chunkychicken

I was helping out a friend with his 93 Sport and we cant seem to get fire to the spark plugs changed the cam sensor and the coil any other suggestions. The guy befor him made a mess of the wiring tring to find the problem but couldnt find it.. Thanks for the help

Jamie22

Check pcm fuse. Just went threw this on my buddies heep. Check the crank sensor ?

chunkychicken

no fuse pannle do you know were that is?

BlueXJ

By the drivers left foot under the dash.
Did you change the cam or crank position sensor??
ECU fuse is a rarely blown item but bears checking as stated above.

chunkychicken

crank sensor sorry it was kinda early when i started this thread.. any other suggestions checked the fuse and it was ok.

gabe

Are you getting fuel,if not it could be the computer on the driver's side fender right next to the air box.Mine went bad and I did not have spark or fuel,so check to se if you can here the pump.I got one at a junk yard for 30.00 buck's.If it is cold where you are,a way you can sometime's check them is by taking it off and bring it inside warm it up ,and through it back in,and if it fire there you go.That's how I was told to check mine and believe it or not it worked.My old one still work's in warm whethe,not that I need it,but the cold effects them I guess.Just some thing's I had to do,good luck.

farmfuel

Also check this relay called the "auto shutdown relay" located in the relay/fuse box located under the hood close to the passenger's side relay.

If I'm not mistaken, this is what supplies power to the ECM from the key.

chunkychicken

The computer is brand new on this one the guy my friend bought it off of tried to put a new computer on it.. but i am gonna go and check all he wiring to the computer..

chunkychicken

what would cause the 30 amp engine control fuse to blow?

chunkychicken

ok guys i gots another one for ya everytime i turn the ignition switch to start the jeep it blows the 30 amp engine control fuse.. so i am thinking that there is a ground somewere between the fuse box and the switch.. what do you guys think.

farmfuel

Very few vehicles use 30 amp mini fuses. Is the fuse you're refering to inside, or outside? Usally computer fuses are very low amp- like 7.5 or 5 amp, etc.

If you're blowing 30 amp fuses, you've got a short to ground problem. Maybe check your ignition switch. 93 or 94 and older used GM columns- the switch is lower on the column shaft.

That sucks. It sounds like you're chasing a gremlin. Did you check power to the auto shutdown relay?

chunkychicken

where could that ground be i have no clue were to start.. we checked everthing to do with the fuel pump last night so were kinda at a stand still now.

farmfuel

Try to find the wiring schematic for wires going into and coming out of the ignition switch. Your problem could be the switch itself. Like I said, the switch is located on the column shaft down low. It's rectaugular, and will have a lot of wires running to it.

Find the schematic, and figure out where each power wire runs to. Follow those wires and think about the shorting issue when you follow these wires. It's doubtful that the wiring loom is damaged- rats could damage the loom, but unlikely. Your problem is more likely to be found in a hard part; ie switch, relay, solenoid, etc. Any component that has both power and ground running inside of it.

RHD98XJ

I'm going through the same thing on my Cherokee. I'm blowing one or both ASD fuses as soon as the key turns to "on". Have any luck fixing yours? Penny for your troubles. I'm going to look into the fuel pump grounding out, O2 sensors, CPS, and wiring in general. Hopefully get it going soon! Half the battle has been finding out exactly what these fuses are, the plastic cover, the owner's manual, and repair books weren't a help.

Carl48

The 30A fuse you are refering to provides power to the PCM (computer), transmission control module, heated oxygen sensor, and fuel pump.