engine sensors

You can swap or replace this relay if it is compromised ( current limited )

There is a splice on the power source wire to the MAF that can also be compromised

Vee had a suggestion to slightly twist the pins / blades on the MAF to make better contact

As an engineering rule of thumb for every 1.0 liter of displacement at 600 ( or 700 can't remember ) RPM the engine should draw 1.0 grams / sec , this can be seen on a ELM 327 reader / decice

So you should see about 4.5 grams / sec on your engine going up to 225 for the supercharged and 175 for the normally aspirated

 

Some of the ELM 327 devices from reading have a error in the MAF value in the devices software

the value must be multiplied by 10 or 100 to be correct

 

Thanks for the info Parker. I'm hoping that the quick fix I did this AM will see me through. I did a ECU drain/reset. This seems to have eliminated the bogus data (header install necessitated the removal of the 2nd air pump, the EGR pump, primary Cats, and repositioning the O2 sensors.

 

Jagstuart<

Dont know if you come right but I have been down this rabbit hole!

You will struggle finding a new and or reman unit .., only one place that "apparently" can do this in California and it seemed they weren't too keen either!? Trust me I searched far & wide .., that were years ago though ..,

What has worked on mine and another old Jag mechanic friend of mine were what Vee (or Katar) suggested on here a few years ago .., too clean the sensor very very carefully with Maf Sensor / Electronic cleaner. Very important to not use something that will leave any residue (or too abrasive) on the very sensitive wires. I used CRC Maf Cleaner with good results.

You will have to drill out the pop rivets and carefully remove the sensor unit to clean properly then use screws to securely fit the sensor unit back again for possible future cleaning.

If unclear let me know and I will give better details.

Please do share if you found a source that can get these Sensors new and or reconditioned to proper specs.

Ps. XJR6 will only work correctly with the LNA1620AA and NOT the LHE1620AA. If swopped your fuel trims will be way out!

 

The majority of the MAF sensor failures from reading is silicone migration damage of the MAF sensor electronics package different then the Thermistor bulb ( in the airstream ) cleaning with MAF cleaner

Certainly, you can properly clean the airstream components and one of the airstream components is a heating bar that may be replaced with a Lucus normally aspirated X300 version ( maybe , but it may be close ) but the actual thermistor sourcing is subject to a class action lawsuit in all cars to prevent individuals from repairing their own vs. buying a whole MAF unit

The repair consumer won

The thermistors come in many different performance profile ranges to match the maps ( data arrays ) in the ECU

On the airstream comp

Now , how to you correct that ?

But it does give hope of recovering your original MAF

Eat that lawyers

Doc coming

NTC Thermistor to TMP6 Linear Thermistor Replacement Guide (ti.com)

and

Thermistors product selection | TI.com

and

 

Have you tested / calibrated the inlet air temp sensor downstream of the MAF ?

The MAF in it's sensing value / number would be considered as raw data until it is calibrated with the ambient flow gas temp and recalculated in the ECU for it to work with as a true value

I don't know what specifically you are seeing to target the MAF as a fault , codes ?

The inlet air temp sensor can be calibrated against a chart on page X of the Jaguar 801s Doc

or you can pic the garage temp as a single test point to see if it is alive on the ECU return wire

I understand your inlet air temp sensor is really buried on your SC engine

 

Hi Parker 7,

Interesting to know it's actually the Silicone that eventually damages the electronics .., or at least one of the causes.

Will have a proper read through the article you posted when time permits - busy now with my rear shock removal (bushes needs changing actually only the top shock isolator bushes but will do the others as well as its not a 5 min job).

Luckily I am good for the moment re a working MAF. Reading 4.5 @ idle P (650 rpms)

But I do hope there will be an alternative Maf available soon again for the XJR's .., when I looked around there were many advertised as the correct sensor for the XJR's but when I stared asking more questions it became clear they were not the correct ones! Wrongly advertised!

I do believe there to be many XJR owners over the years that have had the wrong (LHE1620AA / Normally Aspirated) sensor installed .., I actually found one on a XJR in the scrap yard over here that had the N/A version ..,

When I had my TB cleaned (SC removed) I gave my inlet air temp sensor a thorough clean ..,

 

It sounds like there might be enough interest to warrant me engineering a replacement MAF for XJR6 (LNA1620AA) cars using a later generation "drop-in" element, and fine tuning the cross-sectional area of the AFM body to give the correct transfer function to match the voltage to airflow curve in the ECU.

In the meantime, your best chances of finding an XJR6 MAF is a breakers yards.

 

You would have to take into account those that have a higher flow rate then the factory setup of standard pulley , impellors . and intercooler pumps

 

The transfer function of any alternative MAF that I engineered really ought to match the voltage-airflow data in the ECU, which is "hard-coded", and cannot be changed. I use a different approach for anyone who has modified their engine in a such a way that it has increased the airflow by more than about 10%. This was necessary when I modified my own engine by fitting an M112 supercharger.

 

Increasing The fuel pressure to make up for the data maps that only allow for a max value of pulse width ?

The fuel pressure may and I say may be able by a modification of the existing FPR ,

On the max side pulse width is one thing but on the other end is idling concerns if too much fuel for a existing short pulse width limits

The original data maps may have a margin on the high side and low side

 

I use standard size injectors and fuel rail pressure on my XJR with an Eaton M112 supercharger (22% increased airflow). I have just reprogrammed the AFR in the main fuel map to compensate for the MAF not being able to measure the increased air airflow, above 1018kg/hr, which occurs at about 4000rpm wide open throttle. Below this speed and load all of the engine ECU calibration is standard.