Hard Start when cold
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Joined: Mar 2006
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ok- i think the ~10 volts in 'run' is normal.
the ~7 volts in 'crank' is not- that's low.
i'm wondering if the relay is going bad on you, and not providing proper voltage to the "I" terminal during starting.
do you have a spare relay laying around?
Posting Guru
Joined: Mar 2006
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understood- i'm with you on the not wanting to throw money at it.
first off- with the engine off, what is the voltage across the battery terminals?
racking my brain thinking of a way to test the solenoid- this is the best i've got:
disconnect the cable from the starter side of the solenoid (the cable that goes down to the starter).
red lead of voltmeter goes to battery side of relay
black lead goes to the "I" terminal
with the key off, you should see 12v.
turn the key to 'start'- what voltage do you get?
the voltmeter reads the *difference* in voltage between two points.
the battery side of the relay should have 12v
when cranking, the "I" terminal should, too...giving you a reading of 0.
if you get something other than 0...then there is a voltage drop inside the relay.
first off- with the engine off, what is the voltage across the battery terminals?
racking my brain thinking of a way to test the solenoid- this is the best i've got:
disconnect the cable from the starter side of the solenoid (the cable that goes down to the starter).
red lead of voltmeter goes to battery side of relay
black lead goes to the "I" terminal
with the key off, you should see 12v.
turn the key to 'start'- what voltage do you get?
the voltmeter reads the *difference* in voltage between two points.
the battery side of the relay should have 12v
when cranking, the "I" terminal should, too...giving you a reading of 0.
if you get something other than 0...then there is a voltage drop inside the relay.
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Senior User
Joined: Jun 2005
Posts: 274
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From: Wichita, KS
My battery is at 12.5 volts. With the starter cable disconnected from solenoid, red lead on the battery side and black lead on "I", I get 12.5 volts with key off. With the key in "start" position it drops to 5.5 volts.
Posting Guru
Joined: Mar 2006
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that means you are *losing* 5.5 volts inside the relay. time to replace it.
what you should have seen was a big fat 0 with the key in 'start'.
here's why:
you've got 12v on the 'hot' side. you SHOULD have 12v on "I" in crank.
the difference between those two points is 0.
instead...you've got 5.5.
that means there is a 5.5v difference between those two points.
12.5v -5.5v = 7.5v, which is exactly what you're seeing at the coil in 'crank'.
keep that old NAPA coil as a spare.
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Senior User
Joined: Jun 2005
Posts: 274
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From: Wichita, KS
First of all, thanks for all the help so far. In case you couldn't tell I'm not a guru when it comes to electrical.
Well I replaced the solenoid and started it up. Good enough; so I thought I'd repeat my first test to check voltage during cranking. This consisted of the negative lead on the battery negative post and the positive lead at the coil + post. When I went to crank it it gave two clicks then everything electrical went dead. I have 12.5 volts at the battery but no lights, no electric fuel pump, nothing.
What could I have done???
Well I replaced the solenoid and started it up. Good enough; so I thought I'd repeat my first test to check voltage during cranking. This consisted of the negative lead on the battery negative post and the positive lead at the coil + post. When I went to crank it it gave two clicks then everything electrical went dead. I have 12.5 volts at the battery but no lights, no electric fuel pump, nothing.
What could I have done???
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Posting Guru
Joined: Mar 2006
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ouch.
ok- does the horn work?
re-check the wiring at the solenoid, since that's the only thing that's changed. the only wire connected to the *starter* side of the relay should be the big battery cable going down to the starter.
if the 63 wiring is anything like the 65, the power to the cab (lights, horns, etc) is a black/yellow wire that is attached to the *battery* side of the relay.
if that's all proper, then clean the battery terminals and give it another try.
ok- does the horn work?
re-check the wiring at the solenoid, since that's the only thing that's changed. the only wire connected to the *starter* side of the relay should be the big battery cable going down to the starter.
if the 63 wiring is anything like the 65, the power to the cab (lights, horns, etc) is a black/yellow wire that is attached to the *battery* side of the relay.
if that's all proper, then clean the battery terminals and give it another try.
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Senior User
Joined: Jun 2005
Posts: 274
Likes: 0
From: Wichita, KS
Whew!
The battery posts looked clean and I was showing over 12v at the "I" post on the relay as well as at the alternator, but I took the cables off and cleaned everything with the wire brush, and I'm back in business! I guess there was enough corrosion around the contact area to cause problems.
Rustywheel, and others who offered advice, thank you for sharing your knowledge. This site is a great resource and has helped me immeasurably with my truck.
Rustywheel, and others who offered advice, thank you for sharing your knowledge. This site is a great resource and has helped me immeasurably with my truck.
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