Engine problems, really need some help\guidance

[txbikerdude]

First off, I am new to the forum, and I think this is a great new place to call home for all my corvette friends!!! I have a 2008 corvette C6 coupe, standard, metallic silver, Borla stinger exhaust, Kooks headers, and LOVE it!!!

Now I am hoping that you guys can help me out, because I am at a total loss as to what is wrong. A couple days ago I am driving down the road and my right front wheel hits a medium size pothole - nothing to write home about as I have driven over it (or swerved around it) for several months now. Now this time immidieatly after I hit my my car started running rough, very rough actually. I made it to work and pulled in my parking space. I tried starting it again but it would not start. the engine would turn over, I could smell fuel, but no start. I let it sit for a couple hours and whent to try it again. it started but idles very rough, around 600-800RPM. I can give it gas and it runs rough and I cannot hold at a steady idle, i let my foot off the gas and it dies. I was brave enought to drive it home although it died on me atleast a dozen times (at stop lights, in N when braking in traffic, anytime there is not a load on the engine).

So when I get home I hook up my fuel pressure and it stays at a steady 60PSI so I know there is not a fuel problem. I took it to the dealer and they put it on a lift and verified no physical damage anywhere to the car, but since I have a HP tune on my car they basically said sorry cant help you. So last night I took the fuel pressure gauge off and noticed it did not drain near as much fuel as it has in the past, but drained it, put it back on and tested, still 60PSI like clockwork. at cold it will idle very rough, let it warm up or give it gas, let off the gas and it dies, like it does not know where the idle is, or something. I also pulled the air intake off and made sure there were no obstructions, etc. which there was not. So I am thinking could a pothole knock a spark plug or plug wire loose enough to cause this? I took the "corvette" tops off the engine and made sure all the plugs were plugged in, etc. I dont have a HP tuner so I cant connect to the engine to see what is going on, but hitting a pothole makes me think I have jarred something loose. I checked as much as I could all the hoses and actually stuck my head in the engine while my wife was in the car holding down the gas to about 1500-2k RPM trying to hear anything out of the ordinary like a loose vacuum hose, etc.

Can anyone help me or give me ideas on what to check? I am pretty engine savvy so any help would be great. It tears me up knowing my car is in the garage but I cannot drive it.

If you are in the Dallas area and want to help, I can pay in Beer...

 

[NORTY]

Sounds like the pothole is the cause of your issue. Is your O2 sensor connected? That can cause one bank to run horribly. Since your dealership won't touch your car, can you go back to your tuner and have them pull your codes? Did you get a CEL? All the rest of your gauges read normally? I think LG Motorsports is in TX, but don't know how close to you.

You might find someone with an OBDII to read your codes. Check your local Corvette Club. (They're like Rotary Intnl., they're everywhere!)

You say "you smell fuel?" Hmmm....hnoes

 

[txbikerdude]

Sounds like the pothole is the cause of your issue. Is your O2 sensor connected? That can cause one bank to run horribly. Since your dealership won't touch your car, can you go back to your tuner and have them pull your codes? Did you get a CEL? All the rest of your gauges read normally? I think LG Motorsports is in TX, but don't know how close to you.

You might find someone with an OBDII to read your codes. Check your local Corvette Club. (They're like Rotary Intnl., they're everywhere!)

You say "you smell fuel?" Hmmm....hnoes

ok replaced the fuel rail seals.. $50 gone. dont smell fuel anymore when trying to start the car. changed out the seals, started the car (cold) started, no errors on the display but still ran rough. so i think ok, let me put the air filter back on (I had left it out when I pulled the air intake out). once i put it back in car no go starty starty.. grrr... I gan feather the gas and it will start but run rough (still no strong odor of fuel anymore). I have a MicroEdge controller on my car and i was watching the O2v, keeping the rpm's at 1,000 (goes between 800 - 1200) I am watching the O2v and it is going from 0.00 to 0.4 to 0.6 and back to 0.0 very rapidly. that tells me maybe there is something wrong with the O2... so maybe I am retarded, is the only O2 sensor the one that sticks out of the side of the air intake hose body that goes into the throttle body? or is there another somewhere? please help!!! still no car, and out 50 bucks.. grrrr

 

[txbikerdude]

ok little update. I just replaced all the spark plugs and still nothing. So so far I have replaced the fuel rail O-rings and the spark plugs, with all the same problems still. so i guess my next thing to look into is the MAF sensor. I do have a question though, on the other side (almost opposite side of the MAF sensor) is another little tube that looks like a vacuum hose that connects in near the passenger side fuel rail. With the engine running I can pull the hose out with no affect, almost like there is no pressure or vacauum, but not sure if there is supposed to be or not. I snapped some pictures so you can see what I am talking about. Ideas?

 

[Hib Halverson]

That is not a vacuum hose.

It's the air intake for the PCV. It connects from the crankcase to the air intake so the crankcase gets filtered air.

I've been reading this thread and in my opinion you are just "throwing parts" at a problem you for which you have no diagnosis. My suggestion is that you put the stock ECM calibration back in and take the car to the dealer for warranty repair.

 

[txbikerdude]

That is not a vacuum hose.

It's the air intake for the PCV. It connects from the crankcase to the air intake so the crankcase gets filtered air.

I've been reading this thread and in my opinion you are just "throwing parts" at a problem you for which you have no diagnosis. My suggestion is that you put the stock ECM calibration back in and take the car to the dealer for warranty repair.

ok, i have the factory tune, what do I need to get it installed back on the car?

 

[NORTY]

To return to a stock config, you'll need:
A. LS1edit or
B. HPtuners or
C. A factory authorized GM dealership


What is a "Microedge Controller?" Sounds like a new shaver from Norelco!


Have you looked into the intake before the MAF sensor to see if one of the carbon filters has become "unstuck" and is lodged in the tract? Is there alot of oil in the tract? If so, then the MAF needs to be cleaned.

 

[mikey772]

Engine starting problems

New to the forum, not sure how to help. My 2005 6 speed will not turn over, makes a sound like deep rushing air. Sometimes it starts/or not. Love the car but this is driving me crazy!

 

[NORTY]

New to the forum, not sure how to help. My 2005 6 speed will not turn over, makes a sound like deep rushing air. Sometimes it starts/or not. Love the car but this is driving me crazy!

In stead of hijacking someone else's thread mikey772, you need to start your own thread. Then, it'll get more helpful attention.