this is getting ridiculous!!!

About a month ago, i put a fuel pump in my 91 HO. Right after that, the crank sensoe took a s**t. Now, i went to rebuild my steering box and it started fine. I drive it 300 ft, and when i try to start it, it wont start. yes, it does crank. When i put the spark tester on the coil wire, it sparks irradicly.
I dont trust my dad enough to diag. it, so im asking you guys.

I'd start with the normal tune up stuff, it often acts up more at the season change (humidity and rain). Distributor caps are notorious for picking up moisture and carbon tracking, green and white corrosion starts growing in there, the gap between the high voltage lugs and rotor in the distributor grows with age. Plug cables can also be a sore spot.
I live in a wet climate, the plug cable connectors corrode pretty quick, especially on the distributor cap. The high voltage side of the ignition system is one place WD-40 seems to work OK and it does displace moisture, but don't use it on normal connector especially sensor connectors (it has a wax in it, probably paraffin).
Any connector that cuts down the available voltage to the coil also affects spark. I just went through that, my coil connections were corroded. Don't really know if it was the ground half or the power half of the coil supply that was acting up, I cleaned it all and it really perked my spark up.
Erratic spark is often a high voltage short to ground, either in the cap (cross fire) or the cables. A weak spark is often coil supply voltage or to much resistance in the coil to cap wire.
I'd also have a look at the CPS connector, I clean mine at least twice a year, takes minutes and is cheap insurance. Check your battery voltage (dead cell/low voltage/poor connections/grounds), most things real run just fine with 9 volts or so (though it does kind of turn over slow), but the ignition system doesn't do well, especially at start up, when the starter steals much of the available power.

When working on the steering box you didn't happen to come in contact with CPS harness, I'd check that connection.

OK put a coil in it, and didnt fix it, BUT, when i hook my dads scanner up to it, the RPMs jump all over the place. even down to -3000. oh, and i put an ignition stater in it too. ( the thing under the cap that is a little disc)

anybody?

XJAnthony said:

OK put a coil in it, and didnt fix it, BUT, when i hook my dads scanner up to it, the RPMs jump all over the place. even down to -3000. oh, and i put an ignition stater in it too. ( the thing under the cap that is a little disc)

Click to expand...

Did you replace just the coil, or the coil and ignition module?

sorry, but whats the module?

XJAnthony said:

sorry, but whats the module?

Click to expand...

The part the coils bolted to, where the wires plug in.

on the opposite side of the coil? (not the distibutor side)

There is no ignition module on your 91. That was only for renix.


K

I'd check out the basics, before I'd change anything. Then move on to components and stuff.
If you have a timing light, you can hook it up to each individual spark plug cable and just shine it at something dark and see a miss. If you have a miss on one cable and not on another it's probably a cable. Cables will occasionally through the spark to another cable, they are touching and fire a plug (partially) in another cylinder, at the wrong time. It's called cross fire. It also happens inside the distributor cap, from moisture, corrosion and carbon dust from the center contact in the cap.
If it's missing at all the plugs, look at the coil wire. Check the Resistance. If it's still misfiring on all cylinders, check for weak spark. If you jump a spark to ground at a plug cable end, it should be blue/whiite and sharp. If it's mostly yellow, you can often see it splash on the ground you are using. Low voltage to the coil, will also cause a weak spark. A marginal battery (or charging system), will also cause a weak spark. I've had weak spark, because of moisture in connectors, I'd guess it was causing a current leak, near where I really needed as much voltage as possible.
If everything is crisp and sharp and you still have a miss, it may be a weak CPS signal, caused by a flaky connector or even a fatigued wire under the insulation.