Problem may also happen in the daylight if you turn on the head lights. The increased electrical amp demand is reducing the volts in the electrical system in one or more places.

Your alternator might be partially dead, and instead of putting out 130 amps, may be only putting out 60 amps. It will charge battery and run things during the low load conditions, but when everything gets turned on, it can't keep up with demand. Of course this can also kill the battery. You can have tested for free at auto parts store. Or test yourself with volt meter. Volts at battery should read 13.8 - 14.4 at idle, nothing extra on. Turn on everything stock (not the sixteen Hellas) and volts should stay above 13.2. Also check battery with truck not running, everything off. Let's say you get 12.6 volts. Turn on head lights. If volts drop to 11.5 under this small load, battery is weak. Included is a pix of a WalMart $20 volt tester that plugs in cigar lighter if you want to see volts while driving.

You can also have a variety of issues with either battery cable needing to be cleaned, all the wires at the front of the underhood fuse box need to be clean and tight, and you can follow the (-) cable from the battery and be sure all connections to frame ground are clean and tight.

The tranny will sense volts below 9 volts and go into limp and turn on M&S lights. In this cndition it does not throw a check engine code.

Tachometer gets drive directly from ECU. If you were in a D1, the tach comes from an extra wire on the alternator and is prime evidence of a bad alternator if failing. In the D2, this little blurb from the RAVE -

When the ignition is switched on with the engine not running, the ECM will generates pulses equivalent to 228 rev/min for diagnostic purposes. The tachometer will not register a reading, as it only indicate engine speeds above 228 rev/min.

So tach could indicate that power problems are arriving at the ECU.

Of course, you can also have the wierd problems like a cracked fuse link #1 in the underhood fuse box, all those bolts need to be tight and clean (just like everyone likes it).

 

This morning it will not start. I thinking maybe it's the crank position sensor, and maybe it was just a coincidence it was happening at night? How do I go about troubleshooting the sensor?

 

The litmus test for the crank sensor is that enginne turns over at normnal cranking speed, but no spark. You can pull off a wire and test with a plug, or use a pocket tester (see Lisle LIS19380 Spark Tester Indicator#) that flashes when held next to cable.

The sensor is a magnetic pickup, the nose is closely spaced in the drilled slots you see in the disk in this photo. Not the teeth of the flywheel. Spacing is critical, so be sure spacers go on back on the same way they came off.

Attached pages from a Rover tech manual, not part of the RAVE. The sensor produces an AC signal, about 6 volts peak. Might be able to read with a meter. But flywheel and reluctor disc have to be turning to make pulses.

Think Rock Auto has these in the $35 range.

 

Thank you!!!!. It turns over with plenty of juice, just wont fire. I didn't have time to really troubleshoot this morning, but I'm thinking with the ignition failing randomly, then no start this morning that's what I'm looking at. Thanks again for your help!!

 

Got the new crank sensor in and all is well Thanks for your help S.B.!!!

 

Bet you have the sharpest Disco in LA - "lower Alabama"