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My granddaughter's 2008 Civic Hybrid stopped running for her last week. It would restart after the key was turned off, but after a minute or two, the engine would stall and die. It seemed like a fuel supply problem. The symptom seemed to be a fuel pump or fuel filter.

I towed the car to my mechanic friend and we agreed it made sense to order a new fuel pump and filter.

My mechanic friend replaced the fuel pump and filter. I went today to help my mechanic friend finish putting the car back together, but when we started it up again, the problem was still there. We worked on it for a while, but could find the problem. The 12v seemed weak, so we replaced it and that changed nothing. We noticed that turning the key to full off position appeared to reset something and then the car would start again, run for a minute or two, then stall and die. The way it stalls really feels like a fuel supply problem, but the way it resets by turning the key to the full off position feels like a computer problem of some sort.

I have a 2008 Civic Hybrid that I drive, so I am thinking I will take that car to my mechanic's shop so that we can start swapping parts from my car to my granddaughter's car to see if we can identify the problem part.
Has anyone run into this kind of problem? Does anyone know an easier solution than swapping parts from a healthy 2008 Civic Hybrid to the ailing 2008 Civic Hybrid?
Thanks
Mike

 
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Find a mechanic that can do better diagnosis before you end up with 2 non-working cars

 
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My mechanic is pretty good and very experienced. I am also decent and experienced, but I am old. We have a major league obdii scanner, but we don't have Honda dealership diagnostics. I am concerned about the possibility of killing two cars by trying to diagnose one. I was hoping someone here might have run into this mysterious stalling problem and could point me in the right direction.
thanks for your words of caution.
Mike

 
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green key on the dash?

 
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No, but that kind of idea is where I am headed. I think the ECU is shot. I am planning to replace it and then do the key.immobilizer.ecu programming required to make things do. What about the question about how to check the pressure on the fuel rail. Is there a port hidden somewhere? The way it stalls and dies screams fuel shortage to me.
Thanks
Mike

 
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the fried ECU usually happens when the alternator bolts are loose. Were they at some point in time?

 
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alternator bolts were never loose to my knowledge. I bought the car less than a year ago for my granddaughter, so I have an incomplete history. Everything under the hood looks undisturbed. That's an interesting suggestion

 
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the thing that bothers me about the ecu idea is that the problem was intermittent, then hit hard and stopped the car. that doesn't seem like electronics which I would expect to fail suddenly and completely. But the fact that turning the key to the full off position reset something that allowed the motor to get fuel again for a short period of time, then stall and die like fuel starvation - that turn it off and get a reset does seem like something electronic.
These things are more complicated than the Model T

 
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Okay. It turns out that these models have a "matchbox fuse and relay box" down below the radiator cap. It looks like this when it is healthy

 
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wait, yours were not healthy?

 
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mine were definitely not healthy. They were zip tied in place and sort of out of sight. They were highly corroded. I soaked them with CorrosionX and stuck in new relays. That fixed the fuel pump issue. For the future, it someone asks about fuel pump relays on a Gen 8 civic hybrid, check the "matchbox" fuse and relay box under the radiator filler and just in front of the 12v battery. The usual civic relays spots in the big fusebox under the hood and under the dash above driver's left foot are both empty and do nothing to move power to the fuel pump.
Cheers
Mike

 
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were you aware that the fuel pump relay for the civic hybrid was in this strange spot instead of in the standard civic fuel pump sockets under the hood and under the dash?

 
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nope, the hybrid is a very different animal...