My 1998 Nissan Sentra GXE (1.6L) has been acting up for the past few weeks, in decreasing degrees of severity. After a varied set of problems and repairs, the engine now hesitates at random, more often when idling than when driving. It sounds like it's about to die completely and then returns to normal in a second. What the heck is going on?
A bit of backstory. A few weeks ago, my fiancé and I were leaving the East Coast to move to Chicago, and as luck would have it, my car died at an intersection the day before we were to leave -- no warning, no check engine light, nothing. The engine would start to rev but wouldn't turn over. We tried jumping the battery to no avail. We pushed it across the road from where it died into a mechanic's lot, who promptly replaced the distributor, as he mentioned the engine wasn't getting a spark at all.
Upon taking the car for a spin, we noticed that the engine would intermittently dip out and back to normal, causing the car to buck slightly. As we drove, the problem got worse. We brought it back to the shop, and the mechanic checked the ignition wires and spark plugs, noticing that the ends of the ignition cables had been wrapped with electrical tape at some point (?), and so he elected to replaced them with new wires.
Unfortunately the problem persisted, and so he adjusted the engine timing a number of times to see if it would help, to no avail. He checked the spark plugs, which all looked pretty good (he showed them to me, and I agreed) and decided it might be worthwhile to replace them. After the plugs were replaced, the car ran just fine. I left, went back to my parents' house with my fiancé, we packed the car up, and hit the road.
The first leg of the trip went fine. But, after waking up in Ohio the following morning, I noticed the engine hesitated once (sort of a 'dip' in the engine sound despite no gear change and consistent acceleration) but didn't worry about it. Later that day, while driving through western Ohio, I noticed it happening again at highway speed. Sure enough, it started to happen more frequently (maybe three times an hour). Given that we had a lot of driving left to do, I began to experiment with things to see if anything else in the operation of the car had anything to do with it -- I tried turning the A/C on and off, turning cruise control off, releasing the accelerator, and turning other various electronic components on and off, but nothing seemed directly correlated to the problem. Fortunately we made it to Chicago without the car breaking down/catching fire/exploding.
While here in Chicago, I tried replacing the fuel filter on my own, as a guy at an oil change shop in CT had recommended it. Part of me hoped that would finally take care of it, but to no avail.
Here in the suburbs, I brought it to another mechanic who hooked the car up to some scopes to measure the electricity output of the car. He noted that while he had difficulty getting the car to reproduce the problem, he did experience it several times. Looking at the output of the testing machines, he noted that during those moments he saw the electricity dipping during several occasions, which was likely responsible for the issue.
In response, since most of the electrical system to the engine is brand new, the mechanic cleaned a number of the circuit connections between the battery and the engine, and also topped off my transmission fluid as it was relatively low. He noted that this didn't entirely address the issue, but it seemed to improve it.
Unfortunately, it hasn't. The engine is still hesitating randomly, and it seems to be worse during idle than while driving. The mechanic assured me that the car likely won't break down again, but I'm not sure if I believe him. He noted that, at this point, it could either be that the distributor was faulty or that, worst case scenario, the car computer needs to be replaced. I'm going to try and get in touch with my mechanic in CT on Monday to check about how to replace the new distributor under warranty, but I'm at my wits end here.
I guess I'm looking for a second opinion, or third, fourth, etc. Is there something we're missing? I have some Seafoam fuel injector cleaner -- would that be worth running through the engine? Part of me is concerned that the reason the distributor blew out in the first place is still lurking somewhere in the car's electrical system, but that may be off-base. If it relates (and I told this to both mechanics) some other odd electrical things have happened with this car, particularly in the weeks leading up to the distributor blowing out:
- A few times, the turn signal slowed down to a crawl, and would speed up again eventually. It seemed to help to manually turn it off and back on again, but still it's weird. May not be related.
- Sometimes the dashboard lights would turn off and back on again at random. This would happy maybe once every few months. Also may not be related, but figure its worth mentioning.
Anyway, the latest mechanic may very well be right and I may need to just replace the distributor again under warranty, but the original mechanic seemed to think that that was unlikely. If any of you folks have a second opinion that you think might help. I'd appreciate it. The car has about 135k miles on it, and has been quite the workhorse for me over the years -- I'd rather not get rid of it as I may be working in the suburbs and would need a car to commute most efficiently. Thanks!
TL:DR -
Car engine is hesitating intermittently. In the last four weeks: it died, had its distributor replaced, started up but was bucking and misfiring, had ignition wires and spark plugs replaced, was driven from New Haven, CT to Chicago in two days, started missing/hesitating while driving with no traceable cause, had its fuel filter replaced by me, had its ignition circuit detailed, and still hesitates, mostly while idling. Mechanic recommended returning the distributor under warranty, and if that doesn't work, replacing the car's computer. I would love a second opinion!
posted by summerteeth to travel & transportation (12 answers total)
You may have a bad voltage regulator, which is built in to the alternator. You fix this by replacing the alternator. however you should have the alternator tested off the car, and a lot of auto part places can do this. You can also have a bad belt that is slipping, this is easy-if you have any ear splitting high pitched noises coming from the car when you start it up, it is likely a bad belt-but the this model may have a serpentine belt and those are different but still need replacement every so often, your owners manual will tell you and the perfect time to change it is when you are getting a new alternator. If the replacement part is cheap and you need to change the belt it might be worth just changing it out anyway as this is one of those items that just goes bad after a while-and ten years might be enough. (new alternator is about 160 for one you want at rock auto)
Do you have any corrosion around the battery terminals? you don't have a bad battery but you might be getting screwy voltages from bad connection on the battery that is messing up your computer (this is a long shot btw)
You could also have a bad sensor somewhere, like maybe the mass airflow sensor(but if this is the case you will likely have a check engine light) or the crank angle position sensor (part is cheap, labor usually sucks for this-a great time to get some other work done usually like timing belt/water pump but not sure on this model sentra).
BTW you don't adjust timing on these cars-no idea what the mechanic was claiming with that one. That is all set by the computer and you CAN'T physically change the timing without remapping the computer which you DON'T want to do.
I don't think you have a fuel problem at all. Generally a fuel problem only shows up at high loads (like max acceleration or climbing a hill) and then gets progressively worse. When you have a problem at idle it is likely an electrical problem.
You should really buy the haynes manual for the car and check out a nissan sentra forum for help on this as well. But don't trust a mechanic that told you he adjusted timing on this car, that kinda went out about 1990 or so on most cars.
posted by bartonlong at 4:09 PM on September 14, 2012 [1 favorite]