Rough Idle and TERRIBLE fuel mileage

Tiny
KEN BENSON
  • 2000 MITSUBISHI ECLIPSE
  • 175 MILES

I'm having an issue with a rough idle along with my gas mileage dropping about 50%. When I start my car first thing in the morning, it will turn over and sometimes stall, or the RPMs will drop low enough where the interior lights illuminate for a second, but the RPMs will go higher. And then back down again. This process will repeat itself until the car warms up. If I press on the accelrator, the car sputs and sputters at first, but reacts normal once the car warms up. Once warm, the car idles as advertised. I cleaned the throttle body, and this helped alot, but has not fixed the rough idle I've also cleaned the Idle Air Control Valve, MAP sensor, MAP sensor, throttle position sensor and I've changed my EGR valve. I've looked for vacuum leaks and haven't found any. With the car running, I've sprayed Carb cleaner all around the engine to try and find a vaccum leak, but nothing. After all this, I dropped some SeaFoam in the gas tank, followed by some 93 octane to a full tank, and, as stated earlier, the car will run/idle fine once warmed up. But my gas mileage is terrible. I normally get about 300+ miles to a tank. I'm at half a tank, and havn't even reached 100 miles yet! I think my IACV is bad. I will diconnect it, start the car, and it will idle at approx 1200 without a hicup.I'll turn the car off, connect it back up, start the car, and the rough idle returns, but could the IACV really be the cause of such a drastic change in my fuel economy? I've also pulled my plugs and to make everything even more confusing, it seems the car is running lean. My plugs had a chalky, greyish look to them. They were not "wet" at all.

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Tuesday, February 28th, 2012 AT 12:47 AM

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Tiny
DRCRANKNWRENCH
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The first thing to do would be to get the trouble codes pulled. Any Advance Auto or Auto Zone will do this for free. That will help you out a lot.
The things that I would be suspect of that might not show up on a code test are the fuel pressure and maybe a bad O2 sensor. O2 sensors usually will come up in a code read, but what you are describing is either that or an exhaust leak near an O2 sensor. The leak lets extra air onto the senor so it thinks the eninge is running lean and it dumps more gas in it. So look for exhaust leak, test the fuel pressure with tool which you can borrow from Advance or Auto Zone and pull the codes.

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Tuesday, February 28th, 2012 AT 12:58 AM
Tiny
KEN BENSON
  • MEMBER

There are two codes p0100 and p0403. I can't remember which was which, but one called out the EGR valve, which I changed, and the other called out either the MAP sensor, MAF sensor, and vacuum leak. Nothing about and 02 Sensor. Although, I have had a code for an 02 sensor in the past. By the way, these two code were pulled after I changed the EGR valve. Thanks for the quick response! I think the IACv with fisx the idle problem, but not the gas guzzling problem. Thoughts?

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Tuesday, February 28th, 2012 AT 1:08 AM
Tiny
DRCRANKNWRENCH
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P0100 is Volume Air Flow, VAF and P0403 is Exhaust Gas Recirculation Return Solenoid Malfunction, EGR.

You might try to clean the MAF with some MAF cleaner, but be very gentle as they are senitive. Again look for a vacuum leak as that would cause poor performance and gas mileage and check the EGR pipes around the exhaust. There may be a leak in the system causing the same sort of issue as with the O2 sensor.
You may have braoke something loose when you did the EGR so re-check your work and look for any metal along the pipe that may have been rusted and it gave way when you replaced it or simply dis-connected.

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Tuesday, February 28th, 2012 AT 1:26 AM
Tiny
KEN BENSON
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Thanks for the help. I'll look for the exahust leak and see if I can find anything. I'm confident I didn't break anything while changing the EGR. It was fairly simple to change, although the location was a pain (between the engine and the firewall). A small vacuum line, 2 small coolant lines, two bolts and the gasket. Although I don't work on cars, I do work on airplanes, so my maintenance practices are the same.

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Tuesday, February 28th, 2012 AT 1:40 AM
Tiny
DRCRANKNWRENCH
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If you work on airplanes you must be EXTREMELY thourough. I used to work for DOD when I lived in DC and I did some work with F/A-22 and F/A-35. Pilots love the F/A-22 and of course would rather have two motors. The 35 is an impressive jumper though.
Good luck and let me know how things go and we can go from there.
Sometimes when a car has quirks that are hard to diagnose, going to online enthusiast forums are a great source. My GF had a 2007? Spyder and if it weren't for pics on enthusiast forum I would have never gotten timing belt done. Forum members go to a lot of trouble to take pics and type up walk throughs with them and work arounds. I want to say it was a 3DSM forum or 3rd generation eclispe or something like that. Anyway it was the best help because it was a bunch of people who live for the car and have seen it all including the hard to diagnose quirks some cars have and you can post and they are happy to help you or direct you to an old post.
Just a thought as it is a good thing to know for any Eclipse stuff. I will try to find the forum if I get a chance.

