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running rich when car fully warmed up

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TsiJohn333

10+ Year Contributor
317
8
Jan 25, 2010
Goffstown, New_Hampshire
The problem starting happening the other day. When my car is fully warmed up, she drives really sluggish, shes running really rich, and the turbo spools up really slowly. It feels like im driving a n/a. Theres no power. I've also noticed on a cold start though she runs perfect. On a cold start she spools up really fast, pulls hard, and i can really feel the power. One more thing to add is that after shes fully warmed up, i noticed that my upper and lower radiator hoses are rock hard and boiling hot. Theres no bubbling in my coolant overflow tank from it getting so hot. i tested for boost leaks like everyone will tell me and i have small leaks at my tb and biss screw (ive had those ever since ive own the car going on 2 years now. i know i need to fix them) Can someone point me in the right direction. someone told me it could be my coolant temp sensor but i dont know why this would make me run rich, spool slow, and loose power when shes fully warmed up.

I drive a 1998 gst sypder a/t, evo III 16g turbo running 10psi, stock fuel system, coil on plugs, 16g exhaust manifold, 3 inch apexi turbo back exhaust, greddy type s recirculating, stock sidemount.
 
It could be a dying O2 sensor causing you to run rich. As far as the power if its starting to overheat the car will pull timing out the back of the car to try and cool itself down.. This will leave you without power. What are your temps? Have you checked to see what your plugs look like?
If not check them and let us know. It very well could be a shot thermostat or bad rad cap. Does the overflow tank even bubble from releasing the pressure as it warms up? If not the overflow hose could be plugged which will make it so the water cant get out. Have you had any smoke out of the back or any oil/water mixing??
 
ill check the spark plugs as soon as my wife gets home with the car. The overflow doesn't bubble at all even when warming up or warmed up. in fact its completely empty and wont release any pressure at all. i tried squeezing the radiator hose when it was as hard as a rock and it wont squeeze at all to relieve pressure. ive been blowing little puffs of smoke while boosting and and a lot more smoke at idle. i believe im burning oil. i noticed as well that my fans have been coming on a lot more lately even when driving on the highway and my engne bay feels really really hot but my temperater guage stays right in the middle where it usually is.

If the engine pulls timing in the back to try to cool down, wouldnt that make me run rich? i dont have a logger but i do have an aem wideband and i have on the way a gm maf with the translator.
 
Lol well there is yuor problem your wifes been driving it.. JK sorry i had too.
If its not releasing pressure that will cause the car to overheat because all that hot air is trapped in there.. Also it will blow something it can only build so much pressure before something has to give. So if i was you id take a peice of wire and push threw the overfflow tube and threw the hole in the overflow tank. If there clear it very well could be a bad lid that is stuck. Id replace that anyways just cause there so cheap.Ive actually got like 3 just incase LOL.
What color is the smoke
BLUE=burning oil
BLACK=running rich
White=coolant.
My guess is its black right?? If so that definetly running rich. What does you WB read under boost?What octane gas do you run?
Ya if the car is pulling timing youll run rich because the fuel is still burning as it comes out of the cylinder. This will also kill the o2 sensor faster and could even melt it although ive never seen that happen. Also do a boost leak check if you can.. Is your translator setup and tuned for your injectors?
If you can answer these questions as well as let me know what the plugs look like that would be good LOL.
AND KEEP HER OUT OF BOOST UNTILL ITS FIXED:p
 
A good logger would help exponentially, we could see what the ECU thinks the coolant temp is, how the O2 sensor is cycling, where the fuel trims are and we could possibly see if the knock sensor is knocking the timing down any.

When the engine gets hot, what do your wideband readings look like?

