2G Rough idle issues

[2gBowen]

Hello, so my 98 Eclipse GST has been having this issue where it runs and drives fine other then when you take your foot off the gas it stumbles and dies (coasting up to a stop sign). I’ve replaced a lot of the vacuum lines as well as just replaced the throttle body shaft seals gaskets and BISS screw o-ring, I’ve also replaced the ISC and did do a FIAV coolant block off plate, tuned with stock MAF on ECMLink.

Anything I might be potentially missing?

 

[92AWDHX40]

https://www.dsmtuners.com/threads/how-to-fix-your-idle-surge-problem.191137/ first start here and get back with us as what you have done after you do these step.s

 

[steve]

Please also post a log. It's not too unusual for cars with lightweight flywheels to die if you don't set ECMLink up for them.

 

[2gBowen]

Please also post a log. It's not too unusual for cars with lightweight flywheels to die if you don't set ECMLink up for them.

here is a log

 

[steve]

This is pretty much a stock car, correct?

I don't get what you're trying to do with MAF Comp or the changes to InjBatteryAdj to start.

In that log were you actually driving the car? The speed data was inconsistent.

Normally with a lighter flywheel you would increase Coasting FC offset on the RPM/TPS tab but with the changes to the open loop thresholds I'm not sure how the ECU is going react. I only saw Injector Fuel Cut once and that was when just before it stalled.

 

[2gBowen]

This is pretty much a stock car, correct?

I don't get what you're trying to do with MAF Comp or the changes to InjBatteryAdj to start.

In that log were you actually driving the car? The speed data was inconsistent.

Normally with a lighter flywheel you would increase Coasting FC offset on the RPM/TPS tab but with the changes to the open loop thresholds I'm not sure how the ECU is going react. I only saw Injector Fuel Cut once and that was when just before it stalled.

The car is stock fuel the only thing I’ve touched was the maf comp to get my afr closer to what they should be what would u recommend setting the other settings too? Also I did buy the ecu used so could be changes previous owner made that I over looked and with a lighter flywheel would I reduce the fuel cut?

 

[2gBowen]

This is pretty much a stock car, correct?

I don't get what you're trying to do with MAF Comp or the changes to InjBatteryAdj to start.

In that log were you actually driving the car? The speed data was inconsistent.

Normally with a lighter flywheel you would increase Coasting FC offset on the RPM/TPS tab but with the changes to the open loop thresholds I'm not sure how the ECU is going react. I only saw Injector Fuel Cut once and that was when just before it stalled.

I made some adjustments I believe I reset everything to stock besides fuel and timing table and here's a log of me driving around the block. confused on why the estimated afr ratio is commanding 11 afr at idle?

 

[steve]

Make sure you have the latest firmware.

v3firmwarehowto [ECMTuning - wiki]

www.ecmtuning.com

What Wideband O2 are you using? Since you're simulating the Narrowband it's critical you get the switchpoint and LinWideband settings correct.

linearitems [ECMTuning - wiki]

www.ecmtuning.com

 

[2gBowen]

Make sure you have the latest firmware.

v3firmwarehowto [ECMTuning - wiki]

www.ecmtuning.com

What Wideband O2 are you using? Since you're simulating the Narrowband it's critical you get the switchpoint and LinWideband settings correct.

linearitems [ECMTuning - wiki]

www.ecmtuning.com

Ok I have done a firmware update but I will double check and a AEM classic wideband I did have to adjust the voltage input to get it to read the same on the computer as my gauge but not sure what exactly the switch point is?

 

[steve]

not sure what exactly the switch point is?

v3narrowbandsim [ECMTuning - wiki]

www.ecmtuning.com

 

[2gBowen]

Make sure you have the latest firmware.

v3firmwarehowto [ECMTuning - wiki]

www.ecmtuning.com

What Wideband O2 are you using? Since you're simulating the Narrowband it's critical you get the switchpoint and LinWideband settings correct.

linearitems [ECMTuning - wiki]

www.ecmtuning.com

ok thank you here is my most recent idle log after some changes i still feel like the estafratio is commanding slightly rich at times but car runs and idles great

 

[jed344]

Looks like you have the wideband logging close and switch point likely close. Though a real front O2 I always prefer vs simulate. I see a few other things though.

Adjust your TPS so at idle 0 throttle and .63V and wide open 100% and 5v.
The idle rpm is raised 100rpm over stock but that's not a issue. Your airflow per rev is a hair low. Stock manual car .25 is what to shoot for. Raise your MAFcomp in the idle HZ a bit and then tweak deadtime if needed to keep the fuel trims within 5% of zero.

