cranks but no start

cwshupe · Apr 6, 2014

Well, 3 weeks ago, my ranger would not start at work. my friend and I did quick diagnose. fuel pump was not pumping and had spark at coil pack. the following weekend I troubleshoot and jumped the relay for the fuel pump and it works, the battery failed and replaced it. still it will not run, towed it home and diagnose some more this weekend. I have spark going to the plugs and rented nodes to check for pulse going to the injector, no pulse. scanned the pcm, codes as follow:
m/c 171,172,175,176,181,189 and 212
212 idm to pcm spout signal loss ckt grounded.
at this moment I think the crankshaft sensor is bad. but, my haynes manual does not really give you enough troubleshooting on this, can someone give me a little insight and information on proper steps in diagnosing this problem.

carey

RonD · Apr 6, 2014

'94 ranger......what engine?

'94 should be using an ICM(2.3l) or EDIS module for spark, either is self contained for base spark timing via the CKP(crank position) sensor, so no CKP pulse equals no spark.
Either module sends the base timing of spark to the computer(PCM), the computer then sets(tells ICM/EDIS) spark timing changes based on it's other sensors.

The fuel injectors on the '94 will most likely be Batch Fire, this means more than one injector will open at a time, Sequential fuel injection required CPS(cam position sensor) to open injectors in time with intake valves.

When key is turned on the EEC relay closes, this sends 12volts to computer, fuel pump relay, ignition module, sensors and 12volts to each fuel injector.
Computer Grounds an injector to open it.
So test injectors for 12volts with key on, if not 12volts(full battery voltage) then find the splice that comes from the EEC relay probably corroded.
Ford fuel injectors are only 14ohms so either wire on an injector will show 12volts with key on, one might be slightly lower but still 12volts, this is normal.

If you have 12volts at injectors then check Grounds around Computer, the computer has several ground points that are not shared internally, a loose or bad computer ground may only effect 1 or 2 systems.
Also unplug the Computer connector(battery disconnected) and have a look at it, these can get moisture inside causing random or bad connection issues.

--weezl-- · Apr 6, 2014

Didn't you say that the fuel pump wasn't turning on? Why did you jump from no fuel pump to the cps? It seems to me that if there is spark, you have a fuel delivery issue...

Follow Ron's advice first, he knows what he's talking about with our trucks, and replied first.

cwshupe · Apr 7, 2014

April 7, my engine is a 4.0 liter engine. haven't check the voltage at injector harness, but will soon have to go to work.
April 8, I check for the CMP sensor the location that my book tell where it suppose to be, it is not. It is the oil pump drive, no sensor or harness going to it. I did come across from another ford website, that certain model with the letter 'X' in the VIN did not come with CMP sensor. going to setup voltmeter and injector harness so I can see if I have voltage. any information is better than none.
carey

cranks but no start

cwshupe

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--weezl--

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