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View Full Version : 89 honda civic intermintent fuel pump power


civic8998
Sep 18, 2010, 05:28 PM
My fuel pump gets power intermintely. Relay checks out fine.has spark.CEL and all other Dumbie lights go off normally after two seconds. Fuel pump is only a year old. I get 12.62 at the connector then drops to 10.35 a second later even when the fuel pump turns on it still does that. I've replaced my MAP sensor and igntion switch hasn't fixed the problem. I don't have a clue what the problem is any help would be greatly appreciated! Thank You!

PS when I have more time I will get more information

TxGreaseMonkey
Sep 18, 2010, 05:33 PM
This link may help:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-7.html#post1245523

Be sure to clean the main ECM ground, located on the thermostat housing.

civic8998
Sep 18, 2010, 05:47 PM
Hi TxGreaseMonkey I hope you would answer this I've been threw pretty much all your posts

What topic should I choose in that link that you think would help me out the most? There are quite a few

TxGreaseMonkey
Sep 19, 2010, 05:23 AM
In the link I gave you above, I would perform all of the tests listed--it shouldn't take too long.

The contacts in the relay may be pitted. As the cross-sectional area erodes through pitting, the resistance goes up by a square factor. Based on the formula Area of a Circle = Pi x R-squared, as the effective cross-sectional area of a points gets cut in half, the resistance goes up four fold. This means that the amperage available to the fuel pump would be 1/4 of what it would be otherwise, when you plug these values into Ohm's Law. Ohm's Law states Amperage = Volts/Resistance. As resistance (Ω) doubles, amperage is cut in half.