So disconnect the resistor and check the fuel pressure? Is this safe running the car without it? Once again, not too great with electricity. I replaced fpr and solenoid yesterday since I got it so cheap and it looked new. Went out and did a couple pills keeping an eye on afr with a friend. This was at 6 something pm so it was fresh out. Car didn't go lean at idle after but the times it has done this it has been really hot out like mid day. I have a cable and evoscan just gotta figure out how to log fuel trims and post it here...

This is the relay correct?

 

Ok Mr. know it all....what's happens if the fuel trims are all screwed up and the relay decides to open up? Even if its permanently wired full voltage it will screw up at part throttle driving, the pressure varies and messes with the trims then when you idle the car it's all screwed up. Or if it idles for a long period of time it goes crazy in the other direction.

 

With it unplugged car did the same thing...fuel pressure same...

 

First things first... make absolutely sure your plugs are good, I would throw a new set in. If you have a plug going bad it will totally mess with the fuel trims.

Yes that's the relay. Unplug it and see if it screws up. You can drive around with the relay removed but DO NOT hit any boost!
You can also remove it and check fuel pressure, probably should do that first.

 

the relay or the resistor?

 

Fuel pressure is still at 40psi idling?
If so unplug the resistor and see if it will run. This will tell us if the pump has been rewired to bypass the resistor. For some reason people have done this?

 

I'm not here to argue with you, I'm here to help OP. If you have something to contribute cool, otherwise i dunno, your wasting your time.

 

The two things you are going to check to log are "Fuel Trim Mid (LTFT), and "Fuel Trim Low (LTFT)" You don't even have to start the car, just switch it to run with the cable plugged in, make sure you select the right cable in evoscan (1.3 or 2.0) make sure Mitsubishi MUTIII is checked and hit Start Datalogger. The LTFT's are stored values and they will populate on your evoscan screen.

 

Fred hit the nail on the head, this is your problem, concentrate on it.
Don't worry about fuel trims until you get the pressures issue corrected.
Did it run with the resistor unplugged?
It should not run with the RESISTOR unpluged

 

I didn't unplug the resistor...I unplugged the relay and it ran...nothing changed, fuel pressure at 40...plugs are pretty new there's no problem with that...when I get a chance I'll log it and post it on here...I wonder if the car has always been like this...wot it's good so when I went for the tune it must've been tuned like this...I didn't have the aem rail with the gauge then...

 

https://www.evolutionm.net/forums/ev...-resistor.html

I have seen a couple evo's with this resistor bypassed. It WILL cause the issues you are having. Not sure why these morons are doing it.
It's so easy to unplug your resistor and check, not sure why you haven't tried it cause it will take 5 min to test.
40 PSI idle fuel pressure IS YOUR PROBLEM!
I'm done

 

I was trying to avoid an in depth post but oh well. Remember way back when you checked the base fuel pressure and it would drop down to 32~33 psi and hold there? Well that's what the factory regulator is set at. The reason it's running at 40psi is either one of 2 things now. The fuel pump is running at full power or your return line/siphon is plugged/kinked restricted whatever. Either way this is 6 psi of unregulated pressure which changes your base pressure relative to how much fuel is flowing in the system. The regulator holds a constant pressure across the injector under vacuum or boost. That pressure is no longer constant its changing in the low to mid load areas playing havoc with your fuel trims. If you were to tee in a gauge on your return line you would see around 5-6 psi in the return line at idle. Usually this will cause an overly rich idle condition so maybe it isn't your problem unless somebody has tunned around it which very much could be a possibility.
I'm not worried tho you and Biggie will get it figured out sometime in the next month or two.

Cheers 2winscroll

 

Well, maybe so but why would the return line be clogged? Today it's fresh out and it's been working fine...I think it has something to do with the heat...I did check the resistor but with a shorty multimeter...I want to try again with a good one...I may get another resistor Monday from another car and out it on to see...

 

This is exactly why I don't help people that much.....because now your a master mechanic and you really didn't want help to begin with.

BTW all you would have to do is tee in a gauge on the return line to confirm. But 5 min work is apparently too much.

 

Dude wtf are you talking about? I'm no master mechanic and if you don't want to help then don't help. I appreciate those who are trying to help figure this out without acting like a dick. Tee into the return line? That would suck to just cut the factory return line. I did the service manual test and when I held the return line closed the pressure went up so I guess you're onto something. If the return line is clogged what is the fix? Do I have to run a whole new return? Also I've been driving the car around all day today and it's been cool here because of a small cold front I guess. Today the car hasn't gone lean at idle it's actually been on the richer side going from 13.8 - 14.5. Maybe temp does have something to do with it?