2000 Honda Accord no spark.

Trying to help out a friend. Her car will intermittently not start. It’ll crank, but no spark. Aside from the unlikelihood of all 6 coils being simultaneously bad, what else could it be?

Not reading any codes at this time.

She reports that in the am, when it’s cold, it’s most likely to not start. When the day warms up, it will.

 

Bump.

Can someone tell me how to test the wires at the coil harness plugs? I’ve checked the power wire and it has 12v, but I’m not sure how to test the signal wire or the ground properly / without cooking the pcm. I’m guessing I could just jump the ground to the neg battery post with a test light, but how do I test the signal wire?

 

This sounds like a problem for someone with more equipment than the average Joe has. An oscilloscope sounds to me like a good way to monitor the signal. Methinks maybe something is temperature sensitive in the ECU, which provides the signal. I wouldn't expect that all coils would fail at the same time.

 

It’s definitely pushing the limits of my experience and tooling. She’s been to three mechanics with no success. So just spending as much time as I can on it. The diagnostics are adding up fast for her at the shops.

 

Is there any way to check the harness plugs with a multi meter?

 

One would use the ohms function, in the lowest range available. The resistance measured through a good connection would be virtually the same as what you read when touching the leads together. The thing to keep in mind is that the force you put on the contacts to make a good meter connection could cause the contacts to meet, making the test meaningless. Piercing the wire back from the connector would be less likely to cause this problem. That could cause other problems, tho.

Thinking about this a bit more, I'm not sure what contacts one would check. There should be one wire per cylinder from the computer. The problem couldn't be in those connectors if all cylinders fail to function. If the vehicle uses the same computer for other functions do the other functions operate when the engine won't start? For that matter, have you personally verified that there is no spark when it won't start? Maybe there is a fuel problem.

 

There is a module up under the dash, it is your problem.

Don’t remember what the name of it is.

Instead of jerking around and testing things, replace the box....might be called ignition module....been awhile since I wrenched on a Honda.

This is common on the older cars, age,corrosion and dirt kill it.

Last one I did was 90 bucks for the part 10 min install and vroom.

 

There are three wires at the connectors. I’m assuming 12v/ground/signal. But I understand that probing them in the wrong combinations can cook the pcm. Sending 12v back into it, for example, I’m guessing might be bad...

It’s definitely ignition related. Intermittently no spark on all cylinders, seems to be somewhat ambient temperature related. I’ve visually verified spark at the plugs with the plugs removed. Plugs look fine.

Definitely getting fuel. I checked when I had the plugs out.

 

Main relay? Replaced it. No change.

 

PCM or wiring harness. There may also be an issue with the crank sensor which is being affected by temperature. Although crank sensor failure on that gen Hondas is fairly rare.

 

No codes for crank or cam sensors and it’s a timing belt job to swap them.

 

I know that.

You are going to have to use some good equipment to diagnose this one if you have it. You may have to scope those sensors if you want to make sure their marks are lined up to what they should be. This one will not be easy for sure.

 

Bummer. Guess I’ve done what I can.

 

Don't feel bad man. You've done what you can and she is lucky to have someone willing to take some time out of their day to help her. I just ran away from an Audi S5 diagnosis today because it had 20 codes stored and was barely drivable today.

 

Ignition switch? How many bloody keys are on the key ring?

One other possible....distributor.

Do this, sit down with paper, write down all the possible electrical areas under the hood that could take on water, rule out coil packs and alternator.

Then go to each system and check for cracks or holes, once you have eliminated that system put all the electrical parts back together with dielectric grease, yup can use wd40 to dry out things like distributors if you see water. You may need to test terminal tension on the plugs.

Lectrickery is fun

 

Judging from the original post, there is no distributor in this vehicle. It sounds to me like it is going to take a bit of easter egging--replacing parts to find the problem. My guess is the ignition module (ecm, or whatever is controlling the signals to the coil packs) is the most likely. 12TRDTacoma's and Gixerkiller's first posts have the right idea.

 

According to the parts fiche the v6 lx and ex have a distributor and they are the only v6 options in 2000.

Hey OP,
Shows us a pic of the engine bay.
If you are still interested in working on this.

 

I’ll post one in a few min

Also this is a 2001 if it makes a difference

 

It might, let me look...

 

The accord had a distributor until 2001, depending on when in the year the engine was produced it may not have a distributor.

To find it you need to remove the engine cover. Under the plastic it should be clear as day. This is one of those 2001.5 things that happens, like the 2nd gen. 2012-2015 was gen2.5.