AMF cover removal

[Nitrate]

1981. 2000. What is the best technique to remove the AFM cover? Is this attached with silicone or some type of glue? I do not want to bugger up the cap. An Explanation from someone who has done it would be very helpfull. Thanks, RB

[Nitrate]

That should be AFM cover.

[4uall]

This might help

http://www.hiperformancestore.com/ljetronic.htm

Step 8 Air Flow Meter (note: I have enhanced adjustment instructions for the AFM on step 12)

The Air Flow Meter or AFM is one of the most expensive components of the L-Jetronic system. Fortunately they rarely wear out or fail and there are plenty of inexpensive used ones available. The AFM is simple in operation. Air entering from the air filter side pushes a little door open. As the volume of air increases it pushes the door open farther. The AFM measures how far the door opens to determine the volume of air. The AFM also measures the temperature of the air. These two bits of information are combined to determine the total number of air molecules entering the engine and that information is sent to the ECU. The ECU then uses this information to help decide how much fuel the engine needs and adjusts injector duration accordingly. Of course the ECU gets information from many sensors but at full throttle the AFM's signal is primary. That means if you want max power a properly operating AFM is critical.

* A bad AFM can cause the following problems: Difficult or impossible hot or cold starting, the starts and stalls syndrome, lack of power, high emissions, and irregular idle.

I am afraid the official Bosch procedures for checking these things are not too good. They recommend using a Bosch tester which I don't have, or probing with a volt meter. The problem with the volt meter method is the chance of damaging something is greater then the chance of finding a faulty AFM. There is a test involving our trusty ohm meter but it is entirely unreliable. This means we are down to basics here.

First, find the AFM's electrical connector. It's on the side closest to the driver and is basically just like the Bosch connectors you have dealt with on other components but it's bigger. Remove this connector and spray the connecting points with electrical contact cleaner and then reconnect it. Next, if you did not already do it, read Step 5 paragraphs 2 and 3 and make sure the microswitch enables the fuel pump to run. This also provides a nice opportunity to change air filters. Next you will need to remove the AFM's black plastic cover. The cover is sealed to the body of the AFM with a strong clear glue, probably an epoxy of some kind. Carefully cut away the glue with a sharp hobby knife and then pull the cover off. This is a time consuming process, just work slowly and carefully and don't break the plastic cover. Once the cover is off inspect the internal components for obvious damage and clean out any contaminants. If everything in there looks Ok it probably is. If you want to keep your AFM's stock settings put the cover back on and seal it with RTV silicone, preferably clear or black. If you are looking for a little more performance scroll down to the next paragraph.

Here is a stock GTV6 AFM sitting on my tool bench. This AFM is used on all GTV6 and 2.5 Milanos. The 3.0 Milanos have a similar AFM but it's a different part number.



@It's fairly easy to adjust the AFM to signal the ECU to send in a little more fuel. This mod gives a minor increase in power and better throttle response. It does not effect fuel economy but it can increase emissions. It's a simple reversible procedure. The AFM's door is held shut by spring pressure. We can reduce that spring pressure which will cause the door to open farther for a given amount of air volume. This will cause the AFM to signal the ECU for a little extra fuel. The procedure is simple. With the cover off look at the workings of the AFM and find the large wire shaped like a "W" and secured with a little bolt. That wire secures a gear and keeps the gear from turning. Mark the gear where it is secured by the wire (that's where my screwdriver is touching it in the photo below). Try to make the mark with a sharp knife so it will not wear off. Now hold the gear still and loosen the bolt securing the "W" shaped wire. Once the wire is free of the gear's teeth rotate the gear counter clockwise five or six teeth and secure it in that position by bolting the "W" shaped wire back into place. That's it! put the cover back on, secure it with silicone and you are done with the AFM.

This AFM's spring tension has been loosened five teeth. You can see the original setting on the gear which is marked by silver paint. Paint wears off, so be sure to make a little notch with a hobby knife so you can return it to its original setting if you need too.

[Nitrate]

During my research I found your article. Having a reference guide like that gave me the confidence to take a shot at tackling the AFM. EXCELLENT photos and write up. Seeing the photos with the arrows was a very big help for me. Thank you for reposting that. RB

[RRoller123]

Jay, the unofficial Librarian of this site, is Back!

[Frog2Spider]

Yo 4uall ...

I took your advice, and followed your instructions on the re-adjust of the AFC. This made a noticable different. Actually, quite an unbelievable difference! This is a great performance mode.
Cost nothing; easy to do; and made a very noticable difference in the throttle response.

What more could anyone ask for? That is unless you have any more little tricks you'd like to share?

Thanks a bunch!
Dave.

[4uall]

Jay, the unofficial Librarian of this site, is Back!

[4uall]

Yo 4uall ...

I took your advice, and followed your instructions on the re-adjust of the AFC. This made a noticable different. Actually, quite an unbelievable difference! This is a great performance mode.
Cost nothing; easy to do; and made a very noticable difference in the throttle response.

What more could anyone ask for? That is unless you have any more little tricks you'd like to share?

Thanks a bunch!
Dave.