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Quite a peculiar dillema I've gotten myself into...

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kylekruchok

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Discussion starter · #1 ·
As some of you may know, I purchased my DSM out of angst. Out of desperation. And out of a vision too far beyond my wallet. This isn't the first time I've done this - but I'll try to stick to the point, rather than writing an extremely long essay that only a fingerful of people will read. (Yes, that is one fifth of a handful)

The Scoop:
1997 Eclipse RS (2.0L (N/A))
After market intake, of the "cold air" variety.

The Dillema
  • The 'beast' is running rich. The mechanic duder said "extremely rich" - no, I don't know what any of this wide band, or narrow band stuff is - let's keep it marginally simple, shall we?


  • Oil consumption, like mad. (1qt/300mi)

  • MAF = stuffed

  • Sooty exhaust (Not blue, or black, or even white smoke.... the tailpipe is just overly sooty / watery. Yes - it appears water droplets are forming in the exhaust... sign of 'running rich' ?)

  • Misfire, on all cylinders. Can't feel it. Not sluggish. No 'popping' sounds.

  • The state of California doesn't like my car.


So, without further ado, ponder this with me.

The engine is burning oil, for whatever reason - and this just so happened to gum up the MAF - which is now reading improperly, throwing more fuel into the engine. Engine isn't burning hot enough to completely combust the extra fuel - giving me the sooty, and 'wet' exhaust. Also, this rich mixture being pumped into the cylinder is causing the misfire, throwing the CEL (Hence California not liking my car).

Am I on the right track? Or am I completely lost?


The 4x4 VVV
 

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#3 ·
Your car does not have a maf sensor. Do a compression and leakdown test. Burning oil would be the first thing to track down, the rest are likely side affects of the engine burning oil.
 
Discussion starter · #6 ·
Sean485 said:
Your car does not have a maf sensor.
Click to expand...
I didn't think it did - only because I literally could not find it. It's been stumping me, really.

If it doesn't have an MAF - how does it measure the air going into the engine, so it gives the proper A/F ratio? - might it just be that it (the computer) was programmed with a certain ratio, and the fact that I've got this cold air intake (which allows more air in) is throwing this otherwise perfect balance out of whack?
 
#7 ·
It uses a pressure sensor along with intake temp, rpm, throttle position, coolant temp and a set of pre-programmed maps to determine correct fuel required. A CAI can affect the accuracy of the maps but the difference is insignificant.
 
Discussion starter · #8 ·
Sean485 said:
It uses a pressure sensor along with intake temp, rpm, throttle position, coolant temp and a set of pre-programmed maps to determine correct fuel required. A CAI can affect the accuracy of the maps but the difference is insignificant.
Click to expand...
So, the (potentially) bad valve stem gaskets (seals - whatever) could have caused excess oil to gum up the MAP? (Assuming this is the pressure sensor you're talking about).

While talking to a friend, he suggested it might be the PCV valve - the air that's going back into the intake / throttle body isn't filtered one bit. Isn't it normally, on a stock system?
 
#9 ·
The chances of oil getting into the Map sensor are slim since it is only pressure reference and there is no actual flow in the line. PCV valve most certainly could let oil into the intake tract, but highly unlikely that it would be as significant as 1qt/300 miles.

I would check for vac. leaks at all the vac. hoses, spray some carb cleaner around the intake manifold/hoses. If the engine idle changes suddenly you have a leak.
 
Discussion starter · #10 ·
I've already tried the carb cleaner trick. I can blow a whole can around in the engine, and it doesn't make a difference (not that I've tried a whole can, but I've tried around all the hoses and such).

Will test for vacuum leaks tomorrow...
 
#11 ·
Doubt it is the PCV either, but it costs like $2 to change so better off doing it anyway.

When the valve seals went bad on my Camaro it would have a puff of black smoke when you first fired up the car. It also would burn it while driving too.
 
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#12 ·
Test out the PCV Valve before you plunk down money for it from autozone etc. I have tested 7 in a row and all of them failed to seal on vacuum before. OEM is the only way to go when it comes to a PCV.
 
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#13 ·
The_EE said:
Test out the PCV Valve before you plunk down money for it from autozone etc. I have tested 7 in a row and all of them failed to seal on vacuum before. OEM is the only way to go when it comes to a PCV.
Click to expand...
This is so true ! I've done the same with 3 PCV at my parts store and they where all leaking. OEM is the only real way to go ! Well at least on turbo car. :)
 
#14 ·
Very possible that your burning oil and your random misfire rich conditions are seperate problems. Find your oil leak/burning issue first. Fix that. Then move onto the other. Or vice versa, but I suggest oil first.

What all have you done to this car since its purchase? Plugs, wires, anything... have you checked any of them. Or did the mechanic dude physicaly check them?
 
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Discussion starter · #15 ·
The_EE said:
Test out the PCV Valve before you plunk down money for it from autozone etc. I have tested 7 in a row and all of them failed to seal on vacuum before. OEM is the only way to go when it comes to a PCV.
Click to expand...
Too late - already plunked down some cha-ching on a new MAP sensor - but it was only half as expensive as I though it was going to be ($65).

I tested for vacuum leaks - everything checks out normal.

I'll also run and get a PCV valve real quick. We'll just have to wait and see if the CEL comes back (reset it after I put in the new MAP sensor) (which seemed to seal properly). :dunno:
 
Discussion starter · #16 ·
I've replaced the following.

Plugs.
Plug Wires.
MAP sensor (most recent investment)
PCV valve
Battery
Battery lead (had a sh!t connection, so it would constantly wiggle around, and reset everything in the car (mostly, the radio)).
Ignition coil pack.
O2 sensors. (Both)
 
Discussion starter · #17 ·
Bump for ideas.

New PCV valve has no effect.... Would getting the original intake make any difference? (nixing the cold air, and going back to stock)

On my way to work this morning, the car died. I mean, like, literally - the engine just stopped. No hesitation. No sputtering just purring - then nothing. The only info that may be helpful would be that the battery light flicked on for a second before she went down. I managed to pull into a parking lot, where it proceeded to start right back up, no issues since then.

The throttle body gasket appears to be really chewed up - might this cause some sort of mis-reading on the MAP sensor, causing the computer to flood the engine? Also, while checking out the throttle plate (when in WOT position), everything appears to be SUPER greasy / sludgey inside the intake manifold - is this normal? I'm used to a light coating of DRY black soot on my other vehicles.

Thanks for any input.
 
#18 ·
In all the searching I did trying to solve my no spark problem I remember reading that a sending unit mounted on the thermostat housing can cause a rich condition if it is bad. If the engine is cold the sending unit I am referring to puts the computer into a cold start mode and enriches the fuel mixture. If this sensor is not working properly then the fuel mixture will remain rich even when the engine is at operating temperature. You might want to check it out. It can not be an expensive part.
 
Discussion starter · #19 ·
If you're referring to the coolant temperature sensor, I've already replaced that too - just did yesterday. Check Engine Light popped right back on.

At this point, I've replaced every sensor, besides the throttle position sensor.
 
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kylekruchok
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