Engine only runs when starter is engaged - Page 2 - Alfa Romeo Bulletin Board & Forums
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post #16 of 39 (permalink) Old 03-31-2019, 07:56 PM Thread Starter
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"Is there any sort of bypass circuit activated when the key is in the 'start' position?"

I'm wondering the same. I'm going to jump the ignition switch harness and spend some time cleaning up the fuse holders tomorrow. That should tell me definitively if it's a bad ignition switch or not.

Thanks for all the replies.
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post #17 of 39 (permalink) Old 03-31-2019, 09:28 PM
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Originally Posted by ghnl View Post
Here's a sketch of the Spider's ignition switch connections. If your car's is the same (seems likely) find the connectors and jump #1 to #3 (on the car side, not the switch side). This should power on all the switched circuits. Then add a temporary connection to #2 and the starter should operate. When the engine starts remove the connection to #2 - the starter should stop and the engine keep running.
Not to hijack the thread but i know what you did in your youth..

Current cars 1975 spyder under resto, 1973 Berlina Resto 1976 Berlina parts car 1972 GTjunior fully restored, 1 complete rolling shell spyder.exit 1989 75 T/S sold
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post #18 of 39 (permalink) Old 04-01-2019, 06:41 AM
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Quote:
Originally Posted by Motoital2.0 View Post
"Is there any sort of bypass circuit activated when the key is in the 'start' position?"

I'm wondering the same. I'm going to jump the ignition switch harness and spend some time cleaning up the fuse holders tomorrow. That should tell me definitively if it's a bad ignition switch or not.

Thanks for all the replies.
I had this something similar with my 69 GTV. The SPICA bellcrank rod had fallen off and the engine would run on the cold start solenoid fuel with the starter on. As soon as the starter was disengaged and the cold start solenoid quit enriching the mixture the car died. Reconnecting the bellcrank rod fixed the problem.

Mike
1969 GTV 1750
1966 Super
San Diego, CA

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post #19 of 39 (permalink) Old 04-01-2019, 10:02 AM
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Quote:
Originally Posted by Alfa69GTV1750 View Post
The SPICA bellcrank rod had fallen off and the engine would run on the cold start solenoid fuel with the starter on. As soon as the starter was disengaged and the cold start solenoid quit enriching the mixture the car died. Reconnecting the bellcrank rod fixed the problem.
Ohh, I like that theory. Honestly, an ignition switch failing in the way I described in post #11 seems far-fetched. You'd think it would fail to deliver current to the coil, fuel pump, etc. in both the "run" and "start" positions; not just in one.

So a test of Alfa69GTV1750's idea would be to connect that always hot jumper to the CS solenoid (after removing the wire from the starter solenoid) and seeing if that will allow it to keep running. Or, just look for a disconnected bellcrank rod.

Jay Mackro
San Juan Capistrano, CA

'65 Guilia Sprint GT
'67 Duetto
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post #20 of 39 (permalink) Old 04-01-2019, 05:33 PM Thread Starter
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Update

Thanks for the suggestion Alfa69GTV1750 but all rods are attached. I was really hoping that was it!

So far I've confirmed that fuel pump has power both at the run position and start.

The car will die with both the green/black wire and jumper attached to the coil as well.

The car starts fine with the cold start hot wire detached but dies like usual when the starter is disengaged.


One thing I did see is that per Wes Ingram the fuel cut off solenoid can cause the symptoms I discribed if the micro switch is shorted. Unfortunately the FCC was unplugged but I'm wondering if it's jammed up or something. I'm going to apply a 12v source to it and see if I can hear it click.


Thanks for the help!
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post #21 of 39 (permalink) Old 04-01-2019, 05:44 PM
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You can determine if the problem is fuel or ignition by having someone spray starter fluid into the air cleaner and then dis-engaging the starter. If the engine keeps running it is a fuel problem. If it quits, it is an ignition problem.

You could also disconnect the cold start solenoid from the starter and power the solenoid with a jumper from the battery while starting it. Same results as above.

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Originally Posted by Motoital2.0 View Post
Thanks for the suggestion Alfa69GTV1750 but all rods are attached. I was really hoping that was it!

So far I've confirmed that fuel pump has power both at the run position and start.

The car will die with both the green/black wire and jumper attached to the coil as well.

The car starts fine with the cold start hot wire detached but dies like usual when the starter is disengaged.


