1987 Jeep Comanche Starting problems

Tiny
CHASE1987COMANCHE
  • MEMBER
  • 1987 JEEP COMANCHE
  • 2.3L
  • 4 CYL
  • 2WD
  • MANUAL
  • 120,000 MILES
I have a 1987 jeep Comanche 2.5L inline 4 cylinder engine fuel injected I can turn on my ignition and have power to all dash light but have no power to my fuel pump or starter why is that?
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Saturday, November 29th, 2014 AT 11:44 PM

10 Replies

Tiny
WRENCHTECH
  • EXPERT
The fuel pump only powers for 2 seconds when the key is first turned on until the engine starts cranking.

If you have a cranking problem you will have to use a test light and follow a wiring diagram to determine where the circuit is being broken.

Let me know if you need anything on the diagram explained.

https://www.2carpros.com/images/external/42225923.gif

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Sunday, November 30th, 2014 AT 4:43 AM
Tiny
CHASE1987COMANCHE
  • MEMBER
I already know that and have that diagram and I'm getting power to the starter from the battery I have wired a push button start under the hood the motor will turn over with that but still gets no power to the pump
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Sunday, November 30th, 2014 AT 6:41 AM
Tiny
WRENCHTECH
  • EXPERT
So, what you are saying is that you ignored the actual problem and rigged the starter to crank. If you had actually looked for the real reason it is not cranking, it would likely lead you to the core problem for both symptoms.
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Sunday, November 30th, 2014 AT 7:04 AM
Tiny
CHASE1987COMANCHE
  • MEMBER
No I havent ignored or rigged the problem I've only connected a push start with two alligator clips attached to the studs on the starter only to see if power was leaving the battery. The starter is not the main concern I can fix that myself my worst concern is the fuel it's a fresh rebuilt engine I haven't been able to crank since rebuilt. If I could figure why the ignition doesn't work the pump I would have the problem under control
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+1
Sunday, November 30th, 2014 AT 7:50 AM
Tiny
CHASE1987COMANCHE
  • MEMBER
I'm just trying to get the engine running so I can go through and fix the rest of the bugs
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Sunday, November 30th, 2014 AT 7:52 AM
Tiny
WRENCHTECH
  • EXPERT
You're missing the point. The two symptoms are likely related and following the troubleshooting to the starter issue will likely lead you to both problems. You can't have an active fuel pump unless it is cranking. The pump only powers for 2 seconds when the key is turned on.

Pursuing the fuel pump issue would amount to the same procedure of following a wiring diagram and testing, except that may be a little more complicated. I say fix the starter first and see if that finds both problems.
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Sunday, November 30th, 2014 AT 8:01 AM
Tiny
CHASE1987COMANCHE
  • MEMBER
Ok I have done that and I've traced it down to the green wire on the diagram I have power all the way until it reaches the green wire and it goes no further
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Sunday, November 30th, 2014 AT 9:09 AM
Tiny
WRENCHTECH
  • EXPERT
OK, it sounds like you are referring to the Dk Green wire that leaves the ignition switch and then turns into green before it goes into the relay. If you are saying that you have power on the dk green leaving the switch but not arriving at the relay, then the issue would be with the connector (C100) where it changes color. That should be powered only when the key is held in start position.
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Sunday, November 30th, 2014 AT 10:16 AM
Tiny
CHASE1987COMANCHE
  • MEMBER
Yes and it's not getting power at all
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Sunday, November 30th, 2014 AT 10:30 AM
Tiny
WRENCHTECH
  • EXPERT
You probably want to verify that at the switch itself but that would mean either the switch is bad or the fusible link is burned out. That link could account for the fuel pump also.

I don't have any info on the exact location of the links but I believe they put them on the firewall, near the battery. Pull on each one and look for one that stretches.
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Sunday, November 30th, 2014 AT 10:36 AM

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