lighttoast

I've done some searching on here and found a few threads addressing similar issues, but they weren't quite the same. Sorry if this is a repeat.

For some time I've been having to hold the key in the start position for a few seconds while the engine catches and starts up. Never really thought it was a huge issue. Just figured it was the starter going and I would replace it eventually. The other day I went to head out and all I got was turning, but no catch. I took the starter off and it failed the test at the store (as I figured it would) so I put in a new one. But I'm still getting the same problem. I replaced the spark plugs because they looked a little on the rough side and still just turning over and over. I sprayed a little ether in the TB and when I turned the key I got a hint of a start but nothing sustained.

I fear that my fuel pump is gone, but I don't know how to test it. If I can't hold the engine on I can't check the pressure at the rail. I can hear it turning on when I put the key in the 'ON' position. aside from that what can I do? It's a DD so I need to fix this soon. Luckily I do have a friend's car for a couple weeks.

Anything is useful. Thanks.

Oh. in case my sig doesnt say. 1997 XJ 4.0L Auto

tjwalker

Doesn't need to be running to check fuel pressure. If the fuel pump is doing it's thing, you should have approximately 49 psi at the fuel rail before cranking the engine. You can rent a fuel pressure gauge at many parts stores (call around) for a few bucks.

And finish the tuneup you started with the new plugs. Install new plug wires, distributor cap and rotor. The importance of tuneup hardware CANNOT be overstated.

Start there. If it still doesn't run, pull a spark plug, keep it attached to the plug wire, place the plug electrode near a good engine ground, have a buddy crank the engine while you watch, you are looking for a strong, blue, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine. Quality spark is VERY important.

Report back what you find!

ogmeme

Check your crankshaft position sensor, seems to be common problem with jeeps. They go out all of a sudden and then car only cranks and won't start.

lighttoast

Are you sure I can test the pressure with the engine off? I thought that the pump stopped running after 2 seconds unless the engine is cranked on. That way it doesn't flood. And if I can, everything I've read says the 49 psi is at idle. Will the pressure still be the 49 psi that I'm supposed to have with the engine running?

As for the spark system, the plugs are all new, the wires are new from the last time i changed the plugs. The distributor cap and rotor haven't been replaced since I've owned the jeep (5 years) but they appear to be in good condition and I've never had a problem with miss firing.

I'll try and test the pressure just to see, but I've been reading up on the CPS and it may be a much easier and cheaper way to fix the problem. And as it is probably the original sensor, it may be best to change it out anyway

SNIDELYWHIPLASH

Yes, he's sure. You want to just turn the key on to prime the fuel system, then turn the key off. The pressure will (or should) remain at 49 psi.

It's still a good idea to replace them, as a part of a routine tune-up.

You should definitely rule out fuel system issues first. If it's fuel related, replacing the CPS won't fix your problem. It may indeed be your CPS, but it's best to determine that through the process of elimination.

Take tjwalker's advice, and report back what you find.

lighttoast

For future reference, the fuel pressure test kit at Auto Zone can be rented for $150. Now, that's a bit more than "a few bucks" in my mind, but at least I get it all back.

As for the actual test, I'm at 48 pounds on the rail. which is a huge relief because that means that the fuel system is working properly. I'm going to check the distributor and probably replace it per all your advice, but I really don't think that's an issue as I was able to burn up the ether and get it rumbling for a few seconds when I sprayed it in.

Is my next step the CPS? Or is there another check I should do first?

94JeepCherokeeMan

Check all grounds and electrical connections. Check ignition coil, too.

lighttoast

No electrical shorts anywhere. Everything else is looking good

lighttoast

I've attached a picture of the CPS connector. The letters are my assumed connector label because they were not labeled on the connector like the haynes manual said they would be. the clasp is on the top in the image. If I have the labels backwards please let me know.

I measured the resistance across the B and C terminals and it settled at 0.8 ohm. there was no resistance across A and B even at the lowest setting on the meter.

What should I be reading? is this proper? If not, please let me know what I'm doing wrong

ogmeme

Don't remember exactly what u should be reading, but get yourself a new one and compare the resistance to that one. If it's the same, i'm sure you can return it since it was never installed. However if it is the original one, I have read that they go out at around 140,000 miles without warning so if your car has around that many miles, thats probably your problem. That was mine.

lighttoast

I've got the engine starting. It runs fine and I'm happy to be driving it again. But I'm still having trouble starting. The first time I cranked it up after the repairs she started up like a dream. Ever since it's been taking 4 or 5 seconds of cranking before it catches. This is exactly what it was doing before it quit on me, which makes me feel like I haven't fixed anything.

Here's everything I've done in the past couple days:

New spark plugs (gapped correctly), spark plug wires, distributor cap, rotor, CPS, starter, oil, oil filter, O2 sensors. I also checked the fuel pressure at the rail and it is 48 psi, well within range. I put some seafoam in the tank and its working its way through.

I'm completely stuck now. How can I move forward and fix this cranking issue?

94JeepCherokeeMan

Did you check your grounds and other electrical connections? Coil?

lighttoast

My electrical connections are all good. I'll check the coil when I get out of work and report back

94JeepCherokeeMan

I'm not trying to be an ***, but sometimes you have to disconnect the grounds and clean them and the mating surface really good. Fords are really finicky lol. But yeah, check the coil lol

D3UC3S

Had a similar issue with the wifes GC. Thought it was CPS. Turned out it was a bad cell in the battery.

Drop another battery in that you know is good and see what happens.

Sent from my iPhone because web wheeling is cheaper...