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-   -   1993 Honda Accord no start, no fuel pressure, changed fuel pump twice! (

  • Aug 4, 2010, 08:14 PM
    1993 Honda Accord no start, no fuel pressure, changed fuel pump twice!
    Was intermittent at first, would die when I was coming to a stop and would take a second to start back up and really pumping the gas pedal after it fired up. It would not start back up one time, got it towed to the shop and the mechanic quoted me $770 for a new fuel pump :/ so I told him I would tackle it myself, replaced the fuel pump and still, same problem. No fuel at the fuel rail. Replaced the filter, filled it with gas, and it fired right up, running off that fuel in the filter for a minute, but no gas is coming from the pump. Blew through the fuel line to make sure there was no obstruction, swapped the fuel pressure regulator and no difference, bypassed to main relay (fuel pump relay) and connected jumper to #5 and #7 on the main relay connector, and when I turn the ignition switch on and test from under the back seat, on the connector to the top of the gas tank, the yellow wire to the positive and black to the negative, I only read 7 volts. The third wire (greenish) reads 12.5volts. The manual tells me the yellow is the fuel pump wire. Also I have checked the relay for continuity, but I do not hear it click when I turn the ignition, and I don't hear the fuel pump but I have put TWO new fuel pumps in since it broke down (my mechanic told me the first one I bought could just have been bad when I bought it new). Also the check engine light is on when I turn the key, solid, and stays on (also the oil light), I tried to jump the blue connector under the glove box (service connector or whatever) to read the CEL code but it stays solid. Could this be a bad ECU? Could a bad ECU cause no fuel pressure?
  • Aug 5, 2010, 06:56 AM

    The ECM is likely bad. If it fails the K-Test, replace it:

    The K-Test: Remove the MAP Sensor connector and turn the ignition switch to ON (Position II). Using a multimeter, check for 5 volts going between the MAP Sensor connector's reference wire (+) and ground. As you look at the connector, this is the socket on the right. Really press the black test lead into a cleaned main ECM ground on the thermostat housing. If the voltage is low, it's probably indicating ECM failure. Most failed ECMs will record a fraction of a volt. To me, the K-Test is simple, elegant, and accurate.

    I've never seen a bad Honda fuel pump. After replacing the ECM, the engine should fire right up. Here's how to replace the ECM:
  • Aug 5, 2010, 10:54 AM

    Well I checked this after reading your reply, and the connector is actually reading 5volts.

    I should add that when I first brought the car to the shop the mechanic told me that it was only getting about 5psi for fuel pressure and its why he suspected the pump.

    I am wondering though, why it only reads 7.3v at the fuel pump, a friend told me that the pump needs 9v at least to run not sure if that's correct or not.
  • Aug 5, 2010, 11:07 AM

    That's encouraging.

    . Test all under dash and under hood fuses with a test light or multimeter:

    Particularly focus on the ACG (ALT) (S) fuse in the under dash fuse box.

    . Clean the main ECM ground, located on the thermostat housing, if you didn't already.

    . Check/replace the main relay.

    . Check the ignition switch for wear, pitting, or melting.

    The focus needs to be on getting the CEL to go out, when the ignition switch is turned to ON (Position II). Once you solve that mystery, the fuel pump issue may go away.
  • Aug 5, 2010, 02:07 PM

    Nice, I found the ECU (EAT ECU) fuse was bad! Replaced it, now I hear the relay click, and the pump prime. Still no fuel pressure to the fuel rail.
  • Aug 5, 2010, 02:17 PM

    Forgot, also the CEL is not on anymore when key is in position II, but flashes sort of when I'm turning it over repeatedly trying to get it to start.
  • Aug 5, 2010, 05:26 PM

    Dropped the tank again, exchanging the fuel pump and putting a 3rd new one in, I can't think of anything else and when I took the tank down there was no fuel even at the place where the line connects onto the tank it was completely dry so the pump is turning on, I mean making noise but not necessarily pumping? At any rate I am trying this again because I can't see any other reason it would not be getting fuel, CEL is off, ECM seems okay, relay clicks pump makes noise... no fuel.
  • Aug 5, 2010, 06:27 PM

    What brand of fuel pump are you using?
  • Aug 5, 2010, 06:55 PM

    I bought the first one off eBay, it's a Tre Performance (which I've read good, and bad about online) I bought it because it was cheap. My mechanic told me that aftermarket parts sometimes just have problems working correctly or are shipped as "bad" parts. I found it hard to believe, but understand it's a possibility that it would be bad right off so I went to Kragen's and bought another aftermarket brand (not sure the brand) but it did the same thing, so I assume neither pump (or both) are bad. The car has over 250k miles on it, I'm not going to invest over $300 on a honda pump. I did not exchange the one at Kragen's, just went and got my money back, and going to install the Tre Performance one again (I know they're cheap but I understand it has a 1-year warranty and if it gets the job done, even for a little while, hey its worth the money it saves me.. )
  • Aug 6, 2010, 04:35 PM

    So I thought I was onto something, I noticed that the sock on the original honda pump was angled differently than the aftermarket socks. It was ANGLED to be flush with the bottom of the tank whereas the others pointed UP away from the gas in the tank. I put the honda sock on the Tre Performance pump and installed it. You can hear the pump fire up, but still no gas. I'm thinking there may not be enough gas in the compartment where the pump sits! It's a small orange compartment inside of the tank... going to try putting more gas in, I'm a little weary about doing this because I may have to drop the tank again, I guess I can just siphon it if necessary..
  • Aug 6, 2010, 04:41 PM

    Personally, I suspected you did not add enough gas from the beginning. I think that's the current problem. The blown ECM fuse was likely the real culprit, not the fuel pump.

    If you add enough gas, I bet the car fires right up!
  • Aug 7, 2010, 12:30 PM

    Whadda you know, you were right.
  • Aug 7, 2010, 12:31 PM

    I'm happy for you! Now, you can move on with other things in your life. Nice job.
  • Aug 7, 2010, 12:50 PM

    Yeah I am really glad its fixed, thank you so much for your help. Seriously, even though it seems like a simple solution, the process of reaching it was not simple and you helped tremendously!
  • Aug 7, 2010, 12:51 PM

    I presume you left the eBay fuel pump in?

    Thank you for the compliment.

    Experience is always the best teacher. Now, you have a better understanding of the Honda fuel system than most people. Someday, you may be able to invest that experience in the life of someone else and help them out of a desperate situation. That's why I do this--one person at a time.
  • Aug 7, 2010, 01:00 PM

    Yes, the Honda fuel system is one of the least understood systems. Problems with it are responsible for more Hondas being "junked" than any other. The interplay of fuses, ECM, main relay, ignition switch, injectors, and fuel pump is difficult to fully understand.
  • May 20, 2012, 06:07 PM
    Had a similar problem. Main (fuel pump) Relay was not being energized. Turned out to be a defective ECU. Would like to troubleshoot the defective ECU but cannot find a schematic.
  • May 20, 2012, 06:39 PM
    Normally, the electrolytic capacitors fail inside the ECU.

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