1994 Accord EX Vtec 5 Door with 270000 mi.

In a nutshell, the car starts and dies within a fraction of a second. It's as if someone turns off the ignition switch just as soon as the car starts. Only trouble code is 15 ("Ignition Output Signal").

I don't think it's a fuel problem as the fuel pump pressure tested good, the engine doesn't miss or sputter as if it is being starved, and the main relay tested good (and a replacement didn't help either.) For the very short time the engine runs it runs smoothly.

A little history: After a broken timing belt and valve job the car ran for about a week. Then one morning it began this “start and die immediately” behavior. My first response was to replace the ignition switch which I learned can cause this kind of problem....to no avaiI. After more time with it I got frustrated and had it towed to a mechanic who spent hours on it without finding anything wrong. That is until he found the carpet damp and pulled the ECU out found some corrosion on the harness connections and cleaned them. The car started and ran until I picked it up and drove it home. However, when I tried to start it the next morning the problem had returned and persisted for a few weeks of tinkering with it..

Then one day it started! I had checked some of the wiring, some voltages and continuity but hadn't changed or replaced anything. The only thing that had changed was a better battery charger to charge the battery after all the cranking. It raised the charge to 13.6 volts instead of the 12.4 by the previous charger. Should that make a difference? I don't know but the car started and ran on my next attempt. Perhaps it was pure coincidence, perhaps something unrecognized had changed, perhaps the higher voltage helped an ailing ECU or ICM or coil or crankshaft position sensor? And the car started and ran hours later. Will it start tomorrow?

I don't have any confidence I can drive it anywhere not knowing for sure tI'll make it home.

Anyone have any suggestions as to what is going on?



Thanks,

Paul

 

Just to be thorough, was the code 15 flashed by the check engine light or the D4 light when checking for codes?

A code 15 from the CEL means the ECU is detecting something wrong with the ignition control module circuit. The root cause can be the ignition control module inside the distributor, the wiring, or the ECU. Most people will assume the code means the ICM and 95% of the time they will fix the issue. In your case, you had water near the ECU, so I'd probably start at the ECU/ECU connector.

First water near the ECU is caused by a water leak in the car. You need to address this first. The most common reason is the drain hose for the A/C unit is clogged and water is spilling from the evaporator onto the ECU. It is a bit tight behind the evaporator and the firewall, but you can unplug the hose from the evaporator and pull the hose from the firewall. See if the evaporator drains water, then clean out the hose.

The other common reason for getting water into the car is a clogged drain on the moonroof. Open the moonroof and find the drains. They are front passenger and rear drivers corner of the moon roof. The other end of the hose ends up in/near the respective wheel well.

Something that will help you a lot is a shop manual for your car. Google CD7_CD5.pdf for a 1994 accord shop manual. The shop manual is invaluable for troubleshooting problems.

When the area near the ECU is dry, clear the codes by pulling the 7.5 amp backup/radio fuse in the engine bay fuse box for a minute, reinstall the fuse, drive the car, then recheck for codes. See what code(s) return. The CEL flashes the engine codes and the D4 light flashes the transmission codes. See the common diy thread on top of the gen tech help forum for instructions on how to read CEL codes for your car.