Dead '85
Thread Starter
6th Gear
Joined: Oct 2013
Posts: 6
Likes: 0
From: Williamsburg VA
Dead '85
Help, pls!
I have an '85 4+3 which was unintentionally laid up for 3-months. When I recovered the car, battery was dead. Charged it overnight. Car started immediately - for about 15 sec. then died and would not restart. Cranks fine. My garage has had it for 6-weeks and has: Replaced fuel pump & distributor. No Go. Only oddity: low voltage at the injectors. I am running out of ideas.
I have an '85 4+3 which was unintentionally laid up for 3-months. When I recovered the car, battery was dead. Charged it overnight. Car started immediately - for about 15 sec. then died and would not restart. Cranks fine. My garage has had it for 6-weeks and has: Replaced fuel pump & distributor. No Go. Only oddity: low voltage at the injectors. I am running out of ideas.
Thread Starter
6th Gear
Joined: Oct 2013
Posts: 6
Likes: 0
From: Williamsburg VA
Working this, now
[QUOTE=AGENT 86;1585575387]How low is low voltage at injectors ?
How many volts at brake fuse and gages fuse (ignition on) ?
Any stored codes in ECM ?
Is there injector pulse ?
How many volts at brake fuse and gages fuse (ignition on) ?
Any stored codes in ECM ?
Is there injector pulse ?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
If the battery is good enough to crank the engine then it should have enough voltage to pulse the injectors. Once the engine starts the alternator is supplying the voltage, so the battery is essentially out of the picture.
How did they determine that the voltage was low at the injectors?
You can measure the voltage by pulling off one of the injector connectors, turning on the ignition and measuring the voltage referenced to ground (any metal part of the engine). It doesn't matter which pin on the connector you probe. You should see basically battery voltage -- about 12 to 13 volts.
How did they determine that the voltage was low at the injectors?
You can measure the voltage by pulling off one of the injector connectors, turning on the ignition and measuring the voltage referenced to ground (any metal part of the engine). It doesn't matter which pin on the connector you probe. You should see basically battery voltage -- about 12 to 13 volts.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The ECM turns on the injectors with a large power transistor inside the ECM. If that transistor is bad you would see the symptoms you describe. Substituting a known good ECM would eliminate that as a problem.
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