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| Intermittent starting problem, have to pump brakes? http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=86392 |
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| Author: | allenj [ Sun Apr 02, 2017 8:23 pm ] |
| Post subject: | Intermittent starting problem, have to pump brakes? |
I've starting having an intermittent starting problem in my 05 Libby over the last 2-3 weeks. I'll turn the key and it doesn't start, dash lights come on but the starter motor does not kick in at all. Wiggling the key, pushing the shifter knob down, doesn't work. But I've learned that when this happens, I can pump the brakes several times, then push really hard on the brake while turning the key, and it starts. The brake is spongy the first time I press it (and won't start on the first press), but firms up after that. No CELs, except for an intermittent P0101 which just started occurring a couple of days ago after cleaning MAP, but this problem predates the code so I don't think it's related. Any ideas? Sounds like some kind of sensor problem, but which one would be affected by the brake pedal? |
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| Author: | WWDiesel [ Sun Apr 02, 2017 10:33 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Brakes have nothing to do with the starting circuit! Your problem may be the rod or connection between the key ignition lock cylinder and the electrical ignition switch which is located on the steering column. Depressing the brake pedal may be just simply moving something in or on the column just enough to make a connection? Both parts are available at AutoZone: Ignition Switch Part Number: LS1027 Ignition Switch Actuator Pin Part Number: 924-704   
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| Author: | allenj [ Mon Apr 03, 2017 6:59 am ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
That's what I thought also, which is why I've been confused about where to start, whether it might be this ignition switch or somehow linked to neutral position sensor or ? I think I'll start by replacing the ignition switch components you mention, they are both relatively cheap and easy to replace (after watching the videos). Thanks. |
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| Author: | WWDiesel [ Mon Apr 03, 2017 9:13 am ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
allenj wrote: That's what I thought also, which is why I've been confused about where to start, whether it might be this ignition switch or somehow linked to neutral position sensor or ? I think I'll start by replacing the ignition switch components you mention, they are both relatively cheap and easy to replace (after watching the videos). Thanks. The Neutral position switch is not on steering column! (Kinda rules it out) You can always place shifter in the "N" position before starting; it should start in "N" just as it does in "Park"! (without touching the brake pedal) It is not required to depress the brake pedal to start in either "P" or "N". Depressing the brake pedal is only required to shift out of Park to any of the other gear.... Good luck, keep us posted as to what you find!
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| Author: | tjkj2002 [ Mon Apr 03, 2017 10:50 am ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Better hope it's not the NSS since it's a whole solenoid pack that costs $700 and located above the valve body inside the trans. |
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| Author: | allenj [ Mon Apr 03, 2017 5:00 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
I just replaced the ignition switch and actuator pin (about $55 from Autozone), and the Jeep started right up. Like I said, it's been an intermittent problem, so I won't be 100% confident for a week or two, but so far so good! Somehow I never realized that it could be started without the brake pedal depressed  Especially with all my other vehicles being manual, it's been my habit for so long I didn't even think about it. Thanks! |
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| Author: | WWDiesel [ Mon Apr 03, 2017 8:35 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Glad it turned out to be something simple!!!  keep us posted... 
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| Author: | allenj [ Sun Apr 16, 2017 9:34 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Update: The failure to start problem is NOT fixed. It was OK for a couple of weeks of normal commuting. But reappeared this weekend on our camping trip, towing our travel trailer. We've learned that the problem only seems to occur if a) the engine is warm b) an engine start is attempted within some limited period of time (< 15-30 min?) after the previous shut down. Neither of these are confirmed for certain, but I think that combination is the most common time it occurs. The more restarts within a certain period of time, the more likely it is to occur, e.g. short trips between stores, or hooking up and positioning a trailer involving several stops and starts. As long as the Jeep is parked for at least an hour between uses, it seems to work fine. |
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| Author: | tjkj2002 [ Sun Apr 16, 2017 9:49 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
allenj wrote: Update: The failure to start problem is NOT fixed. It was OK for a couple of weeks of normal commuting. But reappeared this weekend on our camping trip, towing our travel trailer. We've learned that the problem only seems to occur if a) the engine is warm b) an engine start is attempted within some limited period of time (< 15-30 min?) after the previous shut down. Neither of these are confirmed for certain, but I think that combination is the most common time it occurs. The more restarts within a certain period of time, the more likely it is to occur, e.g. short trips between stores, or hooking up and positioning a trailer involving several stops and starts. As long as the Jeep is parked for at least an hour between uses, it seems to work fine. Well now you know 1 thing,it's a heat related issue. Most common cause is a crank sensor and yes this issue can happen without a code being stored. Being a CRD you could have heat soak issues with the high pressure pump that did not occur in normal DD driving,only under heavy loads like towing. |
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| Author: | geordi [ Sun Apr 16, 2017 9:59 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Crankshaft sensor is probably just starting to be on its way out. Usually the result of it failing is refusal to start when warm. IDparts.com has them, not too much money. They aren't hard to change, just annoying to get to. Under the turbo on the passenger side of the bell housing, facing the front bumper. 5mm socket cap bolt. |
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| Author: | joe_ [ Sun Apr 16, 2017 11:08 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
You said in your original post that the starter motor doesn't kick in at all. Is this still the case? If so, roll down the window and listen for a single *click* coming from the engine compartment when you turn the key to Start. Could be that your starter is getting worn out. |
