ignition problem, fuel problem or what?
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Joined: Nov 1999
Posts: 67
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From: Visalia Ca
ignition problem, fuel problem or what?
My 86 has been running great until now. Starts and then doesn't start. Had a
fuel pump problem I thought. Replaced it. It will start and then just quite. This
happens at idle or just going down the street. I've got spark and fuel. What
would cause this. Someone told me it could possibly be the oil presure switch.
I'm going to replace it but if it continues what then? Need help.
sharkman
fuel pump problem I thought. Replaced it. It will start and then just quite. This
happens at idle or just going down the street. I've got spark and fuel. What
would cause this. Someone told me it could possibly be the oil presure switch.
I'm going to replace it but if it continues what then? Need help.
sharkman
Melting Slicks
Joined: Oct 2002
Posts: 3,193
Likes: 1
From: Cincinnati Oh
Re: ignition problem, fuel problem or what? (sharkman)
you might want to:
#1 - verify the fuel pressure by checking it at the shrader valve (pass. side fuel rail).
#2 - when was the last time you changed the fuel filter?
#3 - are the plugs and wires in good (relatively new) shape?
#4 - what is the oil pressure read out on the dash: does it go to zero BEFORE the car stalls out or after?
#5 - does the car run for any length of time, sputter, or stall out, or does it just catch & idle for a second and then quit?
#6 - if the fuel pressure, plugs and wires check out, you may want to consider a bad ignition module or coil. Does the car rev at all?
Just my thoughts...
[Modified by Ramanstud, 7:38 PM 7/5/2004]
#1 - verify the fuel pressure by checking it at the shrader valve (pass. side fuel rail).
#2 - when was the last time you changed the fuel filter?
#3 - are the plugs and wires in good (relatively new) shape?
#4 - what is the oil pressure read out on the dash: does it go to zero BEFORE the car stalls out or after?
#5 - does the car run for any length of time, sputter, or stall out, or does it just catch & idle for a second and then quit?
#6 - if the fuel pressure, plugs and wires check out, you may want to consider a bad ignition module or coil. Does the car rev at all?
Just my thoughts...
[Modified by Ramanstud, 7:38 PM 7/5/2004]
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Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: ignition problem, fuel problem or what? (sharkman)
Someone told me it could possibly be the oil presure switch.
I'm going to replace it but if it continues what then? Need help.
sharkman
I'm going to replace it but if it continues what then? Need help.
sharkman
RACE ON!!!
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: ignition problem, fuel problem or what? (CFI-EFI)
It could be the oil pressure switch because when the engine starts and is generating oil pressure, the oil pressure switch is the only source of 12v to run the fuel pump. The fuel pump relay is only activated for 2 seconds when you begin cranking.
Race Director
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From: The Top of Utah
Re: ignition problem, fuel problem or what? (jfb)
It could be the oil pressure switch because when the engine starts and is generating oil pressure, the oil pressure switch is the only source of 12v to run the fuel pump. The fuel pump relay is only activated for 2 seconds when you begin cranking.
It is NOT the oil pressure switch. When the oil pressure reaches about 4 pounds, the switch closes and provides a parallel (circuit) to the fuel pump relay, current supply. Unless the relay is bad, the oil pressure switch wouldn't even be noticable if it were bad.
Pro
Joined: Oct 2002
Posts: 586
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From: Schmuckville SA
Re: ignition problem, fuel problem or what? (sharkman)
IAC can do that if it is stuck...Pull it and adjust to the 1 1/8" spec and see if she starts.
Thats assuming you have spark and fuel. HTH Good Luck
Thats assuming you have spark and fuel. HTH Good Luck
Safety Car
Joined: Feb 2002
Posts: 4,212
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From: Sun City West Az
Re: ignition problem, fuel problem or what? (Unriced)
Check your primary grounds for good clean contacts. You may have a bad one and the vibration of "running' the car may be causing an intermittent contact. Just a thought.
Also, I'm in agreement with CFI-EFI as to the wiring of the oil pressure switch.
[Modified by ittlfly, 11:41 AM 7/6/2004]
Also, I'm in agreement with CFI-EFI as to the wiring of the oil pressure switch.
[Modified by ittlfly, 11:41 AM 7/6/2004]
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: ignition problem, fuel problem or what? (Unriced)
IAC can do that if it is stuck...Pull it and adjust to the 1 1/8" spec and see if she starts.
This happens at idle or just going down the street.
It sounds like an intermittent ignition problem. I would be doing all the trouble shooting tests in the service manual, while wiggling the applicable wires during the individual tests.
RACE ON!!!
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Joined: Nov 1999
Posts: 67
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From: Visalia Ca
Re: ignition problem, fuel problem or what? (sharkman)
Thanks, guys, lots of ideas for me to try. She starts fine and after running at
idle she just quits. No shudder, cough nothing just quits. Does this while going
do the street to. I might get a few miles one day and the next I might not
make it out of the driveway. I've got spark, oil pressure shows to be around
55 to 60 most of the time. Could the ignition module do this. All wires appear
to be in good shape and connectors look fine. I even blew them out with air
for dust ect. Is there a roll over switch or something that might cause the
ignition or fuel pump to shut off?
sharkman
idle she just quits. No shudder, cough nothing just quits. Does this while going
do the street to. I might get a few miles one day and the next I might not
make it out of the driveway. I've got spark, oil pressure shows to be around
55 to 60 most of the time. Could the ignition module do this. All wires appear
to be in good shape and connectors look fine. I even blew them out with air
for dust ect. Is there a roll over switch or something that might cause the
ignition or fuel pump to shut off?
sharkman
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
When it won't start, unplug an injector and connect a low power 12v lamp across the injector socket and crank the engine. You should see the lamp pulse while cranking. If it does pulse, measure the fuel pressure and then watch the pressure after a crank and turning off the ignition. If the pressure drops rapidly, you have leaky injectors causing a hard start due to rich mixture.
How about the cats? 