So last night i was welding in new floor pans and this morning i went to start the car and it wont start. i realized i didnt disconnect the battery when i was welding. is this my problem. what can i do? i need this puppy to start

 

I never disconnect the battery when i weld on a car, and neither do millions of exhaust shops.

have you checked the fuses?

 

ill check them out right now

 

i checked i few fuses they all seemed fine. which ones should i check not too sure. also pulled a spark plug and it was dry so i might be getting spark but no fuel. there is gas in it and it was running just a couple days ago. the only things i have done are weld in a small patch for the floor and also piece in a 10" section of brake line.

 

Not sure where you were welding but if it was on the front drivers side by the front of the seat did you remove wires grounded to the floor because that is where the ground for the fuel pump and gas gauge attach.

 

they dont disconnect the battery ground at the shop?!!! they should be, you can end up magnatizing the crank. then any particles in the oil or elsewhere will stick to to journals and eat up the bearings and journals

 

What kind of welder? If you're using an arc welder, you can screw up electronics if the ground strap is still hooked up to the car body. If you're using oxy/acetalyn you're probably alright. I'd look under the car and ensure you didn't cut wires.

 

um... where did you hear that?



When welding current flows between the ground clamp and the electrode, it doesn't magically go into your crank and magnetize it. If anything the battery will absorb any random noise on the system.


In the time it took you to read this topic at least 10,000 cars just got welded on with the battery connected. Probably more.. lol

 

its a self shielding welder so no gas was used. was welding in some new floor pan pieces. still cant get it to start. its turning over but wont start

 

can you hear the fuel pump running?


Grab a can of starting fluid and spray some down in the throttle body, if it fires up and then dies then you might have an issue with the fuel pump circuit. Make sure the ground is good like Pontiac400 said.

 

i can hear the fuel pump yes. and no i did not disconnect the grounds and i was welding in the drivers side mid area. i dont think im getting any spark or fuel. i dont see tbi injectors spraying nor did i get spark when i put a spark plug wire near a piece of metal

 

ok so a buddy just told me the computer could be fried but he said do a test to figure that out. so i have a dc voltage tester and i put one end to a ground and the other to one of the four wires leading into the tbi injectors and turned the key to give the car power and there was a signal going through.. so if he was correct this means my computer is not fried... is this true and what else could be the issue. i really need to get this thing started

 

ya ive welded on my car without disconecting the battery. since i was pretty young at the time and was just learning, i connected the ground to a bracket and the current traveled throught the crank, ( magnatizing it) so i guess it didnt just "magicly"go through the crank. when it started to knock i took it apart and had steel dust and particles all over under the caps. everything was chewed up. a small bolt would attract right to it. so maybe before you judge you should consider the possibility. if you ask any instructor they will tell you to disconnect the battery. if you dont, it doesnt mean that something will go wrong, cause usually if you attach the ground as close to the workpeice as you can, the current will go that way and you wont have a problem. but you can fry electronics. maybe it doesnt happen too often, but it does happen

as far as "noise " goes.......what? where did that come from? what noise?

 

if the ecm is good, check the inline fuse on pss. side fender by charcoal canister

 

could be ign module?

 

how can i test if ecm is good?

 

thats mounted near the battery on the passenger side fender right... if so yeah i checked that and it was good

 

i dont know you may have fried the ign module or messed up a relay or somethin sorry if im not much help

 

no any help is better than no help. can i check to see if ignition module is ok

 

even with the battery disconnected, most the time unless disconnected, exhaust grounds to the motor through the headers/manifolds. so if you're welding on the exhaust, you're "magnetizing" the crank, battery or not. i'd say blame your oil pump or oil level if you have metal in your pan and burned bearings or you've been revving it too high, too long.

original poster, you mentioned spark fuel and other than that, air are your 3 priorities. you have fuel, you have air, check spark. take a spark plug wire off and put a screwdriver in the boot and get it close to ground metal like the exhaust or head. when you crank it, assuming the motor does turn, check to see there's a spark off your screwdriver. no spark? go upstream to the distributor and check that your coil provides spark to the distributor through the same process. take the spark plug wire from the coil to the center of the cap and test for spark. if no spark replace the coil after checking the connections. if you have spark then check connections at the distributor for voltage and you might have to replace the module inside.

 

ok well im not getting any fuel or spark. when i took the wire off and did the test there was no spark. i just changed cap rotor and plugs 50 miles ago.

 

did you check the coil. and how do you know you have no fuel, didn't you say your fuel pump turned on

 

well no fuel is coming from injectors when trying to start. how do i check the coil?

 

coil is same as spark plug test. take the wire from it that goes to the distributor and screwdriver in the boot to ground, should spark when trying to start. have you done as previously mentioned and sprayed starter fluid in the throttle body. that's something to try after you fix your no spark.

 

ok so i just went out and bought a multimeter. to be honest i have no idea how to use this thing im completely a noob when it comes to electrical which is probably the reson i cant figure this darn thing out. i wanna check anything and everything with this multimeter so i can narrow down my problem. first of all how do i use it and what should i check.?

 

well to find voltage you can set it to 20v which is the lowest setting above the maximum voltage of anything on your car (12volt) connect the black wire to the ground and red to the V+. to get familiar with how it works take the black wire and put it on your car battery's negative post, take the red wire and touch the battery's positive post. you should have 11/12 volts or something. so to use it on circuits you can just leave the black one on anything grounded like bare metal, the motor, screws without paint on them, the alternator, and then take the red one and probe wires you think will carry voltage. its not smart to just probe things, you should get a wiring diagram or manual so you actually know what wire you're poking, its purpose, expected voltage, and under what type of key (off, acc, run, start).

i would check the wire that comes off the alternator at the back and find its voltage, follow that wire until you find a fuse in a weather resistant deal, and see if that fuse is blown.