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ECMlink Running rich when letting off throttle

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mattp_65

Supporting Member
515
167
Aug 16, 2004
Granite Falls, Washington
Why am I running rich after letting off the gas pedal on a normal cruise. My Afr would go to about 9.0
I'm breaking in the new motor and I just did an idle and cruise tune and still having issues of running rich after letting off on throttle. I will post log when I get home, but how to post a log when max limit is 488kb, my cruise log is about 1mb? But any one have any ideas?
Also now I'm almost stalling out when coming to a complete stop. Idle set at 900 rpm. Running now from 500-900 rpm. Any help is appreciated.
Thanks
Matt
 
You TPS is not adjusted correctly and the ecu is not reverting to coasting fuel cut.
 
You TPS is not adjusted correctly and the ecu is not reverting to coasting fuel cut.

Thanks Viper! I have my idle working now and going lean on decel like it is suppose too. Now right after I let go of the gas my AFR goes to 9.0 then directly maxing out at 18.0
Is this Normal?

thanks
Matt
 
When you let go if the gas your afr should have 3 line dashes and not a number. Do you let go of the gas and keep it in gear or do you put ir in neutral

3 line dashes? Meaning 18.0:1 ratio

My car is in gear due to that I am still breaking in my motor. But after motor break in I still keep it in gear til I stop.
Thanks
Matt
 
3 line dashes? Meaning 18.0:1 ratio

My car is in gear due to that I am still breaking in my motor. But after motor break in I still keep it in gear til I stop.
Thanks
Matt

Yeap, there should be no gas being used thus givin you a lean mixture. Are you sure you wideband isn't to close to you exhuats mani or it isn't angled 20-30* causing it to get built up with sut? What kind of external wb you using?

Also if your using dsm link the fc offset will help you with the staling if you just went from rec bov to atmosph bov.
 
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Thanks Viper! I have my idle working now and going lean on decel like it is suppose too. Now right after I let go of the gas my AFR goes to 9.0 then directly maxing out at 18.0
Is this Normal?

thanks
Matt

This is because you cut off the engines air supply with your foot faster than your ecu cuts off the engines fuel supply.
 
I have the same wideband installed before cat, I get the same problem when letting off the gas. I bet going I to the ECU settings and making a few tweaks will take care of that. I'm going to do mine tonight. And ill let you know what happens.
 
hey guys im having the same problem and i have a few ideas about what it could be.
my bov is vented... i know i know its bad to vent but i cant recirculate it because of my crappy inner-cooler piping and yes im on the stock maf. so i think my car may be doing it because its vented. another thing is that i just switched to a big turbo a few months ago, would that have anything to do with it.
finally my boost estimated and my air fuel estimated are both completely wrong. like 20 Hg of vacuum at idle when really i have 10
 
Any ideas what else can cause it same problem here but tps is adjusted right to .63v likening was explained to and read so many times already any help appriciate motor is fresh woth evo 3 anD supporting mods
 
Any ideas what else can cause it same problem here but tps is adjusted right to .63v likening was explained to and read so many times already any help appriciate motor is fresh woth evo 3 anD supporting mods
Should have started a new thread...
Have you verified the closed throttle switch is functioning? Is this for the 1g or 2g?
 
It's a 1g and yes idle switch tested fine and I adjusted it while tb off the car so I had a good adjustment on it I adjusted till switch was shut then gave ruffle 1/16 of a turn just enough to keep throttle blade open and I doubble cked it because ei was having idle issues and it was working fine I think I iac is acting up though I can't get it in the range it should be I dono if this would affect anything I'm not running nb simulation I'm using stock narrowban o2 and as well the nb o2 is stuck at .20v it's not fluctuating like i have read it's soposto could this be the culprit? It shutters hard enough to some times stall the car out
 
My recent experience, is i prefer simulating the narrow band, it swings based on set values, and provides a more steady AFR on the WB, also makes matching target A/F and WB A/F easier. Since your 02 is only used under 40-50% throttle (i believe) so idle and light cruise.

