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Car problems

Crazlaser

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Hi guys, haven't been on here in a long time. I still have a few lasers but had to sell most of them. Anyways right now I'm having car problems. I have a 2003 mitsubishi eclipse gt and right now both banks in the engine are running rich, codes p0172 and p0175. Looked at the long term fuel trim data and it's at -12.5

Both upstream o2 sensors are fluctuating perfectly, but both downstream ones are fixed rich. ~0.85v

The car runs fine even up to high speeds but sometimes bogs at a start. The car also idles low, which makes me think the o2 sensors are reading incorrectly causing the computer to remove fuel and idle low. I've cleaned the IAC, I have installed a new MAF and a new bank 1 downstream o2 sensor for a different code about two months ago.

I thought maybe the cats or the o2 sensors but it seems strange that both would go bad at the same time, and both would be stuck rich. The air filter is not clogged.

One major thing is the car runs like crash after a heavy rainstorm. The spark plugs and wires were replaced last year. If anyone has any ideas please let me know.

Thanks so much.

Sean
 



paul1598419

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Sorry. Outside my area of expertise. I understand what you are talking about, but don't know anything about your particular car. I need to have some routine maintenance done to my car next month. Nothing spectacular. Oil and filter change, rotate the tires and such.
 

CurtisOliver

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I wish I knew how to help. But nice to see you on though. :)
 

ElectricPlasma

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Those OBD codes only tell what the problem is, not where, which is what you need to find out. With an incorrect air/fuel mixture there are one of hundred different things that could be going wrong. There's either too much fuel or too little air. I think the best place to start might be to get a high level scanner and have a mechanic diagnose the issue for you, and then see if you can do the repairs yourself. One thing that comes to mind is inspecting your fuel injectors, they could be leaking/dripping. That might explain the sub-par idling as well. But "idk tho". It could be anything.

How many miles are on the car, and is it standard or automatic?
 

Crazlaser

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Those OBD codes only tell what the problem is, not where, which is what you need to find out. With an incorrect air/fuel mixture there are one of hundred different things that could be going wrong. There's either too much fuel or too little air. I think the best place to start might be to get a high level scanner and have a mechanic diagnose the issue for you, and then see if you can do the repairs yourself. One thing that comes to mind is inspecting your fuel injectors, they could be leaking/dripping. That might explain the sub-par idling as well. But "idk tho". It could be anything.

How many miles are on the car, and is it standard or automatic?
It's an automatic unfortunately, but the transaxle is brand new because the last one failed. It has around 97k miles on it. I think I'm just going to take it to my local shop I use. The time diagnosing this thing as a diy repairman isn't worth it.
 

Benm

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It depends a bit on what the actual cause of the sensor failure was - maybe the rainstorm and some water ingestion actually damaged both sensors in a similar fashion. If you have a good repair shop available just go there, reasonable chances they've seen the same problem before and know how they fixed it.

The repair shop will probably have an exhaust gas analyzer as well, which could tell if your engine is actually idling/running rich or it's just a sensor fault and combustion is normal (i.e. correct fuel/air ratio in reality, but misread by the sensors).

If you live in state that requires periodic emissions testing or so such you can probably combine it with that.
 

djQUAN

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Yes, possibly the cat. As mentioned, have a shop use an A/F sensor test the exhaust if the downstream ones are reading right. There could also be a possibility that the wiring gets wet during rains and alters the output voltage of the o2 sensors. Have them inspect the wires and plugs.
 




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