Idle Surging

[fi5hGSR]

Good Morning All,

Vehicle - Lancer CC GSR with VR4 4G63

I've recently developed Idle surging in my car and I've done some research in regards to what could be contributing to the problem. The only time I can get it idle without surging is if I retard the timing using the cam sensor - Here are a few other problems.

- Idles surges and will stall when the throttle is blipped
- I think its also running rich
- I notice when I activate central locking it drops the idle alot

Things that I have tried so far

ISC - (This has been cancelled as I am using an EMS Dual Sport)
New Coolant Temparture Sensor
Checked timing (Spot on)
Throttle Body (Off working car)
Coils (Off working car)
Spark Plugs
New Fuel (Eflex)
Vaccum leak test (no leaks)

When cruising it feels like its missing or not enough spark - on boost its perfect pulls like a champ.

- If feels like as if the fuel mixture is wrong hence why its surging and when I retard the timing its balancing it out - not sure tbh. The more I think about it - would a stuffed o2 sensor cause this as well? Could the ECU be stuffed?

Any help will be much appreciated -

 

[4piknup]

What does the wideband say?
Is it in closed loop at idle and cruise?

 

[fi5hGSR]

What does the wideband say?
Is it in closed loop at idle and cruise?

Don't have wideband gauge and only time I can tell is if I plug it into a lappy which I can only do when I take it to the tuner - trying to avoid them atm cause its bugging the crap outta me

 

[GeoKez]

You say a new coolant sensor? Can you confirm this is working properly? If your ECU thinks your coolant temp is -20 it might be fueling it as such.

Just a thought.

 

[fi5hGSR]

You say a new coolant sensor? Can you confirm this is working properly? If your ECU thinks your coolant temp is -20 it might be fueling it as such.

Just a thought.

Yeah i did a resistance test in hot water to see the volts change - I can't remember exact numbers but from memory the parameters were correct when I researched online this was on a new sensor - Also I forgot to mention this only starts happening when the car warms up - cold start is perfect hence me changing the coolant temp sensor

 

[captainTeeBag]

hi mate.i had the same symptoms a while back and it was the tps. mine behaved exactly like yours. new tps and set it up and done. was bout $70 for brand new one. was a bitch to get the old one off and ic you do replace my advice is to change the 8mm bolts to a panhead alan key

 

[turbovr4]

Don't know if this is any help, but I because I didn't run water lines to the throttle body in the MG I had idle surge with the idle speed cutout working and no idle if the car was hot and restarted1/2hr later. I heard it was to do with the throttle body wax pellet air bypass. Any way all I did to fix it was just screw the seat of that valve under the cover plate all the way down. All fixed with no idle issues now on my Haltech computer.

 

[fi5hGSR]

hi mate.i had the same symptoms a while back and it was the tps. mine behaved exactly like yours. new tps and set it up and done. was bout $70 for brand new one. was a bitch to get the old one off and ic you do replace my advice is to change the 8mm bolts to a panhead alan key

Thanks for the info - Did your symptoms only happen when it warmed up? Can you tell me where I can get a brand new TPS for $70?

Don't know if this is any help, but I because I didn't run water lines to the throttle body in the MG I had idle surge with the idle speed cutout working and no idle if the car was hot and restarted1/2hr later. I heard it was to do with the throttle body wax pellet air bypass. Any way all I did to fix it was just screw the seat of that valve under the cover plate all the way down. All fixed with no idle issues now on my Haltech computer.

Not sure what valve you mean by the wax pellet bypass cause under the block off plate is just a gasket? - I also cancelled the water lines.