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Tuesday, February 28th, 2012 AT 2:22 AM
Tiny
KEN BENSON
  • MEMBER

Thanks! I like to think I'm very thourough. Thats why at times like these, when I am beyond my capacity of what I know, I get frustrated. I know the car is getting too much fuel, thus the 50% cut in mileage. My mind understands that, but its the figuring out 'why' part that I get stuck. Like you said, something is telling th car computer to feed it more gas. But what part is telling it to do that? I know that if the car runs a certain way, and then runs better when I disconnect the IACV, that tells me its bad. UGH! I'm ready to change the MAP, MAF and the IACV at this point, but 2 out of the 3 have a hefty price tag on them. So I don't want to just start changing parts, without the confidence that one of the parts will fix the vehicle. Thanks again for your help. I won't be able to get 'under the hood' again till the weekend, so hopefully I will have sopme good news to report then. Btw. Where you 'used' to work, you hit the nail on the head! 15's and raptors!

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Tuesday, February 28th, 2012 AT 2:39 AM
Tiny
DRCRANKNWRENCH
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Yes the Raptors are awesome.
When you get back to me tommorrow I will get a IACV test instruction set for you. It is actually simple. You just disonnect it with the electrcis still connected, sometimes coolant lines too, have a buddy turn the key and see if the solenoid/plunger moves. If you have not cleaned out the portsfor the IACV, it may be a good time to clean that and the trhottle body. When you do so always spray cleaner from the outside into the intake manifold so you don't cram deposits further into the ports. You might also need to check or replace the TPS if we have not discussed that. I will get with you tommorrow and get a fresh look at it. After 50 or 60 questions I kind of get them all muddled together.
I will reply ASAP when you post.

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Tuesday, February 28th, 2012 AT 9:40 AM
Tiny
DRCRANKNWRENCH
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I want you to have this link on a Vovlvo I went back and forth with forver until it got straight. It hink the MAF is more of a suspect the more I think about it. After you read this, I remembered it as I was logging out, you might agree or dis-agree. Let me knwo what you think.

http://www.2carpros.com/questions/2005-volvo-xc70-car-stalls-after-starting-runs-maf-unplugged

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Tuesday, February 28th, 2012 AT 9:49 AM
Tiny
KEN BENSON
  • MEMBER

I have read about that IACV test, but haven't tried it yet, but its definitly on the list of things to do. I'm very curious about it. Thanks. Is there a similar test for the TPS? I don't have a multimeter at the house, so my testing abilities are limited. I think I'll start with what the car is throwing at me via codes. EGR solenoid (p0403), and the MAP/MAF sensor(p0100) and go from there. I do question the integrity of the MAF sensor. While the car is running, I can tap on the top of the sensor, and the RPMs will change. I read the thread concerning the Volvo. What kind of test did he do to figure out the root cause of the loose clamp on the intake?

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Wednesday, February 29th, 2012 AT 2:22 AM
Tiny
DRCRANKNWRENCH
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There is a voltage test for the TPS. There are three terminals on the TPS. I forget which two you put the positive and negative on, but you will see that pretyty easy. If you get the polarity wrong most multimeters just read negative voltage. When the TPS is closed it sholud read.5 Volts and at WOT it should read 4.5-5.0 Volts. Not all are adjustable. If you get a replacement BLOX makes an adjustable one. If you ever need aftermarket stuff, go to horsepwoerfreaks. Com. If you get the right person they will remember me as I still talk to them. Not for parts as I don't have my 1990 Integra that I put a 1998 GSR JDM Motor and trans in. I totalled it. Just some bolt ons and an adjustable fuel pressure regulator with an AEM Air/Fuel ratio EUGO meterr for tuning and it was so fast. I beat a new mustang by a few car lengths. Then I got beat by an S2000, not a surprise. I did not have the redline set properly though, I was shifting at 6500 RPM and I set it to 8500 where it should have been and it pulled so hard all the way. I had it going 120 in third gear with a few RPMs left. Pretty sick but it takes a lot of HP the faster you go to gain speed so I guess it would have done 140+ or so. I don't remember the accident as I hit my head a few times. It looked like it bounced between the bash and the steering wheel because the wheel was bent backwards and I had a bald spot on my head in the shape of the steering wheel, I am so glad it grew back. I really misss it and the guys at HPF are real enthusiasts and are like having a Tech support person and Sales person all in one. They will give you EBAY prices if you ask too. Anyway, be careful when you drive because all I could have done was to have been messing with the radio or lighting a cigarette and where I went of the road was a drop off so I could not avoid the telephone pole I hit. In a fast car sometimes you don't realize how fast you are going. 55 MPH is slow in a 140 MPH car and you would not believe how I got cut wide open by the seat belt buckle. Think about the force it would take to cut someone open all the way to there abdominal cavity with a belt buckle. I have a scar across my chest from the seat belt. I know I am going on about me but whenever I have a customer with a fast car I just feel kind of obligated to tell them how quick things can happen as it does not take much pedal to get going another 20 MPH unlike other cars.
So, The BLOX TPS is slotted for adjustment. I actually found TPS adjustemnt in our manual. I am attaching instructions and FIG4 which is the pinout for the connector. If I captuered the MIRAGE stuff, just ifnore it, you don't need FIGs 5 and 6.
I found EGR tests and have FIG for them. The only MAP info I could find is to check for vacuum leak between it and manifold.
So, I am attaching all said stuff and the files are labeled and are jpegs.