One thing I did see is that per Wes Ingram the fuel cut off solenoid can cause the symptoms I discribed if the micro switch is shorted. Unfortunately the FCC was unplugged but I'm wondering if it's jammed up or something. I'm going to apply a 12v source to it and see if I can hear it click.


Thanks for the help!
Del likes this.

Mike
1969 GTV 1750
1966 Super
San Diego, CA

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post #22 of 39 (permalink) Old 04-01-2019, 07:48 PM
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Quote:
Originally Posted by Motoital2.0 View Post
One thing I did see is that per Wes Ingram the fuel cut off solenoid can cause the symptoms I discribed if the micro switch is shorted. Unfortunately the FCC was unplugged but I'm wondering if it's jammed up or something. I'm going to apply a 12v source to it and see if I can hear it click.
If the car is getting fuel when the starter is running, then I don't see how the FCC would shut the fuel off when you go back to "run". Since the FCC is unplugged, it wouldn't know whether the starter was running or not, even if there's some weird electrical connection. Still, it'll be interesting to see if it clicks when power is applied; there must be some fault that caused the PO to disconnect it.

Quote:
Originally Posted by Alfa69GTV1750
You can determine if the problem is fuel or ignition by having someone spray starter fluid into the air cleaner and then dis-engaging the starter. If the engine keeps running it is a fuel problem. If it quits, it is an ignition problem.
I like that idea.

Jay Mackro
San Juan Capistrano, CA

'65 Guilia Sprint GT
'67 Duetto
'91 164L

Last edited by Alfajay; 04-01-2019 at 07:53 PM.
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post #23 of 39 (permalink) Old 04-02-2019, 06:19 PM Thread Starter
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Update

Alfa69GTV1750, that was a good suggestion! The does continue to run when I spray start fluid. So fuel is being cut but not ignition.

Alfajay, I'm not sure either but I pulled this from the Wes's roadside manual.


"IV. SYMPTOM:
Engine stops suddenly or exhibits random "cutting-out." Restart attempts fail, although the engine
may initially fire, but then die as the key switch is released from the start to the run position.
1. POSSIBLE CAUSE: Shorted Fuel Cutoff Solenoid (FCS) microswitch on bottom of pump causing
steady current to be delivered to the FCS, thus cutting off all fuel delivery. Restart attempts may result in
initial firing until the key switch is released because with the key switch in the "START" position, current is
cutoff from the FCS microswitch. Thus, there is no power to the shorted microswitch. When the key switch
is released to “RUN,” power is restored to the shorted microswitch and the FCS again cuts off the fuel"

Also the FCS has a solid click when 12v is applied and I can hear it click again when removed so it's probably not stuck.
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post #24 of 39 (permalink) Old 04-02-2019, 06:30 PM
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I'm not a SPICA expert, but that means with the starter engaged, the SPICA system is delivering enough fuel to the engine to start. I can't think of anything that would give these symptoms other than a problem with the throttle rods to the SPICA pump. Are you sure the long rod is connected at the pump?

What happens if you give the engine full throttle when running with the starter engaged? If you try that and the engine dies, it may be that while cranking, the engine is running on the cold start solenoid only which is powered from the starter.

Inversely, what happens if you disconnect the cold start solenoid? Does the engine still start?

Quote:
Originally Posted by Motoital2.0 View Post
Alfa69GTV1750, that was a good suggestion! The does continue to run when I spray start fluid. So fuel is being cut but not ignition.

Alfajay, I'm not sure either but I pulled this from the Wes's roadside manual.


"IV. SYMPTOM:
Engine stops suddenly or exhibits random "cutting-out." Restart attempts fail, although the engine
may initially fire, but then die as the key switch is released from the start to the run position.
1. POSSIBLE CAUSE: Shorted Fuel Cutoff Solenoid (FCS) microswitch on bottom of pump causing
steady current to be delivered to the FCS, thus cutting off all fuel delivery. Restart attempts may result in
initial firing until the key switch is released because with the key switch in the "START" position, current is
cutoff from the FCS microswitch. Thus, there is no power to the shorted microswitch. When the key switch
is released to “RUN,” power is restored to the shorted microswitch and the FCS again cuts off the fuel"

Also the FCS has a solid click when 12v is applied and I can hear it click again when removed so it's probably not stuck.

Mike
1969 GTV 1750
1966 Super
San Diego, CA

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post #25 of 39 (permalink) Old 04-02-2019, 06:40 PM Thread Starter
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Yeah, this has got me stumped as well.

