03 Cobra, Boost Problem?

[bear.miller]

I have an 03 Cobra w/ 60,000 miles and I am having a problem. When I'm full throttle the boost gage goes up but I'm getting eally bad surging or stalling. The car is pulling hard but should be giving me more. The car was running hot a few days ago. My friend was trying to put water in the radiator. He accidentally put water in the intercooler reservoir. I dont know if that is my problem or not. Any ideas!?

 

[Uncle Meat]

Done any extended high speed runs lately? Does your car have any of the "Cooling Mods" installed? Might want to get a cylinder leak down test performed just to be safe...

As for adding water in the intercooler reservoir, not a problem.

U.M.

 

[bear.miller]

Yes, ran over 120mph yesterday, seems fine at high speed. In 3rd gear it seems like the car needs a new spark plugs. I havent changed the plugs yet. I just got the car on April 3rd. I'm trying to figure out what all has been done to the car. No cooling mod. The car seems to be stock other than, It has a Demolet, Tunable Induction kit on it with a K&N filter, and a Steeda Idle Kit. The car may have been doing this before the overheating. Since the overheating, I have been a little paranoid and seem to notice every little thing about it.

 

[Uncle Meat]

You may want to get it on a dyno and check the A/F ratio. I had a Demolet on my '03 for a while until I found out that it caused erratic MAF readings due to the laminar airflow around the curve in the intake pipe just prior to the MAF itself. It also leaned out my A/F ratio. You want a straight through design CAI on these cars like the K&N FIPK, the JLT RAI, or a Steeda CAI.

When I spoke of an extended high speed run I meant 5th gear, WOT, 150-160MPH for a mile or two... This will KILL a stock 03/04 Cobra!!! The PTW (piston to wall clearance) is very small from the factory and the extended high speed runs can cause the piston to expand more than the cylinder bore and then it starts scuffing the Teflon off the piston skirts. Continue to push it and you'll start melting rings and pistons...

I still feel the most prudent thing you could possible do right now is get the car on a dyno. Check the A/F ratio, do a compression test, do a cylinder leak down test. You need to know the current state of your engine before you push it again... Just my 2 cents...

U.M.

 

[hotcobra03]

whats going on?

hey i remember when i had 60k....couple of questions,,,my first big problem came at this time,and your story sounds close to what mine was doing.....


1--is check engine lite on?


2---have you seen ck eng lite flash while driving?


When you say overheated,,,,how bad?...did car shut off?

 

[2003SLVRSNAKE]

hotcobra03, no check engine light at all. and yes the car shut off. U.M., I am kinda of skeptical of the demolet induction.

 

[hotcobra03]

running rough

another question...on a cold startup(1st start of the day) will it start and stay running on its own?


mine has been a dd ,and runs everyday,,has been almost trouble free..except for a miss problem that happened a couple of times..


list of things that made mine miss;

driverside head,,was the first...happened at 60k...car would start but you would need to run at 2000rpms till warm,,to get it to idle smooth.

2nd problem..driverside head,at 205k..this time car would start and idle..but was loosing power..getting slower by the day.

3rd problem after head repair..o2 sensors went bad (from overheating head,,fluid on o2s shorted them)

4th problem was a broken spark plug..at 225k ..was on stangnet to ask about a 4th gear hesatation while driving slow...plugs were new (they can break at anytime)''

look in the throttlebody openeing and look for oil..the pcv valve lets alot of oil to pass thru and clogs up the supercharger making air harder to pass thru intercooler....

with no enginge lite on i would check plugs,,clean air filter and maf sensor,,than when was the last time fuel filter was changed...(my first was at 193k)

 

[2003SLVRSNAKE]

Thanks for the info hotcobra03. Cold startup, the cars fires right up, no problems. It stays running. I am going to change plugs, air filter, and fuel filter this weekend. Also I will the the TB as you suggested. I am not sure about determining a faulty MAF sensor without a CODE being sent.

 

[hotcobra03]

things to check

Thanks for the info hotcobra03. Cold startup, the cars fires right up, no problems. It stays running. I am going to change plugs, air filter, and fuel filter this weekend. Also I will the the TB as you suggested. I am not sure about determining a faulty MAF sensor without a CODE being sent.

FWIW..im under my hood weekly if not daily...not because it breaksdown..but to prevent breakdowns...

the 03 cobra is one of the easyiest cars to work on that ive owned.. at first it looks crazy,,but you will find it to be like working on a lawnmower,, i got 100 bucks that says you can change spark plugs from the drivers seat,,,lol just kidding ,,but they are pretty easy...

i would do a compression test and a vacuum test,,,,


i also suggest looking at vacuum lines,and hoses....

the pcv hose at back of supercharger is know to crumble and leak,,
the vacuum hose for the egr valve is another..it could come in contact with the egr tube and melt