1996 Talon N/A: Shuts off at stops

[ZacFields]

Hey Guys,

Got a whole new problem with the talon today. The good news is that it starts up and runs fine. Other good news is that I had the alternator and the battery tested today and they both tested perfectly fine, and I replaced the air filter and spark plugs today.

Bad news is that when applying the brakes to slow the car down to a stop, the RPM's slide down to around 500 normally and sometimes as low as 250 or less, thus causing the car to shut off sometimes.

I've replaced the spark plugs (needed to be replaced anyways as the old ones were starting to get corroded), and the air filter (also badly needed to be replaced).

Some ideas I've got through googling are a fuel pump and/or O2 censor. I also saw some people blaming it on the transmission but I couldn't imagine that being the problem in this case.

Anyone? I have a feeling it probably is the fuel pump or O2 censor. Anyone know how hard those things are to replace?

Zac

[Luminatorz34]

zac atleast check the tranny fluid. it could be possible the tranny is putting a load on the motor at stops like that, and not disengaging like it should. as far as the o2 sensor. its really simple to change out. and the fuel pump is not. it pretty much involves you dropping the tank out from under the car and pulling it out of the tank. can u hear the pump straining at all? you might wanna look at a fuel filter too. cheap and easy to fix. but these would be symptoms of the car running bad all the time, like it would stutter and jump trying to take off or start in the morning.. it might be possible the idle air screw came loose a few turns. what does it idle at in park?

[TbTalon94]

I don't see any of those problems causing it to die while you brake. It sounds like an electrical problem. How exactly did they test your alternator? The fuel pump can be changed without dropping the gas tank. It's a WHOLE lot easier then that. O2 sensor is also pretty easy...but i don't think either of those would fix your problem.

I'd go over your grounds, make sure none are loose..make sure your battery terminals are tight and aren't hitting the hood anytime. Check the tranny fluid and make sure everything else checks out.

[Drifte]

you should get a CEL if your 02 sensor is bad anyway. Id check the trans fluid and grounds. Barry's old eclipse did the same thing, and it was in a fire that caused electrical problems if I remember right. His would die in drive if you werent moving and stuff. See what happens if you pop it in neutral when coasting or coming to a stop. Make sure your idle in park is about 750, to high the torque converter may be causing it to stall, to low and same thing.

[ZacFields]

Idle in park is between 750 and 1,000 usually. Sometimes when I first start it, idle is right at 1100 but once the engine is warmed up and all it idles right around 750.

The first thing I thought was electrical, because my car had the same problem for a while and it just turned out that the negative end of the battery wasn't making a connection, so sometimes when I hit a bump the car would shut off quickly. The only reason it's harder for me to think it's electrical this time is because this shutoff is just so smooth compared to when it happened to my cavalier. My cavalier would just instantly shut off when I hit a bump. This problem is strange because when I brake, the RPM's just ease down to 500, then sometimes 250 or less. Sometimes it doesn't shut off, and sometimes it does.

Tranny fluid is good. Nice and red and its at the correct level.

Also, autozone checked my alternator through the battery. Started up the car and measured how much power was getting sent to the battery.

I'll take a look at some things tomorrow on my day off.

Zac

[RandomHero]

check cam sensor and crank sensor, my Blazer was doing that exact same thing.

[ZacFields]

^ I'll have to look into that Matt. Haven't done so yet, though.

I talked to Trevor today for a minute, but I've got some new information about this that I wasn't aware of (Ashley drives the talon usually, not me). This is only a problem when th engine is cold. Once the engine is warmed up, this problem completely disappears, and the RPM's only go down to about 750 (which I believe is standard) at stops.

Does this change anything for anyone's estimates as to what the problem is? I checked the tranny fluid again today and it's red like it's supposed to be and it is full (possibly a little higher than it should be, though). I did notice that the tranny fluid seemed to be a lot more "watery" than I thought it should be. Thought tranny fluid was thicker than oil, but could be wrong about that.

Anyways, yeah this problem disappears when the engine's warmed up completely.

Zac

[Ashley]

it has a hard time starting when its a little cold, too. i have to hold the key down for a long time for it to actually start. idk its probably normal since its older and cold.. but i never really had that problem last winter, just lately.

i think the car is just doomed. :Hangman:

[ZacFields]

Yeah. It's the stupidest thing ever I think.... we drove the car all day today. This morning when we first started driving it, it was a little rough for about 10 minutes of driving. It was sliding down to 200 rpm's or so when I would stop and come dangerously close to shutting off. Then at one stop I decided to see if I could shift it into neutral to see if that would help anything, but in the process of changing the gear to neutral the car shut off.

That was the last we saw of the problem today. I took Ashley to the doctor, then we went to Sams Club, back home, to the post office, to Ashley's parents house, to Target, to westdale mall, then back home. Only that first 10 minutes did the car give us ANY trouble.

So whatever is wrong with the car, it's not a problem if the car is kept warm. I just need to find out what it is so I can see if it can be fixed cheaply. The car runs fantastic otherwise. The hard-start problem that Ashley is talking about, I believe is tied into this same problem.

Zac

[Drifte]

really hard to say. Give it a full tune up and see what happens is all I can suggest. Not any way I can think of to test fuel pump strength, and i dont see it being the problem as its just when the cars cold. Fuel system cleaning, fuel pump, check all vacuume lines as a slight leak may not be much issue when the car is warm and wants to run, but problematic when cold. If it seems to take a long time to get it to fire, theirs a good chance it is your fuel pump. I know chevys old pumps actually kinda wear out vs what ive dealt with where they just die. car will run less than desirable, but theirs no real sign of it being bad. Try running some high octane fuel through it with fuel additives/cleaners. Make sure you change your fuel filter too tho.

so auto shop w/ injector/fuel system cleaner. maybe grab a new pcv valve cuz it cant hurt. Put in some good gas, and the additives and fuel filter. No change, try a pump. you know people so it wont cost you much.

