need help narrowing down a problem

2455 Views 19 Replies 8 Participants Last post by Insightful Trekker, Apr 17, 2005

dfiore

Discussion Starter · Apr 9, 2005

I did some experimental driving and this is what I found:

If I push the gas pedal down 1/3 everything's fine. If I push any more than 1/3, the car supplies more gas, but the gas engine isn't doing anything with it and it gets sluggish.

I've had alot of things checked and the dealer can find nothing. I need to understand what happens with the spark current or timing when you push the gas harder and it's supposed to take off faster. The gas is coming in, but something else is not happening.

Other than that nothing else is wrong.

1 - 20 of 20 Posts

pretzelboy

· #2 · Apr 9, 2005

How many miles does your car have?(can't help you with problem just noticed your sig line).

Aaron Cake

· #3 · Apr 9, 2005

How are you proving that "more gas" is going into the engine?

Do you have an OBD-II tool you can use to observe A/F ratios and timing?

How's lean burn? Working as well as it used to?

Timing is set by the computer. It won't change unless the system in in fault. Do you have a CEL light?

What has the dealer checked so far?

dfiore

Discussion Starter · #4 · Apr 9, 2005

RE mileage

I have just over 204,000 miles. The dealer hooked it up to the computer and could find nothing wrong. I know it is using more gas because the display tells me so and I run out of fuel faster than I used to. Maybe the dealer didn't take it out and "gun" it. I'm thinking there has to be something wrong that doesn't throw a code you can simply read. If there was I'd like to think they'd find it.

Dan

figgy

· #5 · Apr 10, 2005

I am learning as I go along about EFI systems like ours, so I may be wrong, but from what I understand, one possible thing might be that it is putting too much gas in for each ignition cycle so that you are just wasting it and not burning efficiently at all.

For scan tool data fields, if that is the case, your oxygen output should be low (via O2 sensors), maybe your ignition timing advance out of whack dealing with too rich a mixture. A smog check should also measure uncombusted gasoline in the exhaust.

Can your dealer look for gas in the exhausst? That would seem the simplest test for incomplete combustion, and no one can argue if they find it.

It has to be going somewhere, if it isn't burning, then it is going out the tailpipe unburned.

dfiore

Discussion Starter · #6 · Apr 10, 2005

extra exhaust

I have kind of noticed more of a stink, now that you mention it. I'll ask the mechanic when I get my next oil change in the next 30 days. Thanx

Aaron Cake

· #7 · Apr 10, 2005

An engine that is running rich should throw several codes. The most repeatable will be P0420 (I know, as I've been there, done that).

Can you tell me what the voltage is for your LAF sensor while driving at 40 MPH NOT in lean burn? Should be around 0.5V or so. Under lean burn, it will drop much lower (though I have not determined the exact range).

A stink is a problem, and likely indicates a failing cat. What does it smell like? Eggs or fuel?

The dealer should have an exhaust gas analyzer that looks at the 4 main gasses. It will be easy to tell if the car is running rich.

With all those miles, have you changed filters and plugs?

Insightful Trekker

· #8 · Apr 10, 2005

A P0420 is a CAT code. And will set as a reflection of:

1) An "overloaded" _or_ marginal CAT. Anything that causes poor combustion efficiency.
2) A bad CAT.
3) A _SEVERELY_ overloaded CAT in imminent danger of failure. Should be accompanied by severe loss of power e.g. misfires.

Some "stink" is a normal by-product of combustion when sulfur is present. Hi sulfur fuel will smell worse and may be a normal consequence. An "overloaded" CAT will as a consequence produce more sulfur compounds in the exhaust. I'd find a low sulfur brand ASAP!

An exhaust analysis would be a very good diagnostic test to perform. 5 gas analysis being the best CO, CO2, HC's, O2, & NOx. Depending on the percentages coming out of the tailpipe at idle & speed much can be determined as to what is happening (or not) during the combustion process.

By Dan's previous posts he's got 70+K on his second set of plugs right now. Should be OK for a full 105K interval.

With Dan's very high mileage its important to not forget the EGR _plumbing_ can get clogged. Which _requires_ EGR plate removal for cleaning.

HTH!

See less See more

dfiore

Discussion Starter · #9 · Apr 11, 2005

The EGR may be the weay to go

Is there a procedure for this cleaning? I, unfortunately do not have access to all the test equipment, and my dealer who has done well for me so far cannot find any codes signifying anything. I'll try the EGR cleaning if someone can give me a procedure and maybe a picture or 2, but after that, I have hold out for a new Insight or IMAS.

Dan

Aaron Cake

· #10 · Apr 11, 2005

Insightful Trekker said:
A P0420 is a CAT code. And will set as a reflection of:

1) An "overloaded" _or_ marginal CAT. Anything that causes poor combustion efficiency.

That's why I was using it as an indicator of an overly rich engine. As the service manual explains, this code is common in a misfire/rich situation. It instructs that all other codes be troubleshot before P0420...

By Dan's previous posts he's got 70+K on his second set of plugs right now. Should be OK for a full 105K interval.

Ideally. Yet my plugs showed significant wear at 100,000KM (~60K miles). Mine were WELL out of spec.

Is there a procedure for this cleaning? I, unfortunately do not have access to all the test equipment, and my dealer who has done well for me so far cannot find any codes signifying anything. I'll try the EGR cleaning if someone can give me a procedure and maybe a picture or 2, but after that, I have hold out for a new Insight or IMAS.

EGR cleaning is very easy. But I often find it trumpeted as a magic bullet to cure all Insight problems. So it might help in your case, but I doubt that it will.

