'94 B2300 No Spark Problem

[kdowney50]

I have several problems with my old, up to now reliable B-2300. Last week the engine overheated when the water neck failed. The engine knocked and rattled until I could get it to a safe place. It would not restart after it cooled down. I pulled the head, (expecting a blown head gasket) and found the head was cracked between the Intake & exhaust valve seats on #1 Cylinder.

No problem. I replaced the head. While I was at it, I replaced two of the four injectors, (#1 & #4) the timing belt, the spark plugs (8), the spark plug wires, and the serpentine belt.

After all parts were in and double checked the engine would not start.

Troubleshooting revealed:

Good fuel pressure.
Timing marks line up at TC.
Battery is fully charged.
NO SPARK at ANY Sparkplug.

I ohmed out the spark plug wires. They are good. I have battery power to the center pin on both distributor packs. (This engine has a distributorless ignition system) The resistance from center to outside pin is 0.7 ohms. The secondary (output) side of the packs ohms out at 13k. I changed out the ICM. (that's the module bolted to a flange on the lower front part of the intake manifold. It is labeled Motorcraft DIS)

I'm running out of ideas. Any help would be deeply appreciated.

 

[wizkid00104]

Sounds like it is the coil packs. I don't know what their resistance should be but if you have checked everything else. By process of elimination, I'd say it was the coil packs.

Another guess would be the alternator. I am not sure how the engine is wired, but suppose that the coil packs draw their power directly from the alternator in stead of the battery. If the alternator went bad, then you would get no spark. That may be way out in right field, but it could be a possibility.

 

[Ranger-92XLT]

Saw this question yesterday and I was thinking the coil as well, but wasn't sure...You can get a new one for not too much $$ - might be worth the try seeing as how you're kinda stumped...

 

[Earl43P]

Could be the Crank sensor.

I have a slew of 93 schematics and "info" that I will be happy to e-mail you. They should be the same as a 94's. Simply PM me your e-mail address and I will send you the whole lot of them.

 

[kdowney50]

Thanks everyone for your replies. Turns out I sheared the magnet off the Crankshaft Position Sensor during reassembly!

Here's what happened: I removed the crank damper and Crankshaft Position Sensor Bracket to replace the Timing Belt. What I failed to notice during disassembly was the washers behind the CPS Bracket that held it in proper alignment with the Crank Damper. When I reinstalled the bracket, I failed to put the washers back in. Thus, the CPS was out of position when I manually turned the crank to time the engine. So, I sheared off the magnet.

For those of you unfamiliar with how the the Crank Position Sensor works, here is a brief explanation: The CPS is a Hall Effect Switch (an electronic device that senses the presence or absence of a magnet) It is closely aligned with the crank damper which has two concentric rings on the inside. (It looks sort of like a double walled cup) These rings have "windows" cut out of them. As the crank spins, the "windows" on the crank damper alternately block then open the space between the CPS sensor and magnet. This "Hi-Low" signal tells the Powertrain Control Module what position the crank is in so it can accurately control ignition timing, fuel delivery etc.

I bought a new CPS ($118.00) and damn near sheared it off before I realized my mistake. So I found some washers and made sure the CPS was properly aligned before moving anything. There ain't much room for error with that setup.

An education is expensive. Especially when you attend the school of "Trial and Error".

I have the CPS installed but ran out of daylight before I could get the beast finished. Stay tuned for further developments.

Last update: I got her running tonight! (6/17) It has an annoying tick under the valve cover but I can't hear it with the radio turned up. hahaha.

CYA!!