ecu-main relay issues
06-28-2009 | 07:26 PM
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Joined: Jun 2009
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From: Wisconsin
ecu-main relay issues
hello all - my first post and having issues w/88 Accord. here's what's happened and what I have done.
started with boy getting into minor accident and popping drivers side window. Car was running fine, except I noticed temp gauge went up to normal temp on dash in a matter of a min. or so - coolant level ok.
we put plastic over window to attempt to keep rain out. one morning the car would not start. it would turn over and start for a second then die. seemed like it was not getting fuel.
As I started checking things I saw about an inch of water had accumulated on the back seat drivers side floor from rain getting in broken window. cleaned it up without thinking much of it.
first and easiest fix was replace fuel filter. virtually no change, would run for sec and die. After several attempts a buzzing noise started from under dash and engine compartment when I would turn ignition to start position. Tracked dash buzzing to main relay and engine sounded like the fuel injectors were firing. pulled relay and performed continuity test per Haynes repair manual - failed all 3 tests and I replaced it.
Installed new relay and did the same buzzing as the old one, with buzzing from injectors. I went back to Haynes manual to get more ideas, and saw that the ECU is under the drivers side seat and controls the injectors, which I instantly thought of the pooled water.
I pulled it out, dried it out and cleaned off a little corrosion that had started to form around the edges of the circuit board. put it back in and no change in noises.
I did find in checking things that if I left the large harness unplugged from ECU and turned the car over it would start and run until it ran out of gas, which leads me to believe that when the harness is plugged in and the buzzing occurs it is flooding the engine.
In checking for shorts from the water, I found a lot of moisture in the harnesses running from the ECU to under the dash. I dried out the harnesses and checked the connections. Did not help anything.
So is my ECU shorted out from the pooled water? I also read on a post that a bad temperature sensor (engine temp gauge from beginning) can send bad signals to the ECU. could that be the problem? another post said unplugging the computer fuse can reset it, where is the computer fuse - I do not see any labeling for it.
Please help with any ideas - and sorry for the long explanation.
started with boy getting into minor accident and popping drivers side window. Car was running fine, except I noticed temp gauge went up to normal temp on dash in a matter of a min. or so - coolant level ok.
we put plastic over window to attempt to keep rain out. one morning the car would not start. it would turn over and start for a second then die. seemed like it was not getting fuel.
As I started checking things I saw about an inch of water had accumulated on the back seat drivers side floor from rain getting in broken window. cleaned it up without thinking much of it.
first and easiest fix was replace fuel filter. virtually no change, would run for sec and die. After several attempts a buzzing noise started from under dash and engine compartment when I would turn ignition to start position. Tracked dash buzzing to main relay and engine sounded like the fuel injectors were firing. pulled relay and performed continuity test per Haynes repair manual - failed all 3 tests and I replaced it.
Installed new relay and did the same buzzing as the old one, with buzzing from injectors. I went back to Haynes manual to get more ideas, and saw that the ECU is under the drivers side seat and controls the injectors, which I instantly thought of the pooled water.
I pulled it out, dried it out and cleaned off a little corrosion that had started to form around the edges of the circuit board. put it back in and no change in noises.
I did find in checking things that if I left the large harness unplugged from ECU and turned the car over it would start and run until it ran out of gas, which leads me to believe that when the harness is plugged in and the buzzing occurs it is flooding the engine.
In checking for shorts from the water, I found a lot of moisture in the harnesses running from the ECU to under the dash. I dried out the harnesses and checked the connections. Did not help anything.
So is my ECU shorted out from the pooled water? I also read on a post that a bad temperature sensor (engine temp gauge from beginning) can send bad signals to the ECU. could that be the problem? another post said unplugging the computer fuse can reset it, where is the computer fuse - I do not see any labeling for it.
Please help with any ideas - and sorry for the long explanation.