[Skypig]

As some of you may recall, I have been fighting with multiple misfire codes, CEL's and severe herky jerkies. Well, problem(s) solved.

Ok, remember that the conditions during which the misfire codes would show up were 1. Less than 3/4 tank of gas and 2. end of a long (13 mile)downhill coast, as power was re-applied. Same conditions every time on my daily 244 mile commute up and down the Grapevine in So. California.

Looking at this, I was thinking that the fuel tank pressure was dropping off during the downhill (throttle off, low manifold pressure) phase. I think it was so slow that the evap sensors did not see a "gas cap off" situation, and by the time it would have, I had re-applied throttle and the tank started pressurizing again. (This is a pure guess.) However, the loss of fuel tank pressure caused a quick, across the board lean burp and subsequent misfires due to momentary fuel starvation/instability when the throttle was applied. I informed Honda of these conditions and suggested a leak down test on the tank. They said that the car does that and it couldn't cause a misfire anyway.

When I left Honda on Thursday last week, I bought a new gas cap (Based on my gut feeling about the above.) I drove from Santa Monica up the 405, after they had cleared the codes and with the old gas cap still on. While coasting down the Sepulveda Pass with 1/4 tank, the misfire codes popped up again. I stopped in Santa Clarita, cleared the codes, filled up and installed the new gas cap. From that time on, no codes.

I have driven 3 commute cycles (732 miles) so far, no codes, no light, same conditions exactly. And, the best part, the 'herky jerkies" have completely vanished.

So, for what it's worth ($30.00), it was evidently a poorly sealing gas cap after all.

 

[Insightful Trekker]

Hmmm,

Difficult to imagine a gas cap allowing a misfire.
Long time in fuel cutoff mode then throttle application-lean burp, yes.

But its hard to argue with sucess.

If however you end up with egg on your face, wash with soap & water and return for further discussion, please!

 

[cakley]

:shock: :shock: I'll buy a new fuel cap today! edit well I bought a generic fuel cap and it didn't help. It fit the car perfect but I'm not sure if it was "correct".

 

[Skypig]

Well, I have 1,220 miles since the new gas cap and no codes, CEL's or herky-jerkys. Still suprised that the fix was so simple, but I think there was some weird combination of things that came together with my unique daily drive. Who knows.

All I know is that the car drives better, the mileage has come back up to where it was before the CEL problems and it definately runs better. If they would have captured the freeze frame data the first time, they may have figured it out. But, since they did'nt (twice), I had to solve it myself with a lot of observation and recording, help from all of you, and a ton of dumb luck!

Thanks.

 

[benchilds]

Does a new EGR valve solve the problem?

I took our Company's Insight back to the dealer with this annoying misfire,
they said they had just had one in with the same problem. They investigated and said it needs a new EGR Valve and so did the last one they fixed. They are charging us £489 so I thought I'd investigate.
There are only 200 or so Insights in the UK, and I think our dealer has sold about 6 of them, so to have 2 back in as many months come back with the same fault sounds like a big problem.
I read from Cakley's survey that a new EGR didn't fix his problem, I'll add to the survey when ours comes back.
How much have others had to pay to have the EGR valve replaced?

 

[Tim Maddux]

About $400 US for me. Not covered by extended warranty.

Original threads on this subject:
http://www.insightcentral.net/forum/viewtopic.php?t=13
http://www.insightcentral.net/forum/viewtopic.php?t=880

 

[Calpod]

I had the same problem with mine for about 6 weeks, I tried to order an EGR valve but they back ordered it, (4 to 6 weeks) so I decided to take it off, spray WD40 and let it soak overnight, it solved the problem, I have been driving it for about 2 weeks now and no problems at all, even my wife noticed the difference, try the WD40 before you buy the new EGR valve, you have nothing to lose! :lol:

I tried the cleaner a couple of times, but it didn't work for me.

 

[BillClark]

makes sense about the bad seal on the gas cap; most fuel injected systems are closed systems and must have 37 psi to work properly and provide return to the tank; if there is a pressure drop due to a bad seal, then something will malfuction like not enough fuel pressure and a starving or herky jerky; most of the symptoms sound as if car is out of gas and actually is is starved because of insufficient PSI.

 

[Aaron Cake]

makes sense about the bad seal on the gas cap; most fuel injected systems are closed systems and must have 37 psi to work properly and provide return to the tank; if there is a pressure drop due to a bad seal, then something will malfuction like not enough fuel pressure and a starving or herky jerky; most of the symptoms sound as if car is out of gas and actually is is starved because of insufficient PSI.

...Except that the fuel tank itself is not pressurized. The fuel pump pressurizes only the lines. The pump moves fuel from the tank, through the filter, through the fuel lines, to the fuel rail, past the regulator, then down the return line and back to the tank.

The tank is only pressurized (and only very slightly at that) due to thermal expansion, evaporation, etc.

 

[kapps]

I've noticed the herky jerky appears when the engine is cold and you aren't driving at a sufficient rpm. It seems like the engine wants to go into lean burn in 5th in the 35-40 mph range and it just can't handle it when not at temperature. Downshifting into 4th eliminates the problem. I've also noticed that even when the engine is warm, it will continue to jerk until you bring the engine over 2500 rpm or so and then it will immediately stop jerking when you go into a low rpm, high mileage cruise. Wierd, huh?

I'm almost completely convinced it's due to the lean running nature of the engine. All engines will do this when they run lean but the Insight is able to cope with it (mostly). Running up to a 22:1 A/F ratio with a normal engine will destroy it.

 

[Insightful Trekker]

See the old thread:

http://www.insightcentral.net/forum/vie ... e80aac77f2

for a fuller picture of this fragmented thread.

kapps:

You've hit on an aspect that is a _normal_ consequence of the Insight's design.

The real problem is judging the severity.

Some Insighters (as far as can be told via a message board posting) have a much more than normal severity. For the worst reported severity none have tried cleaning the EGR plumbing AFAIK.
Should one of the three EGR ports that distribute EGR to its corresponding cylinder become clogged (and its just a matter of time before it happens to all Insights) the other cylinders will not perform an equal share of the "work" therefore causing jerking, bucking, surging during EGR on time. Which by the Insight's design is much more frequent that most other cars.

Still, at the levels you and I are still experiencing its best explanation is one of being a consequence of lean burn conditions. Nothing more.

HTH!