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General Running really Rich

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DSM_15_2G

5+ Year Contributor
39
17
Dec 6, 2018
Serbia, Europe
Hi guys,

I am posting here because I think It's related to the engine management side...

I have 2 problems at the moment.

1. The car is running really rich
2. I have a high idle

Let me introduce the story behind the problems so maybe someone can help me out. Anyways, my car started out as a European GS 1999 Year with an NA 4g63. Had the car for 3 years now, and few weeks ago I turboed the car with the stock GST/GSX parts.

When I bought the car, it had an open air filter and a 3 inch catback exhaust with the catalytic converer on it. The car had great MPG. Some time later I decided to remove the catalytic converter and as a result, the car started to smoke, smell of gas and I had terrible MPG, spent 60$ on 25miles. Worried, went back to the shop and rewelded the cat back on, and the problems went away.

Took the car to the shop to do the maintenance : All the belts, fluids, filters, brakes, suspension, valve stem seals, oil leaks, etc. I gave them the stock exhaust to replace the catback, because the drone and the noise on the highways was killing me. (NA cars are much louder)..

Got the car from the shop, pulled great but they've told me they left out the cat, so they installed the stock exhaust but instead of the cat, they installed a pipe. I was a bit worried that the MPG issue might arrise.

I could smell the gasoline but the MPG wasn't bad but it wasn't like before.

Drove the car as is for some time before I started replacing stuff on it. Replaced spark plug wires, coil pack, power transistor unit, front O2 sensor, fuel pressure regulator, spark plugs, maf, water temp sensor, mishimoto rad and more but I can't think of it right now. All the parts were new OEM.

Nothing changed. So I decided to go to the exhaust shop and weld the cat back on, maybe that will solve the issue? Nope, on the exhaust it felt the car was choking and the MPG went drastically down. Again I went to the shop and put the pipe back on.

Drove the car ever since then as is. Then all of a sudden, my car would crank for 5-6 seconds after youd drive it for a while and let it sit for more than 10 seconds.

Tried to find the solution until I realised the cyl 4 spark plug was 100% black and smelling of gas (btw, my oil smelled of gas as well) and I think I've had a leaking 4 cyl injector.

At this point, I already gathered turbo parts and all maintenance new oem gaskets, and parts.

I took off everything except the engine. Installed all the new gaskets (intake manifold, TB, Exhaust mani (golden 4ply oem), all the turbo gaskets etc.), rebuilt the used (new for me) TB my buddy sent me from the US, new oem thermostat and radiator cap, new oem pcv valve, new oem everything basically and literally LOL

I thought since Im changing everything, I'll do it right and never look back. Oh and on the turbo swap I've used the 95 gsx eprom ECU.

As I finished everything, went to fire up the car and saw that I need to change the wire order since my car is 99 (cam sensor) and the ecu is 95.

After that the car fired right up and idled at 2k rpm.

Slapped a 2.8 inch full exhaust, from the o2 housing all the way to the end. Instead of cat it has a muffler to look like a cat for inspections and to reduce noise.

Also used Injen Intake pipe and a gtr r34 bov with adaptor. Everything else was stock.

The car would idle at 1.8k rpm cold and when hot it would drop to 1.3k and hold it steady there.

Replaced FIAV from my old gs TB to the GST one and used new FIAV gasket. After that, the car idled great.

Note. All of this time since the car is turbo, it pulled great ( boost leak tested it, no leaks), but it still smelled of gas like crazy (I removed egr and evap canister, left the solenoids plugged in). My mpg was like before (fine but not great).

Then one day, I used the car as always, then I went to start it and go home, as it was cranking I would hear a pop sound and it would crank for a second longer but as soon as it fired up it ran to 2000 rpm idling. Drove it as is home and let it sit. The day after I disconnected the battery, inspected the hoses and everything seemed fine. I brought my old TB with its TPS and started the car up, but plugging the OLD tps on. The car idled at 2k rpm still but then dipped to 900 and I just plugged my TPS back and it ran fine again (still smelling of gas as always).

So yesterday,after a few days from the idle issue, bought Bosch O2 sensors (both front and rear) went to replace them. Since the turbo swap was done the car would idle for some time and get a CEL but the car rides fine. Thought it was the rear o2 sensing the cat is gone. So I bought those extensions. And while installing the extension on the rear o2 I replaced the front one in the o2 housing.

Drove the car home, the CEL popped up again and I was like ah f*** it...

That same night, went to start the car and it popped while cranking and the car again started idling at 2k rpm.

The next day (today) tried unplugging the battery and the tps thing, but it doesent change the idle.

Tried unplugging the maf, it drops it to 1700, then unplugging tps it drops it to 900 rpm but the car runs rough as if it will die. Unplugging the iac motor doesent change anything. I tested resistance on it and it tested 32 ohms on all pins.

I also pulled the plugs to inspect them and to my surprise they were all black and smelling of gas


Note; the car idles at 2k rpm even when cold and hot

Im at a loss right now. Basically replaced everything on the car and its still giving me nuts LOL

I know you guys will tell me to first get the code, (I still think its either the rear o2 or the emissions things). and get a data logger but I spent way too much money on the car so far, and Im in europe so even if I ordered Wideband or ECM link, it will take at least a month to arrive.