I've been doing these tests, since your either spray idea, with a remote starter switch. The engine responds really well to throttle response when I turn the bellcrank with all arms moving as they should.

My next move I guess will be hooking up a pressure gauge and seeing what I'm getting at rest then seeing if I get a spike or something during cranking.
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post #26 of 39 (permalink) Old 04-02-2019, 06:56 PM
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Disconnect the cold start solenoid and see what happens. Even if you are using a remote starter switch, the cold start solenoid is engaged when the starter is powered.

Quote:
Originally Posted by Motoital2.0 View Post
Yeah, this has got me stumped as well.

I've been doing these tests, since your either spray idea, with a remote starter switch. The engine responds really well to throttle response when I turn the bellcrank with all arms moving as they should.

My next move I guess will be hooking up a pressure gauge and seeing what I'm getting at rest then seeing if I get a spike or something during cranking.

Mike
1969 GTV 1750
1966 Super
San Diego, CA

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post #27 of 39 (permalink) Old 04-02-2019, 07:03 PM Thread Starter
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Sorry about not answering that. It starts up fine with the css disconnected. Not much difference.
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post #28 of 39 (permalink) Old 04-02-2019, 07:08 PM
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Sorry, but I'm all out of ideas....I'd reach out to Wes Ingram.

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Sorry about not answering that. It starts up fine with the css disconnected. Not much difference.

Mike
1969 GTV 1750
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San Diego, CA

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post #29 of 39 (permalink) Old 04-02-2019, 07:27 PM
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with the key switch in the "START" position, current is cutoff from the FCS microswitch. Thus, there is no power to the shorted microswitch. When the key switch is released to “RUN,” power is restored to the shorted microswitch and the FCS again cuts off the fuel"

Also the FCS has a solid click when 12v is applied and I can hear it click again when removed so it's probably not stuck.
OK, we're making progress. Alfa69GTV1750's suggestion to spray starting fluid was the breakthrough - now we know it's fuel related and not ignition. And we know it's the Spica pump, not the fuel pump.

That quote from Wes Ingram comes close to explaining the situation. And the fact that your fuel cut-off switch was disconnected suggests that a PO encountered this problem and dealt with it by disabling the FCS feature (which results in backfires on deceleration).

Like Alfa69GTV1750, I'm not a SPICA expert either. For example, I didn't know that the ignition switch sends current to the fuel pump and coil in the "start" position, but not to the FCS - I wouldn't have thought it was that complex.

Quote:
Originally Posted by Motoital2.0
the FCC was unplugged but I'm wondering if it's jammed up or something.
But something still has me puzzled: If the FCS microswitch was disconnected, how did the Spica pump know when the ignition key was turned from "start" back to "run"?

Quote:
Originally Posted by Motoital2.0
It starts up fine with the css disconnected. Not much difference.
Unlike a disconnected FCS, a connected CSS would know when the starter was on. I can imagine a situation where the Spica pump is set so lean that the engine can't run unless the CSS is enabled. But you reported that it behaves the same way whether the CSS is connected or not, so I'm still baffled.

Jay Mackro
San Juan Capistrano, CA

'65 Guilia Sprint GT
'67 Duetto
'91 164L

Last edited by Alfajay; 04-02-2019 at 07:41 PM.
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post #30 of 39 (permalink) Old 04-02-2019, 07:31 PM
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Maybe the FCS is wired incorrectly? Could it be frozen in the wrong position and the click is the solenoid, but not the valve? Maybe take it out and see if there is external movement when energized and de-energized?

Quote:
Originally Posted by Alfajay View Post
OK, we're making progress. Alfa69GTV1750 suggestion to spray starting fluid was the breakthrough - now we know it's fuel related, and not ignition. And we know it's the Spica pump, not the fuel pump.

I think that quote from Wes Ingram explains the situation. And the fact that your fuel cut-off switch was disconnected suggests that a PO encountered this same problem and dealt with it by disabling the FCS feature (which results in backfires on deceleration).

Like Alfa69GTV1750 said, "I'm not a SPICA expert". I'm sort of surprised that the ignition switch will send current to the fuel pump and coil in the "start" position, but not to the FCS - didn't know it was that complex.

But something still has me puzzled: If the FCS microswitch was disconnected, how did the Spica pump know when the ignition key was turned from "start" back to "run"?

Mike
1969 GTV 1750
1966 Super
San Diego, CA

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