My friend has a 98 Accord EX with a V6 3.0L Auto trans. He has been having trouble with what we think might be vapor lock.

The accord will not start after he has driven the car for awhile or its a real hot day. If it wont start after driving he will wait awhile and then it will start.

What can you do to get rid of vapor lock? There are no mods to the car and he only uses it for dd.


UPDATE: Here I've moved my results to the first post since others are just joining and reading the first post. Did I test these correctly?

 

vapor lock?

this sounds like a commmon problem on older accords and it is the main relay or ignition coil.

 

So are you saying one of these are bad? The main relay or ignition coil?

 

By the description of the problem.. yeah, it does sound like main relay, seen this happening on many accords already.

 

Darn, well at least its the cheaper of the two. Now why would it be the main relay? Does this have something to do with the vapor lock? Or is it something different?

 

As i was told, once the main relay gets a little hot after a few years of use and what not, a bad connection takes place. I switched main relays with a friend of mine who simply soldered whatever was wrong in it. But again, this is what i was told, and that's what he used to do, go to junkyards.. find relays... solder them, and sell them.

 

Nice, Thanks for the advice. Ill have to switch this out and let everyone know how it goes. Is there anyway to test it first before I spend the money on a new one?

 

I don't know how to test it, but... i'll tell you one more thing...lol.. a lot of people put their main relay on the freezer for a day.. and said it works awesome for many weeks to come before starts acting out again.
But again, do a search on main relay, see if you could test it yourself and hopefully, there's nothing else that could be causing the problem on this accord.

 

A freezer lol. There are some weird ways to do thing I guess. Ill try doing that and if it fixes it then I just buy a new one. How long do you think it should be in the freezer?

Yeah I hope that is the problem. Is this the cause for most vapor lock issues? How about when the car shuts off when driving even?

 

Man, i've heard of leaving it for a few hours, sorry that i can't be of any more help.

 

This could be useful, taken from the accord FAQ!

http://home.earthlink.net/~michaelpk..._MainRelay.htm

http://techauto.te.funpic.org/mainrelay.php

 

Does anyone have any wiring diagrams for the main relay?

The car is not getting spark. Does this relate to the main relay?

 

I thought that only cars with carburators got vapor lock? I dunno, I'm from the lowlands - Illinois (I'm about 400 feet above MSL).

About twenty years ago I was with some friends in a '69 Pontiac going to Utah during the summer. The car kept stalling out, starting in Kansas and throughout Colorado and Utah, maybe once every few hours - it would just have to sit for 30 minutes or so. On the return trip we were traveling through Apache territory and of course it stalled out again - lucky it wasn't the 1880s or we would have been scalped - but this old Apache came up and told us it was vapor lock. Took a wrench we had, stuck it in the flap on the carburator, and we left it there never to have vapor locak again.

 

I would test your ignition module. My wife's Honda Accord did the same thing. Did the car lurch forward while driving highway speeds (50+ MPH)? That was one of the signs for myself to let me know. Then, BAM, would not start. Tested the module, replaced it, and have not had a problem since. DO NOT quote me but the main relay I thought controlled fuel, not spark.

 

It happens sometimes in sometimes in pgmfi's , but I don't think its vapor lock anymore. It wont cause a no spark symptom.

 

I have not even drove the car since its a friends of mine. Is there a way to test it without a meter?

And I also thought that the main relay controlled fuel and not spark. I'm just making sure.

 

I always thought the Main Relay controlled fuel only also. To test at home, all you need is a multimeter that does VDC (volts-direct current) and continuity (basically this test makes sure there is no breaks in your wire, and a service manual. You CAN take it out and Auto Zone can test it, but the test equipment there is hit or miss (used to work there). Give me a little bit and I'll post the correct procedures for testing it at home.

 

sweet thanks bro. I guess I better get down to the store and get a service manual and a multimeter.

 

Okay so the manual told me to measure the resistance between the terminals on the coil.

Resistance between the two outer most terminals (#1 and #3) should be between 0.34-0.42 ohms. It was actually 0.7 ohms.

The secondary winding resistance should be between 17.1-20.9 kil-ohms. It was actually 19.9 kil-ohms.

So after testing that I tested the ICM. The manual said to test the terminals for voltage. If the middle one has no voltage your to check the ignition coil. No voltage was found during my test.

So I'm pretty sure its the ignition coil. What do you think?

 

Suscribed I have a friend with the same problem I think hers is the main relay but your not getting spark thats electrical related I wouldn't even bother the main relay until I figured that out. And yes it does manage the fuel to my understanding.
I would find out why it's not getting spark. Try to jump it, test battery, test alternator,test igniter inside of dizzy, test ign coil. You can do it all free at Autozone

 

If you read my post above I just tested the coil and ICM and got negative results on the coil.

 

Does it look like I tested everything correctly?

 

For the symptoms you list, I'm more inclined to say it is the ignition control module aka ignitor, inside the distributor. Tests for the ignitor are unreliable since the condition is intermittent. For that matter, so are tests to the main relay.

For future reference, vapor lock is a problem more likely to occur on carburator cars due to the lower fuel pressure in the line. The fuel pressure in FI cars virtually eliminates this problem.

 

If its the coil or ICM why wouldn't the CEL be on?

 

Where is the ECU located on this car? Is there a connector to jump that will make the dash light blink to read the code?