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Discussion Starter #1
Hey All - 2004 Ody turns over strongly but won't start. Spraying starter fluid will run the car as long as I keep spraying so I looked to the original fuel pump which stopped making the familiar noise. The fuel pump had power on one of the pins so I replaced it as well as the fuel pump relay - same story - no fuel pump sound/turns over but no start. After checking the wiring diagram, I provided accessory power to the black/yellow at the fuel pump and she started right up and it ran fine so I could drive home. The car is basically hot wired so I can drive it but I want to fix the problem. The after market alarm cuts the starter motor - so that's clearly working fine. I'd prefer to actually fix the problem instead of driving it "hot wired". Any suggestions?
 

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Does the green key symbol in the instrument cluster light up when you're trying to start it? Is it solid or flashing?
 

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have you checked the fuel pump cutoff switch in the back? back into something hard enough and it will flip the switch, not even sure if it has a switch but imo it has to do with the fuel pump relay
 

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This is the main relay under the dash on the driver's side. Really common in all Hondas that get old. If you are handy, the burnt solder connection can be fixed. Or just get a new one. Just search here for main relay and all will be revealed.
 

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This is the main relay under the dash on the driver's side. Really common in all Hondas that get old. If you are handy, the burnt solder connection can be fixed. Or just get a new one. Just search here for main relay and all will be revealed.
OP says they already replaced the main relay.

To the OP, was the replacement relay new or used?
 

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OP says they already replaced the main relay.

To the OP, was the replacement relay new or used?
Well, I'm an idiot and missed that. However, I would still like more details about the replaced relay box. Did anyone look at it inside to
see if there were burnt spots? I still suggest doing a search on "fuel pump relay" if the op has not. Lots of good troubleshooting steps.
 

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have you checked the fuel pump cutoff switch in the back? back into something hard enough and it will flip the switch, not even sure if it has a switch but imo it has to do with the fuel pump relay
Sounds interesting. I have never heard of this Pinto switch. Do you have any more details?

Other comments on this thread:
Hotwiring won't bypass the immobilizer - even if you get the fuel pump to run continuously, either the fuel injectors or the coils or both won't be working if the ECU is not happy with the immobilizer state. I've tried that. I've also hotwired around a problem with the ignition switch, but not to circumvent an immobilizer problem.

A debugging step I would do before buying parts, given that it starts OK, is to get a secondary 12V power source (e.g., a spare car battery sitting on the floor in the back) and power the fuel pump directly with alligator clips from that. That removes a lot of variables and would be a useful test.

Of course careful circuit analysis with voltage measurements and sufficient current flow should get to the problem quickly as well.
 

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Discussion Starter #9
Green key symbol goes on for a few moments and then goes out. Initially I thought it was the Immobilization system but since the green light goes out like normal now I don't.
 

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All fuses on my driver's side kickpanel (including fuel pump) are good (tested by ohm meter) and all fuses have power - some hot some keyed hot. Checked all fuses in that fuse box and under the hood and all are good. Replaced fuel pump relay to no avail. Inspected old fuel pump relay and it looks fine. The new fuel pump relay was not OEM - didn't seem to matter.

UPDATE - a week later I'm basically driving the car hotwired from ignition switch to the fuel pump black/yellow with no issues. I can't find any fuel pump cutoff reset switch as some people have mentioned. There are a few things I need to check as I've had some helpful suggestions that I haven't checked yet. Thanks All! I will check all suggestions I haven't tried and report back.
 

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It is really easy to remove the "guts" from the relay and look for burn wires. But if the new aftermarket one is "working" then I would look for some chewed wires. Try tracing the wires from the pump. Rodents are known to chew on wires and are know to cozy up to warm vehicles as winter sets in.
 

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We'll see if the site lets me post this wiring diagram. This is for my '99 EX, when I was debugging an intermittent problem with the immobilizer.

BTW, the green light on for a couple of seconds and then off is exactly how it should work when everything is good. So no problem there. You should also see it flash a few times when you shut down, which indicates it is arming the immobilizer.

Hopefully that diagram and the notes will help you see what the wires are doing. If you've got it hotwired, it means you've probably found the problem. There's not much more to it.

Also, if you can figure out how to get the site search to work, you may be able to find a post about 6 years ago in November when I described how I hotwired around a failed ignition switch when 400 miles from home over thanksgiving. Fun.

main relay immobilizer circuit marked up.jpg
honda99 main relay.jpg
And here also is a pic + diagram of the main relay. Be warned that the numbers (1 2 3 ... 7) cast into the plastic do not match with these numbers, so ignore the ones on the plastic.
 

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Discussion Starter #13
Hey "Old School" ET AL - Great diagrams of EXACTLY what I could not find in my aftermarket manual - really appreciate it. I've been repairing a lot of other items since my car runs just fine "hotwired" but I will get to this and report back. I checked the short distance the wiring runs under the car between the fuel pump and where it comes back in through a grommet behind the driver's seat and it appears just fine and checks out OK with an ohm meter. I've been running this issue by several mechanics and one suggests that the electrical side of the key may be failing to power the fuel pump relay - thanks the diagrams now I know what to check. How big of a deal and expense is it to replace the ignition?
I really appreciate the forum and will report back if I end up finding the cause.
Rick
 

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Glad my diagrams were helpful to you. I work on so many different things that I find I need to take careful notes to avoid needing to re-learn something when I get in there the 2nd, 3rd, etc. times, so I keep track.

Replacing the electrical portion of the ignition switch is easy. Search this forum for the part number, 35130-s0x-305, and you'll find some good info. TSB on Honda instructions in there. I've got some posts in there about how to do a quick inspection, how to hotwire around it, and how to approach the recall / warranty aspect of it. On my '99 at least, there is a safety recall where they will replace it for free forever, as many times as it fails. Not sure if that may apply to your car.

Since you can understand those diagrams and can hotwire around the problem, you may already be at the point where you are ahead of the pro mechanics you're consulting with.
 

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my van is doing Same thing here. why does it cut off. wait little bit and runs fine again. I have no codes shown up in computer. so what do we do to not get stuck again?
 

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it's doing it now and I have full tank and it's doing it now. I'm stuck again. seems to be doing it more today for some reason. I am trying not to get frustrated. I know cars but way too many sensors to go wrong and cause this.
 

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Fix or replace the main relay. this particular thread goes down some other paths, only because the primary reason this happens was already fixed. Working and then not working and then working again are symptoms of a failing solder connection. When this happened to me, I sat beside the road and tried to figure out what could be wrong. Actually looked up the issue on the odyclub, called my son in law (who works at a auto repair shop) and had him bring a relay to me after work. After sitting for awhile, my van started and ran fine all the way home. (I did take a surface street route and did not get back on the freeway) Once home with the relay removed, it was obvious one of the spots on the circuit board was fried. We actually reflowed solder on the old one snd put it back. I drove it another 2-3 years without issue. I did keep the new aftermarket relay onboard just incase. If you are not seeing anything with the little flashing picture of a key on the dash, indicating an issue with the immobilizer system (the van does not recognize the key), it is almost always the relay. As I probably said above, this is really common on all Honda vehicles of this vintage, as they age.
 
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