I'm new this to board, but have been a reader of it for quite some time. I am the owner of a 1995 Trans Am, that I purchased last summer. Unfortunately, about 3 weeks ago at college my car died on me after I pulled into a parking lot. My Dad is an excellent mechanic and has been one for 40 years. So, I believe we have done all that is done to heal my car but no luck. Thus far we have replaced the Optispark with a new one, new sparkplugs and wires, new ignition module, and a new map sensor. Tonight we tried to crank it up, but it did the exact same thing when we tried to start it before. It will try to turn over, then nothing. It's like it is misfiring, and just won't start up. The computer does not throw a code, so could the computer be a possibilty? We think it could maybe be the timing chain. Does anyone know???!! I really need help, we've got lots of money poured into a car that doesn't work!! Thanks.

 

Is it getting fuel? You need to check the fuel pump, and the fuse.

 

I had close enough the same problem I found out 2day that I blew my timing chain so that why my car wont start. I just change plugs and wires about a month and opti been change so hopefully it help you maybe. My car a 94z28 with 160k so my parts need an upgrade.

 

Do a fuel pressure test to see if it's

A. Getting fuel

and

B. Holding pressure

With no vacuum from the motor, the gauge should read between 40 and 45 PSI. Then shut the ignition off and see how long it takes the pressure to bleed down. If the pressure is low and bleeds off slowly, it's probably the pump, if it bleeds off quickly then it's probably the regulator.

To see if the timing chain is broken, remove the driverside valve cover and use the starter to turn the motor a few times. If the valves move, then the chain is fine. Unless it jumped a tooth.

Ps. The computer can't store/throw any codes until the car has actually started.

 

Could possibly be a busted MAF sensor. I was having similar problems with my car, and I followed the same route as you (changed plugs/wires/optispark/coil, although not the MAP) and still nothing. If you unplug the MAF it should run in speed density mode. By unplugging my MAF and letting it run on speed density (you'll have your fans on full-speed all the time and it will give you an SES light) I was able to start my car up perfectly. When I plugged the MAF back in, it would die and sputter and crank fine but not turn over. I'd say just try unplugging the MAF, it's a 2-second check-safe.

 

You didnt give much info to go on but I would start with the basics. Especially before replacing expensive parts. Do you have spark? Do you have fuel? Are the rockers moving steady while cranking? I am new to the LT1 but I was a GM tech for 8 years. Once you find the area that is trouble then go from there.

 

Check spark on coil and plugs. Check fuel pressure. You can actually spray some starting fluid or carb cleaner in intake and crank it. If it fires for a second after it - probably fuel problem. How is your fuel filter? Your engine will start running with almost all sensors unhooked (badly). Check timing chain as 97WS6SCharged said. Good luck.

 

I don't think it's the MAF because the MAF isn't supposed to kick in until the car is warm. At worst the MAF would cause your car to hesitate but now die out.

When you said it misfired after replacing all the parts do you mean it actually started then began to stumble really badly then died or do you mean it never started?

What if anything was the most recent change to the car before it died?

 

I know on the older 2.8 and 3.1's if it backfired once through the MAF sensor it was shot. I dont know about the new ones

 

Okay, so now we have put a tester on plug wires 1 and 3, and they didn't fire regularly, just occasionally. This we tested just by turning it over. We put the tester on the coil wire and it fires regular. We did a compression test, and it doesn't seem to be out of time compression is 120 pounds. We tested the fuel pump and it has 42 pounds and holds. We think it is in the firing, is it possible the computer is shot, since we have changed the optispark, and ignition module. By the way, we did unplug the MAF and it still didn't crank. Details on my car not covered earlier, a 1995 Trans Am LT1 engine with 107,000 miles. My father has fixed many things such as the intake leak, and was in good running order before this problem. Thanks in advance for all of your help.

 

Remember, those plug wires are only going to fire every 720 degrees of crank rotation. So you have spark and you have fuel but it still won't start.

Question... when you replaced the opti spark, how did you put it on? Did you snap it into place first or use the bolts to pull it onto the motor?

 

open up the Throttle Body, and spray some starter fluid down the intake manifold, it worked for me when my car wouldnt start

 

sounds like you covered all your bases, only thing i can think of is go under the hood, take the cover off for the fuses and relays, it's a square black box with one screw in the center, and check the ignition fuse, mine poped on me one time for no apperent reason and i spent hundreds on coils, opti, module, plugs, wires and all it turned out to be was a 10 cent fuse... and the car fired right up, the good thing was i returned everything i bought and it only cost me 10 cents for a 10 amp fuse...

 

Well my car finally ran tonight, and it turned out just to be the coil!!! I had tested the coil and it tested good, but evidently enough spark was not coming from it or something, but either way once we replaced she ran perfect. Thanks for all the help guys in tryin to pinpoint the problem.