RareCJ8 Posted August 19, 2014 Share Posted August 19, 2014 Just back from a 5 day camp event and 4x4 poker run. Odd experience: when driving through a really long, relatively rough trail section-- nothing special just an endless road of water mellon size rocks, and at faster than a crawl felt like rig was running over heavy washboard. the suspension usually absorbs these sort of terrain features. Go to neutral and coast, the bump bump stops. Come to stop and rev RPMS and at idle or up to 1500 RPMs engine running VERY rough. Sounds like a boat exhaust. bubbub bubbub, sputtering and running really rough. Cycle RPMs up higher, back to idle and repeat couple times and then all is well and she runs like it should. the symptom reminds me of the carb days when it would load up off camber. First Q is any comments or suggestions? Can EFI get confused from relentless pounding? Fuel pressure was perfect. no pressure in tank-- opened cap. full tank of gas. then to add to stress, all of a sudden when starting twist key forward and the screech of starter stays on, manually dial back key to stop it. its either a spring on starter spur or in the key lock assembly (which i completely rebuilt with new parts last winter) SMH, its always something... but this random rough running engine is a concern. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted August 19, 2014 Administrators Share Posted August 19, 2014 Sounds like a rich mixture, more specifically like the engine is running on its warm-up mode. We could suspect other things if the engine did not clear out as it does when you rev it up and back. You might pull a convenient spark plug when the engine is acting up. Look at the fuel mixture signs of color at the plug. What's the exhaust pipe coloration at the tailpipe end? Does it look richer than usual when the engine is acting up like this? This could point to the coolant temp sensor or a thermostat set too low. What's the engine operating temperature when this is going on? Do you need to test the temp sensor ohms-resistance reading? Is there an exhaust restriction of any kind? When you check the temp sensor, also check the terminal connection and attachment stem of the temp sensor. The vibration/pounding could be opening the circuit or sending a false or intermittent reading to the PCM. If turning the key manually back to "On" from "Start" mode seems to stop the starter run-on, I'd suspect the key switch. To isolate the starter as the trouble, try manually starting the engine by using a jumper directly at the solenoid (bypassing the key switch altogether). See if the starter runs on when you release the jumper. Caution: Make sure the transmission is in neutral with the parking brake set and wheels chocked. Don't run over yourself performing this test! With the Motorcraft/Ford-type solenoid (mounted at the inner fender), you can perform the jumper test easily. If you are not sure of the poles, it's the hot battery lead across to the small terminal marked "S". This essentially mimics the key start mode. Make sure that the solenoid is not sticking, too. The Motorcraft starters are notorious for "sticking" in run-on mode or not releasing the drive and staying engaged. If you suspect the starter, that's a good possibility. We had an '87 Grand Wagoneer 360 V-8 with Motorcraft starter that decided to lock up the drive. By the time I disconnected the sizzling battery lead, the starter and battery cable were toast. Beware. Moses Quote Link to comment Share on other sites More sharing options...
Kevin's 83-CJ8 Posted August 22, 2014 Share Posted August 22, 2014 I have to say I really like your Jeep. I looked at some of your Jeep pictures and it is really nice. I like the roll cage work and roof rack. So the sound that you described with the gurgling sounds like what I find happens when I sit with the engine idling too long. The exhaust gets moisture in it. I think it is condensation or maybe gas build up. You said that when you run the RPM’s up it blow’s the pipe out and it is better. If it ever happens again, have a friend look at the exhaust when you blow it out and see if liquid comes out. I find that when it happens for me, I park up hill (with the pipe down) and run the RPM's up and it blows a lot of moisture out. I had the same issue with my new ignition switch sticking. I loosened the attachment screws just a bit and it moved freely. Kevin Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted August 22, 2014 Administrators Share Posted August 22, 2014 Brilliant, Kevin! If this is the cure, it makes perfect sense...Headers often make condensation worse... Both suggestions need follow-up, RareCJ8! Let us know how this works out. Given the driving conditions when the behavior developed, loping along at lower speeds, condensation could be the culprit! Thanks, Kevin...Here are details on RareCJ8's Scrambler: http://www.4wdmechanix.com/HD-Videos-Jeep-CJ-8-4.6L-Stroker-Power.html. Moses Quote Link to comment Share on other sites More sharing options...
RareCJ8 Posted September 17, 2014 Author Share Posted September 17, 2014 We're leaving for (smoky) Rubicon early tomorrow so will look at this issue if it acts up. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted September 18, 2014 Administrators Share Posted September 18, 2014 Very interested in knowing how this condensation issue turns out, RareCJ8! If that's the source, we'll work on a solution... While the Rubicon is always fun, all of us at the Sierra region have been affected by the King Fire in El Dorado National Forest. Safe travels! Moses Quote Link to comment Share on other sites More sharing options...
RareCJ8 Posted September 23, 2014 Author Share Posted September 23, 2014 Got to observation point and turned back. Too smoky. Moved south to deer valley trail and camped there 3 days. Perfect. No smoke and jeep ran great. Click thumb for full screen. In the rain. A cj6 and cj8 Visiting buggy Nice scenery Packed up ready to roll Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted September 23, 2014 Administrators Share Posted September 23, 2014 Great setting, RareCJ8, you do know how and where to have a good time...Glad you got away from the King Fire smoke, we were inundated at Fernley, Reno was even worse... Thanks for sharing! Glad the CJ-8 behaved well... Moses Quote Link to comment Share on other sites More sharing options...
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