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Wednesday, February 29th, 2012 AT 6:31 PM
Tiny
DRCRANKNWRENCH
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I am not sure if images took to post. So I am sending them again, there was some error message I have never seen before.
Let me know if you don't get them. There are 7 files.

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Wednesday, February 29th, 2012 AT 6:34 PM
Tiny
DRCRANKNWRENCH
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There, you should have them all now.

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Wednesday, February 29th, 2012 AT 6:35 PM
Tiny
KEN BENSON
  • MEMBER

Yeah. They are all there. Can't thank you enough for all the input/incite. Sorry to hear about the accident, but glad to hear all is well now. I bought my Eclipse brand new (Dec 99), so I've had it for a long time. It's like a member of the family, and I'm not ready to give up on it just yet. Especially with today's gas prices. I'd much rather drive the Eclipse to/from work than my other vehicles. I will start turning wrenches this weekend, and I will post Monday. Hopefully with some good news. I'm looking to change the EGR solenoid, MAP, and MAF. One at a time of course to see if there is any change. The TPS does have the elongated hole mounts for adjusting, so I'll look into that as well.

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Thursday, March 1st, 2012 AT 4:21 AM
Tiny
KEN BENSON
  • MEMBER

Ok. I had some time this morning to work on my Eclipse. I tried the IACV chaeck, and it checked out. IACv moved as advertised. I picked up a MAF sensor and MAP sensor from a local Pick and Pull the other day, and was eager to see what would happen. Changed them both, turned the key, and the car came to life! No hesitation, idled fine, throttle response was good. Pulled the MAP back off, and re-installed the original. No issues. Must of been a bad MAF sensor. Drove the car to work (approx 20 miles) without any issues. Idled fine at every stop, bu thte big one was my gas mileage. The needle barely moved! Everything seemed great. Until! Pulled into the gym parking lot, went for a 2 mile run, showered, got back to the car, turned the key, the car turned over, then immediately died! Turned the key again, started, and died. The car didn't even try to catch itself. Idle didin't bounce or anything, it didn't drop to 300RPM, and then race back up to 1000RPM. As soon as I pulled my foot of the accelerator, it died. The last time I turned the key, I kept the RPMs up, and slowly removed my foot from the accelrator, and the car idled real low (approx 500 RPMs) but didn't die. Drove into work, and at every stop the car idled low, but didn't die. Came close, but kept a very low idle. Even with the AC on, it didn't die. I did mess with the TPS about a week ago. Do you think I should adjust it back to the original position since it has the slotted mount holes? I didn't change that EGR solenoid yet, could that be the cause? Thoughts!

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Thursday, March 1st, 2012 AT 10:40 PM
Tiny
DRCRANKNWRENCH
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Since the EGR code came up, it must have something wrong unless the codes weren't cleared properly. There is a function in the scanner to clear codes. If you adjusted the TPS, you should adjust it back or even better adjust it using the information I sent you. It could very well be affecting the idle. Odd though that it worked fine for a while. Let me know what happens when you adjust TPS. Since you got the info you should at least check it after you put it where you think it was before.

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Friday, March 2nd, 2012 AT 12:24 AM
Tiny
KEN BENSON
  • MEMBER

I'm sure there are "proper" procedures for clearing the codes. All I'mm doing is disco'ing the battery for a while. Before I starting farting around with the TPS I marked the mount bolt and the mount with a dab or paint, that way I would kno where the original position was. I'm going by Auto Zone tonight to have the codes scanned again, to see if anything cleared, or anything else shows up. I'll post tomorrow what happens after I re-position the TPS. I don't have a multimeter so I can't do the voltage check on the TPS.

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Friday, March 2nd, 2012 AT 12:44 AM
Tiny
KEN BENSON
  • MEMBER

Ok. Stopped by Auto Zone on the way home and got codes downloaded. Little bit of a surprise. The code for the EGR solenoid showed up again. No surprise. The surprise was 505 Idle Air Control. I thought I might get by without having to change it. But now not so sure.

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Friday, March 2nd, 2012 AT 2:18 AM
Tiny
DRCRANKNWRENCH
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You might try cleaning out the ports when you replace the IACV. Just make sure you spray cleaner from outside in towards the intake tract of the manifold. Otherwise you mgiht push deposits farther into the ports. Even though it moved it may not be reacting correctly. The EGR vavle is a bit baffling since you double checked it. Aslong as you are sure the seal is good to the manifold, I don't know what could be going on with that. I lost my access to my service manual but I should have it again soon. There may be a procedure for clearing codes and that would set the story straight.

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Friday, March 2nd, 2012 AT 4:12 AM
Tiny
KEN BENSON
  • MEMBER

I changed the EGR, but I think the 403 code is pointing more toward the solenoid. I ordered one from Auto Zone and I pick it up today.

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Friday, March 2nd, 2012 AT 1:23 PM
Tiny
DRCRANKNWRENCH
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Okay, let me know how it turns out.

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Friday, March 2nd, 2012 AT 8:13 PM

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