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[petehoyt]

My daughters 93 4-banger started a weird pattern of starting some days, then not starting the next. When not starting it turns over strong, but there's not even a hint of firing. Next day, it fires up perfect. While running, it always runs perfect. It doesn't hesitate or stall. Checked the timing belt.. it's okay (learned that on my other daughter's 1988 Ranger). I didn't check for spark yet, I know that's the first thing I should do.

I've got the Haynes manual and I can see there are about 4000 things that can cause a "no start", but I have to ask a few questions:
1. What do they mean by you can "backprobe" either terminal on the SPOUT connector?
2. From the wiring diagram, it doesn't make sense why no PIP signal means you should replace the crankshaft positioning sensor? Does it make sense to you?
3. Are there two separate but identical connectors that plug into the ICM (C155 and C156)? If so, are the wire colors the only way to tell which is which?
Here's the only clue I have: Last week, a wire on the starter was loose. The starter wouldn't turn over. I crawled under the truck and when she tried to crank, a spark popped from the solenoid connector. Tightening the nut on the bolt fixed the problem.
Is it likely the sparks at the starter fried something? What is the most likely component to fry, that would give intermittent starting? I'm guessing the ECM, or maybe the Crank sensor. What is the cheapest to replace?

 

[Harris]

A new crankshaft position sensor will run about $85.00 while the ECM is a little higher at about $120.00.
http://www.partsamerica.com/ProductDetail.aspx?MfrCode=NIE&MfrPartNumber=FF440P&PartType=762&PTSet=A

http://www.partsamerica.com/Product...IE&MfrPartNumber=ECC2888&PartType=248&PTSet=A

Even though the crankshaft position sensor isn't too terrible to replace, you don't want to do it if you don't have to. It is just a couple of magnets and not a whole lot on it to mess up. The part is expensive, relatively, and it is a little annoying to get to. Using a scantool will reveal if the problem is with the ECM, though.

Some of the guys on this site may know more, but I am pretty sure a spark at the starter would not damage the CPS.

Most likely you have a loose ground somewhere, since electrical parts tend to work correctly or not work at all. The best thing would be, after checking the vehicle for loose connections, catching it when it won't start and checking for spark. At least no spark/no start would rule out a bad ground or connection in regards to the fuel pump.

Just make sure that little grey ICM has all of the little grey bolts tight; it took me a long time to realize that problem once...

 

[petehoyt]

A new crankshaft position sensor will run about $85.00 while the ECM is a little higher at about $120.00.
http://www.partsamerica.com/ProductDetail.aspx?MfrCode=NIE&MfrPartNumber=FF440P&PartType=762&PTSet=A

http://www.partsamerica.com/Product...IE&MfrPartNumber=ECC2888&PartType=248&PTSet=A

Just make sure that little grey ICM has all of the little grey bolts tight; it took me a long time to realize that problem once...

Thanks, I will definitely check that, since the starter problem was a loose nut. I still wish the manuals were clearer.