 

[4piknup]

The water lines feed into the wax pellet area. When the wax is cold the air valve is open allowing extra air in allowing a cold idle.
When wax is hot the port is blocked and fast idle air valve is shut. No extra air

 

[fi5hGSR]

The water lines feed into the wax pellet area. When the wax is cold the air valve is open allowing extra air in allowing a cold idle.
When wax is hot the port is blocked and fast idle air valve is shut. No extra air

Yeah No water lines going into the TB - whole thing has been cancelled and a block off plate is there instead

 

[4piknup]

Mate, you/we can guess all day what is wrong with it.
I reckon either buy a wideband and plug your laptop into it. Or run it back to the tuner to tell you.
Quicker and easier.
And if you start replacing parts on a guess, it will be cheaper to take it back

 

[fi5hGSR]

Mate, you/we can guess all day what is wrong with it.
I reckon either buy a wideband and plug your laptop into it. Or run it back to the tuner to tell you.
Quicker and easier.
And if you start replacing parts on a guess, it will be cheaper to take it back

Totally agree with this - just thought I will get some insight just incase I can try something with what I have already. Thanks everyone for the info.

 

[fi5hGSR]

hi mate.i had the same symptoms a while back and it was the tps. mine behaved exactly like yours. new tps and set it up and done. was bout $70 for brand new one. was a bitch to get the old one off and ic you do replace my advice is to change the 8mm bolts to a panhead alan key

Mate you might be onto something here - I tried to adjust the TPS and I noticed it was on 13% closed throttle - tried to adjust the TPS to be 0% closed throttle and 100% open throttle - not possible if its at 0% it'll be 92% open throttle and the TPS had to be turned all the way back (Max) - I d/c the TPS and the car runs and does not stall! still hunts a little when I shift down or blip the throttle but I think this is due to the TPS being d/c - also noticed its constantly on 25% when d/c. Thanks Again guys

 

[khubner1]

heres setting the tps correctly you will need an ohm meter.
.9k ohms at closed and 5k ohms at WOT
http://122.148.77.132/4gt-manuals/tps.html

 

[captainTeeBag]

Mate you might be onto something here - I tried to adjust the TPS and I noticed it was on 13% closed throttle - tried to adjust the TPS to be 0% closed throttle and 100% open throttle - not possible if its at 0% it'll be 92% open throttle and the TPS had to be turned all the way back (Max) - I d/c the TPS and the car runs and does not stall! still hunts a little when I shift down or blip the throttle but I think this is due to the TPS being d/c - also noticed its constantly on 25% when d/c. Thanks Again guys

yeah mate mine only really played up once warmed up. it will run pretty average without the tps set correctly or faulty. i got a hyundai sonata tps off ebay. you need the three pin tps not the 4 pin. was a pita to get to the lower bolt. youl need to remove the fuel rail and have some patience. make sure you use an ohlmeter as jack said but its not a difficult job to set it up

 

[captainTeeBag]

if you drive with the tps disconnected you willuse alot of fuel. the ecu will be using the afm and o2 sensor data to try and calculate fuel requirements. throttle response will be total poop.

 

[captainTeeBag]

i found the link khubner posted handy however you dont need to plug it in to the loom with alligator clips etc. just set multimeter t.o ohlms and adjust the tps untill you get the correct resistance values for closed and open and check that while moving the throttle from closed to open you have a smooth rise in the resistance values

 

[fi5hGSR]

Ok Update: New TPS Installed and calibrated according to khubner post (Thanks Mate) - Car is back to beast mode - Idles awesome - no more bucking and jerking through the rev range and it hauls arse :thumbsup: But there is still an annoying issue I need you guys to help me with again

- When I do a sudden drop in RPM e.g. shift from gear (Any gear) to neutral the rpm dips like real low 400rpm more or less and stalls. This will happen 7 out of 10 times The car will start right back up no worries and all is well until I do the same.
I've manage to stopped this by coasting in gear to let the revs drops slowly then shift in neutral and this will hold idle. I've done a tone of reading on the net and they say clean TB etc this has already been performed when I was trying to fix the surging issue.

I've also noticed when I start the car cold and once it warms up to operating temp it cuts off and stalls - I then need to start the car with the gas pedal down abit to get her going again but after idles fine etc.

Please help again !

 

[GeoKez]

Idle control solenoid be my guess. Big thread on here bout it.

http://www.4gtuner.com/topic/19963-idle-speed-control-problems/

Try what Jack say's in the opening post. Unplug ICS and see what changes, you will know more after that.

 

[khubner1]

that'll be an issue with the ISC (idle speed control)