checking L-jetronic airflow meters

Clarence Wood clarencewood at centuryinter.net
Fri Jun 18 20:23:28 GMT 1999


Hi Greg and all,
  At last I can strut my stuff! (:>
  I have a 1982 280zx Turbo and had to replace my AFM.  Before you go for the expense do the following:
  Either completely remove the AFM from the car, which makes it easier to work on, or remove the cap that covers the variable resistor and electronics; this cap is held in place by what appears to be a silicon glue, use a sharp knife and cut around the cap edge where it meets the metal then carefully pry off; if the cap lifts a little you can slip the cutting instrument under the cap and cut the holding agent.  The important thing here, is that the resistance, as the air flap is opened, will go up and then go down, in other words it is not linear, so unless you have a good AFM to compare yours against you can't really determine if the resistance is correct.  
  Once the cap is off, look for signs of wear on the carbon surface where the 'brush' rubs as the air flap is opened.  If there is an obvious wear spot in the wide open area, or in any other area, you can patch this by purchasing some "Quick Grid" repair resin made by Loctite (you can get this at AutoZone or any other auto parts store, sold to repair rear defogger units on cars; its a liquid conductor made with silver; about $8.00 for a very small, .05 fl oz, 1.4ml bottle).  Using a small brush, coat the worn area on the AFM; do this a couple times. 
  

At 03:29 PM 6/17/99 -0500, you wrote:
>How can a Bosch L-jetronic airflow meter be checked out? Or even set to
>factory specs? I have a 83 nissan turbo car that running terrible on the
>top end. It's dumping so much fuel as to stall the motor. Checked all
>sensors thoroughly except the flow meter. Not sure how to know if it is
>set right or even reading right. Factory manuals say to just check for
>continuity. I think it's based on a 5 volt refernce signal that lessens
>as the airflow increases. CAn I tap into one of the lines and just
>measure voltage or what? Even used meters are going for upwards of $200,
>so replacement will only be done if I can tell if this one is bad.
>Somebody has "been in it" already, so no telling where the spring
>tension has been moved to. Any ideas or advice?
>greg
>
>
>



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