Your WB should be able to provide the ECU with the simulated narrow band signal, this is a box you can check.

Side note, its easy no make mistakes, especially with phones, but look over your text so you can catch any misspellings.

But its expected to lean out right after letting off throttle. Idk what exactly your solving ?
 
hera few half puls some driving arund motor still breaking in
 

Attachments

  • log.2015.10.12-01. first few half pulls and test run.elg
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It's a 1g and yes idle switch tested fine

Your log show clearly that your idle position switch isn't working. Either you have lost the ground to the throttle body, misadjusted it, or there is an issue with the wiring.
 
^^^ You beat me to it but that switch has to function to tell the ecu you are coasting or idling. Double check the ground strap to it and that it is plugged in.
 
Your log show clearly that your idle position switch isn't working. Either you have lost the ground to the throttle body, misadjusted it, or there is an issue with the wiring.

Ok I do not know appearently what I'm looking at it don't understand what line or value is showing its not working.. please explain if you could please..

^^^ You beat me to it but that switch has to function to tell the ecu you are coasting or idling. Double check the ground strap to it and that it is plugged in.

Their is no ground strap to it just a wore off the back for the harness I took the brace from cas to tb out and read if doing it run a drunk to one of the bolts so that excatly what I did I have a ground right off the negitive batt terminal to tb bolt for a ground

Also would any of this be a reason my front nb o2 is not occilating? Or moving around like it should? Or could it possibly be locked in closed loop or open loop from link.. I did buy link used and had settings in it alreafy
 
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Ok just checked it again switch shows contunity with tb closed as soon as tb opens it goes to 1 on ohm meter so I'd assume switch is functioning and grounded and adjusted good how would I ck the wore going to switch to make sure it's working? Also is their somthing in link that could affect this function in the tab for tb the idle switch is enabled and I'm not using tps for switch nor the second option when it won't work while moving ..
 
What year is your car and what year is the ECU (Part number)?

If you add IdleSW to your list of displayed values you'll note that it never goes to 1. In the ECU Config under the RPM/TPS tab in the TPS and Idle Switch Controls you have the idle switch operation enabled as it should be but since you're not simulating it the ECU is expecting to see the voltage from the ECU to the IPS be grounded by the switch when the throttle is closed. The green wire from the runs to ECU pin 6 or 14 depending on the version of the ECU (90 or 91+).

With the ECU on you should see close to 0v at the IPS terminal with the throttle closed and 12v with it opened.

The IPS depends on the ground strap attached to the top of the TB over to the stud on the elbow and the ground wire from the firewall to the intake manifold bolts holding the throttle cable adjuster.

Are you running a 2G MAF?
What size injectors?
Please disable the MAF Clamp function.

And yes, it looks like your front O2 is dead but it could be a wiring problem.
 
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Modle year was in between yrs car is titled as a 90 but all engine components are a 91 style I'm running 2g maf fic 650cc the ecu is out of a 91 I can get numbers I was concerned when I got the ecu as it had some kind of internal Conversion when I researched it it was for a 91-94 ecu Converted to a 90ecu I asked Tom ar ecm link about it he said if it was running alright not to worrie or switch pins I think we're 6&14 at that time the car had more problems to worrie about then this issue but now it's a new motor and is acting up with it what I remember reading was the pins that needed swapped for for the tach that I though but my tach was working fine so I figured it was okay so I'm assuming the pins may need swapped because the ecu was Converted?
 
If the car is a 90 then you need to figure out the wiring harness to know where the two pins are being run to and then check the ECU to make what it wants.

On a 90 wiring harness the green IPS wire runs to ECU pin 6 and on a 91-94 harness it runs to pin 14.

Right now you have the MAF clamp enabled, please turn it off.
You also have both the DA table for injector deadtime modified as well as the Global Deadtime set. The DA table is just slightly different from stock so you can reset back to stock.

The O2 sensor wiring doesn't interact with the throttle body ground. Was the O2 sensor new when you put this engine in?
 
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