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Discussion Starter · #1 ·
I'm not quite sure if this is the problem but this is my assumption. Any help would be appreciated as things are even worse when it is winter.

So... i had rpw long tubes put on my 2005 gts in the summer. i never had any issues with my car running besides high fuel consumption (i also used an aggressive tune with it). Anyway, i helped with the installation but didn't complete this on my own. The thing i thought was odd was there are 4 O2 sensors (from what i remember). From my understanding, you're supposed to extend the O2 sensors from the exhaust manifolds down to the exhaust. What my friend did.. was we put in a test pipe (no cat) and put in two of the O2 sensors. The other two he spliced and tapped them into the other two O2 sensors (therefore only 2 are really being used, and not 4). Again, during the summer nothing is wrong but now with the rain and snow.. i think the connections are getting wet and when im driving, my car starts cutting out like it isn't getting any gas. To keep it from dying, i have to push in my clutch and rev it up then put it back into gear; playing with it back and forth. So that right there is the problem... therefore does it make sense the O2 sensors are the problem?

Finally.. i'm getting roughly 10-12 mpg (not tuned). could the O2 sensors be the cause of that? a mechanic that works at the dealership said the O2 sensors work independently causing it to run too rich.

Any help would be appreciated.. thank you!!
 

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From my understanding, the front 2 o2 sensors force corrections, and the back o2s are just there to throw codes if there's too much or too little unburned fuel. So, in theory, they could cause you to run too rich as the fronts and backs are measuring slightly different things. Personally, I would put the time in to extend the sensors to their correct position... I would think Mitsu put them there for a reason.
Have you disconnected the battery recently?
 

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(b)org banugee
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First off all -- you should be throwing all kinds of codes with that set up, even when the weather is not bad. If your SES light isn't on, you should scan it and see, because I guarantee the computer is not ok with this.

Yeah -- the way you connected the upstream O2 sensors was a really bad idea. The two upstream sensors control the fuel trim. They should be tapped into each header somewhere. The downstream sensors are not just upstream ones with longer wires. Those that have put a downstream one in an upstream spot accidentally have had problems. Using the same two for upstream and downstream sensors was an extremely bad plan.

I'm betting you are not only throwing codes for the sensors, but you are probably throwing fuel trim malfunction codes.
 

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Discussion Starter · #4 ·
Thanks a lot i had no idea. i actually don't know what codes i'm currently throwing but should go to autozone and check. I definitely am throwing codes though. I don't even know what ones he tapped into. Now here is my next question... i do want to get this fixed and my friend (who is the mitsu mechanic and the dealership i bought the car from) is getting prices for me to fix the O2 sensors (for labor). Now i told him i have the O2 sensors still but he said he suggests getting new ones as he wouldn't be comfortable using splicing it back together.

Don't they have to be spliced anyway as they have to be extended? Since we're on the topic.. you said the 2 upstream sensors go to each of the headers.. where do the 2 downstream sensors go? anywhere in the exhaust?
 

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(b)org banugee
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On the stock setup the two downstream ones go below the pre-cats, and before the main cat. If you have any sort of cat, you should probably put them below it, but it doesn't matter too much. Just use the anti-foulers.
 

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New daddy
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Thanks a lot i had no idea. i actually don't know what codes i'm currently throwing but should go to autozone and check. I definitely am throwing codes though. I don't even know what ones he tapped into. Now here is my next question... i do want to get this fixed and my friend (who is the mitsu mechanic and the dealership i bought the car from) is getting prices for me to fix the O2 sensors (for labor). Now i told him i have the O2 sensors still but he said he suggests getting new ones as he wouldn't be comfortable using splicing it back together.

Don't they have to be spliced anyway as they have to be extended? Since we're on the topic.. you said the 2 upstream sensors go to each of the headers.. where do the 2 downstream sensors go? anywhere in the exhaust?
Just put the downstream sensors somewhere in the exhaust where you have enough room to put a couple spark plug anti-foulers on them or buy the rear o2 sensor simulator. They are basically the same thing.

Road Race Engineering's 4G Eclipse Parts and Performance
 

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Discussion Starter · #7 ·
Yes! i have heard about the anti-foulers.. if i use them it should get rid of the SES light for the sensors. I did want to do that.. currently there is no cat but he did pick two locations that gave him plenty of room for the o2 sensors. i should be able to put in the anti-foulers.

I remember now tho.. since the upstream o2 sensors were in the pre-cats.. he spliced those two (the upstream sensors) into the downstream sensors which are located in the exhaust. Now that you told me those are used for fuel trims.. i'm probably just dumping fuel haha. My car continuously lets out a stream of smoke... and i noticed when it was dry out.. there were dark spots on the cement at the end of my exhaust?
 

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(b)org banugee
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You ought to have the upstream ones above where the two banks combine. The ECU performs fuel trims separately for each bank.
 

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Discussion Starter · #9 ·
Okay i'm starting to think it might be something else that is causing the car to cut out. It did it all this morning and it only seems to be getting worse. I started blaming the weather thinking that the cold/water/snow could be getting on the connections where the o2 sensors are spliced into each other under neath the car by the exhaust.

