When I was looking at my AFM, I noticed one of the contacts was corroded. Actually both sides of one of the contacts were corroded. I tried to clean them, but didnt do a very good job. Could this cause my 3500rpm studder, and my shitty idle? If it makes a difference, my Autometer A/F guage doesent work too well. It doesent cycle on/off with the oxygen sensor. Could I use a N/A AFM with my TII? I have an extra one laying around. If not how much can I expect to pay for a used one. And is there a way to get the prong out of the harness, so I can clean it better? I would prefer not to soder a whole new harness on there.

 

Hey, the AFM's for an N/A and TII are different, at least their part numbers are different. Probably differently calibrated. As far as the AFM causing your problems, yes, that's quite possible. To test, my suggestion is this: Get access to the flap in the AFM. Pull the rubber protector off the connector just enough to enable you to get access to the green/blue stripe wire connector pin. Meter this to ground. Turn on the ignition. It should read < 1V. Now slowly push on the flap, until it is wide open. The voltage should increase perfectly linearly to about 5V. If this all works, the air flow part of the AFM is working. The other thing that could mess you up is the air temp sensor in the AFM. For a numbering convention, let's assume the AFM has the black thingy on top and the pin towards the front is 1. With the engine off and the unit uplugged, the resistance reading across pins 5 (or 3, if 5 is corroded) should be about 2,000 ohms (80 degrees in engine compartment). It will be less if it is hotter in the engine compartment, more if it is colder. Checking for corrosion, pins 1 & 2 are the fuel pump switch (this has got to be working, or your car would start and never stay running), pins 3,4,5 are voltage supply pins (pins 3 & 5 are the same connection (so if one is corroded, no big deal), pin 6 is the air flow signal, and pin 7 is the intake air temp signal. From this, you can determine what the bad pin affects.

I paid $40 for an N/A AFM a couple of years ago. I don't know what they get for a TII one. Also, taking apart the old one won't give you any better access to the pins for cleaning. I know, I took one apart.

Lemme know if you have any questions.
Irv, Keith's dad

 

I knew you would come through Irv. As I remember, the pin directly in the middle is corroded. As far as cleaning, I was referrring to cleaning the harness side of the AFM, So I wouldnt have to soder a new black AFM harness on, but I would get a new AFM.

 

up

 

Yeah, that pin is the 5V reference voltage for the AFM, it won't work well without it. I will check the pins on my car tomorrow.

Irv, Keith's dad

 

The air flow meters are different,N/A can measure up to 600 cubic meters/hr,the TII-720 m3/hr.You can use contact cleaner(the chemical kind) and then use a dielectric grease on the connectors before closing them.

 

Thank you Irv, and Six. Id would really like to stay away from replacing this, as I am FLAT broke. Ill go to the local autoparts store, and hardware store, and see if I can find some contact cleaner. Again thanks guys.