96 XJ | Crank No Start
10-11-2016, 11:24 AM
#1
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96 XJ | Crank No Start
Bought an XJ about a month ago and now it cranks but does not start. Orginal owner put in a reverse post battery so it was stretching out wires and would need to be shaken sometimes to start. I got a new battery and new terminals, also cut back old wire to be safe. He also had a sound system in the car which has wires all over the place which I do not know is relevant but maybe.
Back to the Crank no start... New Battery, has spark (tested with a tester), fuel pressure at 45 psi. Check fuses but not relays. I can hit gas while starting and it sounds like it wants to start but nothing. Should I check cylinder pressure or is there some other alternatives that will be easier. Thanks.
Back to the Crank no start... New Battery, has spark (tested with a tester), fuel pressure at 45 psi. Check fuses but not relays. I can hit gas while starting and it sounds like it wants to start but nothing. Should I check cylinder pressure or is there some other alternatives that will be easier. Thanks.
10-11-2016, 01:10 PM
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I thought if it had spark at all 6 cylinders then it ruled out the cps. Also sprayed fuel into throttle body didnt start when cranked but did start up when I hit the gas pedal. Checked all resistence to fuel injectors and were all to specs. Used a sparker tester and pulled a plug as well and the spark was orange and to me I always observed the spark to be white.
10-11-2016, 01:50 PM
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Year: 1996
Model: Cherokee
Engine: 4.0L
downstream o2 maybe? just throwing it out there, I've had weird problems when mine decided to give up. not a crank no start but it would take forever to get started and even with the pedal to the floor it wouldn't go over 30-40 mph and bog down every 2-3km i drove. replaced the downstream o2 and all problems are gone.
10-11-2016, 10:27 PM
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Giving up is not an option for me. But heres an up date on what Ive since last post. Quick overview: Spark to all cylinders ( using spark tester and pulling plugs and connecting to ground), fuel pressure at rail is 45psi (to spec), tested resistence at fuel injectors (all to spec), new battery and terminals, checked all fuses but not relays, tried door unlock trick and putting in nuetral, checked compression in all cylinders ( mean pressure at 135psi), sprayed throttle body cleaner in throttle body and it started for a second.
So, basiclly I have narrowed it down to the injectors are not injeting fuel. Since I have pressure to the rail and the injectors are good, it comes down to the pcm communicating to the injectors. The pcm I feel is the issue. The ground from the pcm to the engine block is covered in oil and grime from the gasket above it leaking. I will replace the gasket then remove the pcm and let you guys know what happens. If anyone else says it is the cps....lol. But seriously( If your know what you are talking about, you would know that if the cylinders have spark the cps is ruled out). Please let me know if you have any USEFUL information.
So, basiclly I have narrowed it down to the injectors are not injeting fuel. Since I have pressure to the rail and the injectors are good, it comes down to the pcm communicating to the injectors. The pcm I feel is the issue. The ground from the pcm to the engine block is covered in oil and grime from the gasket above it leaking. I will replace the gasket then remove the pcm and let you guys know what happens. If anyone else says it is the cps....lol. But seriously( If your know what you are talking about, you would know that if the cylinders have spark the cps is ruled out). Please let me know if you have any USEFUL information.
Last edited by RKucish; 10-11-2016 at 10:33 PM.
10-12-2016, 07:05 AM
#6
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I just answered your original question with the most common problem. Maybe it is the PCM, like you stated, but when the most common cause to a "crank but no start" issue is the CPS, you should at least check it.
Hope you figure it out. Let us know what it turns out to be.
Hope you figure it out. Let us know what it turns out to be.
10-12-2016, 07:21 AM
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Year: 1996
Model: Cherokee
Engine: 4.0L
I just answered your original question with the most common problem. Maybe it is the PCM, like you stated, but when the most common cause to a "crank but no start" issue is the CPS, you should at least check it.
Hope you figure it out. Let us know what it turns out to be.
Hope you figure it out. Let us know what it turns out to be.
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10-12-2016, 08:26 AM
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10-12-2016, 07:51 PM
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Year: 1995
Model: Cherokee
Engine: 4.0
If the CPS is bad, there will be no spark.
He says he sprayed throttle body cleaner into the inlet and it fired.
Sounds like a fuel issue.
I know someone who had the " crank no start " symptom and he just knew it was the CPS. ( because he read it on the internet ) Turns out his problem was the distributor pickup sensor. He also left only after I taught him how to read codes.
