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Doug
Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8562
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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Doug C only] Doug! This is Orniz( lancer es 2006) Feels

Customer Question

[Doug C only] Hi Doug! This is Orniz( lancer es 2006) Feels good to have you back! The car is having random misfires mostly all the time p0106 (MAP out of range) and P0300 fuel trim peaks +20% no other codes. Could use your advise here.
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  Doug replied 1 year ago.
Hi Orniz, how have you been?
The fuel trims are certainly a concern, that's a lot of extra fuel there. I would be suspicious that the misfire fault and even potentially the MAP fault are going to be related to what is causing the fuel trims to go so positive. Remember that if you are seeing +20% that is indicating the computer is adding 20% more fuel trying to get it balanced... meaning there is likely far too much air in there somehow.
If you monitor the fuel trims and pinch off vacuum hoses one at a time and wait, do any of them cause the fuel trims to drop after 3-5 seconds (note that the EGR hose will cause it to stall, you can skip that one)?
If you spray brake cleaner around the engine/intake/hoses while the engine idles, does the idle fluctuate at all?
Customer: replied 1 year ago.
Ive been good man ups and downs as allways but we remain positive. How had you been? I sprayed brakecleaner no change. I pinched white green and yellow the only one that decreased fuel trim is yellow( is that the egr?)
Expert:  Doug replied 1 year ago.
Yellow should be the dump side of the EGR solenoid, so no worries there.
So if we are certain there are no air leaks, internal or external.... how long has this been going on, more than one tank of gas?
Can we check fuel pressure and belt timing?
Customer: replied 1 year ago.
This ocurred to me after letting tank go almost empty, it happened when i finally came to a complete stop arriving at work. Last repair i made was replacing fuel pump and strainer ;had no problem until this happened.
Expert:  Doug replied 1 year ago.
That certainly may be relative.
Can we either check the fuel pressure (running pressure check, requires a "tee" fitting for the fuel rail) or pull the fuel pump out and see if there are any sealing issues with the pump in the housing (damaged o ring, rotted hose, etc)?
Customer: replied 1 year ago.
It began just yesterday and was intermitent, noticeable at high speed.(misfire). Today it was really bad. Fuel pressure and timing i will get those later one no rush.
Expert:  Doug replied 1 year ago.
Gotcha.
With the engine intact from leaks, we need to focus on those as your only possible way to get too much air in after leaks would be valve timing, insufficient fuel pressure, or as a long shot a stuck O2 sensor.
Let me know what you find, we can pick up whenever.
Customer: replied 1 year ago.
Thanks man. Glad to team up again!
Expert:  Doug replied 1 year ago.
You got it :D
Customer: replied 1 year ago.
Hi Doug, just checked belt timing is perfect. While i had not performed fuel pressure test. I noticed O2 1X1 was slower than the 1X2 after cleaning connector now it reads 0 voltage. Can i confirm easily if it is the O2?
Expert:  Doug replied 1 year ago.
Hi,
If anything the 1x1 sensor should be faster than 1x2.... however it is important to note that if the fuel trims are WAY off (and they nearly are), the O2 sensor is going to slow considerably as it being super lean or super rich is going to cause it to alternate less.
There is no accurate way to differentiate between a sensor that is reading slowly because of failure versus because of mixture... a wideband sensor reading would be required for comparison.
Overall... it is rare and unlikely for the sensor to be at fault if it is not also setting trouble codes for the sensor. With the MDP and lean faults, it is more probable that the O2 reading is a side effect of the mixture.
Have you pulled the fuel pump for inspection to make sure you aren't bleeding off pressure from a bad hose or o-ring etc?
Customer: replied 1 year ago.
Hi Doug just checked fuel psi( direct w/t fitting) it was 40 psi so i replaced fpump Assy and now i got 55psi. Now here is the thing, fuel trims now dont get up to25%. No i got 15% at max and the car continues to idle rough specially when turning ac on. So I am wondering if an intermitent coil problem is out there. What do you think?
Customer: replied 1 year ago.
I checked without a T fitting just direct pressure.
Expert:  Doug replied 1 year ago.
Hi,
The increased fuel pressure will cause the fuel to come back closer to range and your trims will go down, that is typical.
As for the roughness....
Idle the engine and then unplug one injector at a time and note the running condition. Is there any one cylinder that does -not- run worse when the injector is unplugged?
Customer: replied 1 year ago.
Important to mention the lean code 1'x1 appeared 2 days ago. I will do injector test tomorrow(too tired) good night my friend
Expert:  Doug replied 1 year ago.
No problem
Customer: replied 1 year ago.
Ok got some good info of the test. Cylinders 1 & 4 unpluged have no effect. 2&3 unpluged make car stop. I could hear some clicking from #1 through a screwdriver.
Expert:  Doug replied 1 year ago.
Thanks, ***** ***** cylinder 1 or 4 is combusting then, that would certainly cause a rich condition!
Please pull the #1 spark plug wire and check for spark while running or cranking.
If there is no spark, please swap the two coils and see if there is still no spark on #1 or if the problem follows the coil movement to #3.
Customer: replied 1 year ago.
We killed this one fast Doug! I noticed 1 are 4 are related. Checked #1 for spark no spark checked again pushing for contact there was intermitent spark. I remembered having an issue with silicon grease making starch at connections. Bingo! Starch everyware clean again! Feeling goood! Thank you my friend!!
Expert:  Doug replied 1 year ago.
Oh fantastic!

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