Okay, I have a no start issue with a Jeep.

Im not familiar with Jeeps and the way the work. I am a Honda person.

This is the issue.

The Jeep does not start. It sparks, it cranks, and it does not turn over. I checked the fuel pump for volatge. There is voltage to the fuel pump. I can feel it prime with my hands on the gas tank. However it does not stay on the whole time. Only for a few seconds, than it turns off?

Can this be the issue, or is it something else.

 

HCEG refugee???

Does the pump run while the starter is engaged?

 

I cant confirm that.

I can confirm that when you turn the key to the ON postion, the pump does activate. But for a short while.

 

This is correct it is priming the system.

You might check the fuel pressure at the fuel rail, there is a valve on there. Your Crank Position sensor may also be bad.

 

I would say that fuel delivery could be the problem, considering you have spark at the plugs and its turning over.

Have you actually pulled a couple plugs to make sure that the electrodes aren't worn off? I have see it more than a couple times.

Also, make sure to actually check the fuel pressure. SOME fuel pressure isn't the same as CORRECT fuel pressure. Also ran into weak fuel pressure causing a no start situation, although it will usually hit once or twice even with weak fuel pressure.

Can you keep it running off of ether? (don't try that, if you don't know how to do it)

 

Well, I did pull the plugs to examine them. They were crusty as anything. I replaced them and all the plug wires as well, standard maintence. That didn't work.

I did see that valve on the fuel rail. IDK what exactly to use to see what the fuel pressure is. Even if the fuel pressure is week, something should crank over.

There are a few more possibilties, timing, compression for starters. Does anyone know where I can get a PDF file for the car. Like a Helms. IDK if they make one for this, but the Helms is a complete guide to trouble shooting everything with car, including wiring diagrams, and the whole cars make over.

 

This may be a dumb question but if you pump the gas pedal does it start? I had a no-start problem with mine a month or so back. I thought fuel pressure problems, plugs, and injectors at first too. Had to hold the gas to get it to start, and keep holding it down until the auto choke or cold weather start system (something like that, I'm no expert at engines) completed and ended its timed cycle.

 

Unplug and replug in your CPS. Should fix it temporarily. When you get time replace your CPS.

Crankshaft position sensor.

 

Where is that exactly located?

 

Rear of the Valve cover on the right side. You can run a lil google search and find more info. CPS for Cherokee or something like that.

 

The Crank position sensor itself is on the back side of the engine on the driver's side mounted to the bell housing. The plug however is on the driver's side of the engine towards the back and should be pretty easy to get to.

It could look something similar to this.

Though the connections changed depending on the year of your Jeep.

 

Although he said he was getting spark. If the CPS isn't working at all he shouldn't be getting any spark.

Is it hitting at all?

You can also check the CPS before confirming that it is the problem, what year is your XJ?

If its post renix (91 or newer)

http://autorepair.about.com/library/faqs/bl077g.htm

If it is a renix (90 or older)

http://www.lunghd.com/Tech_Articles/...iagnostics.htm

 

I have already confirmed that there is spark coming from the coil, and out of the plug wires. I pulled the plugs there selves and they were corroded, so I replaced them thinking it might be the issue, but never the less, it was not.

Its a 93 cherroke I will check the CPS today.

What about a MAF sensor. Do these cars have a MAF sensor? If so, what is the poper proceddure for checking it

 

No mass air flow ! If you have spark, cps is working. Check fuel pressure as well as fuel pressure regulator.

 

I am talking about the crank shaft position sensor and you can have spark and your CPS still be bad. Actually your CPS can cause and amazing array of different problems.


I copy/pasted from this site

C.P.S. (Crankshaft Position Sensor)
(AKA: CKP and / or engine 'Speed Sensor' in some Daimler-Chrysler publications.)
Do Not Confuse this with the CAM Position Sensor located in the "distributor"! Make sure your counterdrone knows which one you are talking about!


This is the BIG Kahuna of problems for people with no start, hard to start & stall out issues! You do NOT want to have this fail far from home, wheelin' alone, tools in the garage and no spare anyhow... heck, even if ya did have the tools, helpers and a spare it's a major pain to fix beside the trail! This thing is kinda like a serpentine belt; ya won't remember to replace it until it breaks! Unlike a serpentine belt, SOMETIMES.... just sometimes, ya can limp on home... maybe. The CPS should be a regular maintanence item for any Jeep owner but the change out interval is more likely related to heat & vibration rather than miles. If anyone knows the actual time interval recommended by the factory on these, please let me know and I'll amend this page.

CPS: You can check it's basic function but be aware that sometimes the darn things can be 'intermittant' but still read 'ok' when measured due to engine heat/temperature. Even so, these tests will show up a borderline CPS more often than not.

Check the connector first
If you've just stalled out with same symptoms... unplug the CPS & plug it back in. If your motor fires back up you might get off easy, but don't count on it lasting forever. I dunno what doing this accomplishes other than cleaning the connector contacts enough to let additional voltage through to the computer. If unplugging & replugging worked then unplug the connector again and clean those contacts off. Then apply some OX-GARD, or other electrical contact cleaner & protectant (dielectric grease).

There is a distinct possibility that you're not getting a signal due to a faulty connector itself as well. Some people have cured their CPS problems by simply cutting the connector out of the harness and SOLDERING the wires together (Use heat shrink or electrical tape around the wire, of course!) Other's have replaced the connector with a newer, waterproof version from an electrical or automotive supply store.

Test#1 - Get a volt/ohm meter and set it to read 0 - 500 ohms. Unplug the cps and measure across the CPS connector's A & B leads. Your meter should show a CPS resistance of between 125 - 275 ohms. If it's out of that range by much; replace it. (* - Note: HO engines are measured from the B & C connectors and should have near zero ohms.)

Test#2 - You'll need a friend to help ya with this one.
Set your volt/ohm meter to read 0 - 5 AC volts or the closest AC Volts scale your meter has to this range. Measure across the CPS leads for voltage generated as your friend cranks the engine. (The engine can't fire up without the CPS connected but watch for moving parts just the same!) The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5vac, replace it.

Desperate last ditch tip to get home or a few more miles from a failing CPS: - Other than the unplug/replug trick... MJR passed on a trick of using a flat bar and a hammer to 'adjust' the CPS by smacking the CPS bracket and forcing a weak CPS just a tad closer to the flywheel. This lets a weak CPS get a stronger pulse and hopefully generate enough voltage to feed a good signal to the computer again. WARNING! - If ya smack it too hard... it'll go in too far and the flywheel will eat the CPS! Start walking.

Either way, if it fails ANY of the tests... you should replace it and save your self some major pain later. If not, at least carry a spare CPS but be aware that it's a royal pain in the *** to change on a cold motor and ya really don't wanna do it at night, on the trail and with a hot motor if ya can help it!

UPDATE:CPS SENSOR HARNESS REPLACMENT TECHNICAL BULLITEN IN PDF FORMAT.
This one is a 'last resort' fix if you've replaced the CPS already & it didn't fix the problem. The issue is a crappy harness which this bulliten addresses through a replacement of the actual CPS harness. (They call it a CKP harness for some idiotic Daimler-Chrysler reason...)

Tech Tip: - To more easily remove & replace the CPS use a floor jack to support your transmission cross member, remove the two bolts & two studs (replace those with bolts if you break one), then lower the transmission cross member by about 1-2 inches. This will give you enough room to get your hands & tools in for the CPS work. (Especially if you have big hands!)