Ok guys this problem has been going on for almost a year. I wrote about it a few months ago ans then it quit for a few days so I thought it was gone. Ive done a search for ignition switch on here but didnt see anything pertaining to my question. First a quick rundown of the symptoms: started while driving down the road the car just dies. when I try to start it it starts but barely runs and smells like raw fuel and dies within 5 to 10 seconds. when I try to restart it, it does the same thing. sometimes this dying happens driving normal,sometimes when Im on the gas hard, or sometimes it does it when Im starting up cold or after it has sat for a few minutes. eventually i would get it started by reving it up when it fired but that was a very tricky way because it would take about 15 tries to get it running with the drive by wire. OK now the weird part: when it does the problem if i start the car and hold the key to the crank position it will run fine. If i rev it up and clean it out while holding the key to start i can let it go and it will be fine until the next act up. Ive gotten so good with it now that when it dies driving down the street i just turn the key to the crank position while im still coasting it will fire back up( lucky i have an A4 so it doesnt actually turn the starter while in drive) Sooooooo.......... could it be the switch? has anyone ever seen this problem? I tried my other key and it does the same thing. I erased all my codes and the first time it acted up i retrieved the codes and there were none. Im starting to think its mechanical and not electric but i dont wanna start throwing parts at it. any help would be great. thanks, Normand

 

What codes do you get? You said you cleared them out, what were they? I would guess the MAF is dirty.

 

lurk

 

what are the codes for a maf problem? if there was a leak between the maf and the throttle body what would symptoms be? and lastly what the heck is lurk?

 

The codes for an MAF problem are P0101, P0102, and P0103. These codes are MAF performance codes. However, you may have a dirty MAF or a problem with it that could be causing a different code. The tempco resistors in the MAF could be dirty and not tracking properly. This could cause you to run very rich. Another thing it could be is O2 sensors. It might not be an intake or exhaust leak. Leaks usually make you run lean. You could have a leaky injector. Without looking at the codes then trying corrective measures we could guess all day. Also, you may have code, but the might not be related to the problem. You may not have any codes for the problem.

 

Curious problem. Older cars had a ballast resistor in the ignition circuit that was bypassed in the start position on the ignition switch to deliver full voltage to the coil for starting. When the key was released, the ballast resistor was put back in the circuit and reduced the voltage to the coil to extend coil life. I don't have a clue if the C5 has a voltage reduction circuit like this, or if it can be intermittent, but I think the problem is in the start/run ignition circuit but probably is not the switch.

Any electrical gurus on here that know if there is a circuit/function on the C5 as described above that might be the cause?

Charlie

 

just so everyone knows the car has an ls 6 with dart heads and mti cam with kooks lts, no cats with x pipe, ti z06 mufflers, ported throttle body, billet ends on the maf and cold air filter. i had it dyno tuned about 14 months ago when i put the engine in and it ran fine for about 8 months before the first symptom.
codes from the last 2 weeks(because i erased them all then):
p 0410 c
p 1571 h
p 1689 h
u 1096 h
u 1064 h
u 1016 h
any help would be great. Im goin crazy here. thanks all

 

The P0410 code is secodary air injection failure. Couldn't find 1571 and the others are communications error codes

Charlie

 

I'm wondering if you have a leaky injector.
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I'm wondering if 2 of the codes were copied correctly. As said above, the P0410, which is current, is the secondary A.I.R. injection. Which I doubt could cause your symptoms, at least after warmup. However a P0140 is HO2S circuit insufficient activity Bank 1 sensor 2. That is the HO2S behind the driver's side cat. You could have a clogged cat, or the sensor is just gone. I suspect you have lazy O2's which got lazier after a while after the tune. It happened on my car. After a while they started throwing codes and I ended up replacing the front 2 HO2S. That would be a place to start if the code is a P0140.
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The next code P1571 I couldn't find either. However, a P1517 is Throttle Actuator Control (TAC) Module Performance. I've gotten this very occaisionally if I stall the car. I think the TAC tries to make the throttle blade swing too far too quickly in an effort to keep the engine alive. In your case it could have happened when you stalled and tried to clear it up.
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P1689 is Traction Control Delivered Output Torque. Wheel spin? I've gotten this when I tried to pop the clutch when I stalled while rolling.
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As for the other codes being comm codes, that can happen whenever the engine stalls and you try to refire right away. They are history also.
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My guess is either you have a leaky injector. Or something is happening with your O2's. If you can have it scanned that may reveal more. You may be running too rich overall.

 

does a leaky injector leak to the atmosphere or to the cylinder? the injectors only have about 3500 miles on them as they were in the crate motor ls 6 when i installed it new. thats how many miles ive put on in the 14 or 15 months ive had the engine in. will it take a gm scan to find out for sure?

 

You have a 99. Unless the grounds have been checked, that is the most likely and most probable cause of your issues. The cost of ground maintenance is ZERO DOLLARS AND ZERO CENTS! Start there. See my stickey in at the top of the Tech section. If you have any questions after reading that post (get a coffee and a sandwich, it's LONG! ) Just let me know. Also check your battery terminals for corrosion and proper torque. Clean the terminals and cable ends and Torque the bolts to 11 ft/lbs.

cruisemon

The old ballast restistor is LONG GONE! We dont need to worry about that stuff any more. GM replaced that with a column lock issue just to keep us on our toes!

BC

 

I won't take a gm scan to find out about a leaky injector. A system like EFILive with a good OBD2 scanner can run tests to see if that is the problem. However, why not give Bill Curlee's advise a shot. 1) You will be cleaning up your ground system and that can't be bad, and 2)If you don't do it now, you will have to do it later. As he said, it doesn't cost anything and you will get some benefit. If that doesn't clear up the probelm at least you won't be wondering if it's bad grounds.

 

well guys Ill do some ground cleaning this weekend and post the results. thanks

 

took apart the two grounds that are on top of the frame rails in the engine bay and they are as clean as brand new. are all the other ones the same design? thanks

 

Read Bill Curlee's sticky. It even shows all the ground locations.

 

No,,,Some are crimp/solder eyelet type connections under a 10mm nut.

BC

 

well Ive checked grounds and still the same intermittent problem. So i bought a new ignition switch and put it on and guess what? same old problem! still stalls for no reason on occasion and holding the key all the way to start lets it run as if nothings wrong. I pulled the codes and here they are:
p0410c
p0706h
p1571h
b0432h
b1001h
u1040h
b0521h
u1016h
u1064h
u1040h
u1176h
u1088h
u1160h
b2262h
b2285h
u1096h
u1064h
u1016h
i do have a ported throttle body and my maf is the stock center descreened with billet ends. anyone wanna take another stab at this? this has been going on now for almost 2 years. thanks

 

I am working on this issue. The key to figuring this out it to find the circuits that are energized and allow the car to start and run when the key is turned to start.

Stay tuned!

BC

 

thanks Bill, your my hero if you figure this thing out.

 

2 days now with no stalling. hope you think of something. thanks