1994 firebird trans am question

[mustangridah314]

This car was running good until the heads were cracked by running it while the radiator had a hole it in(hot). This car sat for about 2 years in the summer and winter before New heads were installed by me and my dad. When we started the car the idle was too high. We took it to a local shop and they fixed it. Drove it for about 200 miles and it cut off and wouldnt start. We tried over and over to start it and it started backfiring, then it sounded like a vacuum while tryin to start it after that. Took it to a shop and they put a new starter, distributor cap and rotor. They still couldnt get it to start but it was tryin to turn over, so they unplugged the O2 sensors and it stayed started. Here are my questions, Do you think we flooded the engine and damaged the fuel injectors trying to restart and restart? or do you think we just need new 02 sensors? if so well then why is the car is stalling and lacking power, I damn near have to step on the pedal hard for it to accelerate?

MEINIEKE MUFFLERS said there's a crack in the passenger manifold but we already knew that when we bought the car, that wouldnt stop the car from running bad.

Here's what we replaced brand new
RADIATOR
WATERPUMP
STARTER
DISTRIBUTOR CAP (ROTOR)
NEW PLUGS AND WIRES (AFTER AND BEFORE WE GOT IT HOME BOTH TIMES FROM THE SHOP)
REMOVED CATALYNTIC CONVERTER (MUFFLER SHOP)
3 OIL CHANGES IN THE PAST 2 MONTHS

[Al 96 Ram Air T/A]

If you're saying you have a cracked passenger side exhaust manifold, it most definitely will cause a problem. You're letting oxygen into the system pre-O2 sensor.

Second, there's a good chance the Optispark was soaked when the heads cracked. At the very least, you probably should have replaced the distributor (Optispark) and not just done a cap and rotor replacement. I attempted to replace just the cap and rotor and wound up messing up the optical sensor. The car would take a long time to start, then die out after running poorly.

Take care of one problem at a time. If the crack in the manifold is letting air in or exhaust out, replace it. It's a lot of work, but used manifolds are a dime a dozen. You can pick one up for $25.

[Jeff_in_Atl]

It shouldn't use the O2 sensor until it gets to a certain temperature when it goes from open loop to close loop. The O2s shouldn't cause it not to start when it is cold.

I think if you push the accelerator to the floor when trying to start it the computer goes into clear flood mode, turns off the injectors, and keeps firing the cylinders to clear the unburned gas out. At least that is the way EECIV Fords work. I thought all cars did that. You shouldn't have to disassemble the car to clear a flood start condition.

There are lots of reason the car might die. You just have to go through the systems one by one to figure it out. Joe has a good list which I figure he will post up shortly.

Let me say this, LT1 have a problem where over time they can build up carbon in the EGR tube and the EGR valve. I had one that the carbon hung the EGR valve open and it will not start if it does that. You can take the valve off and clean it and the tube but it is a PITA to clean the tube. The dealer has a machine to do it.

[Injuneer]

Have you scanned it for codes?

[FTA1995]

Sounds like lost compression from this case, also, i noticed you said you changed the oil 3 times in two months, why? Was there coolant in the oil?
Is there any oil in the coolant? You could blow O2's outwith coolant contamination.
I think its compression because you say power is also not up to normal and you replaced all the ignition components etc. Is it also possible you put the distributor cap on crooked a bit so the timing is goofy? There's a few combinations I can think of that would suit these symptoms.

[mustangridah314]

THE CAR STARTS UP FINE AND NO LIGHTS COME ON, ON THE DASHBOARD, UNTIL I DRIVE IT FOR 5 MINUTES. IT WILL GIVE ME A LIGHT JERK LIKE IT WANTS TO CUT OFF BUT IT NEVER DIES OUT. THE CAR IS MISSING BAD, IT DRIVES LIKE A 4 CYLINDER UNTIL YOU STOMP ON THE GAS PEDAL. I WENT TO AUTOZONE AND ADVANCED AUTO PARTS AND THEY SAID THEY COULDNT DO A CODE CHECK ON IT CAUSE IT NEED A SPECIAL KEY TO SCAN IT. I DROVE IT TO WORK WHEN IT WAS FINE, WHEN IT DID STOP ON ME I OPEN THE HOOD AND A HOSE CONNECTING TO THE WATER PUMP DID COME OFF POURING OUT ANTIFREEZE DOWN BY THE DISTRIBUTOR. COULD THAT BE THE PROBLEM, WHEN THE MECHANIC PUT ON THE NEW DISTRIBUTOR COULD HE HAVE MESSED THE TIMING UP? SOME GUY AT A MUFFLER PLACE SAID ITS MISSING REAL BAD AND HE THINKS ITS A FUEL INJECTOR PLAYING WITH ME. I DONT KNOW WHAT TO DO, I DONT WANT TO JUNK IT

[Al 96 Ram Air T/A]

First off, caps lock off please. All caps is the equivalent of yelling...