The valve is located in the front right area of the engine, beside the throttle body. You need to remove the engine cover. The valve is about the size of a small can of pop/soda, with an electrical plug on top, and a cast base plate. Two bolts hold it to the mount. Just undo those bolts (spray them with penetrating oil first), disconnect the plug and the valve pops right off. Clean it out with carb cleaner. If you have a service manual, you can look up the wiring for the valve and find that the two bottom pins activate the valve when 12V is applied. Being able to cycle the valve helps to clean it out. Also clean the passanges in the plate where it mounts. Q-tips work well, but MAKE SURE NOT to get the head of the Q-tip stick in the engine. When reinstalling the valve, use a new gasket after cleaning all the old gasket crud off. Put anti-seize on the thread, and tighten the nuts to 16 Ft-lbs.

If you need to remove the EGR plate, things get more complicated as this requires removal of the intake manifold.

Based on your description (problem is a lack of power, not a hesitation) then I doubt EGR cleaning will solve it. But it's worth doing.

As for the diagnostic equipment, the dealer should have an exhaust gas machine. An exhaust gas analyzer is not dependant on the sensors in the car, and can detect any mixture problems (if they know how to read it right...).

See less See more

Insightful Trekker

· #11 · Apr 11, 2005

From one of several old posts on EGR "cleaning":

Calpod said:
I believe is the valve sticking rather than being clogged, I have removed clogged EGR valves before, and you cannot see the passages at all.

Newer type clogs tends to be slight and at the end of the line where the passage tends to be the coldest and the soot "freezes". This then causes an EGR flow imbalance in that some of the cylinders get a disproportionate amount of exhaust gas during EGR on time and therefore a lesser fuel air charge resulting in jerking, bucking, hesitation, etc. (a power imbalance) The Insight also has an "unusual" amount of EGR "on" time.

johnc

· #12 · Apr 14, 2005

I saw this once on a old gas-guzzler where the cat had disintegrated. Enough of an opening to flow at low r.p.m., but the constriction prevented it from running at higher speeds. Just a thought. Ever change the cat?

jc

dfiore

Discussion Starter · #13 · Apr 14, 2005

changed the cat, but...

I still think the EGR will help, but I think I may have solved most of the problems. I just put in a K&N airfilter and there must be a "sweetspot" for the input suction. I went out yesterday and put a bottle of injector cleaner and premium ($25 total with 1 fuel bar left)

I'll have to save up and buy a new EGR, or I may just go buy an EGR seal and try to clean the one I have.

Aaron Cake

· #14 · Apr 14, 2005

Don't buy a new EGR valve, there's no reason do. Just clean your old one.

Injector cleaner is generally useless as well. Most of it is snake oil, and just a few more ounces of the stuff that's already in gasoline.

JustinGray

· #15 · Apr 14, 2005

I would like to make a small point. It is not really possible for an engine to be adding alot more fuel to the intake air, and not doing anything with it. If it goes into the cylinder, it will burn. Engines dont decide how much fuel they burn, thats why we have electronic engine control.

Now, that said, if you have so muhc fuel you cant burn it all (what is being called a rich mixture) then adding more fuel would actually make your car "bog".

So having made that point... If infact your car is dumping fuel rediculously into the engine at anything past 1/3 throttle, you should notice a definte hesitation from the engine. That will be your best indicator of a rich situation.

I would not trust the mpg meter to tell you when you are rich or lean... too many variables there. Its just not related to your air fule mixture.

Another thing you might want to check on is the throttle position sensor. If somehow its broken and you are detecting a wide open throttle at only 1/3 actually throttle... the engine then starts dumping in acceleration enrichment for WOT which could explain your problem

See less See more

flunkysama

· #16 · Apr 15, 2005

With that many miles, a compression check is probably in order.

I've heard that speed-density FI systems (like hondas) are sensitive to valve timing, so check the valve clearance. Also check the timing chain for stretch/wear.

Checking the spark plugs can't hurt either.

You might want to get a vacuum meter. At lower RPMs, there will be no change in manifold vacuum (and power) at 1/3 throttle than full throttle.

dfiore

Discussion Starter · #17 · Apr 15, 2005

think I'll hold out

It's still getting over 50mpg average. At 205k, I think I'll start saving for the IMAS/Insight2. If it doesn't happen, maybe I'll have a rebuild or just wait till I actually have a problem. The compression and plugs are good.

Daniel

Insightful Trekker

· #18 · Apr 15, 2005

Re: think I'll hold out

HUH :!: :?:

So you don't really have a "problem" :!: :?: :?:

What were we trying to help you with then :?:

dfiore

Discussion Starter · #19 · Apr 17, 2005

You misunderstand

It has problems, just nothing you can put a finger on without spending a ton of money. I'll be cleaning out the EGR valve, but unless something gets worse, I don't think I'll be able to figure it out. The EGR solution has been suggested the most and that is the route I am going to pursue.

Thank you very much!

Insightful Trekker

· #20 · Apr 17, 2005

Re: You misunderstand

dfiore said:
It has problems, just nothing you can put a finger on without spending a ton of money. I'll be cleaning out the EGR valve, but unless something gets worse, I don't think I'll be able to figure it out. The EGR solution has been suggested the most and that is the route I am going to pursue.

Thank you very much!

Check the latter parts of this thread for the proceedure:

http://www.insightcentral.net/forum/vie ... php?t=2429

Your _VERY_ welcome :!:

HTH!

1 - 20 of 20 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.