Battery voltage is quite low at idle, I see it jumps with rpm at the start then settles down and creeps all the way down into high 12's and comes back to low 13's.

ISC position is VERY low. Somewhere in the 30s is a good place. This shows that the BISS screw is opened to much and bypassing to much air. The low number shows it essentially cannot limit anymore air from coming in. You want this in the 30s so then the ECU can limit air or add so the car will not stall or surge.

Your MAFcomp is adding a lot everywhere. I am sure that is not what it need's to hit the target air fuel.

Anti lag turned on I see. This WILL damage turbine wheels in turbo's. I have the photos from my own use to prove. When the set up does not require the use of it then long as you are aware the strain it puts on parts just for the pops and bangs fine. Looking at your settings what it is doing for you in building boost you can achieve with no anti lag and more rpm on the 2 step with much less strain.

With the DA table your base tip in is adjusted but essentially nothing so no worry there.

Your cranking fuel is increased at cold temps 19 and 46 degrees. Likely not needed but again not causing you issues.

You already know your target air fuel max and min are modified. Though I would do things a hair diff 11.0 to 10.8 target is just fine for pump fuel.

There is no serious errors just letting you know the things I saw and possibly things that had been modified you may not have known about.

 

[2gBowen]

Looks like you have the wideband logging close and switch point likely close. Though a real front O2 I always prefer vs simulate. I see a few other things though.

Adjust your TPS so at idle 0 throttle and .63V and wide open 100% and 5v.
The idle rpm is raised 100rpm over stock but that's not a issue. Your airflow per rev is a hair low. Stock manual car .25 is what to shoot for. Raise your MAFcomp in the idle HZ a bit and then tweak deadtime if needed to keep the fuel trims within 5% of zero.

Battery voltage is quite low at idle, I see it jumps with rpm at the start then settles down and creeps all the way down into high 12's and comes back to low 13's.

ISC position is VERY low. Somewhere in the 30s is a good place. This shows that the BISS screw is opened to much and bypassing to much air. The low number shows it essentially cannot limit anymore air from coming in. You want this in the 30s so then the ECU can limit air or add so the car will not stall or surge.

Your MAFcomp is adding a lot everywhere. I am sure that is not what it need's to hit the target air fuel.

Anti lag turned on I see. This WILL damage turbine wheels in turbo's. I have the photos from my own use to prove. When the set up does not require the use of it then long as you are aware the strain it puts on parts just for the pops and bangs fine. Looking at your settings what it is doing for you in building boost you can achieve with no anti lag and more rpm on the 2 step with much less strain.

With the DA table your base tip in is adjusted but essentially nothing so no worry there.

Your cranking fuel is increased at cold temps 19 and 46 degrees. Likely not needed but again not causing you issues.

You already know your target air fuel max and min are modified. Though I would do things a hair diff 11.0 to 10.8 target is just fine for pump fuel.

There is no serious errors just letting you know the things I saw and possibly things that had been modified you may not have known about.

Thank you so much I replaced my alternator getting my idle voltage around 14.5v. ISC also reads 30-31 at idle now. Fixed my TPS but airflow per rev is only .22. I'm not sure how to raise that and what do you recommend adjusting instead of my MAF comp to reach target AFR?

 

[jed344]

MAF comp is what is used with a MAF car to dial in fuel trims and target air fuel yes. This is also what will raise your idle airflow per rev.

 

[2gBowen]

Ok thank you so much idles and runs great now! Still weird I have to add almost 20% fuel with stock injectors maybe need cleaned? I’ve heard about a fuel pump rewire wondering if maybe i have slightly low fuel pressure but all in all runs good

 

[jed344]

Ok thank you so much idles and runs great now! Still weird I have to add almost 20% fuel with stock injectors maybe need cleaned? I’ve heard about a fuel pump rewire wondering if maybe i have slightly low fuel pressure but all in all runs good

You technically are not adding fuel. You are adjusting the metered air flow reading. Then as you adjust it up the car then knows at xxx hertz there is more air then so it then adds more fuel.

 

[dwb]

Is your BOV recirculated?

 

[2gBowen]

Is your BOV recirculated?

Not at the moment

 

[dwb]

Not at the moment

If you're using a MAF, then this most definitely needs to be recirculated to avoid issues coming off throttle, like you described.

 

[jed344]

If you're using a MAF, then this most definitely needs to be recirculated to avoid issues coming off throttle, like you described.

That is the correct way. You can also with ECMLink use the Idle Air Clamp table. This helps with this scenario but is still just a work around.