Strange no start....ideas???
03-01-2013, 01:40 PM
#21
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Don't all cars cycle the fuel pump for a second or two in the start position?
So it now starts but NOT very easily. I need a jump box on there to make it spin as fast as I have ever heard a Miata starter spin on start up than it barely catches and comes to life (still with fuse out).
I have now changed the GAS filled oil and put clean plugs in ran it or an hour or so, I'm sure that the motor is mechanically sound. The lifers have finally pumped up and motor sounds good. But if I turn it off same issue with hard start up.
Where do I go next....
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03-01-2013, 02:12 PM
#23
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When the key is turned to the START position, the fuel pump runs continuously for so long as the key is held here (presupposing that your foot is also on the clutch pedal, or that you have bypassed the lower clutch switch.) This is one of the two things which the ST SIG fuse does (uses power from the starter to close the fuel pump relay).
When you release the key from START, power from the starter no longer drives the fuel pump relay, under the assumption that either the engine didn't start (and the fuel pump is not needed), or the engine did start and there is now enough airflow through the AFM to close the switch inside it and drive the fuel pump relay that way.
When you pulled the ST SIG fuse, you removed the ability for the starter to power the fuel pump relay. By jumping the F/P terminal, you effectively bypassed this (although by a different set of wires, through a different circuit- it is not 100% equivalent.)
The reason that the engine is hard to start now, (even with F/P grounded) is that the ECU is no longer getting voltage from the starter on pin 1C, which indicates to it that it should be in cranking mode- squirting extra fuel and retarding the timing. The 1.6 ECU is an idiot, and it can't tell you're trying to start the engine unless you explicitly tell it so.
So, something about the ST SIG fuse not being there allowed the engine to start without flooding. It would be interesting to see what was to happen were you to start the engine, get it idling, and then install the ST SIG fuse.
As background, how badly has the electrical system of this car been hacked up?
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03-01-2013, 02:43 PM
#24
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Ah. I thought you meant the RUN position. I got that from when you said "...when you move the key from OFF to RUN." The fuel pump should not operate when you move the key from OFF to RUN.
When the key is turned to the START position, the fuel pump runs continuously for so long as the key is held here (presupposing that your foot is also on the clutch pedal, or that you have bypassed the lower clutch switch.) This is one of the two things which the ST SIG fuse does (uses power from the starter to close the fuel pump relay).
When you release the key from START, power from the starter no longer drives the fuel pump relay, under the assumption that either the engine didn't start (and the fuel pump is not needed), or the engine did start and there is now enough airflow through the AFM to close the switch inside it and drive the fuel pump relay that way.
When you pulled the ST SIG fuse, you removed the ability for the starter to power the fuel pump relay. By jumping the F/P terminal, you effectively bypassed this (although by a different set of wires, through a different circuit- it is not 100% equivalent.)
The reason that the engine is hard to start now, (even with F/P grounded) is that the ECU is no longer getting voltage from the starter on pin 1C, which indicates to it that it should be in cranking mode- squirting extra fuel and retarding the timing. The 1.6 ECU is an idiot, and it can't tell you're trying to start the engine unless you explicitly tell it so.
So, something about the ST SIG fuse not being there allowed the engine to start without flooding. It would be interesting to see what was to happen were you to start the engine, get it idling, and then install the ST SIG fuse.
As background, how badly has the electrical system of this car been hacked up?
When the key is turned to the START position, the fuel pump runs continuously for so long as the key is held here (presupposing that your foot is also on the clutch pedal, or that you have bypassed the lower clutch switch.) This is one of the two things which the ST SIG fuse does (uses power from the starter to close the fuel pump relay).
When you release the key from START, power from the starter no longer drives the fuel pump relay, under the assumption that either the engine didn't start (and the fuel pump is not needed), or the engine did start and there is now enough airflow through the AFM to close the switch inside it and drive the fuel pump relay that way.
When you pulled the ST SIG fuse, you removed the ability for the starter to power the fuel pump relay. By jumping the F/P terminal, you effectively bypassed this (although by a different set of wires, through a different circuit- it is not 100% equivalent.)
The reason that the engine is hard to start now, (even with F/P grounded) is that the ECU is no longer getting voltage from the starter on pin 1C, which indicates to it that it should be in cranking mode- squirting extra fuel and retarding the timing. The 1.6 ECU is an idiot, and it can't tell you're trying to start the engine unless you explicitly tell it so.
So, something about the ST SIG fuse not being there allowed the engine to start without flooding. It would be interesting to see what was to happen were you to start the engine, get it idling, and then install the ST SIG fuse.
As background, how badly has the electrical system of this car been hacked up?
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03-01-2013, 07:15 PM
#25
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That is exactly what I would expect it to look/sound like with ST SIG removed and F/P grounded. So that's a good thing.
It's been molested, it just hasn't told daddy yet because it's confused and ashamed.
It's been molested, it just hasn't told daddy yet because it's confused and ashamed.
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03-01-2013, 09:02 PM
#26
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Started her up and then installed fuse. Stays running no change at all. Then I shut it down and same no start issue. I did not pull a plug but I can assume me they are fuel soaked.
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03-01-2013, 09:53 PM
#27
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So thinking about this, I'n guessing that pin 1C is a 12V signal? If so any harm in trying to add 12V when I start it and than turning it off when it gets running? Being that the FP is jumpered I see no point in energizing the FP relay, right?
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03-02-2013, 11:47 AM
#28
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The scribe Qi was asked to provide the diagrams for a large system design document, for the purpose of increasing its readability. The finished work was delivered to master Banzen for review.
Banzen found some of the diagrams straightforward, but many were extremely puzzling. The Dataflow section was illustrated with the digestive tract of a fish, rendered in intricate detail with all the major organs labeled. Scheduled Jobs showed the phases of the moon juxtaposed with various herbs. The Functional Overview concluded with a glorious depiction of the reproductive cycle of the white dolphin.
At first Banzen assumed an error, yet closer inspection revealed footnotes in the figures which referred back to particular sections of the design document. In all cases the connection between figure and text was utterly mystifying.
“I read the document through twice, very carefully,” said the master to the scribe. “And nowhere in it could I find the significance of the bisected fish, the lunar harvest calendar, or most of your other contributions.”
“Twice,” repeated Qi with satisfaction, and left the room.
The master was enlightened.
Banzen found some of the diagrams straightforward, but many were extremely puzzling. The Dataflow section was illustrated with the digestive tract of a fish, rendered in intricate detail with all the major organs labeled. Scheduled Jobs showed the phases of the moon juxtaposed with various herbs. The Functional Overview concluded with a glorious depiction of the reproductive cycle of the white dolphin.
At first Banzen assumed an error, yet closer inspection revealed footnotes in the figures which referred back to particular sections of the design document. In all cases the connection between figure and text was utterly mystifying.
“I read the document through twice, very carefully,” said the master to the scribe. “And nowhere in it could I find the significance of the bisected fish, the lunar harvest calendar, or most of your other contributions.”
“Twice,” repeated Qi with satisfaction, and left the room.
The master was enlightened.
At the moment, I am the master having studied the dolphin twice. I understand what I see with great clarity, yet its significance is not yet known to me.
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