Car Troubles: Stalling (Sometimes)

dacount97

Ok, so I got a new Jeep (1993), new to me at least. When I'm driving it (manual, 5-speed) and I am coming to stoplights, it idles to about 100-200 RPMs until I stop fully, then pops back up to 1000 or so RPMs like normal. Every so often it stalls out when it gets so low, but the low rpms only happen every other or every 3 days.

My usual mechanic can't or doesn't have the time to re-create it, so I'm shooting in the dark here. I have tried fuel injector cleaner, no difference. It has started to concern me, because when I'm in the middle of the intersection and it starts to do this, it's like no gas is getting to the engine when I hit the gas until it decides to rev back up again. Which , if I needed to accelerate across an intersection would be a bad thing. Anyone in H/A have any ideas before I just blindly turn it over to a new mechanic?

Aurin

Check the spark plugs? Could be carbon-covered... hmm

Oil changed recently?

Trying for the cheapest things here. :P

mcdermott

Aurin wrote: »

Check the spark plugs? Could be carbon-covered... hmm

Oil changed recently?

Trying for the cheapest things here. :P

I had a very similar problem and it turned out it was the spark plugs. They were way overdue for a changing.

Not that this is necessarily what your problem is, but checking the "cheapest" things before taking it to a mechanic is sometimes a good idea. Nothing quite like paying somebody $30-$50 to tell you your spark plugs needed replaced. Hey, I was 16 and didn't know shit about cars...shut up. :P

Silmaril

When you fist fire her up what does she idle at rpm wise? It might be as simple as just adjusting the screw on the carburettor to up her idle revs. Happened with my second hand Mazda a few years back. She'd stall at junctions almost all the time. A small adjustment, and she ran perfect.


It might not fix it as it only happens to you evey once in a while, but that might just mean it only needs a very small adjustment.

SporkAndrew

Silmaril wrote: »

When you fist fire her up what does she idle at rpm wise? It might be as simple as just adjusting the screw on the carburettor to up her idle revs. Happened with my second hand Mazda a few years back. She'd stall at junctions almost all the time. A small adjustment, and she ran perfect.

Same thing happened with my 1983 Fiesta. One half-turn of a screw and it was running as fine as a 21 year old car could at that point..

Is it specifically happening on cold / damp days? I also had a hairline crack in the displacer that the HT leads go into which was causing moisture to build up and stop the engine from firing properly, which lead to stalls, failed starts and all sorts of problems. £5.50s worth of parts fixed that.

dacount97

Thanks for all the suggestions! Just to clear things up, the entire low RPM / stalling issue is random (this morning it didn't happen at all) and I've been trying to see if it's cold engine, low oil pressure but it seems none of that effects the frequency of it happening.

I also don't want to screw something up to where it won't run at all, so I'm going to get a Haynes manual to check on some of these things. Do I need anything fancy besides a socket wrench to check the spark plugs? Will it be obvious if they are dirty or is there an acceptable amount of buildup? I'm a noob when it comes to car things, I can check the fluid levels and that's about it.

Thanks again!

Silmaril

Seriously, I would fiddle with the Carb screw first. It'll be by far the most simple thing, and will at least let you know if its something more serious.

a penguin

a '93 Jeep has a carb?


Check your vacuum lines as well. In fact, check the intake hoses as well. I've had idle problems that were a cracked vacuum line (cheap fix), as well as one where the air intake hose going from the air flow sensor to the engine was cracked so the engine wasn't getting as much air as the computer thought it was, so too much gas and sputtersputtersputterohgodI'mgoingtodie... some duct tape and quicksteel fixed that right up.

edit: spark plugs are too long for most standard sockets, so you might need to go buy the fancy padded socket guy to get them out. Check for muchos carbon buildup.

mcdermott

Silmaril wrote: »

Seriously, I would fiddle with the Carb screw first. It'll be by far the most simple thing, and will at least let you know if its something more serious.

I believe a 1993 Jeep will be fuel injected.

EDIT: Beat'd! Next thing you know people will be telling him to check muffler bearings.

Aurin

Spark plug boot puller + spark plug socket (normally has rubber inside of the socket to keep the spark plug from getting damaged, they are made of ceramic!)

That should be all you need to check the spark plugs. If they're dark colored, change em.

FearTheCow

Check all your vacuum lines.

wmelon

Does this only happen when you're slowing down? If so does it happen when you coast or just when you use the brakes? If it's only when you use the brakes then it's likely either the line running to your brake booster or the brake booster itself.

Serphimera

Check/replace the spark plugs. The are really cheap, so if there is any crud just replace them.

mcdermott

Serphimera wrote: »

Check/replace the spark plugs. The are really cheap, so if there is any crud just replace them.

Yeah, and even if it doesn't fix your problem you probably just saved yourself a future headache. Plus I think it affects gas mileage, but I'm not sure.

Weretaco

Intermittent stalling could also be a fuel filter issue.

Unless you have one of the stupid designed cars with the filter in the tank, it's a quick and cheap replacement that should be done as part of your normal maintenance anyway.