No power to fuel pump

Tiny
JUNIORTAMPABAY
  • MEMBER
  • 1988 JEEP WRANGLER
  • 4 CYL
  • 2WD
  • MANUAL
  • 186,000 MILES
1988 jeep wrangler no power to fuel pump. Fuel pump bench tested aok. Trace wire to relays turn key on no clicking noise can anyone tell me whats wrong
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Wednesday, June 15th, 2011 AT 5:50 PM

17 Replies

Tiny
JDL
  • EXPERT
Any applicable mil codes? Did you also check for spark at the plugs, engine cranking? Sometimes if the computer doesn't see an rpm signal, you can loose fuel and spark.
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Wednesday, June 15th, 2011 AT 6:04 PM
Tiny
CJ MEDEVAC
  • EXPERT
Are your fuses good. Not only good, have you pulled then in and out several times to "scrape off the crustations" (corrosion) that night be in your fuse block or on the fuse terminals. A 12 Volt test light on either side of the Female ends, in the block (fuse installed, key on) would verify that "Juice" was making it thru the fuse and on into the female plug

I have glass fuses in my CJ, sometimes I must clean the "clips in the fuse block" amd the ends of the glass fuses to make some of my accessories work.I have a mechanical, EZ to access fuel pump. Worked on my '77 CJ5 (changed several times, very EZily) for 35 years, same situation on my '46 Jeep for 65 years. Whats so hard about putting the danged fuel pump somewhere EZ to get to nowadays?

I hope the fuse "in and out thing" is the cat's meow! I also use dielectric grease on all connections/ fuses, on anything I mess with too, a tube ain't real expensive! Your Jeep's not getting any younger!

The Medic
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Wednesday, June 15th, 2011 AT 6:52 PM
Tiny
JDL
  • EXPERT
Hey medic, nice picture, you just a young person.

Diagram below.
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Wednesday, June 15th, 2011 AT 7:02 PM
Tiny
CJ MEDEVAC
  • EXPERT
47, Rode hard and put up. Well, never put up!

Thanks Feller, I'll buy you lunch, when you "drop by"!

Where the heck is this feller, Wanting to see a 5 minute old pic of him, "Driving down the road and Showing off in his too"!

The Medic
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Wednesday, June 15th, 2011 AT 7:14 PM
Tiny
JDL
  • EXPERT
I'm 64, haven't had a hard life, just took it hard. Lol

Have a good day.
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Wednesday, June 15th, 2011 AT 7:24 PM
Tiny
RASMATAZ
  • MEMBER
WoW! JD -you moved me down to no.5 in the Sr. Citizen list. Nice Ride there Medic-Gents have a wonderful day-Aloha! Chow-
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Wednesday, June 15th, 2011 AT 7:41 PM
Tiny
JDL
  • EXPERT
Yeah, that's me, old and cranky.
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Thursday, June 16th, 2011 AT 1:53 AM
Tiny
JUNIORTAMPABAY
  • MEMBER
I've check everything in my jeep all aok except no power to the fuel pump. Check the wires all the way to relays all ok. Also to the harness found harness disconected. Fix but still no power to fuel pump. Please help. Thank you for all help.
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Tuesday, July 12th, 2011 AT 7:43 PM
Tiny
JUNIORTAMPABAY
  • MEMBER
Also can the ECU be the problem. Can't figured what the problem is.
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Tuesday, July 12th, 2011 AT 7:46 PM
Tiny
JDL
  • EXPERT
You waited long enough for a follow up, didn't you? You can't bench test a fuel pump. I've seen plenty that would run on a bench, would not run with a load on it.

At the fuel pump relay, use a jumper wire between red wire, hot all the time and orange wire, the orange wire carries voltage to the pump. If the pump won't run, use a voltage tester on the red wire, is it hot? If the pump still won't run, something wrong with orange wire circuit-- something wrong with pump--- something wrong with pump ground. I'm not sure what else to tell you?
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Tuesday, July 12th, 2011 AT 8:16 PM
Tiny
JUNIORTAMPABAY
  • MEMBER
Yes the red wire bis hot.I conected red to orange and nothing happen, i'm going to trace orange wire to see if theres a break on the wire, will keep you informed and yes it took me long enough to follow up because I had to check everything before asking again thank you for the help and time.
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Wednesday, July 13th, 2011 AT 11:36 AM
Tiny
JUNIORTAMPABAY
  • MEMBER
Hi JDL; which orange wire do I put the jumper wire too, orange w/black or orange only and thanks again for the help.I'll be waitting for your respond.
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Wednesday, July 13th, 2011 AT 12:13 PM
Tiny
JDL
  • EXPERT
In the diagram, for the fuel pump relay, only shows orange wire. Take relay connector loose, use jumper at connector. If the relay plugs into a socket, where you can't see the wiring colors, makes it a little harder.

Also, check ground at the fuel pump connector, black wire. To check ground, use testlite connected to battery voltage, touch black wire terminal, If the lite comes on, the ground should be ok.
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Wednesday, July 13th, 2011 AT 3:05 PM
Tiny
JUNIORTAMPABAY
  • MEMBER
Hi JDL I've check everything like you said aok. Get this I change the ECU and as soon I turned the key fuel pump started working but now I have no power to the Ignition coil. With the old ECU I have power to the Coil and no power to the fuel pump, so you tell me whats wrong because I can not figure this one out. Your advise please, thank you i'll be waiting for your respond.
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Thursday, July 14th, 2011 AT 6:59 PM
Tiny
JDL
  • EXPERT
Your jumping around too much for me.

Primary voltage to coil, is yellow wire, goes hot when you turn on the key.
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Thursday, July 14th, 2011 AT 7:37 PM
Tiny
JUNIORTAMPABAY
  • MEMBER
OK JDL will check out let you know asap update Thanks Again.
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Thursday, July 14th, 2011 AT 8:12 PM
Tiny
JDL
  • EXPERT
Hope you find the problem.
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Friday, July 15th, 2011 AT 3:41 PM

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