I have a 92 camaro rs with a 305 TBI (VIN E) with symptoms no one has yet to solve. When the car would crank, it constantly backfired (steady as if every cylinder was doing it), a pain in the @$$ to get to start, Heavy smell of alchol in the exaust (87 octane gas, smells like a race car running on alcohol fuel), would cut out on it's own, and the ecm would store a variety of codes, usually 2 or 3 but never the same codes. I also got a code 54 once which isn't even listed on my code chart and I can't even find out what it means. These problems started out small(just enough to let you know something's not right) and got to the point where now IF and I do mean IF the car will start, you have to hold the throttle wide open, if not the car would die. Upon the removal of the exaust the car wouldn't start and there was no diffrence in exaust smell from the headers. Here is what Ive done:

IAC - replaced, problem got worse, put old one back in, no benifit
TPS - Replaced, new readings on test: 0.62v w/ 5.02v reference signal
MAP Sensor - Code 33 twice, checked vac and voltage, checked out fine
O2 Sensor - Unknown condition, unheated so no relevance to current
Problem(problems visible at start up, O2 sensor takes a minute to
warm up and send information)
Injectors - Cleaned with carbcleaner and reinstalled, Fuel flow excellent
Unknown pressure( no guage or money to buy one)
Exaust - Removed from headers no change in symptoms
Distributor, Inductive pickup coil, Ignition module, coil, wires and plugs - All
new, plugs turn black quickly, good spark, base timing at 6 DEG
BTDC, Autolite plugs gapped @0.04 instaed of 0.035. Plug
gap and full cleaning of the plugs made no diffrence in symptoms.
Valves - set to 0 lash with engine running, Shut off engine and added 1/2
turn (not 3/4 or 1 as these would cause the motor not to start
or run so horribly it didn't sound like a car at all.)

Any other information I did not include that you may deem nececarry please ask and I will find out and post the results of my findings. Any ideas as to what is causing this or anything I should test please let me know as I as well as everyone else (including trusted ASE certified mechanics that I know and are friends) i've talked to cannot fiqure it out either. Please Help because my pride and joy has been stumping me for months and laughing at me from where it has not moved.

 

54 - Fuel pump voltage low (below 2 volts)

TBIs with low fuel pressure are a PITA to diagnose. Get a gauge on the fuel line and see what's up.

 

Thanks for the code definition. That leads me to another question. On the passanger side of the motor compartment there are three wire connectors that I see. One is the EST Bypass. comming out of this harness besides the EST bypass there are two other connectors both female spade type connectors. One is on a short (maybe 3" long out of the harness) red wire which i think is the fuel pump diagnostic and another wire is about 2 1/2 to 3 feet long, orange, and has three snap rings to hold it somewhere. This one I know I disconnected to do the heads but I cannot finger out where it connects to. Any ideas about these? Also after donig my fuel pump ( Brand New) my fuel gauge reads full even when the tank is empty. Is this relevant to my problem or does this mean I just need to spend another 6 hours redoing it and making sure I did it right? Also, Everything about this car is a PITA. Did GM do this on purpose? HMMMM....... I wonder?

 

The steady backfire thru the intake, like pop-pop-pop-pop, sounds like a valve spring. I've run into it twice (oddly enough, exhaust springs). The symptoms sound just like it. You can see it on a vacuum gauge if you can get it started. The gauge needle will be a blur. I think you should test for a limp/broken valve spring. It's easy enough to do. Remove valve covers and press on the rocker to move each valve off the seat when it is closed, using a hammer handle. It should take considerable force (>75lbs) to move the valve off the seat.
You have to turn the engine periodically like adjusting valves to get each one closed.
Nothing as satisfying as finding one that you can move with your thumb.
Hope you find one, it's a cheap fix.
Other things that can do this, are a flat exhaust lobe on the cam, a bad intake valve seat/valve, or headgasket blown between cylinders (not cheap fix).
EDIT: can you post a picture of the connector on the wire that you can't find where to plug back in?

 

check the firing order make sure you wires are on the right plugs and then check them again to be sure.

 

The heads just had a valve job When I did the haeads and the poping was heard in the exaust. It used to only happen at 55 mph cruising. Then shortly after it would do it at 45mph. Now it's all the time. Also, all valves have no pressure when the motor is off but i did have what I thought was a tap in the valves so i did the adjustment with the motor running. I suspect it is the #2 cylinder if what you say is true because it souded like it had two taps once I backed it off to zero lash. Shouldn't the springs have been checked when the valves were replaced?
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This one I've checked 100 times. I've used a chilton manual, the internet, and what's molded on the intake and they all said the same thing. Not one wire is out of place. I'm 300% positive of it.

 

You need to do a compression test and report back. If it was popping in the exhaust and it got worse, it sounds like there was a problem with the head work (valve/seat).

 

I adjusted the Valves about 7 times. I'm not really sure if I did It right. Could the problem be that I just need to put lock tite on the rocker nuts or did I just do it wrong? C&B (who did my heads) said they checked the springs and all when they did the job and everything was good with them. What else could be tapping besides the valves? The Lifters?

 

I can't seem to find a picture of it on the internet so I'm going to try to describe it as best I can. It is rectangular viewed form the top and front and made of plastic that is solid black with a copper contact on the inside. I'm not even sure it is called a spade connector but it is exactly like the fuel pump prime connector in respect to what it looks like.

 

Will a lean mixture cause the exaust to smell like alcohol? When the car was running and before the exaust smells like it is now I got 11 MPG and it smelled like all the gas wasn't being burned (Rich mixture) and that is when I got the code 54. I also got code 33 but the MAP is fine.All this is so confusing.

 

never messed with fuel injection but my 84 almost did the same thing constant backfireing and could never get the mixture right on it. make a long story short test all of the valve seals the shop could of messed one up. also check fuel presure you can buy a cheap tester at harbor freight
http://www.harborfreight.com/cpi/cta...emnumber=92699