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Discussion Starter #1 (Edited)
I hit 52K on the way home today and also had my first CEL on the car right before I pulled into the garage. I pulled out the trusty SGII and pulled up a P2188 (too rich at idle), but the car was running fine. A little checking around on the Internet seems to indicate a few possible problem areas (O2 sensor, purge valve, etc.).

I just cleared the code after giving the engine bay a quick once over and we'll see if it returns. It's probably nothing, but in case it comes back, has anyone else run into this code on a smart and, if so, what was done to resolve it?

Edit: Nothing has changed (no mods) on the car over the past 10K miles or so. The oil and filter was changed about 2K miles ago and the air filter was cleaned about 8K miles ago. Iridium plugs have 20K miles on them.
 

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Maybe its bad accel enrichment just caught up with it...

Not to get too technical here, but if left uncorrected the AFR goes lean when you accelerate suddenly and rich when you let off the gas suddenly. There's perfectly good correction available for this, but the smart doesn't appear to make the best use of it. I've seen mine go as lean as 18:1 when I punch the gas from a dead stop, and as rich as 12:1 if I let off the gas suddenly from a high-output state. Maybe you just caught a particularly big rich swoop.

Chances are I'm nowhere close to the real problem, but if it doesn't come back that's one explanation for the gremlins...
 

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Discussion Starter #3 (Edited)
Interesting... I come to a quick stop at the bottom of my driveway after climbing a hill to pick up the mail and then take off again. The CEL came on right there at the bottom of the driveway.
 

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Discussion Starter #10
Well, drove nearly 40 miles to work this morning and no light. Maybe just one of those turn it off and back on kinda things. We'll see what happens on the way home...
 

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If the light comes back on, you should start with the Air filter. Its possible its just gotten dirtier then normal.

Does your scan guage show fuel trim? If so I would check it and compare it to a known good smart. See exactly how rich you are running and under what condition. If you had access to a scan tool, I would ask you to look for random misfires that wouldn't generate a code. This would be indicative of a leaking injector. You could then do a fuel pressure test and see if the pressure holds. If it doesn't then a leaking injector could be the culprit. As for O2 sensors, a build up of crap in the tip could cause it to see less oxygen, but that would have the effect of leaning out the system rather than richen. But the ECM would set a Activity code.

Since you don't have a MAF, I would then look at your fuel pressure. See if you have any leak-down when you cycle the key on, then off. Let it sit for 5 min. If there is any leakdown, a bad injector could be the culprit. (This usually coincides with a misfiring on the affected cylinder, so unless its VERY minimal you could probably rule this out).

I hate to say it, but for this kind of code, you visually inspect the obvious, but then you need to start seeing the data before you can narrow down the problem without just "parts changing".

Clean the air filter and see if the problem comes back. Until its a hard code I wouldn't even worry about it.

OH OH OH OH.... I forgot one thing. This car does not have a temperature guage. Check your temp from start-up to warm up and make sure that it is a constant curve. Since the smart doesn't take long to warm up you should be concerned if the guage doesn't get warm ~190 degrees F. THIS WOULD CAUSE A FUEL ENRICHMENT BECAUSE OF A COLD ENGINE AND WOULD CAUSE YOUR PROBLEM. if this is the case you most likely are experiencing a stuck open (could also be intermittent) thermostat.
 

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If the light comes back on, you should start with the Air filter. Its possible its just gotten dirtier then normal.

Does your scan guage show fuel trim? If so I would check it and compare it to a known good smart. See exactly how rich you are running and under what condition. If you had access to a scan tool, I would ask you to look for random misfires that wouldn't generate a code. This would be indicative of a leaking injector. You could then do a fuel pressure test and see if the pressure holds. If it doesn't then a leaking injector could be the culprit. As for O2 sensors, a build up of crap in the tip could cause it to see less oxygen, but that would have the effect of leaning out the system rather than richen. But the ECM would set a Activity code.

Since you don't have a MAF, I would then look at your fuel pressure. See if you have any leak-down when you cycle the key on, then off. Let it sit for 5 min. If there is any leakdown, a bad injector could be the culprit. (This usually coincides with a misfiring on the affected cylinder, so unless its VERY minimal you could probably rule this out).

I hate to say it, but for this kind of code, you visually inspect the obvious, but then you need to start seeing the data before you can narrow down the problem without just "parts changing".

Clean the air filter and see if the problem comes back. Until its a hard code I wouldn't even worry about it.

OH OH OH OH.... I forgot one thing. This car does not have a temperature guage. Check your temp from start-up to warm up and make sure that it is a constant curve. Since the smart doesn't take long to warm up you should be concerned if the guage doesn't get warm ~190 degrees F. THIS WOULD CAUSE A FUEL ENRICHMENT BECAUSE OF A COLD ENGINE AND WOULD CAUSE YOUR PROBLEM. if this is the case you most likely are experiencing a stuck open (could also be intermittent) thermostat.
A dirty air filter is just a restriction in the intake; it should just be the equivalent of the throttle not being able to open quite as far. Unless the smart uses TPS for fueling (which it has no excuse to unless the MAP sensor is dead, which would certainly give a CEL), intake restrictions should be nicely accounted for.

Checking fuel trim is a very good idea; the SGII can do this with an XGauge function. Commands are listed here (PDF). Also look for AFR in there. It may tell you something interesting like when exactly it is going rich. (Look for the first alternate AFR entry; the first entry doesn't work.)

Fuel enrichment due to cold engine doesn't seem likely to me at all. First, if it were running rich when cold, then it would be doing that by design and it therefore shouldn't trigger a CEL for mixture problems. Second, this car doesn't generally run rich when cold. Mine tends towards 14.5:1 most all the time (excepting the aforementioned accel enrichment deficiencies). It goes rich above about 5000 RPM, and of course we don't know what's going on in the first 30 seconds before the O2 sensor is warmed up, but it doesn't seem to be dependent on coolant temperature at all.
 

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Discussion Starter #14
Just wanted to pop back into this thread and report about 800 miles since turning off the CEL and no reappearance, so I'm just going to chalk it up to fluke at this point.
 

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Quite frankly, I'm amazed that we don't see more flukes with the check engine light and other issues... If a person stops and thinks of how much electronic control is going on here and on a 12 volt system... the technology is mind bottling :eek:
 

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Discussion Starter #18 (Edited)
Maybe water in one of the connectors??
This is actually following up on a problem that happened well before the engine wash. Maybe it needed washed? But, believe you me, the first time I started it after the wash I took it for a good run to make sure everything was percolating right up to redline. Of course, it sat for 2-3 days before I fired it up after the wash, so everything should have been dry by then. :)
 
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