lt1 wont fire!!!

**dirttrax** · 04-09-2009, 10:14 AM

I hope someone here can help me out, i hav a 93 model lt1 that wont fire, i changed the ignition module and coil and still nothing. I made sure they both had power, but there is no spark coming from the plug wires or the coil wire. Is there any good way of checking the opti spark or any thing else to check for problems?

when i bought this car the guy told me it had a weak fuel pump and that there was sensor somewhere on the car that would keep it from firing, is this true? i have looked at the wiring diagrams and dont see anything like this.'

any help would be greatly appreciated, thanks in advance.

**Smittro** · 04-09-2009, 10:34 AM

Originally Posted by dirttrax

I hope someone here can help me out, i hav a 93 nodel lt1 that wont fire, i changed the ignition module and coil and still nothing. I made sure they both had power, but there is no spark coming from the plug wires or the coil wire. Is there any good way of checking the opti spark or any thing else to check for problems?

when i bought this car the guy told me it had a wek fuel pump and that there was sensor somewhere on the car that would keep it fron firing, is this true? i have looked at the wiring diagrams and dont see anything like this.'

any help would be greatly appreciated, thanks in advance.

I'd say pm orion or frost. They maybe able to help you.

good luck

**dirttrax** · 04-09-2009, 11:23 AM

thanks, but im new here so dont know who they are, maybe they will see this and can help.

**Smittro** · 04-09-2009, 11:36 AM

Originally Posted by dirttrax

thanks, but im new here so dont know who they are, maybe they will see this and can help.

Ok, you'll most likely see their names in one of the forums just click on their name and go from there!

You can post a visiter message for then to get back to ya. Hope this helps..

**5.0THIS** · 04-09-2009, 11:15 PM

Originally Posted by Smittro

I'd say pm orion or frost. They maybe able to help you.

good luck

He posted in the LT1 section where he will get help from the LT1 owning members.

To the original poster... Is the car throwing any codes?

As for the fuel issue... you can check the pressure at the rails to see if it is adequate. There are writeups with pics on how to do this, pretty simple.

**dirttrax** · 04-10-2009, 06:22 AM

Yeah it showed a o2 fault and a something bout the vats stuff, i bypassed the vats and assume it right cuz it turns over and the fuel pump runs.

**JaycenK** · 04-16-2009, 09:30 PM

What did you use to bypass the vats?

**dirttrax** · 04-17-2009, 05:12 AM

Originally Posted by JaycenK

What did you use to bypass the vats?

First i used the chip in the key, then I got some resistors from work and soldered them in. It turns over and the fuel pump comes on, just wont fire.

**JaycenK** · 04-17-2009, 05:51 PM

What kind of rail pressure do you have on your fuel sysytem?
Also did you inspect the opti harnesses to make sure there are no damaged wires and I'm not talking plug wires?
Make sure there are no damaged wires leading to the coil or the modual.

**dirttrax** · 04-18-2009, 05:33 PM

Originally Posted by JaycenK

What kind of rail pressure do you have on your fuel sysytem?
Also did you inspect the opti harnesses to make sure there are no damaged wires and I'm not talking plug wires?
Make sure there are no damaged wires leading to the coil or the modual.

39 and bout a half on rail, wiring looks good. i pulled the opti today and took it apart, really didnt look bad, but did have some oil in it, i cleaned it and put it back on and still no fire, im guessing its bad, but dont want to buy one to find out its not.

**dirttrax** · 04-19-2009, 08:36 AM

Ok im really confused now, the opti is a 93 i guess cuz it has the small spline drive, but it has a vented cap? Everything i have read is the 93 was not vented, so my question is did gm or someone make a upgradable vented one or has someone rigged a newer cap on mine? i know the cap has been changed cuz the rotor has wear marks as if it has rubbed the cap. but the cap has no marks. and the rub marks are distinct, no doubting it has rubbed something.

**JaycenK** · 04-19-2009, 09:49 AM

I don't think so. When you buy a new GM opti you have to buy specific for the year because not only did they make it vented but they made different drives for them as well. I don't know for sure but if the rotor button is not linning up with the tabs on the cap it will not start. one way to know for sure is to take the cap you have down to a parts store that has a cap in stock and compair them. Have you made sure you installed the opti unit correctly? I dont know if the drive pin on the motor can be installed worng but if it is the timming will be way off and it will not start.

**dirttrax** · 04-19-2009, 01:40 PM

Originally Posted by JaycenK

I don't think so. When you buy a new GM opti you have to buy specific for the year because not only did they make it vented but they made different drives for them as well. I don't know for sure but if the rotor button is not linning up with the tabs on the cap it will not start. one way to know for sure is to take the cap you have down to a parts store that has a cap in stock and compair them. Have you made sure you installed the opti unit correctly? I dont know if the drive pin on the motor can be installed worng but if it is the timming will be way off and it will not start.

Yeah there is only one way for it to go, so its right but i dont know about the cap, i dont know what was done to the car before i bought it. Acording to some tech articles with pics mine does have the stock opti for that year because of the small spline drive, but that it is supposed to be nonvented, but has a vented on it, now that may work but dont know if its the cap not lining up like u said or if the opti internals are bad. Im so lost but i really appreciate u helping me.

**JaycenK** · 04-20-2009, 01:20 PM

No Problem. Just remember that it is usually something stupid or simple that can make you over think the situation. Try one thing at a time and eventually you'll get it. I would take that cap and rotor down to a store and see if it's right for that opti year. We have taked so much about the opti that I forgot to ask you if you checked the crank trigger. I can't remember if 93's have them or not.

**dirttrax** · 04-20-2009, 03:30 PM

I think the crank trigger on a93 is part of th opti, i know its not sticking out of the timing chain housing like some of the later models. I called the local autozone and they said the same thing i read that there is no seviceable cap and rotor for a 93, but i know it has been changed but i guess that doesnt make it neccissarily right, lol!