A few weeks back I was experiencing what I thought was a fuel starvation problem with my 2005 ProCharged C6. Under hard acceleration, it would just quit running at the top of 2nd gear. After coasting for 10 to 15 seconds, it would cough back to life and run fine, as long as I kept my foot out of it. This happened several times, always after running the car through the gears, but, it always sputtered back to life and ran fine. I finally broke down and took it to my dealer. They could not reproduce the problem, but, after talking with the mechanic, he agreed, and the fuel pump assembly was replaced. I drove the car home upon repairs being completed. It was a cold, rainey day. The car ran fine, but, I never really pushed.

Then, it snowed. Then, it snowed again!

Finally got a decent day yesterday, and drove the car. I drove it for about 20 minutes, out to check on the boat at our marina. Never pushed the car past 1/4 throttle. The car sat for about 15 minutes while I chatted with some friends on the dock, got back in and headed home. I drove for maybe 3 minutes, through a residental area, nice and slow, and bam. It did it again, this time at about 15 mph in 2nd gear. I pulled over to the side of the road, the engine coughed and sputtered. I had to pump the accelerator to keep it sputtering, just as if it had a carb, then, about 20 seconds later, it began running as if nothing had ever happened. The car has never backfired during any of this, or thrown a code. It honestly seems like it is running out of fuel.

I'm to the point that I'm scared to drive it for fear of it stranding me.

Please, any suggestions or ideas will be appreciated.

Thanks

 

Might be worthwhile to install a fuel pressure gauge at least temporarily for diagnostic purposes...and you've eliminated bad gas as a possibility?

 

I have considered a fuel pressure guage. I guess that will be my next move, so I can either identify, or eliminate, fuel pressure as the culprit. Gas quality does not seem to involved, but, I think I will pour a few cans of gas treatment in the tank tomorrow, just in case there could be some water lurking around in the tank.

I wonder if a faulty gas cap could be involved? It failed emission testing in December, and they let me pass if I promissed to have it replaced. The dealer had to order it, and, with the weather, I've never gotten by to get it. Hmmmm???

Thanks.

 

I agree with checking fuel pressure first, but after that, I'd start looking electrical.

Just an idea, but could be as simple as a wire getting burned or a bad ecu. A good thorough inspection of some wiring might give you some insights.

 

I got to the dealer this morning and picked up my new fuel filler cap. I installed it, and poured a can of STP gas treatment into a half full tank. I just returned from driving the car about 50 miles. Interstate cruising up to triple digits, first, second, and third gear WOT blasts, and neighborhood slow driving. The car never missed a beat.
I'm beginning to suspect I had some water in the fuel tank. In cold weather, sometimes I use a brushless car wash near my home. The water is at a fairly high pressure, and I guess some of this water could have gotten past the filler door, then into the tank, past the defective seal on the cap. So, I think a new $19 cap and a $2 bottle of gas treatment may have solved my problem. In the future, I will put some rags between the door and gas cap in case some water is getting in there whenever I use the car wash. I think I will also run another bottle of gas treatment through, just in case.
Man, I hope this solves this issue. I was afraid I was going to have to pony up a couple of grand for a high performance fuel system, and I don't need that right now.
Thanks for listening to my rambling. Perhaps this post will assist someone down the road with the same symptoms.

 

Well, !@?*&$#!

I decided to go for a little ride this afternoon, and the car did not even make it out of the neighborhood before coughing and sputtering again. After attempting to hack up a lung for about 1 minute, it smoothed out and ran fine for about ten minutes, then repeated the same scenario. Now, I'm completely stumped. Guess my next step will be a fuel pressure setup in an attempt to isolate what's going on.

 

you are SC with an auxiliary fuel system or a BAP system?

If you are going to put a fuel pressure gage. might as well do the twin pillar mount pressure and boost.

 

The car is ProCharged, 6# boost, and the only fuel system mod is the RaceTronics direct off the back of the alternator wiring harness, straight to the fuel pump. It runs Marren 60# injectors and 1 7/8" headers, hi-flow cats, x-pipe and Corsa Sport duals. The car has run fine for over three years and 20k miles with this setup.
The car runs absolutely perfect, but within the last 6 weeks has begun to suffer these coughing and sputtering attacks with basically zero power. After a minute or so of pumping the accelerator to keep it running, it will suddenly begin to run perfect again. The symptoms are of an engine that has picked up some water in the fuel, but, I have run the car to nearly empty, filled it up and added two bottles of gas dryer, hopefully to burn what possible water may still be around. Nothing has helped. It also has a brand new pump in the tank, installed in December. I have spend a few minutes searching for an electric fuel pressure guage, and that will probably be next, so I can either identify a fuel pressure issue, or eliminate that as a problem.

 

a guy on the forum here is having an issue similar to yours only within a few weeks of his TVS install with a BAP.

man it could be any number of things including an injector, but seems like you would get a code with that.
make sure you include the racetronics fuel system in your trouble shooting. perhaps disconnect it and put put around town like you are doing now and see if that system is at fault or not.

 

After I went to bed last night I was thinking what would be causing this, and the RaceTronics wiring harness did come to mind. It is the only mod to the fuel system and I was thinking perhaps there is a lose connection somewhere. But, even if that is the case, the stock wiring harness should still be suppling current to the pump (at least I assume it does??) I think I will disconnect it from the back of the alternator and see if that will eliminate my problem.

Thanks.

 

Check the relay on the Racetronix hotwire. I have seen them go bad, albeit VERY rarely. Worth a shot..

Jason

 

IMHO You don't need to spend hundreds of dollars on a permanent fuel pressure setup to sort this out! There is a schrader type valve on the front of the driver's side fuel rail that you can attach a diagnostic type fuel pressure gauge to. They run about $20-$50.00 at most auto parts stores and take about 5 seconds to install/uninstall.

 

Yup.

Also, before spending any money, bypass the racetronix harness. Should be a quick swap. I'm pretty sure I read about a very similar issue where this was the cause.

 

I will do that as soon as the weather breaks here. Currenty heavy snow over 1 " of ice. Too damn cold in my garage to attempt it today.

 

 

only 1" must be nice lol

 

exactly....... plug the thing in and tape it up to the windshield so it can be watched while you drive. It sounds like this issue is happening often enough that you should be able to catch it in the act.

I also think you should bypass the Racetronix harness as others have said. Good luck and let us know how it goes.

Andy

 

Being that you have a 05 C6, when the tune is done on your blower, there is a patch that needs to be installed into the tune pertaining to your MAFS.

It has something to do with the amount of air that the 05 MAFS can read. After a certain CFM, the MAF goes nuts, and you end up in reduced power mode.

Check it out... I'll bet I'm right!

 

I dunno, he said it has been modified this way for 3 years & 20k miles. Probably not a tuning issue.

 

30,000 miles without a problem, then this pops out of the blue? I would start to suspect the fuel pump itself.