Alfa Romeo Forums banner
1 - 4 of 4 Posts

·
Registered
1988 Alfa Romeo Spider Quad
Joined
·
201 Posts
Good morning to all on this thread but I'm having the exact same problem went through the same exact process stated above and believe it's the ground wire. We're would I find the below relay that two-point-o ended up grounding?



It turned out to be a ground wire from the tachiometric relay to the ECU.
 

·
Registered
1988 Alfa Romeo Spider Quad
Joined
·
201 Posts
Good morning to all on this thread but I'm having the exact same problem went through the same exact process stated above and believe it's the ground wire. We're would I find the below relay that two-point-o ended up grounding?



It turned out to be a ground wire from the tachiometric relay to the ECU.
Is it the wire that runs from 87 black/white to the negative ignition post?
 

·
Registered
1988 Alfa Romeo Spider Quad
Joined
·
201 Posts
Mborras.
I see we are chasing similar things from my other thread. I also see this is an old thread, but useful.

I call the tachiometric relay the "fuel pump relay" or "drive relay". On my 84 spider, the black/white wire on that relay is on pin 31b and is the tachy signal from coil (-) . Do not ground that wire. The ignition ECU switches that wire to ground during cranking/driving. That same coil terminal (-) should also have a shielded yellow wire that is the tachy signal to the FI ECU pin 1. This yellow wire carries the tachy signal that is massaged by the FI ECU to provide the FI pulse. (Tomorrow, I will spend some time figuring out if I get the tachy signal back at the ECU.)

In re-reading two-point-o's post, I believe he spliced and hard grounded the black wires on pin 85 of the main relay (which is also connected to pin 31 on the fuel pump relay). My schematic has those black wires grounded through the FI ECU. If those black wires were not grounded, the FI ECU would not get power, nor would the injectors get their 12V supply (via the main relay), and the fuel pumps wouldn't give their initial pre-crank kick. So, I think there would have been bigger issues if those black wires weren't actually grounded through the ECU. I do not see how two-point-o would have measured 12V at the injectors if these wires were not grounded, since the main relay would not have been energized. I also don't know if we're all talking about the same car/jetronic. Do you have a schematic?
Thanks for the response. I believe I have narrowed it dow to pin 16-17 ground from AVV
No continuity from either wire and no voltage.
Going to try some magiver on it this afternoon and try to bypass to see what happens I have the color Palauan version of the wire diagram been pretty helpful.
 

·
Registered
1988 Alfa Romeo Spider Quad
Joined
·
201 Posts
My understanding is that pins 16 and 17 are two of three grounds needed for the FI ECU. The other is pin 5. Yes, those wires ordinarily go to a ring terminal that is bolted at the AAV mount. I'm most interested if that is your issue!
For me, I have continuity and grounds are good, which is a good thing, but not-so-good in that I have to look elsewhere.
Good luck. I'm waiting with bated breath.
I have nothing at 16&17 I did a continuity and volt Test and zero. Now thinking on ways to bypass might get foggy and remove the actual pins and tap in a ground wire in both and mount to the chassis somewhere to see what happens.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top