While driving my 94 Accord down the highway this weekend I happened to see the tack, speedo, and gas gauge drop to zero for a second then come back to life. The car seemed a little sluggish after that but it kept going. A little while later it happened again. I shut off the radio and started listening to the engine to see if I could hear anything strange going on. A little while later I heard a relay and the guages died again and this time my D4 light was blinking. I stopped the car and shut it off to see if the D4 light would reset and stop blinking. The car would not start. I waited about 5 mins and the car started and the D4 light was not blinking. I got about 15 miles down the road when it happened again. Only this time the guages did not come back and the car was dead. I coasted to the shoulder and let it sit about 10 mins and it fired back up. I gauges died one more time on me on the way home, but I made it without any more issues.

When I got home I took the ECU out and checked all the connections for corrosion or anything else. Nothing out of the ordinary was found. The connections seemed good and tight and nothing was burnt on the circuit board in the ECU. I put the ECU back in and on the way to work today the gauges died on me again. The engine did die on me, but the guages are still flakey.

Does this sound like the ECU is starting to go? Any other ideas as to what the problem could be?

Thanks,
Mish

 

I wouldn't blame the ECU until I ruled out bad connections anywhere else in the wiring harness. Over at the main relay, where the ECU gets it's power from. Or maybe a loose plug on the back of the cluster??

One hint is the gas gauge. I don't believe the ECU is involved in that circuit at all, but you better check that with a circuit drawing for '94.

 

I took out the ECU this past weekend and all of the connections going to the ECU were fine. No corrorsion or anything were seen on the plugs or connectors. All the plugs were in connected very well, so I don't think it is a connection problem at the ECU. Maybe somewhere else possibly though.

Here is some more information. The first time I saw the problem it was a very hot day here in Texas. Yesterday morning it was a little cooler and the problem only happened once on the way in to work. On the way home yesterday it was raining and the temps were much lower and I didn't see the problem at all. So now I am starting to think that this issue is temperature related.

Also, hearing the relay click back on when the guages come back is making me think that I am running in to a low voltage situation that causes the relay to open like when you shut the car off. The Alt that I have on there is the original one and I am currently running around about a 1700 Watt system off of it. I have been patiently waiting for the alt to die, but it just keeps going and going.

I am starting to think that the voltage regulator in the alt may be starting to go. This may be why the relay turns off the ECU. I thought about this before, but the stereo never shut down while I was listening to it. It could be possible that the shut down voltage for the ECU is higher than the stereo systems. I know that most stereos will run down to around 10V. Maybe the shut down voltage for the ECU is 11V or even 10.5V. That may explain why the deck never shut down.

My plans are to wait for another hot day here. Shouldn't have to wait too long for one here . Then I'll run the car for a few minutes on the highway to get it nice and warm. Take it home and let it run in the hot sun in the driveway. While it's running I'll hook up my DMM to the output of the alt and look for some fluctuations in the output voltage. Hopefully I'll see some and then my problem will be solved with a new High Output alternator.

If you have any other ideas, please let me know. I love my car and want to get it running right again.

Thanks,
Mish

 

Well the car is fixed now.

I was on my way to work Friday when my engine stopped again. Usually it would start back up while I was driving, but sometimes I would have to coast to the side of the road and let it sit a few minutes before it would crank again. This time, it would not start back up and had to be towed to the shop Not many things worse than seeing your car on a flat bed first thing in the morning.

I had gone through all of the electrical stuff and determined that everything was OK except the Alt needed replaced. Ordered a high output one and put it on this weekend.

When the car was on the side of the road (luckily my wife was right behind me and she stopped to help out) I had my meter and was watching the voltage as my wife tried to start the car. Everything looked fine. I didn't see anything that would point me to the direction of an electrical problem causing the problem. At least not one under the hood. I eventually gave up and had the car towed to the shop.

They called later that day and said that they had traced the problem to the ignition switch. This made sense to me since the radio never cut out when the engine did becuase it was running off the ACC. The problem was with the switch in the "ON" position. I got it fixed and have not had any problems so far.

I had had problems getting the car to start sometimes for a long time. Sometimes I would come out of work after the car had been sitting for hours and try to start it. The car would turn over and start to run when I had the switch in the "START" position, but when I released the starter the car would then die. Letting it sit for a few seconds it would usually start back up after a few trys. This went on intermittently for some years. Very rarely ever happened, but I had noticed it was happening a little more in recent months.

Figured I'd put that in there to help others who may have been experiencing the same problems.

Mish