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Kurte9542 · Oct 8, 2012, 05:55 PM

I'll start by thanking TxGreaseMonkey, because I know I'll need to. Also, I promise to report back until this issue is resolved.

Cranks but won't start. When the key is turned to "ON", fuel pump does not run, CEL Stays on. If key is left in "ON" position, after some time, (at least 5 minutes, sometimes as long as close to 10 minutes) the fuel pump will run for 2 seconds, the CEL goes out, and the car will start. Cycling the key does not seem to speed up the process.

I did the K-Test (during the no start condition), MAP gets the 5 volts. I replaced the main relay, but it did not fix the problem. I'll admit I did not wait to see if the new relay would have the same effect after the 5-10 minutes.

After I reconnected the old relay, I wiggled all under the dash and under the hood fuses to check for a bad connection while the key was "ON", but did not have any effect.

I'm in south Florida, and the car seems to have more difficulty in the morning when it's a bit cooler outside. Also, it seems that as days go by, I'm having to wait longer before the fuel pump kicks on and the CEL goes out.

Thanks again. I will most likely be able to report back tomorrow at about this time.

TxGreaseMonkey · Oct 8, 2012, 07:44 PM

Nice job.. . This looks like a fun one.

Guiding Principle

When you turn the ignition switch to ON (Position II), does the Check Engine Light (CEL) come on and then go off after 2 seconds? If not, the problem is with the ACG (ALT) (S) fuse, in the under dash fuse/relay box; ECM (perform the K-Test); main relay; or the ignition switch. Perform tests in that order.

Therefore, I would:

. Clean the main ECM ground, if you haven't already, which is located on the thermostat housing--apply dielectric grease.

. Remove and clean the ACG (ALT) (S) fuse in the under dash fuse box. It's likely Fuse No. 24.

. Check the ignition switch for wear, pitting, or melting. I doubt that there's a problem with the ignition switch, but you may want to cover all the bases.

Since the CEL does not always go off after 2 seconds, when the ignition switch is turned to Position II, I suspect intermittent ECM failure. My hunch is that, if you perform the K-Test many different times, the voltage will not always be 5 volts--sometimes it will be around .3 volts. The solution will likely require installing a new ECM (get an exact Honda Part No. match)--shop for price and warranty. The electrolytic capacitors in these older Honda ECMs eventually start to leak, which creates all sorts of intermittent problems.

Kurte9542 · Oct 9, 2012, 03:50 PM

The ECM ground was tight and looked pretty good, but ran some sandpaper over it anyway. The ACG fuse connections were OK too. Next I went to repeat the K-Test.

I had the hood open and my meter connected to a ground. I turned the key ON - no fuel pump. Walked to the passenger side of the vehicle, unplugged the MAP sensor, checked one side of the plug - 4.77v, checked the other side - 5.07 volts. Re-checked both sides with the same results and then plugged the MAP sensor back in. About 1 second after the MAP was reconnected, the fuel pump ran for 2 seconds and shut off, the CEL was out when I walked back to the driver's side. When I cycled the key, the fuel pump ran normally and shut off after 2 seconds.

I didn't mess with the ignition switch, since getting to it was not as easy as the other items. I feel like the ECM is most likely the problem after what you said, but I think I have to "catch" it being "bad". I am going to repeat the K-Test in the morning, which is when the car has the most trouble. I'll report back in about 12-13 hours. Thanks again!

Originally Posted by TxGreaseMonkey

Nice job . . . this looks like a fun one.

Guiding Principle

When you turn the ignition switch to ON (Position II), does the Check Engine Light (CEL) come on and then go off after 2 seconds? If not, the problem is with the ACG (ALT) (S) fuse, in the under dash fuse/relay box; ECM (perform the K-Test); main relay; or the ignition switch. Perform tests in that order.

Therefore, I would:

. Clean the main ECM ground, if you haven't already, which is located on the thermostat housing--apply dielectric grease.

. Remove and clean the ACG (ALT) (S) fuse in the under dash fuse box. It's likely Fuse No. 24.

. Check the ignition switch for wear, pitting, or melting. I doubt that there's a problem with the ignition switch, but you may want to cover all the bases.

Since the CEL does not always go off after 2 seconds, when the ignition switch is turned to Position II, I suspect intermittent ECM failure. My hunch is that, if you perform the K-Test many different times, the voltage will not always be 5 volts--sometimes it will be around .3 volts. The solution will likely require installing a new ECM (get an exact Honda Part No. match)--shop for price and warranty. The electrolytic capacitors in these older Honda ECMs eventually start to leak, which creates all sorts of intermittent problems.

TxGreaseMonkey · Oct 9, 2012, 06:47 PM

When performing the K-Test, you are only interested in the MAP Sensor's reference voltage, which is from the female connector on the far right (as you look at it).

If the problem now goes away, it was likely from South Florida corrosion on the main ECM ground. Be sure you removed the 10mm bolt, cleaned the 3-wire brass connector with abrasive cloth, and coated the back of the connector with dielectric grease.

Kurte9542 · Oct 10, 2012, 05:32 AM

Did the K-Test this morning. At first the voltage was about 3.7, and crept up to 4.1. The fuel pump wouldn't run and the CEL stayed on. I had to go to work so I didn't test anything further. I'll take a look at the ignition switch and perform the k-test again this evening when I get home...

TxGreaseMonkey · Oct 11, 2012, 05:55 AM

3.7 volts is not good enough--your ECM is failing and is the reason why your engine intermittently won't start.

Kurte9542 · Oct 12, 2012, 04:15 PM

Yeah, I figured from what you said. Looks like I can get one re-manufactured from Autozone for around $350 with a one year warranty. I feel better about that than getting a used one. The car, which my step-son drives, has been starting OK for the passed few days. It'll have to get bad again before he'll be willing to spend $350, but I think he will. He loves that car. When we fix it, I'll let you know. Thank you so much for your help. If you ever have a question about an outboard boat engine or boat system, I hope I can return the favor.

Originally Posted by TxGreaseMonkey

3.7 volts is not good enough--your ECM is failing and is the reason why your engine intermittently won't start.

TxGreaseMonkey · Oct 12, 2012, 04:28 PM

Also call Advance Auto Parts and O'Reilly Auto Parts. For $350, you should be able to get one with a lifetime warranty.

Kurte9542 · Apr 21, 2013, 06:16 PM

6 months and the story is finally concluded... The ECM finally died for good last week. The ECM seemed to have the most trouble when the humidity was high. During the winter, our humidity is low and it actually did fine for a while. Then in March, the problem started to creep back until last week the car stalled after starting and wouldn't restart again. We got a used ECM off EBay for $90 and the car runs well now. Thank you so much for your help!