BruceB

Greetings,

1996 Jeep XJ Classic 2WD, 155000 miles. Owned since 1998, extremely well maintained.

Went to start it this am and all it would do is turn over, no start.
This is what I have verified.
Battery good, swapped with another newer battery, no joy.
Cleaned and verified grounds to starter, to block, to chassis from battery, from rear of engine to chassis., no joy,
Swapped relays around three times, no joy.
Electric verified with light tester all fuses good.
Verified 5 volts in sensor circuit.
No codes through key on/off method.
Did ohm/resistance check on CPS on leads 2 and 3 and the only reading was "1", this is on a Harbor Freight Cen-Tech Multimeter and on every ohm setting.
From what I have read, the CPS is usually the culprit.
What say the experts here...am I on the right trail?

djb383

When u turn the key to the run/on position, do u hear a high pitched hum from the rear?......if not, fuel pump may have quit.

BruceB

Could just be me, but I have never heard the fuel pump since I have owned it. At one point while trying to start it I did smell gas while running through a diagnosis checklist.

adamj

Yep. I would start with that first.
If you don't hear the fuel pump priming when you first put the key to "on" (not start right away) then fuel pump could have gone bad. Check the fuel pump relay to make sure it's not just the relay.

Edit: Re-read your initial post that said you checked relays already, I would check fuel pressure at the fuel rail to make sure you are getting fuel.

BruceB

Thanks..will check after work tomorrow...battery is disconnected at the moment and heading out for some sushi...Local Chrysler Jeep Dodge dealer tells me that the OEM CPS is on National Backorder and I don't like aftermarket stuff on the Jeepster. Anybody have the OEM part number so I can try and search one out?...that is if I need it..

djb383

The XJ fuel pump is really quiet.....might need someone in the back with their head below the rear bumper listening.

firehawk618

You could just get one at a local parts house for now then install the one that's on national backorder once it comes in. Then keep the old/new one as a spare.

One thing you can try to rule out fuel issues is just spray a little ether / quick start in the throttle body and see if it fires off for a minute.

Also check for spark. Do both of those in either order.

Go from there.

Whatever you do please don't start just throwing random parts at it guessing.

Oh yeah, since I assume you're obdii if your CPS is bad wouldn't you be able to retrieve codes and see if the computer is detecting a pulse or not?

Rogue4x4

19 years, and it's your first no start? That is awesome!

As far as the national backorder is concerned, I recently got one without issue from my local parts guy at O'Reillys, his day job is a Chrysler parts rep. Cost me $99, and had it in days. You might wanna call around to other dealerships, they may have one.

TheGreatGazoo

found this hope it helps if you are reading your meter right and you have 1 ohm that is a low resistance, then your cps is shorted.

CPS TESTING PROCEDURE 1991 – 2001 4.0L H.O. engines

1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (See Image). Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.

BruceB

Going to slide out from work today and pick up a Fuel Pressure Tester. Besides..I needed a new "add" to my tool collection...haha..Double checked the ohm resistance reading and it still read "1". The meter is a couple of years old so I am going to replace the battery and retest to see if that makes any difference. I really appreciate the input, I have always believed that input from others is a whole lot better than me trying to figure it out on my own.

tjwalker

The first thing to do with a no start is to verify spark. Very easy on your 96.

Remove 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 (suspect ignition coil for weak spark and the coil can also be tested for both primary and secondary resistances)

If the spark is good (and only if), then try a small splash of gas into the intake or a shot of starting fluid. If the engine starts and runs for a few seconds, you have identified a "fuel delivery problem".

The above are quick and dirty tests that can be performed by anyone and go a long ways towards isolating where the root cause of your problem is.

Good luck and keep us updated!

cruiser54

I would test the CPS first.

dr.zoidberg

First thing id do is check and make sure you have a strong blue spark. Tjwalker gave directions on how to do that. If that checks out ok then look at fuel. Check fuel pressure at the rail. Should be 49 psi plus or minus 5 psi. If youre outside thoes numbers the fuel pump is your issue. Check fuel pump relay and make sure it's working properly before blaiming your pump. If you have good pressure at your fuel rail...next thing id check is the cps.

BruceB

The instructions on this multi meter states that while doing an ohms/resistance test if the display displays a "1" to set it to the next higher setting. I started at 200, then 2000, then 20k, then 200k and then finally at 2000k. At the final setting, and the highest, when I make contact with the b and c connectors the display displays a number between low of 1461 to a high of 1999 for just a brief second or less and then goes to the "1" display. I repeated this several times and the numbers flashed in the 1500's, 1600's,1700's,1800's and 1900's. Once when it started low, it looked like it flashed to a higher number before going to the "1" again. Correct me if I am wrong, but is this indicating infinite resistance? or...is my $5.00 multi meter just a pos...

TheGreatGazoo

"1" is a dead short that is 1 ohm. if you have 1 on all ohm's scale you have either a broken meter or your component is shorted. 1 is like taking the two meter leads and touching them together you should get a 0 or 1 = shorted together. fyi if your not familiar with multimeters always buy a auto ranging multimeter vs a meter that has scales on it. they are cheap and perfect for the do-it-yourselfer. im a 26year veteran of the IBEW local 3 and use auto ranging meters mine is the fluke 87 but expensive. for the do-it yourselfer something like the Equus 3320 meter is perfect around 20 bucks.