ranger with intermitting starts
 

I am working on a 98 ranger with the 4.0L V6 engine with standard trans. my trouble is it will not always start with the key, the motor will turn over, but it is not getting spark. fuel pressure reading test at 63 lbs, which is in specs. I can roll start it and it will start every time, once it is running, it runs fine. I can start it 5-6 times with the key, then there will be that one time it will not start, I know it's ingnition(no spark) because I have check it. I have changed the ignition switch (not the tumbler) and I have changed the clutch safty switch. I just switched some of the relays in the main fuse block, that didn't help. anyone out there ever had this problem? Thanks.

One of the differences between using the starter motor to start the engine and push starting it is, more voltage is available for the ign system when push starting it. A good place to start looking is the battery , cables, cable connections, including the ground cable at the engine. Connection terminals can look fine , but still offer resistance and thereby lowering the power available for the ign system to function properly. Let us know what you find.

Thanks for the reply. that was the first direction I went, I changed both ends of the cables at the battery, there was no corrosion on the cables back under the insulation when I stripped them back. I installed the type of battery clamps that need to be filled with solder. the lady who owns the truck bought a new battery about 6-8 months ago. I put a load tester on the battery and it held good voltage. I put a new starter in for her less than a year ago. I will check both the ground and the positive cable at the ends where they bolt to engine and starter. getting to be one of those mysteries!

I did a check on both the positive and negative cable ends, opposite the battery ends and both were tight. I took them both off anyway and cleaned all contact serfices. I double check the battery with a load tester and battery holds at 11.3 volts, it's fine. when I went to get the truck from the lady's house it would not start with the key, I roll started it and it has been starting with the key since, but could act up at any time. could a crank sencor cause someting like what's going on?

We need to make sure we are on the same page when describing what's happening.
When you say it would not start with the key does that mean it does not crank over or it cranks over but will not start running? If it cranks over but refuses to start running depending on what the check engine light does can help possibly pin down the problem. If the engine cranks over and the check engine light goes out it means the crank sensor is sending a signal as required. If when cranking the light stays on then the crank signal is not getting to the computer which could mean a sensor , wiring or PCM.

as I stated in my first post, it will turn over with the key, but will not start. it will fire up and run when roll started. I pulled the right kick pannel off and checked the plug at the PCM, seemed loose. I unplugged it and checked all pins and sockets for corrosion, they were ok. I plugged the harnes back into the PCM and put a wire tie around the plug to help hold it tight to the PCM. these rangers do not have a bolt or a screw through the center of the harnes plug to do that. she says it's been starting since. Good to know about how the check engine light will act when cranking the engine, Thanks. will put that info in the memory banks. Thanks for the help, and we'll see what happens