CashMunson

iTrader: (1)

okay it started with a code 33 problem one day out of nowhere. Since then I rewired my fuel pump relay and MAF power relay. I replaced the maf power relay. I tried a new maf sensor also. None of this fixed the code 33. I then found out about another guy with a corvette having the same problem, he fixed it by changing the MAF tables in the chip. I had this done and it fixed the code 33 and the car ran great. A couple days ago I revved the car up to around 5k to make sure the new custom serpentine setup I put on would not have any belt slippage. The custom setup worked fine, alternator works good and the belt doesn't slip. The next time I tried it the car backfired very loudly out the exhaust and then about 5 seconds later it died. I looked down and there was smoke coming out of my air filter. I pulled the filter and the smoke smelled of gas pretty bad. I tried starting the car back up and it would just turn over and over for 5-10 seconds then it would start up and then just die back out. I pulled my plugs and all of them were fouled. The car has a new igntion module, new maf power relay and now new spark plugs. The car still has the same starting problem. My fuel pressure is only set at 46 psi with 24 # injectors. I took out the custom chip yesterday and put back in the stock chip. The car started right up and idled good but it gave the code 33 again. When I put the custom chip in, the car does what i've already mentioned. I'm hoping the backfire didn't damage anything internally. After it happened everything went to ****. The car was running great until that moment. Any ideas would be helpful. The timing is also set right on 6 degrees so i know it's not that.

dankhound

The backfire probably didnt do any internal damage, but it definatly could have damaged the maf. Does the wire in the maf look dirty or damaged?

CashMunson

iTrader: (1)

the wire in the maf is connected and doesn't look dirty at all, I checked that yesterday. I'm gonna try a new burnoff relay on monday when I get back from a big raffle down in wv. I know what an intake backfire sounds like and it didn't sound like that at all. It sounded like all exhaust backfire and a huge puff of black smoke came out the tailpipe when it happened.

the thing that confuses me the most is that the car starts up and idles good and even revs up pretty good with the stock chip, i put in the custom chip and there is no more code 33 but the car runs like crap. And what's even more confusing is the car ran great with that custom chip until it backfired.

Vader

Just for clarity, "backfire" is through the intake tract, "afterfire" is through the exhaust.

If you did indeed experience a backfire, it may well have cracked teh MAF hot wore. You can find out by metering the analog output voltage from teh MAF when teh engine starts. It shoudl run long enough for you to get some indication. Expect between 700-850 mV at a medium (850-900 RPM idle). If you get no output voltage from the MAF, it could well be damaged. Of course, you need to verify that the MAF is getting power on the correct terminals before you test the output.

I'm guessing that the PROM tuner disabled the MAF error codes or set the parameters for MAF faults so wide that you'll never get an error code.