Air Flow Meter Problems - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 8 (permalink) Old 12-28-2014, 08:42 PM Thread Starter
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Air Flow Meter Problems

Hello,

I am restoring an 86 Spider for my son and it was running reasonably well before I began doing some under hood clean up. It's been three months since I ran it and it turns over but wont start. I checked the fuse behind the passenger seat, jumped the battery to assure strong voltage, etc.

On Centerline there is a technical article that instructs to push in the flap of the AFM with the ignition on and the relay behing the drivers seat will click on to send fuel to the injectors. I dont hear a click.

Is there a way to check if the AFM is sending the signal and the relay is not working? Or is there a way to check the relay in general.

I did remove the cover off the AFM and cleaned the connectors and contacts but no luck.

Any help would be greatly appreciated!
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post #2 of 8 (permalink) Old 12-29-2014, 04:18 PM
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Good source for Bosch FI troubleshooting:
L-jetronic Fuel Injection Technical Troubleshooting Article
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post #3 of 8 (permalink) Old 12-30-2014, 05:57 AM
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Quote:
Originally Posted by alfa4419 View Post
On Centerline there is a technical article that instructs to push in the flap of the AFM with the ignition on and the relay behing the drivers seat will click on to send fuel to the injectors. I dont hear a click.
That info is misleading. The Alfa Romeo GTV6 has a switch in the AFM to power on the fuel pumps. The Spider does not. The Spider has a drive relay that gets a tachymetric signal from the coil to 'know' the engine is running & thus send power to the fuel pumps. To ensure the pumps get power during cranking (before the engine starts) there is a by-pass circuit when the key is in the 'start' position.

Go through all the checks in the L-jet diagnosis page. Also (perhaps firstly) check system voltage during cranking. It can sound like it is cranking over OK but if voltage drops below ~ 10.5V the computers will not power on. Don't use a dash gauge (if your car has one) for this test - they are not designed to measure during cranking. Connect a voltmeter to the battery. With everything off, a fully charged battery should show ~ 12.6V. Now see what it reads during cranking. If it drops below 10.5V check all connections between the battery & starter - including & especially the ground cable's connection to the body and the ground strap between the bellhousing & the body (in the transmission tunnel).

- - Eric
don't read this
~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


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post #4 of 8 (permalink) Old 12-31-2014, 11:02 AM Thread Starter
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Thank you for that! I believe the problem is that I am not getting fuel to the injectors, so was stuck on the AFM. I jumpered the fuel pump from the fuel pump relay and it comes on. The coil resistance test checked fine. My next step is to check the voltage during cranking to make sure the control unit is turning on and then moving on to testing the in tank pump I suppose. I need to remove the cold start injector to see if fuel is reaching the motor also. Anyway, thanks for the help...this will keep me busy over the weekend!
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post #5 of 8 (permalink) Old 12-31-2014, 03:30 PM Thread Starter
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Moving on with the trounleshooting, the voltage on the battery during cranking was decreasing to 9V so I replaced it. The new battery maintains >10.5V so that's good now.

the two sensors that manage the Cold Start Injector checked out in terms of resistance. HOWEVER, I pulled the Cold Start Injector, cranked the engine and no fuel was delivered. I jumped the relay and the fuel pump comes on, at least makes a sound, but I still don't get fuel from the CSI.

Can it be that the fuel pump is "audible" but not actually pumping? In the meantime I am going to move to the in tank pump to check that
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post #6 of 8 (permalink) Old 12-31-2014, 03:49 PM
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Just as a matter of curiosity, have you checked that you have spark and that such spark is at the correct cylinder?

-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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post #7 of 8 (permalink) Old 08-11-2019, 09:19 PM
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I'm looking at these older posts because I have a similar problem with my 89 Spider, and was wondering how your problem was resolved.
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post #8 of 8 (permalink) Old 08-13-2019, 03:03 PM
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sellingmine.. look below in for sale
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