1994 Accord EX failed E-Check. It failed on CO (2.6%) and HC (700+ppm). It's running rich. What's your best guess as to why?

 

that sounds like a completely dead convertor with HC levels that high. The person might've ran leaded gas thru the car at some point. How are the O2 levels thru the range? Do they fall off completely or are they present?

If it passed on NO levels, EGR function should be fine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RotaryBzzz &raquo;</TD></TR><TR><TD CLASS="quote">that sounds like a completely dead convertor with HC levels that high. The person might've ran leaded gas thru the car at some point. How are the O2 levels thru the range? Do they fall off completely or are they present?

If it passed on NO levels, EGR function should be fine.</TD></TR></TABLE>
The converter is good. The o2 sensor is bad on our analyzer. (It would be nice to have one again, i've been waiting for about a year now for a new one.)

They don't check for nox, and don't usually pay any attention to it, but I did notice a hesitation on the preliminary test drive. The EGR ports were plugged, cleaning them improved the numbers slightly.

 

ah...i forgot about the O2 sensor. I thought the CO numbers were alittle low in comparision to the high HC numbers. A high mileage might've given more insight to the O2 sensor if it was something like 120k+ miles...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RotaryBzzz &raquo;</TD></TR><TR><TD CLASS="quote">ah...i forgot about the O2 sensor. I thought the CO numbers were alittle low in comparision to the high HC numbers. A high mileage might've given more insight to the O2 sensor if it was something like 120k+ miles...</TD></TR></TABLE>
The o2 sensor on the car is fine.

 

First replace the spark plugs, but it sounds like a bad/fouled injector if everything else is fine. Same thing happened to my friend's car. He had some dirt get into the injector becuase his filter was bad. The dirt held the injector open enough that one cylinder was very rich. He got them professionally cleaned and it passed easily the second time.

 

Mine failed for the same thing. My ppm was around 550+

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CD7 &raquo;</TD></TR><TR><TD CLASS="quote">First replace the spark plugs, but it sounds like a bad/fouled injector if everything else is fine. Same thing happened to my friend's car. He had some dirt get into the injector becuase his filter was bad. The dirt held the injector open enough that one cylinder was very rich. He got them professionally cleaned and it passed easily the second time.</TD></TR></TABLE>
The spark plugs and injectors are good.

 

^^^

 

Hows the air filter?

Any mods on the car?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by niedejb &raquo;</TD></TR><TR><TD CLASS="quote">Hows the air filter?

Any mods on the car?</TD></TR></TABLE>
Air filter is good. No mods.

 

check the whole fuel system, change the sparkplugs,what kind of octane gas do u use 93 and up i hope stop goin to that same gas station,change the oils,put some octane boosterin,check the fuel pump,check the catalyc converter. do it all or take it to someone who you know.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by preluder &raquo;</TD></TR><TR><TD CLASS="quote">check the whole fuel system, change the sparkplugs,what kind of octane gas do u use 93 and up i hope stop goin to that same gas station,change the oils,put some octane boosterin,check the fuel pump,check the catalyc converter. do it all or take it to someone who you know.</TD></TR></TABLE>
No problem with the fuel system. The spark plugs are good. The gas is good. The oil is good. The fuel presure is within spec. The cat is good.

BTW, this isn't my car. This car came into the shop to be diagnosed and it took me a little longer to figure out than usual. I just thought i'd see how good you H-Ters are. If you want to play.

Any other ideas?

 

I don't play raindeer games but I DO like this game...um still thinking...

What we know:

Spark plugs - good
O2 sensor - good
Cat convertor - good
Injectors - good
O2 sensor - good BUT was it plugged in?

Ok...if O2 sensor came back ok, it had to give an signal that it was there. So that means it was plugged in. OR - Was the O2 sensor actually plugged in?! I assume if it wasn't it would throw a checklight.

Question #2: How does the car idle? Does it misfire through the range when revving?

Question #3: Is the engine exhaust manifold damaged in anyway? Like is there a big gapping puncture fore of the O2 sensor?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RotaryBzzz &raquo;</TD></TR><TR><TD CLASS="quote">I don't play raindeer games but I DO like this game...um still thinking...

What we know:

Spark plugs - good
O2 sensor - good
Cat convertor - good
Injectors - good
O2 sensor - good BUT was it plugged in?

Ok...if O2 sensor came back ok, it had to give an signal that it was there. So that means it was plugged in. OR - Was the O2 sensor actually plugged in?! I assume if it wasn't it would throw a checklight.

Question #2: How does the car idle? Does it misfire through the range when revving?

Question #3: Is the engine exhaust manifold damaged in anyway? Like is there a big gapping puncture fore of the O2 sensor?</TD></TR></TABLE>
LOL, no reindeer games here.

1. The o2 sensor is plugged in. There are no stored codes.

2. It idles slightly rough, but at the proper speed.

3. No holes or exaust leaks at all.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">2. It idles slightly rough, but at the proper speed.</TD></TR></TABLE>

Ah-HA
Sparkplug wires arranged incorrectly off the distributor. OR aftermarket sparkplug wires misrouted to the cylinders.

