Ok so the other day i went out to start up my 98 Z28 with its new 408 for its weekly start up. The car is on open heads cause im waiting my umi torque arm and body relocation mount before i put my true duals on. So i start it up and its running fine and is warmed up so i give it a little gas and hold it at about 2000 rpms. Shortly after it reached 2000 rpms it just shut off, no sputtering or trying to stay on it just shut off. So i tried to restart it and it just cranks away. So i checked for fuel pressure in my rails and there was quite a bit of pressure in it but i didnt put a gauge on it so i cant say what the exact pressure was. Next i swapped the ignition fuse with the fan 2 fuse and it just kept cranking. So i kept cranking on it and it tried to start several times but it would only fire a few times and then it went back to just cranking. I doubt its a bad crank senor because i put a brand new on on the engine when i built it. It has 3/4 of a tank of fresh gas and the fuel pump primes. I did notice when i started it last week early in the morning that my alternator had some white smoke coming from it so i shut it off. Then when i restarted it this last time there was no smoke and it died like i said earlier. So if my alternator went bad would it prevent the car from starting. I also noticed when i crank on it for a few seconds that my oil pressure comes up to its normal pressure. All the lights work and the radio works. Also when cranking on it my voltage sensor goes down. Like i said its tried to start but its like it runs out of spark. Any input would be awsome.

PS: I already posted in the mantainance and repare section but got no replies so i thought i would try here.

 

Wish I could help, it's a bitch when this sort of thing happens & you can't figure out what's going on.
Bump anyway, someone may know.

 

I know now im not the best trouble shooter with the LS engine platforn but ive tried damn near everything i can think of without throwing money at it. I just hate these random issues that come out of nowhere.

 

Well, if you know you had smoke coming from the alternator, you need to take it to Autozone and let them check it to see if it still charges. Even if that's not the starting problem, it still needs to be checked out. You should never have a smoke leak there.

 

I was planning on getting it checked out when i put in my new solid motor mounts because i was a dumb *** and didnt do them when i put my headers on and after all the fun of putting the headers in they are gonna stay there lol. I asked around here a while back about a smoking alternator and everyone said it was probably some escaped power steering fluid that dripped on to it and finally got inside and burned. My idea is if my alternator is dead that the battery doesnt have enough power to power the injectors, coil packs, and keep the starter powered. Its tried to kick on a few times but like ive said its like the engine runs out of spark. Ill do a spark check today to try and confirm this.

 

If your battery has enough energy to crank the engine at a somewhat "normal" speed, it has enough to operate the PCM/ignition/fuel system.

The engine will run without a functioning alternator-drawing power from the battery until it's dead.

Toss a charger on the battery. Check for codes. Check for spark. Check the fuel pressure with a gauge. Fresh fuel filter? Check for vacuum leaks-like the brake booster hose. Check all other sensors & their plugs: MAF, TPS, MAP, crank & cam sensors. ALL fuses good? Good grounds & battery/positive connections?

 

I have had the battery on a charger all night. Im going to see if it will start with a fresh battery. The battery was pretty low when the car shut off while running so we will see what happens with a charged battery. Ill recheck my vacuum lines again, and does anyone know if autozone rents fuel pressure gauges. Ive scanned for codes several times prior to pulling the battery and only came up with a A/C clutch High Voltage Code# 1539. And what is a A/C clutch? Also whats the best way to check for spark that doesn't require a nice shock?

 

Get a spare or old spark plug-it'll be your test plug. Pull the spark plug wire off the spark plug in the engine and onto the test plug. Lay the test plug on some metal part, crank the engine and check it for spark.

 

Thats so simple and smart i cant believe i didnt think of that sooner. Now is it possible to hear ur coils fire if the engine isnt running and its jut cranking. Cause today i went out to recheck my vacuum lines and see if the freshly charged battery would do anything and when i had my buddy crank it over a few times i heard a faint rhythmic clicking.