My 2008 FEH sometimes fails to start for as long as 10 minutes. I turn the key, all guages light up, but the engine does not turn over. I can hear a clicking noise that sounds like it is coming from the passenger side of the vehicle, but I don't know what it is. I found a thread on another site where someone described the exact sme issue I am having. When I followed up to find out how it was resolved, the owner said he ended up taking it to the dealership where they changed his MECS pump and solved the problem. I had this pump changed at about 50K under warranty and I now have over 133K miles on it. Does anyone think it could really be the MECS? I am not receiving any messages saying to Stop Safely or Pull Over. I changed the 12V battery, but the problem continues and seems to be getting worse over time. I have been thinking about changing the MECS myself, but when I check it out, it is humming so I figure it is working. I've seen a service bulletin saying to verify coolant flow into the MECS reservoir as a next step. How excactly do I "check the flow?"

 

Any OBD codes?

 

Sounds like relays going out.

 

MECS coolant flow can be checked by looking into the rearmost passenger side coolant bottle. Flow should be constant and relatively strong. It's still very possible your current MECS pump is failing -- just because it's humming and making noise does not mean it's pumping correctly.

 

No. A failed MECS pump couldn't prevent the engine from starting.

 

The fact you can hear the clicking suggests bad relays, I normally can't hear them click much when I start mine. They aren't that expensive to replace, I would just replace them all, they're just about impossible to test reliably, lots of intermittent failures until they're completely toast.

 

I decided to go ahead and change the MECS pump since I wasn't convinced it was working. The new pump is working well and now I see coolant flowing into the reservoir, so I'm convinced the old one was dead. The starting issues have not improved, so I tested my relays with a multi meter. All seem fine, but I am thinking of installing some new relays after reading the comment from hondarider90. All the fuses look fine. Can anyone tell me which relays could cause the problems I am having? I'm guessing PCM Relay, but I'm not sure.

 

If your 12V battery is at the end of the road, you can experienced the symptoms stated in your post. Been there and done that.

 

Don't just start throwing parts at the car, that will get expensive and frustrating. Billyk24 is probably correct, a weak 12 volt battery. Borrow a known good battery from another vehicle and see if that resolves the problem.

 

The 12 volt battery is fine. I replaced it about 6 months ago and had it tested before my original post. Everything checked out fine.