However, i remember when my car was cutting out a month ago, i took my battery to Autozone and it was only holding a 4.x charge (i think recommended is 12-14). I bought a redtop duralast and once i put that in, my car stopped cutting out and ran great again. So aside from my fuel problems, the car running crapping might be because my alternator is bad. If it were bad, how long do you think a redtop would last fully charged (with getting little or no charge from the alternator)?

As an example of how it is running, if i'm in low rpms, it wants to cut-out and die. If i take off in 1st from a low rpms, i can have my foot 3/4s the way down on the gas and it acts like i'm not giving it any gas at all. All of a sudden, it will finally catch and start going.

I'm frustrated! :mad:
 

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BoomGoesTheDynaMitt
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Okay i'm starting to think it might be something else that is causing the car to cut out. It did it all this morning and it only seems to be getting worse. I started blaming the weather thinking that the cold/water/snow could be getting on the connections where the o2 sensors are spliced into each other under neath the car by the exhaust.
I think the problem is more from those sensors being spliced to each other and has nothing to do with the cold, shorts, getting wet, etc.

However, i remember when my car was cutting out a month ago, i took my battery to Autozone and it was only holding a 4.x charge (i think recommended is 12-14). I bought a redtop duralast and once i put that in, my car stopped cutting out and ran great again. So aside from my fuel problems, the car running crapping might be because my alternator is bad. If it were bad, how long do you think a redtop would last fully charged (with getting little or no charge from the alternator)?
No idea... maybe a day if your lucky?? It would depend on tons of factors but mainly whether or not the stereo, headlights, defroster, etc were being used. Have the alt checked when you go to have the codes scanned.

Scan the codes. No one can tell you whats wrong without the codes, although if I am following what you say about the O2 sensors then those are DEFINATELY a problem. Have them completely redone, correctly this time. Yes, you can use your current O2 sensors and just splice the wiring to extend them. 1st though, you should use a DVM to ensure that the sensors fall within specs (measure resistance/ohms).

I'd guess that at a minimum you are throwing:
- many many O2 codes
- fuel trim malfunction codes
- multiple/random misfire codes

Fix the O2s and then go fom there. I bet fixing that wiring clears most if not all of your codes and running issues. As Citm2000 said those front sensors need to each be on their own bank/header and NOTHING should be spliced into them. Their location in the header will be important as well, in order to get an accurate measurement.

As an example of how it is running, if i'm in low rpms, it wants to cut-out and die. If i take off in 1st from a low rpms, i can have my foot 3/4s the way down on the gas and it acts like i'm not giving it any gas at all. All of a sudden, it will finally catch and start going.
That is exactly how my car ran when I was getting random misfrire codes due to a faulty/dying O2 sensor. But boy, went it started moving it waslike a bat out of hell! Almost scary and dangerous in traffic. Start with the sensors! That is where your frustration is coming from. All 4 sensors should be on their own circuit and should not be spliced into each other or into anything else. The ONLY splicing that should be done is to extend the sensor wiring so it can reach the O2 bungs in the headers. And be sure that each sensor is plugged into the correct harness. Having a rear O2 plugged into a front O2 harness will cause some serious issues. I did that once and the car would buck and stall repeatedy.
 

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(b)org banugee
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You can get about 50 miles on a fully charged battery with no alternator if you only start the car once and pull the fuses for some of the higher drain devices. Remember -- a jump does not give you a fully charged battery. Your battery has probably also been ruined by this. If you put a brand new battery in, expect to get about 50 miles of daylight driving.
 

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Discussion Starter · #12 ·
Hmm maybe its starting to go out then? i don't know. I've got about a month of driving on it. Well over 50 miles. Im going to have the battery/alternator checked today as well as what codes i'm throwing... :sadwavey:
 

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Discussion Starter · #13 ·
Spyder! Thanks for the response i just saw it. I didn't see it when i posted last time. I called up a shop and they'll provide the bung, install it, and re-wire the o2 sensor (granted i provide it) for $45-$65 per header (and for the money i'm wastin away in gas) its absolutely worth it.

Just wondering... did everyone have to do this with the RPW headers? I find it odd that these are twice as expensive as OBX headers.. yet OBX has the bungs already in place + direct fit. I know the quality isn't as great but my friend uses them in his turbo '00 GT with no problems..

I'm stopping by the garage after work to get an estimate and see if he can check the codes for me... Thanks again for all your help! Will post results asap. Depending on what they say.. ill look to have this done Thursday or Friday.
 

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Discussion Starter · #14 ·
citm2000 called it...

So here is my update. I took my car to O'Reilly Auto Parts for a test on my battery and alternator. Remember when my car was cutting out before and i tested my old battery, it wasn't holding charged. I bought this new redtop and my car started working perfect again and has for the last month.

The test showed 100% charge on battery and that the alternator was working.. So i went to Autozone to get my SES light checked (forgot to at O'Reillys...) and the grand total is:

25 codes!!!

