I have a 1995 Ranger with a 3.0 L that will crank but has no spark. Was running find. The other day went to start it would not run no spark at plugs.Have pos. power to the coil pack with key on but not getting the neg. pulse to coil pack when cranking motor. Had a friend try to scan the codes but his scanner kept displaying to turn on ignition even with the key on. He was using the OBD-2 under the wheel XLT 87 mentioned that he believes that plug is non functional and the codes need to be pulled from under the hood is that correct. I have replaced the crank sensor already do I did not want to clear codes before I pulled them. Have 1.5 volts at crank sensor with key on. The fuel pump runs when the key is turn on. Can it be the ignition switch or would a bad cam sersor prevent spark and how can I test it? Thanks for any help.
Yes I did backprobe the crank sensor one manual said take check it on a ac scale. First I use a digital meter then tried analog. No pulse but it would come up to 1.5 volts slowly cranking the motor, so I replaced it. Have not backprobe the new sensor. Going to try that maybe I had a bad one out of the box. Based on having power to sensor I think I should see a pulse there even if the pcm is bad.
Back probed the new sensor still no pulse. When I check for volts I check each wire to ground and get 1.5 volts using dc seting on the meter. In my Explorer manual it said when backprobing the crank sensor use ac seting on the meter. But does not say how to connect should I connect wire to wire or a wire to ground. I used a loner scanner form Autozone tried to pull codes again. The scanner showed a connecting falt it could not connect to computer. I begining to think that my 1995 may not be truly OBD-II or my computer is bad. You would think that with volts at the sensor and the engine cranking I would get a pulse even if the computer was bad. As long as the sensor was good.
I used a loner scanner form Autozone tried to pull codes again. The scanner showed a connecting falt it could not connect to computer. I begining to think that my 1995 may not be truly OBD-II or my computer is bad. You would think that with volts at the sensor and the engine cranking I would get a pulse even if the computer was bad. As long as the sensor was good.
Your '95 is a transition year vehicle. It's OBD-II, but only a few types of code pullers will work on it. Try a search in the Ranger Forum on the subject and you will come across some posts on it.
Iíve noticed that my fuel pump sounds like it running when turn the key on. It does not stop after a few seconds I think the regulator is dumping fuel back to the tank. If the fuel pressure regulator was bad would this cause a no pulse condition from the pcm? Does the pcm check for fuel pressure? Is there a sending unit going to the pcm? What tells the pump to shut off?
The PCM does not receive any signal that tells it what the fuel pressure is.
There is a timer internal to the PCM that turns the fuel pump off, if there isn't a signal from the crankshaft position sensor. The problem could be that the contacts are stuck together in the fuel pump relay, letting the fuel pump run all the time...
My problem was that the PCM went bad. Before I replaced it I checked all of thewires going to the PCM. To make sure it was not a wiring harness issue. I don'thave the truck any more so I don't have the wiring schematic.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>