Without knowing more than just the symptoms you listed, it's going to be hard to pinpoint where the problem is here.
 
haha its cool. she loves working and driving dsm's just as much as i do. shes the one who installed her turbo on the car (of course i double checked everything) but neways getting off topic, i have an extra cap from my old talon laying around so ill change that out. i always run 93 and nothng else. my buddy said it was black smoke he saw coming out of the exhaust when i was on the highway but during idle its white smoke. Under boost my WB just goes 10.0 and holds it there but i think its more than that tho. Idling its 14.7 to 14.6. im still waiting on my translator setup to come in the mail. The wife isnt home yet so im gonna have to do another blt and check the plugs tomorrow and ill let you know what the results are. :thumb:
 
its the original thermostat and im on a stock fuel pump and stock 450 injectors for right now.
 
Well id change the thermostat its really cheap although i highly doubt that the problem they won't stop the car from releasing pressure.
Black smoke would indicate very rich and the 10 that your WB reads would also.. Running 93 id shoot for early 11's at the richest.. Also is it cold there?? That could be why your seeing white smoke..
Lol what do your plugs look like has your wife got home yet??
Also il be on hear for at least another hour or two so don't be afraid to reply haah im a night owl like no other and if im on the cpmuter at anytime you can garentee ive got a dsmtuners thread open somewhere as well as our local forum hear in idaho.

On a side note ive never seen a WB that read lower then 10 so don't be afraid to lean her out a bit if you can.. Althoug i don't know why its so rich if your on stock fuel system and injectors.. Sounds like that a boost leak from hell.
 
its not cold here, its kinda hot. i just pulled the spark plugs and they were pitch black and i changed them a month ago. im gonna change them again today. i havent had a chance to replace the thermostat or the radiator cap and ill do that when i change out the spark plugs. i also did a boost leak test and the only boost leaks i see are from the throttle body and the biss. there not to bad tho. i have no leaks at my injectors because i just changed out the seals on them which i doubled checked anyways and there not leaking. i also checked maybe i had an exhaust leak but i dont hear or see any. i hope by changing out the plugs, thermostat and the radiator cap work. i really miss boosting. :cry:
 
Well the pitch black spark plugs is because your trying to burn a hole in our ozone with that rich ass tune LOL. And ya i know how you feel man but its not worth blowing her up.. I would say a stuck injector but there is no way that would happen in all cylinders. If yuo change all that stuff out and it doesn't fix it then maby try your temp sensor a bad one would cause the car to stay in open loop mode and maby even go into limp mode both of which are really rich..
What was your WB reading in boost before you noticed this problem??
 
ok im gonna try to change out everything and let you guys know. I know this is a stupid question but where is my thermostat? I've never had to change one before.

My wb was reading around 10.2 before but that was WOT. i dont even need to go WOT for it to show 10 on my wb now.
 
Last edited:
anyone know where my thermostat is?
 
The thermostat is in the housing just to the left of your valve cover (opposite of the timing side). It is also where your cap is. There should be 3 bolts that hold the housing on, and the thermostat sits right in there.

I hope thats descriptive enough LOL
 
LOL thank you man. i know right where it is now.: :)
 
well i replaced the radiator cap and did a coolant flush and replaced the spark plugs. Im still running rich but not as much as before. My wb ready around 10.2 now but i still have a lot of pressure in my radiator hoses. i opened up the radiator cap when the hose was fully pressurized and the car fully warmed up and all the came out was air no coolant. i think i have an air bubble somewhere or its my thermostat. im gonna replace the thermostat tomorrow and add more coolant.
 
I just fixed it today. i replaced the thermostat and that didnt do anything. My hoses were still getting a lot of pressure in them. i took off the coolant hose that goes from under the radiator cap to the overflow and tried blowing through it but couldnt at all. so i took off the radiator cap and blew through the hose again and was able to. i went to autozone and picked up a new radiator cap. i put in on and blew through the hose again and was able to slightly blow through. took her for a spin and SUCCESS! it was the radiator cap. Thank you everyone for helping me out. No more running rich or inflamed radiator hoses. :thumb:
 
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