If the car was stuck in "cold-engine/start enrich mode", I would imagine the idle would be perfect.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RotaryBzzz &raquo;</TD></TR><TR><TD CLASS="quote">

Ah-HA
Sparkplug wires arranged incorrectly off the distributor. OR aftermarket sparkplug wires misrouted to the cylinders.

If the car was stuck in "cold-engine/start enrich mode", I would imagine the idle would be perfect. </TD></TR></TABLE>
Plug wires are good and going to the right cylinders. The ECT sensor is working properly also.

 

OK...I'm running out of answers...

If it's running rich, there should NOT be a vacuum leak in the intake manifold POST throttle body. A vacuum leak in the manifold would tend to lean out the mixture and drop HC & CO content.

Now, MAP and TPS sensors throw codes when they malfunction. HOWEVER Chiovnidca already said that no codes were being stored. New question & thought of the day:

(forgive my ignorance)

Do sensors/components throw codes only when they die or can they throw codes when they only malfunction?

Say for instance the MAP sensor didn't die but was "stuck" measuring a false highER airflow under throttle conditions. And it was "stuck" measuring a false lowER condition at idle. Visually, kinda like this:

lower[[[[[air flow]]]]]higher
---[o]---------------- &lt;--REAL correct airflow at IDLE
-[o]------------------ &lt;--what the sensor "sees" at IDLE = leans the mixture too much

---------------[o]---- &lt;--REAL correct airflow at WOT
------------------[o]- &lt;--what the sensor "sees" at WOT = richens the mixture too much

So the sensor(s) are always reading too low at idle (and over-leaning the mixture)
AND under load (WOT), the sensor(s) are always reading too high (and over-richening the mixture)

SO...you get the two things this 94 EX is doing:

Idle : rough (if it was too rich, the idle should be smooth)
WOT (per analyzer) : high HC & high CO content b/k there is too much fuel being dumped into the mixture

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RotaryBzzz &raquo;</TD></TR><TR><TD CLASS="quote">OK...I'm running out of answers...

If it's running rich, there should NOT be a vacuum leak in the intake manifold POST throttle body. A vacuum leak in the manifold would tend to lean out the mixture and drop HC & CO content.

Now, MAP and TPS sensors throw codes when they malfunction. HOWEVER Chiovnidca already said that no codes were being stored. New question & thought of the day:

(forgive my ignorance)

Do sensors/components throw codes only when they die or can they throw codes when they only malfunction?

Say for instance the MAP sensor didn't die but was "stuck" measuring a false highER airflow under throttle conditions. And it was "stuck" measuring a false lowER condition at idle. Visually, kinda like this:

lower[[[[[air flow]]]]]higher
---[o]---------------- &lt;--REAL correct airflow at IDLE
-[o]------------------ &lt;--what the sensor "sees" at IDLE = leans the mixture too much

---------------[o]---- &lt;--REAL correct airflow at WOT
------------------[o]- &lt;--what the sensor "sees" at WOT = richens the mixture too much

So the sensor(s) are always reading too low at idle (and over-leaning the mixture)
AND under load (WOT), the sensor(s) are always reading too high (and over-richening the mixture)

SO...you get the two things this 94 EX is doing:

Idle : rough (if it was too rich, the idle should be smooth)
WOT (per analyzer) : high HC & high CO content b/k there is too much fuel being dumped into the mixture</TD></TR></TABLE>
No vacuum leaks.

On OBD1 Hondas, like this one, the readings have to be pretty far out of spec to throw a code. On OBD2 Hondas there is a much tighter margin for error before a code is thrown.

The MAP sensor doesn't measure airflow, it measures presure.

This MAP sensor is in proper working order. (it's not stuck)

The engine is running rich at idle.

Here's a bonus: All of the sensors are in good working condition.

Any other ideas? Let me know if you give up.

It looks like everyone else is afraid to play.

 

Fuel pressure is too high. Regulator broken or clogged return line.

PCV valve not working correctly

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by niedejb &raquo;</TD></TR><TR><TD CLASS="quote">Fuel pressure is too high. Regulator broken or clogged return line.

PCV valve not working correctly</TD></TR></TABLE>
Fuel presure is within spec. The regulator and return line are good.

The PCV system is in good working order.

 

Ignition timing is off. Its retarded to the point its not completely burning before the exhaust valves open.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by niedejb &raquo;</TD></TR><TR><TD CLASS="quote">Ignition timing is off. Its retarded to the point its not completely burning before the exhaust valves open.

</TD></TR></TABLE>
I checked the ignition timing. It was advanced at 35 degrees BTDC. What should I check next? Your almost there.

 

Charcoal canister and evap system for the fuel tank not working correctly.....?

Damn how much more do we have to guess.

 

You put a turbo on it?