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wont start after arc welding?

hell

NAXJA Forum User
Location
tucson az
the other day i used an arc welder on my 89 and forgot to disconnect my battery now i cant get it to start. it cranks over its got fuel pressure everything else seems ok untill i get to the plug wires for my distributer. its getting charge (11/12) volts from the coil but after that i have no volts no, spark in the plugs. i replaced the distributer and its still not working. what could it be did i fry a computer or something. i went thru alot of wiring under the hood and it doesnt look like i have any shorts.:dunno:
 
check the CPS with a multimeter, the process has been posted here many times. usually a no spark condition is caused by a faulty crank position sensor (CPS).
 
Just two cents.., but I have read in my old full size FSM that before welding, to disconnect the wires on the alternator, not the battery. However, many I know do neither, sort of a crap shoot I guess as to what damage in the circuits can take place. In your case, I am in the dark as to what component is damaged.
 
even if the alternator was effected that's the charging circuit, it wouldn't keep the jeep from starting ;) check your crank sensor. it's on the bellhousing on the drivers side, about the 11 o'clock position. your 89 will have 2 connectors going to the CPS I believe, and they connect to the harness up by the throttle body.
 
i've been welding my rock sliders for the last two nites. never touched the battery or alternator. jeep started right up /shrug

You got lucky,I welded my front frame stiffeners and forgot to disconnect the battery, fried a 2 month old optima. Thank goodness for warranty at autozone.
 
door hinges.
its kinda fast but then it slows down after it cranks for a little. and sometimes it cuts out mid stroke and then kicks back in while trying to start.
 
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I hate to say it but my bet is on a fried ECU.
 
ive been doing this for a longtime and never hurt anything maybe ive been lucky but if your cautious about where you put the ground lead you should be fine
 
Many years ago I was doing some welding on a heavy equipment for about the 2,000 time in about 2 years. This time the battery blow a 4" X 6" piece out of the top with some of the lead plates still attached. Luckily, it had the British Lucas electrical system consisting of a generator and a remote mounted regulator. A new battery and every thing was perfect again. I would not try that on one of these modern electronic vehicles. I always disconnect the battery and the ECU. Many welders get lucky and have no problem welding without disconnecting the electrical and many others end up with blown electronics. It have been rumoured that by putting the groung clamp as close to the work (area to be welded) as possible you could reduce the negative impacts.

It will be rather difficult to say exactly what part or parts is damaged without testing each part. The above posts give some hints as to where to start.
 
He said 12 volts from the coil not too the coil, unless he meant"too the coil".
So from the coil to the dizzy is where power is lost?
Or do you have voltage to the dizzy.did you replace the cap and rotor with the exchanged dizzy?
 
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