stranded electrical problem

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=124961
Printed Date: May 04, 2025 at 2:37 AM

Topic: stranded electrical problem

Posted By: aksnowbrder
Subject: stranded electrical problem
Date Posted: December 10, 2010 at 2:01 PM

Hey all, I have a 98 civic ex that doesnt start and I'm pretty sure I've narrowed it down to an electrical problem.

I'm getting 0 volts to the fuel pump, so I checked the main relay its not getting power from the fuel pump fuse, which I pulled, and that's good. While it was out I checked power at the fuel pump fuse and I only got about 2 volts to the fuse itself.

So far I've tried a new fuel pump, new filter and new main relay with no luck. I've been hearing things like bad ECU, bad grounds, or shorted wire. Anyone have any insight to this? I'm going crazy over here.

Other problems I have/had before the car stopped working were when I'd use my turn signals sometimes my tach would bounce to zero, or if I had cruise control on and used my signals it would cut out.

Please help! :(

Replies:

Posted By: howie ll
Date Posted: December 10, 2010 at 5:04 PM

Bad grounds or engine bay loom problems?
Is your main 50 amp ignition fuse in the engine bay fuse box OK? I'd also physically check that fuse box for corrosion.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Posted By: oldspark
Date Posted: December 10, 2010 at 7:11 PM

aksnowbrder wrote:

I only got about 2 volts to the fuse itself.

By that you mean at the fuse itself - one side measures 0V, the other, the other is not +12V?

Unless that fuse is switched - which it shouldn't be - it should be +12V with IGN on.

Check if you have +12V on one side of your injectors (with IGN on), else +12V at their resistor pack if low-impedance injectors.
That's in case injectors & pump share the same IGN relay...

The other problems sound like bad ground(s), but could be bad supply - eg corrosion - as HowieII wrote.

FYI:
Fuel pump relays are triggered by alternator charge lights for carby cars, or alternators or air-flaps or the ECU in EFI/EMS cars. (Spark sensing can also be used whether for carby or by the EMS. And any system that uses oil pressure is a bad system!)

The power for the fuel pump (fuse) should be from the battery but can be via the main ignition relay (as used with EFI/EMS).
Both of those will be through a large fuselink.

So it should be battery-fuselink-(maybe IGN relay etc)-fuse-relay-pump.

A problem fuselink should give problems on other circuits.

IGN relays can be multi-pole (DPST etc) - maybe only one side has failed else suffers a bad connection.

If fuel pump relays are powered via the IGN relay, it is usually the same side/circuit as the injectors