Now, stop asking muffler-monkeys to help you figure out what's wrong with your car. The combined knowledge on this board is better than you'll find at almost any shop.

As for the wacko who said he can't scan your codes...stop asking him for help. A key??? Sure buddy, and my desprockinator is leaking headlight fluid on my brake fan.


Now, you need to give us more information. Start with the codes. We need to know what codes are stored in the computer. Without that, we are guessing.

Be that as it may, we've given you a few ideas...namely O2 sensors, Optispark (distributor), or injectors. My choice is still Optispark, but again, we need you to first follow our instructions. We'll do our best to help, but first...please don't ask local-yocals to diagnose a car they truly have no idea about. An LT1 is not a 57 Chevy my friend...


One final thought - You said "they" replaced the cap and rotor, right? You later said could they have messed up the timing when they "put on the new distributor". So which is it> new cap and rotor, or complete Optispark distributor? There's a big difference and it would help us help you.

[Injuneer]

You can scan your 94 with any OBD-I scanner. You can not use the "key" (or a paper clip, which would work just as well), which is little more than a piece of metal, which shorts the ALDL pins and causes the codes to flash on the SES light. 1993 is the last model year you could do that on the LT1 ECM.

Typically, the shops like AutoZone can only scan OBD-II computers (96 and newer).

Auto Xray makes a low $$ OBD-I scanner that you can find used on eBay for less than $100. Also, there are FREE scanning software downloads available. All you need is the correct cable, and you can make your own for less than $100.

Until you scan it, you are just wasting your time.

Yes, a small drip of water/coolant from a leaking radiator hose can cause major problems with the Optisprk distributor - typically misfires and loss of power.

Personally, if my engine was running poorly, I wouldn't make a habit of "stomp(ing) on the gas pedal"..... good chance you may do even more damage.

[mustangridah314]

Sorry about the caps dude, lol I didnt realize I was typing like that until I click submit lol. I know you guys are trying to help me and I'm doing my very best to find info on the car to help you guys help me. So ill be back later with more info.

Vacuum hoses did have a leak in it when we replaced the heads. They fixed that. They replaced the Cap and Rotor, Starter. I got the cat converter, straight pipe. New heads, thermostat,wires and plugs, battery.

Now we already knew that there was a crack in the manifold. But the car ran like it was great no problem until it ran hot and they heads got cracked. Now since all the other things got fixed the car wouldnt stay started so the guys at the shop had to unplug the passenger side manifold 02 sensor for it to stay started. I check the other side and the other 02 sensor is still plugged in. The car is missing real bad but it will drive its just that it feels like a v6 or a 4cylinder until you stomp on the pedal.

[Injuneer]

The problem is not the passenger side O2 sensor. It's the crack in the exhaust manifold. That allows the fast moving exhaust to pull air into the exhaust, the O2 sensor "sees" the extra O2, tells the PCM the passenger bank of the engine is running lean (when it isn't), and the PCM starts pouring excess fuel into the passenger side of engine, making it run excessively rich. Run it too long in an extremely rich condition, and there's a good chance you will wash the lubrication off the cylinder walls, dilute the oil, damage the rings, bearings, etc. "Stomp" on it, and you increase the chances of SERIOUS damage.

Running it with a known cracked exhuast manifold is not a good idea.

[Al 96 Ram Air T/A]

Yup...Fred (Injuneer) said it better than I could...a crack is bad for many reasons. Get it fixed sooner than later.

Also, you've confirmed my other suspicion. The shop did not replace your distributor. On our cars, replacing only the cap and rotor is hit or miss. If the car is running rough because of ignition related issues, and if the Optispark distributor is old or was soaked, you need to replace the unit. Be aware, on your car, the Opti. was not vented. Therefore, they failed sooner than vented units due to corrosion.

If and when you replace it, make sure you ask us what to use. Getting a "no-name" unit is like playing Russian roulette. While you don't need to get one from the dealer, there are safer bets out there that won't break the bank.

[FTA1995]

I lucked out with my opti, got it for 89 bucks on ebay, totally a no name but looks like i got the empty chamber on the revolver lucky me knock wood.