8 of the codes were due to o2 sensors which to my surprise; all of them said TOO LEAN. Those 8 were duplicated by 1 and 2 banks so that accounts for 16 of them. Here are some of the other codes he printed off on receipts:

P2228 - Barometric pressure sensor circuit low

P0102 - MAP/BARO or MAF/VAF sensor condition. The PCM has determined that the mass air flow input is lower than expected for the current engine operating conditions.

P0203 - Fuel injector circuit condition- Injector number 3. The PCM has determined that a malfunction exists in the electrical circuit for cylinder # 3 fuel injector.

P0113 - IAT (Intake Air temp) circuit. The PCM has determined that the input from the intake air temperature sensor is higher than expected for the current engine operating conditions.

P0202 - Fuel injector circuit condition- Inject number 2. The PCM has determined that a malfunction exists in the electrical circuit for cylinder # 2 fuel injector.

That's all that i have... I guess my question is.. any further explanation on the codes.. and could any of these codes be showing up because the o2 sensors aren't correct? A local race shop has o2 sensor bungs in stock so im hoping to have them welded into the headers this weekend. From there:

1) I have both downstream o2 sensors in the exhaust.
2) I have one front o2 sensor available that was cut off with about 3 inches of the wire hanging out. Is this one usable?
3) The 4th o2 sensor was cut right at the end so there is no wire available to splice into. I'm buying a replacement for this one...

If my bungs get put in this weekend, should i:

A) keep the setup and put plugs into the bungs until i have 2 upstream sensors available or:

B) Undo the spliced o2 sensors, redo the downstream sensors so they're correct, and re-wire one of the front o2 sensors and put a plug in the other one (until i get my replacement).

Thanks a million guys!!
 

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BoomGoesTheDynaMitt
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The most important thing you need to get fixed are BOTH UPSTREAM (primary - closest to engine) sensors. Until those are fixed the car is going to be missing a lot of power (best case). Sounds like your MAF (air intake) sensor may be unplugged or fauty as well. Check the connection/plug. If it is good I would clean the probe with electronics cleaner. Or maybe there is just a leak somewhere around the MAF :dunno:
 

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Discussion Starter · #16 ·
See i forgot to mention that part. When i first took it to the dealership, they told me the MAF was the problem (cause he put in a replacement and my car ran perfect again). However, i replaced my battery (w/o fixing the MAF) and the car seemed fine so i figured it wasn't the MAF. Now that i'm throwing this code.. maybe it is the MAF. I do have a AEM intake that is currently setup as a short ram. The MAF from dearership is $600+ but they're telling my warranty company its stock so they'll cover it (minus $100 deduct) so maybe i should do that as well...

Thanks
 

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BoomGoesTheDynaMitt
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Clean the MAF sensor (small probe hanging down on the inside of the tube/box) using a $4 can of eletronic cleaner (radio shack/car parts store) before buying a new MAF. I think yours is just dirty which may explain why sometimes it works and sometimes it doesn't. Have you oiled th cne filter on your AEM yet? Usually problems occur shortly after oiling the filter IF you used too much oil (which many people have, including myself). Spraying it with cleaner takes 1 minute and could save you some $$$. Also, you can probably find a used MAF here for under $100. I picked up a spare for $50 :yesway: and it runs great. Some parts are good to grab and have on hand, especially when they are priced so low! Thought I saw another MAF/MAS for sale recently.

:edit: BTW, I still think your front O2s are causing the majority of your codes.
 

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Discussion Starter · #18 ·
Thanks again for the response. I got a new replacement o2 sensor. i still have to get my o2 sensors bungs this week. I remember now that i put in 87 octane (stupid) last week when i always run 93/94. i wonder if doing that (and running 89 here and there) messed up my injectors. I have my MAF under warranty and the dealership will keep quiet on the aftermarket parts.. so my deductible is only a $100 if i put my stock intake back on first before they do the replacement.. so i could go that route and have a brand new one.

I've never oiled my aem cold air since i got it. I have an estimated 5,000-7,000 miles on it. is that a problem? I was thinking that since im getting codes on the 2nd and 3rd injector... that its just spitting fuel and not giving it the fuel it needs so its cutting out. If i hold the gas down at a certain pos at 3-4k rpm.. it will eventually cut out and start dropping (like i turned my car off).. but if i push the pedal to the floor (give it more gas), then it finally starts going again.
 

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Fix one known problem at a time...you know there are issues with your O2 sensors...get that taken care of and then have the codes checked again. A lot of times, multiple codes will be thrown when there's only one thing wrong since the computer will often try to compensate with something else. I've seen O2 sensors throw codes for quite a few things before. It's possible your MAF took a dump or needs to be cleaned as well, but I'd start with what you know is wrong and then reevaluate it after that's fixed...
 

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(b)org banugee
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Get you two upstream sensors working -- clear all codes. Then run it and deal with the remaining codes that crop up. I have lower expectations that you can fix your MAF than others. I think that if checking the connections and its orientation doesn't fix it, it's probably dead. I think the IAT sensor is built into the MAF.
 
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