Measuring resistance from 7 to 8 will provide difficult to interpret results. The best way to check the AFM slider is to put battery voltage across 9 to 6 (positive on 9, negative on 6), and then measure the voltage between 7 and 8 while you move the wiper around. This process is documented on page EE-13 of the 77 FSM)

The AFM is Dr. Bosch black magic and voodoo.

As for the dent in the wiper? I don't know what you mean. Can you circle what you're talking about on your pic?

Repairing a fuel injected car can be a pain in th A*se..😭

I would before doing anything to all the sensors in the system advice to FIRST do a compression test on the engine so you KNOW that the engine is mechanicaly in good order! Very important as with the electronics on these cars many things can go wrong. (Buy a good compression meter not expensive.)

Then also check every vacuum line and all the rubber hoses in the inlet system.. a small leak will throw the systems ECCS* (NOT A ECU, how many times do i have to say this... sorry.. anyhow..) the ECCS* get complete faulty readings when there is a air leak even a smallest one will ruin how the engine will run.

Also, Cleaning the electric contact with a good contactcleaner, like they use in boating is a good one look it up!

Cleaning contacts can be a temporary thing when you do it with a nail file, i would be very careful with those.. (At first the contacts will work but later on they will fail if they were silver or gold contacts.)

A lot of contacts have golden or silver contact points.. Golden contacts should really be cleaned with contact cleaner (or alcohol) as also silver contacts (But not necessarily on silver) @Yarb ) Copper contacts can be cleaned up with a small (nail) file without a problem.)

As a (ex) electronics guy i also know in audio there were a LOT of silver contacts and.. not many people i think know this:

Oxidized silver conducts electricity even better than silver itself! Really! So cleaning the silver-plated contacts is completely unnecessary and harmful, because you're making the silver layer even thinner.

Again, the conductivity of rusted (black!) silver is BETTER than of silver itself!

Further, as we all know gold does not rust so that is not a problem, clean it with alcohol and a cotton swab.

ECCS is what Nissan called the computer for the ZX's. The 280Z's used an ECU. He has a 1978 280Z.

At best you could correct people for adding the E. Electronic or electrical control unit.

I think he's talking about the bend in the wiper arm.

15 hours ago, Zed Head said:

I think he's talking about the bend in the wiper arm.

I'm almost... say 95% sure that bend in that contact arm is original.. It's there for adding just a little more stability to the contactarm.

Little update as I don’t have much time to work on the car. After connecting the AFM to a spare battery and testing the voltage on pin 7 I noticed very inconsistent voltage readings and a lot of gaps in the carbon track even though it doesn’t look damaged. And yes I know the AFM has a logarithmic scale with a range of 0 – 9 Volt, Its basically just a voltage divider and a potentiometer in one. Here is a picture I found together with the link and some other useful links (last one is for a Range Rover but it’s the same concept and same Bosch style AFM).

https://www.atlanticz.ca/zclub/techtips/afm/sizeupgrade/index.html

https://www.atlanticz.ca/zclub/techtips/afm/index.html

https://www.gomog.com/allmorgan/AFMadjust.html

After a bunch of searching I did fine more reference pictures of the Datsun 7 pin AFM’s and other Bosch AFM modules of the same type, that bend is 100% not supposed to be there. I did notice that if I press the copper part of the wiper hard against the carbon track I do get some sort of reading but so maybe somebody tried to “fix” the AFM by bending the wiper. Unfortunately the track has failed in its entirely and I can’t find anybody that can fix the circuit board. Enlarging the bolt slots and moving the wiper to a fresher part of the track also didn’t work.

This lead me deep into the Bosch AFM rabbit hole that is the world of Datsun / BMW / Porsche forums. I found an Australian forum post that mentions a slightly larger 90’s Toyota AFM being plug and play for his L28E 280Z(X?) with the part number F201 13 210 (197100-3420). This is also a 7 pin style AFM With the same internal (and pin) layout as the Datsun 7 pin AFM’s. When looking if I could find this AFM in Europe I actually found one at a local junkyard from a 1988-1992 2.2i GT Turbo 12V Ford (USA) Probe for €25,- so I ordered it immediately to try and test this theory (same AFM was also used on the Mazda 626 and 929, also found a part number from Standerd "MF9107"). The original post did mention you need to loosen the tension on the flap by 3 teeth as the flap is bigger than the Datsun AFM’s.

https://www.viczcar.com/forums/topic/6951-larger-afm-for-a-280zx

If this doesn’t work I will continue to look for an replacement Datsun AFM that doesn’t break the bank (I know, that’s a tough one). I might also look into making a custom plug and play MAF swap. I found a US based company called Split Second that makes MAF to AFM conversion modules and MAF conversion kits for BMW’s. They also have a 0-9 Volt module (PSC1-009) that might work with the stock Datsun ECU in theory.

https://splitsec.com/product/psc1-009-programmable-signal-calibrator-afm-to-maf-hv-output

https://splitsec.com/wp-content/uploads/technotes/TN2_AFM_to_MAF_Conversion.pdf

And yes I will post all my findings online as there isn’t much information to be found about AFM sensors and there alternatives. Also no I don’t want to carb swap my car, I want to stay EFI but don’t want to spend thousands yet to upgrade the entire EFI system.