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| Author: | allenj [ Mon Apr 17, 2017 9:52 am ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Correct, when this happens the starter motor doesn't kick in at all. I haven't specifically listened for the single "click" before, I'll try that next time it happens. Or I may just throw a crankshaft sensor at it, they're $82 on idparts. If it's the starter I'll probably take it my mechanic, from the videos I've seen that isn't a simple DIY job for a driveway mechanic like myself. |
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| Author: | WWDiesel [ Mon Apr 17, 2017 10:49 am ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
joe_ wrote: You said in your original post that the starter motor doesn't kick in at all. Is this still the case? If so, roll down the window and listen for a single *click* coming from the engine compartment when you turn the key to Start. Could be that your starter is getting worn out. Forget the crank sensor! It WILL NOT prevent the starter motor from spinning the engine over!!! Your problem is in the starting circuit!!! Back to basics: If you do not hear the "click" as joe suggested; your starter relay may be going bad. It is located in the power distribution center under the hood. You can simply swap it with one of the other relays to test! Also, you can remove the relay when you are in one of the no start situations and jumper pins 30 to 87 and when you do this if starter motor spins, then your problem is not the starter, but in one of the starter circuits feeding the relay, i.e. ign. switch, neutral start switch, etc... If when you jumper pins 30 to 87 and starter does not function, then your starter motor is bad or you have a bad connection at the starter or bad (+ or - ) battery cable connection and the starter is not getting enough voltage to spin or a loose or bad ground between engine and battery. Check all connections for cleanliness and tightness... See pages 8F-33 & 8F-42 respectfully for more information on DIAGNOSIS AND TESTING - STARTING SYSTEM & DIAGNOSIS AND TESTING - STARTER RELAY http://www.colorado4wheel.com/manuals/J ... Manual.pdf   
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| Author: | allenj [ Tue Apr 18, 2017 11:42 am ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Noted, thanks for the detailed post. I haven't done anything yet, I'll go through the starter and circuit troubleshooting steps the next time I have the problem. |
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| Author: | allenj [ Wed Apr 19, 2017 7:56 am ] |
| Post subject: | Re: Intermittent starting problem when Jeep is warmed up |
I think WWDiesel had it right. Yesterday I ran several errands to different stores after work, a good recipe for causing this problem, and sure enough it happened. I rolled down the window and listened while turning the key - no click, nothing. I located the starter relay. It was stuck and I was unable to remove it by hand to swap it with another relay, but the Jeep started, maybe just from wiggling it. I went by the Jeep dealership on the way home, picked up a new relay for $21, and replaced it with the aid of pliers when I got home. Since then I've started it several times with no problem, but haven't really done the typical failure scenario yet, so stay tuned. |
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| Author: | WWDiesel [ Wed Apr 19, 2017 10:36 am ] |
| Post subject: | Re: Intermittent starting problem when Jeep is warmed up |
allenj wrote: Since then I've started it several times with no problem, but haven't really done the typical failure scenario yet, so stay tuned. GREAT! Keep us posted as to outcome!
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| Author: | allenj [ Fri Apr 21, 2017 10:37 am ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
Update: The problem is persisting. I still have more troubleshooting to go, trying different things each time it happens, I haven't refined the failure any further yet. Next up is to try jumpering the starter relay when it happens, but (assuming it spins the starter) the problem is so intermittent I'll have to try it several times. It often starts on the 4th or 5th attempt, just when I'm getting ready to try something. Summary so far: Replaced ignition switch, ignition switch actuator pin, starter relay Disconnect and reconnect battery cables, check both grounding points between battery and firewall, they are tight. Stay tuned, I'll let you know when I have more test results to report. Thanks. |
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| Author: | WWDiesel [ Fri Apr 21, 2017 12:18 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
When it fails to start, can you hear the starter relay clicking? have you tried placing the shifter to Neutral and see if starter will engage when this happens? What to check in power distribution center under hood where starter relay plugs into if you can: [note: numbers in () are corresponding relay terminals] 12v at terminal 10 (30) all the time (from battery) terminal 8 (85) should be grounded anytime shifter is in "Park" or "Neutral" (if no ground, neutral start switch is bad) terminal 7 (87A), not used so don't worry about it terminal 6 (86), should have 12v present anytime the ignition switch is turned all the way to the start /starter engage position ------(this one energizes the relay if ter. 8 is grounded) (if no voltage present on ter. 6, ign. switch is bad or problems with 12v feed to ign. switch) (check fuse 28, 15A, it feeds this circuit)
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| Author: | allenj [ Sun Apr 23, 2017 9:13 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
No, I don't hear any clicking. And it won't start in either Park or Neutral when this happens. I tried to do your latest circuit troubleshooting post, but couldn't get a reading on pin 8 with my test light, and didn't try 6. It was probably operator error since the Jeep started right up afterward. One time so far I was able to jumper the start circuit after a failure to start, and the starter did spin. But when I put it back together the Jeep started promptly, so that may have been coincidence. That's the difficulty with intermittent problems, any troubleshooting step has to be repeated for multiple failures to draw a meaningful conclusion. I also tried disconnecting the trailer brake controller to see if that helps, no conclusion there yet. Thanks. |
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| Author: | allenj [ Wed Apr 26, 2017 6:59 pm ] |
| Post subject: | Re: Intermittent starting problem, have to pump brakes? |
OK, I finally got a definitive no start test. I had run some short errands, then parked it for about an hour. When i came out, no start. The trailer brake controller is already removed at this point. I removed the starter relay and jumpered the starter pins 30 to 87: The starter motor runs, no problem (key is in ON position). I put the relay back in, get back in, still no start, no noise at all. I tried with the shifter in N and P positions, still no start. I let it sit for another 20 minutes or so, tried it again, no luck. I tried several different twists, finally pushed the key in hard and that seemed to do it, it started. That isn't definitive yet as I think I've tried that before, but I'll experiment more with that next time. |
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