Can anyone suggest me anything?

Ill leave two photos bellow of how the car looked before and how it looks now.

(Btw, my knock sensor leaked out, I bought the oem evo8 one and will replace it when I cut my 27mm socket, because I cant get to it any other way)

Im waiting on the black sillicone hose for the bov, yes I know its short and ugly LOL

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Last edited:
It sounds like a vacuum leak somewhere, possibly the intake gasket? or bad injector seals or injector seals that dont seal right because they are not in straight or something, you can use propane or with caution (have a water bucket nearby) you can start the engine and let it idle while spraying carb cleaner or brake cleaner near any areas that a vacuum leak might exist such as the places I mentioned to see if the idle changes, if it raises or drops that indicates a leak in that area, use a straw on the can to better pinpoint the area don't just spray it all over, is the ecu chipped? and are you for sure using the factory 450cc injectors if its not? is your tps adjusted to the proper voltage? there is a closed throttle position switch in there that allows the isc motor to take over the idle when it sees a closed throttle, if its not adjusted properly then it will never see that you desire an idle from it.

You can try letting it idle and pull the intake pipe from the throttle body and use your fingers to plug the isc and fiav air intake holes in the front of the throttle body to see if the idle drops, then we know its a problem with them or not. Is your biss screw adjusted properly?
 
At this point, changing parts isn't going to solve this problem... you need data.

Do you have access to a palm pilot? There are a ton of ways to check on information while the car is running to compare what the numbers should be vs what you are seeing. (Long term / short term fuel trims, etc) There are OBD2 scanners that will give you real time information now, which could help you a lot.

As far as guessing.... you check your base fuel pressure?

I will post more if I can think of anything.
 
Like frosh29 said .
I know that you spend alot of time with dsm and getting informations about it but now its time to make a step forward.
To really understand whats going on in your car you have to see the signals from the sensors and understand what the ecu is doing with them.
Get a odb reader, a diagnostic tool , a data logger.
Measure and adjust things properly and you will find out what is working right and where the problem is.

I recomend you this channel of this guy to get a feeling whats called automobile diagnostic to solve Problems.

https://www.youtube.com/user/mattshadetree
 
@motomattx As far as the injector seals, I've replaced everything with new oem stuff, new seals, orings, gaskets, everything. Just to eliminate intake manifold gasket issue I replaced that one as well with oem part. I will boost leak it again and go from there, I don't feel safe risking it to flame up LOL

@frosh29 Changing parts won't solve it because I already changed everything with new oem parts, everything is changed literally. As far as the loggers, I did buy EVO Scan, saw on here that people use those cheap VAG cables to data log but I didn't give it a try yet smh, I tried 2 scanners (no luck), tried a black obd 2 scanner (no luck). I am waiting for a blue elm obd2 (5$ thingie) to arrive tomorrow to try that one (will that one work to get fuel trims?) for now just to get the CEL code, even though I think its either rear o2 because of the cat or emissions stuff. If not, I guess I'll just buy ecm link

As far as base fuel pressure, I am assuming you are talking about fuel pressure regulator? I've replaced it and no change, today I replaced coolant temp sensor and no change

@Phantomdmod Hey bro, yeah, lots of time and lots of money went into the car
I am getting those blue little elm obd2 readers tomorrow to try it out (because I haven't had luck with other scanners before, none of them work).. Hopefully I get this sorted soon
 
Shotgun trouble shooting is expensive and leads to frustration, you need to bust out a multimeter and start testing your sensors. By the symptoms you're describing my best guess (without you testing anything) is the coolant temperature sensor. If it fails the ECU thinks it's -74*F and will try warming up the car by running rich and keeping the idle up there, it just never warms up. Which is also why it's a good idea to, at the least, pull the CEL code.
 
Shotgun trouble shooting is expensive and leads to frustration, you need to bust out a multimeter and start testing your sensors. By the symptoms you're describing my best guess (without you testing anything) is the coolant temperature sensor. If it fails the ECU thinks it's -74*F out and will try warming up the car by running rich and keeping the idle up there, it just never warms up. Which is also why it's a good idea to, at the least, pull the CEL code.


Hey Gofer, thanks for responding to the thread, as far as the coolant temp sensor, I have two new oem spares and tried them all, no change at all, not to idle nor the rich issue

I am trying to get the ecm link and the wideband so I can actually see what's going on inside the car but till then I'm trying to find ways to check everything
 
Btw, is idle supposed to change when you unplug the IAC? I tested the pins, they all have 32 ohms on them but when the car is running, as I unplug it nothing changes, when I unplug MAF it drops from 2k to 1.5k and when I disconnect tps it drops to 1k but it sounds like its going to die

I pulled each injector connector and the idle would stumble, meaning they are fine (had them flow tested/cleaned before I installed the injectors 450cc stock)
 
@gofer @frosh29

At long last, got myself ECM and had a buddy set it up for me via remote tune. We read the codes, it was the rear o2 due to no cat + mdp because I dont have it.. He also leaned out in higher rpms to 11 something and added the anti lag.