If anybody has a 0-5 Volt (or 5-0 Volt) AFM module that needs a rebuild / modernization I found an interesting company in Switzerland called SyncroSweets that swaps the wiper potentiometer for a modern programable potentiometer that’s plug and play.

https://www.syncrosweets.ch/en/luftmengenmesser

Edited September 9Sep 9 by Mitchel0407
Added details about the Ford Probe AFM donor car

Good news! First off, the Ford/Mazda/Toyota (and so on) AFM actually works! In my opinion this is a huge win for everybody that wants to keep these cars alive.

I started of by opening up the new AFM and having a look inside. To open the new AFM was a bit more difficult than the Datsun AFM as they used a ton of silicon sealant and plugged the idle air screw from factory. The sealant can be carefully removed with a knife and the plug can be drilled out to access the idle air screw. Inside the AFM looks a lot like the Datsun unit with the exact same functionality. The resistance values between pin 6-8 and 8-9 where higher then the Datsun AFM but I still hooked the AFM up to a 12 volt battery to check for the voltage outputs as that actually matters for the stock Datsun ECU.

In stock configuration from the junkyard Ford (USA) Probe the AFM gave a reverse logarithmic signal range from 1,42 to 7,77 volt. Starting at 1,42 volts when the AFM is closed and then rising quickly to around 5 volts before slowly climbing up to 7,77 volts. This is within range of what I was expecting so I decided to try and install the AFM into the car to test it out and try and dial it in.

The new AFM is significantly larger than the old Datsun AFM. To install the new AFM, the intake booth and the rubber booth between the AFM and throttle body, needed to strech over the larger AFM unit. Luckly both where flexible enough and didn’t tear. The stock electrical connector just plugs right in so that was great. The new AFM unit unfortunately doesn’t have bolt holes in the bottom like the Datsun unit but mounting can be fixed by a custom 3D printed or metal bracket. I just left mine loos as I just needed to test it for now and drive to the inspection station.

I had to tighten the spring (clockwise) a bit more than the 3 teeth described in the Australian forum post but that may be due to my engine having other issues causing the car to run rich. After installing the car fired straight up and with a bit of tightening and loosening of the spring I got the car to run way better than before. One nice thing about the new AFM is that you can adjust the spring gear a lot easier. Just carefully lift the little arm to the left and use your finger or a flathead screwdriver to adjust the gear. Then just let the little arm go and make sure is seated properly (rotate the gear anti clockwise a bit to properly seat it). The blue mark was the original tooth position but in the picture I rotated the gear the wrong way.

As a side note I did clean my injectors and replace the fuel pressure regulator at the same time. I also found out my AAR was faulty and leaking a lot of air past the valve so I disconnected that and plugged both sides of the hose. The cheap meter I installed said about 28psi which is low but as the car is running rich and not lean I will exclude the FPR and fuel pump as a problem for now. My injector are probably just bad which sucks but the car still runs good enough for now. I also replaced my Bosch spark plugs for NGK BR6ES with 1,05mm gap and a replaced my 1,5 Ohm ignition coil with a 0,6 Ohm one just in case.

I had the car inspected yesterday and the CO gas values where down to 2,4% (4,5% allowed) and all other values where good so I’m happy. Although the car ended up failing due to rusted thru frame rails and a crooked rear axle probably caused by a twisted chassis. I started a legal dispute with the auction company and previous owner as the both sold the car as “without rust and free from structural damage” but that is something for another thread.

This probably the end of this thread. Although feel free to revive it if somebody has any questions and I’ll try to help out. I believe that posting information like this will help massively to understand these cars and keep them alive .

Edited 2 hours ago2 hr by Mitchel0407
Spelling and extra information

Happy ending on the 280z injection, well done Mitchel!

Repair on these injection systems can be opening a big can of worms!

I hope to put my engine back into the car in the next 1-2 years and hopefully it wil still run as good as it came out but one never knows for sure..

I got myself a injection test meter for these systems original from Nissan/Datsun! So if you want to test your system with this special tool we can do that some time.

Which auction house screwed you with the rustfree nonsens?

Greetings from Limburg, Mart.

The special meter.. (Never used? and 40+ years old..)

2 minutes ago, dutchzcarguy said:

Which auction house screwed you with the rustfree nonsens?

Route 66 Auctions wich is owned by E&R Classics in Waalwijk (The Netherlands).

Honestly I don’t recommend ever buying a car through there auction. The bidding was vague and none transparent as you can’t see who bid on the car. I don’t need to know the bidders name but some reference or time stamped bidding history would have been nice as I strongly suspect the seller was driving the price up. The auction fee was also pretty high (9% + 21% tax on the 9% auction fee) especially for the lack of service and buyers protection the auction company offers.

I already had contact with them over the phone, the guy told me to send an email to there administration and hung up on me. That was pretty rude but fine. So I emailed my findings to there administration and this morning I got an email in which they tell me “the condition of a vehicle can be subject to a persons perception”.  I get this but then they shouldn’t have claimed the car was free of rust and structural damage.

Basically they try and tell me to just get lost. This will be the first and last time I will ever buy a car from or through that company.

11 minutes ago, dutchzcarguy said:

The special meter.. (Never used? and 40+ years old..)

That’s an awesome piece of kit! Once the car has been repair and on the road again I’ll come visit to test it out!