Angel84-928

As part of the resurrection of my '84 I was performing some tests on the fuel injection system using the 928 Air Flow Control Service Information Manual. Pg 18 has some test values for Air Flow Sensor.

Terminals --- Test Values ---- My Readings
Pin 6 Pin 9 --- 200-400 ohms ---- 564
Pin 6 Pin 8 --- 130-260 ohms ---- 364
Pin 8 Pin 9 --- 70- 140 ohms ---- 202
Pin 6 Pin 7 --- 40- 300 ohms ---- 101
Pin 7 Pin 8 --- 100-500 ohms ---- 302

Is there a schematic available for this unit? Can those high reading be adjusted down or is it just signs of an aging unit?

Fabio421

AFC? Do you mean air flow meter (AFM) ?

Angel84-928

Si

Edit: Fixed

Mrmerlin

does this chart or manual you have cover the 84 Euro, i am having problems and would like to find out more info?? My car runs rough and feels like its chugging when I drive it

Forgot to add my car has the 2.2 LH system so it has a Mass airflow sensor

Fabio421

Angel, the "door" swings against a copper track. You can clean up that track with an eraser for better reading. But to answer your question, the AFM can be adjusted. The proceedure is in the WSM.

Angel84-928

This manual focuses on the L-Jet. '84 Euro should be running LH, right? The WSM has a pretty good troubleshooting guide for LH. Hmmm. Let me look at all the files I have. I might something on it.

PM Mark (Tampa928) he might be able to help you out.

Fabio421

Are you off work already? If so call me.

Angel84-928

Nope, not off work.
After you told me that the AFM adjustment procedures were in the WSM I found a similar test there but its showed different test values for AFMs built after Date Code 044. Mine has date code 250 which puts my reading within.

So I've ruled out:
1. Relay (checked good)
2. the wiring to the Injectors (Noid & resistance checks all the way back to the CE panel)
4. inductance readings for each injector is good.
3. grounds (Checked)
3. the AFM (readings are within new test values)
3. Fuel pump (plenty of pressure)
4. Spark (inductance tester)

All that is left is checking each injector's actual flow. I can get the car to start but to keep it running I have to push the accelerator down above 3k rpm. I'll be building my own Inj checker this week to actually see them spray.

If that doesn't work, I'll be out of ideas.

Tampa 928s

I have an idea on your inj tester I may build one myself.

I have an old fuel pump from my Buick GN and plan on using it.

Take the pump with a long hose into a "Fuel, Toluene, alcohol etc. gas source. Place a fuel line over the inj and rig up a 12v source with a switch "away from the fuel source". Take a clear jar with a lid cut out for the Inj and fire it up. I suppose you could time and measure the fuel delivery amount to see if they are all flowing the same. At a minimum you will see the spray pattern or lack of there.
Good luck

Angel84-928

This is the route I'm taking:


Bosch Injector connector, momentary switch & 12vdc source are easy to put together. I'm not a fan of the "old fuel pump" rig.

Tampa 928s

Watch out you may get on the terrorist watch list, looks like a pipe bomb to me

Jack Riffle

Angel, I have to wonder if your problem isn't fuel related. Have you checked the fuel pump output?

hacker-pschorr

Have you run the car long enough to reach full warm up?

You said "plenty of pressure" what is the pressure? Did you check both regulators?

There is always the chance of a major vacuum leak

Green wire? Ignition amplifier?

I'll think of a few more things as the day goes on.

Angel84-928

I have a pressure gauge on the fuel rail and its reading a steady 35 psi.

I've run it for about 5 full min. Maybe not enough.

I have a pressure gauge on the fuel rail and its reading a steady 35 psi.

I pressurized the intake and found the small "O" ring of injector 3 missing. Fixed that and now zero leaks. Still no runny though.

Wouldn't a bad Green wire keep it from running at all? I'll look at this closer.

Can you expand on this? Is it the silver box on the passenger side, forward part of the engine compartment.

Keep'em comming!

Thank guys! I really appreciate the inputs. Daytona Here I come!! (with a little help from my friends)

Angel84-928

Update on my contraption. Put it together and it works!! I tested an extra injector I had laying around and I got no flow. I took the driver's side rail off and tested #5 and it sprays!!
I really don't like the pattern but it puts fuel out. Good enough for right now. I'm running to the store for some Kerosene to test the other three. Tomorrow I'll work on the Passenger side injectors.

At first glance my injector tester looks full on ghetto but it works. I feel like a mini-McGyver almost.