Starts and Dies 88 spider

[Elio Comello]

Hi Aggie,
Here is the text for an article I recently wrote for the ARCC "Update"

Best regards, Elio

[aggie06]

ok, i have been working to get the car running. tried lots of things the biggest being getting the fuel injectors cleaned, but the issue still persisted.

the latest finding is i unpluged the air fuel meter and the car will sit and idle, its rough but it idles, could this be a bad AFM, and does anyone have a way to test to see if it is bad?

[ghnl]

I don't know of any easy way to test them. I have a spare if you would like to try substituting another one.

[Tifosi]

Somewhere out in the world I know I've seen a way to test using a multimeter.

Of course I can't find it right now or remember the exact process, but it had to do with connecting to specific terminals and then seeing how the resistance changed through the sweep of the flap. (as after all it is just a big potentiometer) Then another hookup to determine if the temp sensor 1 was functional and giving correct output for the given ambient temperature.

Useless post I know, but just wanted to make it known that if one spooks around enough, there is indeed a way to test an AFM without using special diagnostic equiptment.

***

Secondary thought:

Perhaps if there is a VW dealership nearby, and they've been there for a couple decades, they may have the diagnostic tool right there in house, and if there's any luck in the world, a mechanic that still remembers how to work with L-jet.

[aggie06]

let me ask is it reasonable to think it is an AFM issue being that the car will run with it unplugged and not run with it pluged in?

it seemed to make sense to me but could it lead to another issue. i have read that it is unusual for these to fail and cause issues.

[ghnl]

Google found this:

YouTube - Rejuvenating a Bosch Motronic Air Flow Meter

and this: refurbish your Bosch AFM

There's an AFM on eBay: item #200328400374

Or you can borrow my spare to decide if that's the problem or not. You won't need the whole filter housing - the AFM unbolts from the top half.

[aggie06]

well i fiddled with the car again tonight and found two things out.
1) if i start the car with the AFM plugged in but manual turned the potentiometer past midway and the car will run smoothly. if i let it drop past midway then it dies immediately.

2) i hooked up a 9V battery to the AFM and took a volt meter and checked the voltage as i turned the potentiameter. the voltage on the 3rd prong from left stayed constant +/-5V and the 4th prong would increase as i moved the potentiometer always increasing. the 5th would stay at 0V the whole time.

from the first test it made me think that the AFM was bad, but then after the 2nd test where the voltage changed i dont know. what do y'all think. Is anyone close in the Houston area with an AFM sitting around not being used so i could test with it.

[ghnl]

Pry the cover off the AFM and look inside. It seems most likely the way they'd fail is for the wiper arm to wear through the printed circuit board's wiper track. The link above (refurbish your AFM) describes a couple of ways to adjust the psoition of the wiper arm so it rides on virgin territory - thus restoring function to the AFM.

Also, does the flap in the AFM move smoothly through its range of motion. If it sticks or binds anywhere try to figure out why and remedy that. The flap must 'float' on the incoming air for the AFM to be able to meter the, umm, air flow.

And, of course it goes without saying (but for the sake of completeness I will say it) that all the intake air ducts & vacuum hoses must be installed/assembled for the engine to run.

[Tifosi]

Regarding the AFM connections: 2 of them are for the air temp sensor and not associated with the potentiometer. (that's what those two wires are in the still of the vid above)

[aggie06G-pa]

OK Bubba, this is your G-pa.
Any new results after FAM was checked?
aggie06G-pa

[aggie06]

Well i have worked on my old AFM and could not get the car to run so i got another one and the car did the same thing, so that tells me that the AFM must have been OK. Any other ideas. with the AFM past the half way mark on the potentiometer the car will run. Does anyone know if the ECU would have something iside of it that would let the car run with the AFM at half of the potentiometer.

My guess would be that it is something electrical, but that doesnt explane why it will run without the AFM plugged in (all be it poorly)

Ideas??? Im out of them.

[Tifosi]

In theory the engine can run without the AFM, (mine could, but only idle and really roughly), it just won't have an air flow or air temperature input to work with, so the ECU will default to some sickly rich safety map to prevent self incineration. Nothing you could ever drive obviously.

Quote:

Originally Posted by aggie06 pressure gauge as the car starts the pressure remains between 30 and 38 psi. One note as the car died the fuel pressure rose back to the initial pressure before turning the car over to start(38-psi)

[bianchi1]

peterlund.. you ment g.m. or chrysler..not ford.. we are doing ok

[aggie06G-pa]

OK guys---listen up. Aggie06 stated that he could get the engine to run at about 3,000 RPM and it ran well. If he just started it in the normal way, it would only idle for about 3 seconds. All fuel pumps were checked and are working nicely. Injectors have been cleaned and are working. Here is the good stuff---when the AFM is disconected, it will run at idle but not very well. But, when the flapper for the air intake is opened by hand, it idles and runs just like the great Alfa Romeo that it is. Everything is fine. A new AFM Bosch unit did not solve the problem. Therefore his old one may have been OK. I'm just an old duffer (his G-pa) and have had Alfas for years, but not these new ones. I currently have two Alfettas and a garage full of engines and parts. But none are for his 88 Spider. You younger guys have impressed me with your indepth knowledge about Alfas. But so far this Bosch system is eating our lunch. We would appreciate any new ideas or old ideas. And thanks for all the help so far from so many of you. In my hey day we had to write letters, or call John Shankel. I'm taking to much time--please think about this situation.

[peterlund]

Quote:

Originally Posted by bianchi1 peterlund.. you ment g.m. or chrysler..not ford.. we are doing ok