Marty McFly

2004 Honda Civic Si (Canadian): The engine turns over but will not start. This happened in my driveway, 30 minutes after driving it with no problems, 30 km after filling up the fuel tank. I've read many of the threads here but none address my problem. The 15A Fuse #6 "FI ECU" under the hood keeps blowing when I turn the key to position II or ON. When I remove the PGM-FI relay #1 (maroon) behind the glove box and turn the key the fuse doesn't blow (this was because several people reported this relay as being problematic). I tested the relay with a 9V battery and it seems to work fine (it clicks and there is continuity between the 2 outlet pins). I reinstalled the relay. I disconnected all the injectors, the MAP sensor, and a few other plugs that were in the same area under the hood, turned the key and the fuse still blew. I reconnected everything. If I remove ONLY the fuse for the fuel pump (#17 under dash) and turn the key the fuse does not blow. This would lead me to believe that something is wrong with the fuel pump, but why is it that the "FI ECU" fuse blows and not the "FUEL PUMP" fuse? Changing the fuel pump appears to be a big job, so I'm wondering if there is anything else to check before I change it??? I've removed the back seat but haven't pulled out the fuel pump assembly yet. When I put in a fresh fuse for the "FI ECU" and turn the key I can hear the fuel pump run for about a second and then the fuse blows. So the pump makes noise until the fuse blows. At one point I was actually able to start the engine for a second before the fuse blew and the engine stalled. I can't find a wiring diagram in the Haynes manual or online that shows the circuit for the fuel pump and injectors. History: no issues past 3 months. EGR valve replaced in Feb/13 due to MIL on and needed to pass emissions test. Head gasket and O2 sensor replaced in Dec/12. WHAT'S MY NEXT STEP?? CHANGE FUEL PUMP??? OR TOW TO GARAGE???

ezone

I can't see what names are on any of the fuses from here.
EDIT: found the fuse 6. Still no clue yet. That fuse does power a lot of items.
I'd use an ammeter to check draw from each part of all the circuits that fuse feeds.

Disconnect the pump connector on top of the tank, then see if the fuse still blows (it should). If the pump were shorted, fuse 17 should blow, not fuse 6.
I'd use an ammeter to measure pump current draw.

Did you swap out the main relay #2 (pump relay) yet?

Marty McFly

I disconnected the fuel pump and the fuse still blew. I will try to swap out the relay next - just need to go buy one and some more fuses.

I'm not sure which circuits i should be testing for current

mikey1

this is going to be very difficult for you to solve until you get yourself a good wiring schematic

CraigW

iTrader: (1)

Is this the US EX then ??

Marty McFly

Yes I believe it is the US EX.

I'm still looking for burnt wires or bad connectors but no luck. I'm starting to trace the circuit from the FI ECU fuse since i can't find a wiring diagram anywhere

ezone

Check with your public library. Many have a subscription to Mitchell or Alldata.

Print off all the diagrams you can.

Of course, it does no good if one can't make heads or tails of a wiring diagram.

mikey1

i have seen the haynes manual for this car, it has a complete wiring schematic at the back of the manual for the entire car, are you sure you are looking hard enough?

CraigW

iTrader: (1)

This may help.... http://www.7thgenhonda.com/forum/showthread.php?t=1976

It has wiring info. Use EX trim level.

I can TRY to send you sections of factory manual.... the fuel section is over 45mb itself.

PM with an email and I will try it.

Marty McFly

That website was very helpful - i was able to find all the wiring diagrams I needed.

Marty McFly

I looked really really hard through all of the diagrams in the Haynes manual, but no dice. It seems to include everything but fuel system. I found the diagrams by following the link from the post below.

Marty McFly

Update:
After tearing apart the interior of the car and tracing the wires to the fuel pump I have finally concluded that there is nothing wrong with the fuel pump... I followed advice from others' experiences and located the crank position sensor and disconnected it. The car has finally started. So the FI ECU fuse blowing is somehow linked to a short in the circuit for the crank position sensor, which i have yet to locate. So, I've narrowed down the location of the problem to the CKP sensor, but I still haven't solved it yet... back to work now.

anybody know what will happen if i drive without the CKP sensor connected?

khex

I had the same problem:
My car stalled while driving down the highway. Would crank, but wouldn't start. Towed it to shady service center. They found the #6 F1 ECU fuse kept blowing, but couldn't figure out why. They talked about the fuel pump etc - had no clue. So I did a search and ended up here! After reading some people had problems with their Crank Shaft Sensor, I unplugged that and voila! The fuse didn't blow any more and the engine would run! I got the hell out of there since they didn't know crap and limped my car home. Took it back to the dealer that had replaced the Crank Shaft Sensor 11 months earlier (a month after they changed my timing belt and water pump, the Crank Shaft Sensor died... coincidence??) and they found corrosion in the plug and replaced it for free.

My experience is that you can drive the car with the Crank Shaft Sensor unplugged, but it will "buck" a bit when under load going up hills or trying to accelerate hard. I've driven it twice now that way - once to drive it to the dealer, once to drive it home from shady repair shop and then to dealer.

From reading other posts and doing some research, it seems very common to have problems with the Crank Shaft Sensor after replacing Timing Belt and Water Pump. Anyone else have this problem?

Long story short:
dealer replaced timing belt and water pump.
1 month later, Crank Shaft Sensor went bad.
Dealer replaced that on my dime since they wouldn't admit a connection.
11 months later, car stalled and wouldn't start (#6 fuse F1 ECU kept blowing)
Ended up being corroded Crank Shaft Sensor plug.
Dealer spliced in new plug and replaced Sensor for free... good to go!

ezone

Thanks for the pics.

There CAN be issues with liquid entering that connector even without disturbing the connection.

It is a 'known' problem area (to some of us that deal with the cars very regularly).

When I do a timing belt job on this engine I do not unplug that connector. I always unbolt the sensor and move the entire unit out of the way, wires and all.


Your pics indicate some sort of liquid got inside the connection and corroded the terminals over a period of time. This corrosion typically results in an intermittent code or no signal code.

You said it was blowing fuses...seems to me that would be an internally shorted sensor problem.
While this wire corrosion pictured doesn't normally cause fuses to blow.....
The corrosion COULD have got inside the sensor body and into the circuitry to cause it to become a short circuit.

This is all speculation on my part.

At least they covered the repair under a warranty, so that's good.

hdtrc

Thank you everyone for this post.

I have a 2005 Civic EX with the same issue and followed the same procedures as Marty McFly plus pulling every relay behind the glove box, the big grey connector, and all of the ECU connectors.
When I reinstalled the maroon relay, the ECM fuse blew. Then while taking a break I found this post and went right to the CPS, disconnected it, and the car started.

Thanks again.