Piston Slap: Commandeering The Commander's Electrics?
(photo courtesy: productioncars.com)
Brett writes:
Sajeev,
Imagine that, a Chrysler product with electrical problems…
So, randomly it wont start. Currently happens about once a week. He drives it to and from work about 5 miles each way. Fortunately, his wife works with him and they drive 2 cars everywhere so he is never really stranded anywhere. Family dysfunction here: there were many times that he, his wife, myself and my brother would all drive somewhere separately. Anyways, my dad and the Jeep were at my house the other day and I was taking the Jeep to the store. Tried to start it and it just cranked and cranked. Stopped, waited a minute or two and tried again an it started right up. It was like it wasn’t getting spark or fuel.
Second random issue was the front windshield washer pump stopped working. While troubleshooting, I realized that the rear pump didn’t work either. I listened for it but could not hear the pumps turning on. I decided to check the fuses. Once determining that Chrysler indicates that 4 different fuses could affect this on some random forum I figured what the hell. I pulled each fuse from the two separate fuse boxes under the hood and from the one under the dash (one at a time). I didn’t find a failed fuse — but guess what? The pumps started working. Should I slather some dielectric grease on the fuses and hope for the best?
I am guessing these two issues are related. My google-fu didn’t turn up a likely culprit. Any suggestions? He had previously indicated that he is considering a new vehicle, my suggestion was to trade it one a new vehicle before more gremlins show up.
Sajeev answers:
Hey Brett. With no shop manuals in hand, I’d be surprised if these problems are related. Most newer vehicles have unique body control wiring/modules and a mostly sovereign powertrain control module. I mean, Chrysler’s done some bizarre R&D things in the last 40+ years, but…
I reckon we need more information for the no-start condition. Maybe there’s a stored trouble code in the computer? Perhaps the crank position sensor (or maybe its wiring) is intermittently bad, hence the Jeep cannot know the right time to send spark/fuel to the motor? The intermittent nature makes me think that sensor is toast.
According to this thread, there’s one pump for the Commander’s front and rear windscreens. But this thread says there’s two pumps? 2006 might be a transitional year, if the part numbers between 2006 and 2007 on RockAuto are any indication. Fun stuff without a shop manual and no way to leave the Internet for this query!
I’m stumped: considering both front and rear sprayers are not working, I reckon you got one electric motor…and it’s flaky. The replacement looks pretty cheap. It might be worth testing the motor and its wiring with an old fashioned multimeter. Well, after you purchase a proper shop manual to get real insight into the circuit.
Have fun with that!
Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.
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" I didn’t find a failed fuse — but guess what? The pumps started working. Should I slather some dielectric grease on the fuses and hope for the best?" Loose wire at the fuse box, perhaps? (I had that cause intermittent injection pump failures in my old Toyota pickup, well over 100kmi in. The dealer had ... fun diagnosing that, but in a loyalty-earning move did not charge me for the diagnostic hours. Anyway, "randomly dies and fiddling with fuses might have fixed it for no obvious reason" fits in with either "dirty or old fuse*" or "loose wire". * Replace fuses due to age. Seriously. It's ten years old. Replace all the fuses. You won't regret it.)
When playing with the fuses and something starts working again replace the fuses. A lot of the older fuses use lead and i have found the connections do get dirty. I also put my money on a dirty ground connection. After living with 10-15 years old cars in my early life i have found the first thing to check when something does not work is the ground connections. Most of the time it always works but you have to know where all the ground connection are located. That means you have to get the shop manual or at least the electrical manual. When you think of all the salt they use in the snow belt in this country you will always find remains on some connection on a 10 year car that is always parked in the street. Ask me how i know this!