He says he sprayed throttle body cleaner into the inlet and it fired.
Sounds like a fuel issue.
I know someone who had the " crank no start " symptom and he just knew it was the CPS. ( because he read it on the internet ) Turns out his problem was the distributor pickup sensor. He also left only after I taught him how to read codes.
10-13-2016, 12:02 PM
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Year: 1988
Model: Cherokee
Engine: 4.0
Note from DJ
Because I have a 88 Cherokee with the 4.0L engine please take the information I’m about to provide to the OP RKucish and to anybody else that looks at this post with the understanding that I have no firsthand knowledge of how the 96XJ operates; these are just some of my thoughts and concerns.
By biggest concern is in post #5 OP stated that “The ground from the PCM to the engine block is covered in oil and grime from the gasket above it leaking” This is a big NO-NO: poor grounds make poor coffee; poor electrical grounds make for faulty information. This issue must be rectified wright away; it must be taking apart and all the contact points cleaned down to shiny metal because this is the point that the PCM is supposed to get its perfect ground information from; if it’s not perfect all information sent and received maybe in error! I would not even worry about the leaking gasket that caused the mess till after the Jeep is starting. All of the no start problems may disappear after this is take care of.
Here is my next concern in post #3 the OP stated “Used a sparker tester and pulled a plug as well and the spark was orange and to me I always observed the spark to be white”. My concern with this statement is that you may have spark but if it is not good spark you will probably not have ignition when compression is added therefore no start; also OP stated puled a plug SINGULAR not pulled all plugs and checked for spark. If this was the case maybe he checked the only plug that was receiving the firing signal. Along the orange spark problem if it were me I would look over the coil good for any crack in its exterior shell, take some electrical contact cleaner and remove the connector and spray out the connector then plug and unplug it a few times in order to clean the contacts. You could also with the aid of a helper and a spray bottle with water in side and adjusted to a fine spray go out after dark while the helper is cranking the engine spray the coil and its wiring with the water mist and look for a lighting show.
My next concern is OP stated in post #5 that his “fuel pressure at rail is 45psi (to spec), tested resistance at fuel injectors (all to spec) and that he sprayed throttle body cleaner in throttle body and it started for a second”. Now you need three things for ignition good spark, adequate fuel and the fuel air ratio must be correct. So what are we missing from this equation? Possible poor orange spark, Or OP stated in post #5 “So basically I have narrowed it down to the injectors aren’t injecting fuel”. So why not test the injectors with a test light or a VOM multimeter to see if each injector is receiving a pulsing DC voltage. To do this the OP will need a helper or will need to become inventive in that the engine will need to be cranked while the testing is none. If OP is working alone the test light or the VOM multimeter will need to be hooked up to both connector points of each injector in such a manner that he can look for a pulsing DC voltage while he cranks the engine.
Another test that might be used to check to see if the injectors are firing is this; with your foot off the throttle pedal try cranking the engine for about 10 seconds then let it rest for about 30 seconds; repeat this procedure 4 or 5 times then stop. Now start removing spark plugs one at a time and if they look wet the injectors are probably firing; if they are dry that is an indication they are probably not firing.
OP also stated in post #5 that I “sprayed throttle body cleaner in throttle body and it started for a second”. What does this indicate that a poor spark will ignite throttle body cleaner or are the injectors are not firing?
Please keep us posted as to your progress with your Jeeps problem; don’t be afraid to ask questions and please let us know if you solve the problem and what fixed it.
Because I have a 88 Cherokee with the 4.0L engine please take the information I’m about to provide to the OP RKucish and to anybody else that looks at this post with the understanding that I have no firsthand knowledge of how the 96XJ operates; these are just some of my thoughts and concerns.
By biggest concern is in post #5 OP stated that “The ground from the PCM to the engine block is covered in oil and grime from the gasket above it leaking” This is a big NO-NO: poor grounds make poor coffee; poor electrical grounds make for faulty information. This issue must be rectified wright away; it must be taking apart and all the contact points cleaned down to shiny metal because this is the point that the PCM is supposed to get its perfect ground information from; if it’s not perfect all information sent and received maybe in error! I would not even worry about the leaking gasket that caused the mess till after the Jeep is starting. All of the no start problems may disappear after this is take care of.
