Testing the XJ40's Air Flow meter
#1
Testing the XJ40's Air Flow meter
John Pring & Dana Haydel on the Jag-Lovers website have written a document on testing the XJ40's Air Flow Meter. I tried to read it, but I was having trouble - someone has really bodged the html.
See what I mean by clicking here:
11.9 Air Flow Meter
It's important to be able to test before replacing one since I just read where the cost of a rebuilt one is $465.95 each, with a charge of $200 for a rebuildable core.
Some symptoms of a bad one are:
It is now infinitely more usable than the original.
I needed this document and can think of two fellows here who need to read this and test theirs. I thought I would share the rework with all who's interested.
We can now all TEST the MAF, hopefully to fix it by cleaning the connectors or repairing the wiring without having to replace it. Or if it really needs replacing, you'll know it for certain.
PS feel free to inform me of any errors you find in it. I can easily make corrections.
See what I mean by clicking here:
11.9 Air Flow Meter
It's important to be able to test before replacing one since I just read where the cost of a rebuilt one is $465.95 each, with a charge of $200 for a rebuildable core.
Some symptoms of a bad one are:
- poor running conditions
- possibly responsible for a NO START condition and
- potential generation of a fault code (DTC 12)
It is now infinitely more usable than the original.
I needed this document and can think of two fellows here who need to read this and test theirs. I thought I would share the rework with all who's interested.
We can now all TEST the MAF, hopefully to fix it by cleaning the connectors or repairing the wiring without having to replace it. Or if it really needs replacing, you'll know it for certain.
PS feel free to inform me of any errors you find in it. I can easily make corrections.
#2
Originally Posted by John Pring & Dana Haydel (on Jag-Lovers)
Electrical conductivity problems may be resolved by simple cleaning of the connector pins using a quality electronic component cleaner. It may be necessary to bend each male connector pins (in the MAF sensor housing) slightly to insure good connectivity. Pin layout is according to the figure below. Pin 36 is towards the front of the car. Pin identifiers may change from model to model, but the basic function remains the same.
I inspected another diagram for a 1990+, and there were only 5 wires. I somewhat expected this since there is NO manual idle trim adjustment on these models.
#3
The sixth wire on the Air Mass Meters from 1988 to 1990 was simply a ground connected to the housing of the meter. For 1991 and later they decided it wasn't needed. The attached page is the only place I know of that actually depicts that expressly. The page actually applies to the 4.0L AJ6, but the circuits are the same as the 3.6L. It also shows the GR wire as the Idle Trim circuit, and that it was there for '93-'94, but was unused.
Cheers,
Cheers,
The following users liked this post:
Don B (10-31-2020)
#4
Thanks for the addition, Steve.
~~~~~~~~~~~~~~~~~~~~
Here are two pages consisting of an Engine Management Schematic and ECU tests for an XJ6 and VDP 1988 MY. Some of you may recall and recognize this as I posted it earlier on rcarpenter's thread, 88 Vanden Plas still won't start
I've included it here because it not only includes the Air Mass Meter (AMM) on the schematic (from which the above .jpg was taken) but also includes some test procedures (KEY ON, KEY OFF) for it on the first page.
It identifies the 6 AMM pins, 3 of which are GROUNDS -
Engine_Management-XJ6&VDP_1988MY.pdf
NOTE: Wiring Color Codes
~~~~~~~~~~~~~~~~~~~~
Here are two pages consisting of an Engine Management Schematic and ECU tests for an XJ6 and VDP 1988 MY. Some of you may recall and recognize this as I posted it earlier on rcarpenter's thread, 88 Vanden Plas still won't start
I've included it here because it not only includes the Air Mass Meter (AMM) on the schematic (from which the above .jpg was taken) but also includes some test procedures (KEY ON, KEY OFF) for it on the first page.
It identifies the 6 AMM pins, 3 of which are GROUNDS -
- 2 of which (AMM connector pins LI19-1 and LI19-2, BO wires) send their combined ground signals to ECU pin, LI2-3, BO, and
- the third, LI33, is a Power Ground, B wire, connected to LIG32 which is an eyelet located on the Inlet Manifold/#2 Cylinder Firing Stud.
Engine_Management-XJ6&VDP_1988MY.pdf
NOTE: Wiring Color Codes
- N Brown ▇
- B Black ▇
- W White ▇
- K Pink ▇
- G Green ▇
- R Red ▇
- Y Yellow ▇
- O Orange ▇
- S Slate (or Gray) ▇
- L Light
- U Blue ▇
- P Purple ▇
Last edited by Trick Freestones; 05-10-2011 at 04:54 PM. Reason: changed .gif to .jpg, grammar
#5
@Trick Freestones
Hi,
I have a 1990 4.0 with the MAF that has an adjustment screw.
The resistance between pin 1 & 6 is set to 650 ohms.
how much does she listen to?
what is the right attitude?
Hi,
I have a 1990 4.0 with the MAF that has an adjustment screw.
The resistance between pin 1 & 6 is set to 650 ohms.
how much does she listen to?
what is the right attitude?
#6
Join Date: Feb 2014
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Hi Stojan,
Welcome to the Jaguar Forums! It's great to have you with us.
Note that the thread to which you have replied has had no activity since 2011.
Please visit the New Member Area - Intro a MUST and post an introduction so we can learn something about you and your Jaguar and give you a proper welcome.
Cheers,
Don
Welcome to the Jaguar Forums! It's great to have you with us.
Note that the thread to which you have replied has had no activity since 2011.
Please visit the New Member Area - Intro a MUST and post an introduction so we can learn something about you and your Jaguar and give you a proper welcome.
Cheers,
Don
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