It turns out my throttle position was always 4% even if not pressing the pedal (tps not adjusted?) we fixed that and the idle is steady 900 now.

The sluggishness continues though. It is mostly lower rpms and its affecting day to day drivability. Before you say its 2.0 what would you expect, I've driven grandpas Hyundai with 75hp and it feels much stronger/ smoother in lower rpms. Even when going from a stop in 1st gear (giving it 1200-1400 rpm) the car vibrates a bit as if Im starting from 200 rpm. The engine mounts are fine and the clutch is fine.

I was noting that about vibrating because when the car ran fine (usually after reseting the battery for longer periods) and had power, never felt any vibrations even when starting with 2nd gear from 1k rpm let alone 1st gear now

I've done some normal driving log as the car was warming up so if anyone can actually give it a look and tell me if theres anything wrong id appreciate it
 

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  • log.2019.10.30-02.elg
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I see a couple things but at least you are driving it. You need to "uncheck" the Disable Airflow Smoothing with SD,
HERE.....
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And you REALLY need to set your TPS manually to the correct voltage at zero throttle (.63V+) and use the TPS adjustments in link to do fine tuning, if needed.
HERE....
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I looked at your STFT's and they are close. I like them just a tad closer to zero, but they are withing 5-6% and that is ok.
Are you all stock, including injectors??
Marty
 
@1990TSIAWDTALON
Hey man, thanks for looking out!

The car is stock injectors and turbo wise. The only thing that is not is 2.8 full exhaust from turbo to the back with no cat + injen intake pipe. I believe everything else is stock.

Can you tell me what does the first thing do that you advised me to uncheck? And yeah, he fixed the TPS issue via ecm, I wasn't turning it manually. I plan on replacing it tomorrow so Ill play with that tomorrow I guess.

I am having like zero power at lower rpms and overall power drop (boost leak tested it + compression tested) and it was fine.

And I do drive the car everyday as a daily (I use European 100 octane fuel only)

I did find out my knock sensor leaking and I already bought a new oem evo8 one ready to be replaced. Heres a semi pull log I did the same night (looked it at myself and saw 2.1 knock)
 

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  • log.2019.10.30-03.elg
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It is under the "Misc" tab. It is the Speed Density airflow smoothing. You are not running on Speed Density (SD) so you should uncheck that box.
Get the TPS set as close to 0 without any adjusting through LINK.
You mentioned the bad knock sensor, that could be pulling timing out of the tune, thinking the motor is seeing detonation/preignition so get a good unit installed and plugged in (although looking at your log, I don't see it pulling massive amounts of timing.)
Do you know what timing map your friend set you up with to get started? It may have just a bit too much timing.
IF YOU FEEL COMFORTABLE, go out and do a 3rd gear pull at full throttle from 3000 to 5 or 6000 and post it. I am used to seeing the A/F's from a wideband air fuel gauge but it should tell us more about the tune. Watch the knock, if you see any, abort the pull and save the log. Under full throttle, we can see more about the tune.
How much boost? No capture of boost on Link so I assume it is 10-12lbs.
 
@1990TSIAWDTALON

Yeah I know where its located, just thought of what will change in driving when I uncheck it so I can notice.

Yeah I need to replace the knock sensor...
As far as a tune my buddy used I am not sure, do you maybe have some way you can remote check my ecm yourself and maybe you can find out whats going on?

Btw Im sorry about not having wideband, I am working on getting one.

And as far as timing, the car drove the same while it was NA gs, now I just have that turbo power added. So Idk if it was due to the timing used..

I will replace a tps and try to line it up as best as I can too.

As far as boost, I connected the wastegate to the turbo so it should be running stock wg psi.. I am not good at looking at the lap top and driving at the same time, so I could do the pull and whatever happens happens

But I am mainly having drivability issues with lower rpms where I have to give it much more gas pedal whereas where it drove fine It takes just a bit, I hope you understand what Im talking about
 
Sounds like drivability issues for normal driving and the air fuel meter would tell you if you are rich or lean or just about right in those area's.
Keep us posted and I will look at what I can. I am no pro but can always get my cars running pretty decent before having to ask for assistance.
 
@1990TSIAWDTALON
Yes sir, exactly that, drivability issue. I drove in a lot weaker cars 60-70hp and they have a lot more "power" than my car right now. When it drove fine, it was unreal but I hate it being so sluggish at lower rpms so I have to press the pedal a lot to even get to 3k rpm. The engine makes the noise like its doing something but you don't feel the torque at all, its slowly accelerating as if it needs a push LOL. But when it drove fine, when it makes that sound (from the engine), you can feel it accelerating and feel the torque of it

Of course Im not talking about 100% WOT pulls at lower rpms, just normal getting up to rpms driving
 
Heres another log from today, unchecked the air flow with SD thing and tried it now (the pull was with 2nd gear and a bit of the 3rd). Had CEL flash once or twice at higher rpms
 

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  • log.2019.11.05-01.elg
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