Here is my next concern in post #3 the OP stated “Used a sparker tester and pulled a plug as well and the spark was orange and to me I always observed the spark to be white”. My concern with this statement is that you may have spark but if it is not good spark you will probably not have ignition when compression is added therefore no start; also OP stated puled a plug SINGULAR not pulled all plugs and checked for spark. If this was the case maybe he checked the only plug that was receiving the firing signal. Along the orange spark problem if it were me I would look over the coil good for any crack in its exterior shell, take some electrical contact cleaner and remove the connector and spray out the connector then plug and unplug it a few times in order to clean the contacts. You could also with the aid of a helper and a spray bottle with water in side and adjusted to a fine spray go out after dark while the helper is cranking the engine spray the coil and its wiring with the water mist and look for a lighting show.
My next concern is OP stated in post #5 that his “fuel pressure at rail is 45psi (to spec), tested resistance at fuel injectors (all to spec) and that he sprayed throttle body cleaner in throttle body and it started for a second”. Now you need three things for ignition good spark, adequate fuel and the fuel air ratio must be correct. So what are we missing from this equation? Possible poor orange spark, Or OP stated in post #5 “So basically I have narrowed it down to the injectors aren’t injecting fuel”. So why not test the injectors with a test light or a VOM multimeter to see if each injector is receiving a pulsing DC voltage. To do this the OP will need a helper or will need to become inventive in that the engine will need to be cranked while the testing is none. If OP is working alone the test light or the VOM multimeter will need to be hooked up to both connector points of each injector in such a manner that he can look for a pulsing DC voltage while he cranks the engine.
Another test that might be used to check to see if the injectors are firing is this; with your foot off the throttle pedal try cranking the engine for about 10 seconds then let it rest for about 30 seconds; repeat this procedure 4 or 5 times then stop. Now start removing spark plugs one at a time and if they look wet the injectors are probably firing; if they are dry that is an indication they are probably not firing.
OP also stated in post #5 that I “sprayed throttle body cleaner in throttle body and it started for a second”. What does this indicate that a poor spark will ignite throttle body cleaner or are the injectors are not firing?
Please keep us posted as to your progress with your Jeeps problem; don’t be afraid to ask questions and please let us know if you solve the problem and what fixed it.
10-13-2016, 01:08 PM
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I have checked yet..
I can't wait I will have all weekend to work on the 96xj. Thank you for your advice and I learned a lot from forums like these. Just want to make sure the right information is getting passed on. Thank you and I will keep you posted.
10-13-2016, 09:37 PM
#12
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Definitely pointing toward fuel and/or air problem.
Since the advice above was already given regarding fuel. I won't repeat that.
But also attempt a start with the throttle just slightly depressed. This can help rule out an IAC that is not opening to allow air during startup. If this results in a startup (even if the vehicle won't stay running), then you will want to remove the throttle body and clean it, and either clean or replace the Idle Air Control valve.
Since the advice above was already given regarding fuel. I won't repeat that.
But also attempt a start with the throttle just slightly depressed. This can help rule out an IAC that is not opening to allow air during startup. If this results in a startup (even if the vehicle won't stay running), then you will want to remove the throttle body and clean it, and either clean or replace the Idle Air Control valve.
10-13-2016, 09:44 PM
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What if I depress pedal acts like it will start but still doesn't? I've tried that also the valve doesn't open at all during start up. Also wouldn't that affect the idle and driveability more than the start up? Also no code for it.
Last edited by RKucish; 10-13-2016 at 09:47 PM.
10-13-2016, 10:05 PM
#14
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The IAC will effect startup, and any time you release the gas pedal completely (a stop sign, or going down a steep hill, etc).
When you say the valve did not open at startup, are you talking about the large circular butterfly valve? That is only changed by the pedal. The IAC is a small bypass port that allows air into the throttle body even when the large valve is completely shut (foot off the accelerator).
Normally, you can not visually see what the IAC is doing. If it gets gummed up (common) or fails, it will not open and let air in during startup. So you will have spark, fuel, but no air.
Depressing the gas pedal slightly, will let a little air in manually. (only feather the pedal, do not depress it very much).
When you say the valve did not open at startup, are you talking about the large circular butterfly valve? That is only changed by the pedal. The IAC is a small bypass port that allows air into the throttle body even when the large valve is completely shut (foot off the accelerator).
Normally, you can not visually see what the IAC is doing. If it gets gummed up (common) or fails, it will not open and let air in during startup. So you will have spark, fuel, but no air.
Depressing the gas pedal slightly, will let a little air in manually. (only feather the pedal, do not depress it very much).