[ZacFields]

That sounds like a good plan Colton. I've already done the basics of a tune-up (changed the spark plugs, air filter, its still current on oil change, checked all fluids, etc).

I really want to get the fuel filter changed out, because I would imagine that has never been done on this car and it's at about 140,000 miles right now. I'll have to google how to change it, as that's something I've never done before but my dad says I should be able to figure it out.

Zac

[96-eclipse-gst]

I have a 95-99 shop manual sitting around here somewhere includes the 4g63 and the 420a as well. Ill look in to it, I know it helped on my car when I got the fuel filter changed out.

[ZacFields]

Let me know Andrew. Maybe we can do that when we change those struts too. Just let me know what it'll cost for the filter.

The work is just pilin' up man. hehe. I guess better to do it all at once than have to constantly do things over and over.

Zac

[TbTalon94]

Might want to look into the coolant temperature sensor too Zac. When they go bad the car thinks it's colder/warmer then it actually is and it messes with all kinds of things. Definatly would explain why you only have a problem when it's cold out.

[ZacFields]

I looked that up just now. Sounds like a fair guess and it seems easy to replace. Looks like you disconnect the battery cable, unplug it, unscrew it, put the new one back in, and plug the wires back in.

I'll do this today. I'll let you know how it goes.

Zac

[ZacFields]

Just got done changing that out. We'll see if it helps. I have no way of knowing right now though because I drove the car to autozone to pick up the part, so it's warm right now and probably will stay that way for at least a couple hours.

Even if it doesn't work, the part was only $7.99 and it was easy to install, plus the old one looked like crap. I also read that sometimes the problem with this part is the wiring, I know the connection on the old part was green and corroded so there's still a chance there could be some problem with the wiring.

I will update this later. THANK YOU Trevor for suggesting this one. Whether it works or not, my description of my problem matches the failure symptoms of this part to a tee. :)

Zac

[Drifte]

i was gonna suggest coolant temp sensor, but mine never would even start once that went bad. hehe, silly cars. I know u can do a fuel filter its no big deal. I just got done doin one for my bros gfriend. Hers was so bad it was rusted, and leaked fuel out....so it was time in her case (damn ford).

[ZacFields]

Yeah I think i'm gunna do a new fuel filter anyways, because I'm 100% sure it's never been changed and probably either needs it now or will need it soon.

I read a DIY on the internet about it earlier. They said to remove the fuse for the fuel pump and start up the car until it dies. Then try to start it a couple more times to make sure all the fuel is out of the line.

Then looks like it's a matter of unclamping a hose and switching the part out.

Zac

[Drifte]

hehe yea thats one of those "cant sue me" im so safe DIY. Really all I ever do is take the gas cap off and crack the filter lines loose. Usually have a rag under it to catch some excess fuel. I assume yours is in the same place as the turbo dsm's anyways.

[TbTalon94]

So did it fix it Zac?

[ZacFields]

^ Unfortunately no it didn't.

However, it did fix one thing that we're pretty happy about... the coolant temperature guage works now! Before, it worked a little, but wouldn't register anything until the car was already warm.

But as for this problem, it didn't fix it. Man I really hope this isn't a transmission issue. Anything to do with the tranny is usually expensive.

But at least the temp guage works now. ah well. I'd really like to fix this problem, but if I can't fix it, I hope it's something that we can live with until we can afford a new car.

Zac

[Drifte]

well wait...did you replace the right one? I cant remember its been a while, but theirs usually multiple sensors one for the gauge one for the computer. And I was thinkin your car had the last year 4g63, not the 420a...again my memory is pathetic so could be wrong.

[ZacFields]

it's a 420a but there were 2 sensors located in the thermostat housing.

The one I replaced was smaller and was underneath the other one. I don't know what that was sitting above it, but looks like installation would have been very similar. I'll have to look into what that other thing was.

Here is exactly what I got: http://www.autozone.com/R,APP227097/veh ... Detail.htm (http://www.autozone.com/R,APP227097/vehicleId,2141701/initialAction,partProductDetail/store,1912/partType,00113/shopping/partProductDetail.htm)

Zac

[ZacFields]

This is what I believe was above the coolant temp sensor that I replaced. Should I replace this too?

http://www.autozone.com/R,NONAPP16503/s ... Detail.htm (http://www.autozone.com/R,NONAPP16503/store,1912/shopping/accessoryProductDetail.htm)

Zac

[Drifte]

shoot idk zac. i searched the world and didnt get much info from most 420a enthusiests...most seem to be pretty dumb ricer type. But. It reminded me of other things to keep you busy.
95 ECU's are more likely to go bad than on other years.
check for vacuum leaks (intake mani gasket?)
pull the IAC and clean it. It often gums up, which causes it to react very slowly
You can also test it, 38-52 ohms between 1-4 and also between 2-3. Third, while you are
cleaning and testing the IAC, you will want to clean the TB plate and bore
leaky injectors?
96-99 fuel filter loacted in front of the rr tire
95 is next to windshield fluid resevoir.
tps-When throttle is closed, TPS should read approx. 0.4v, when WOT, a maximum of 3.8v.

kinda sounds like dirty iac...but it could be so many little things im not puttin money down on anything!

gluck'

[ZacFields]

I went ahead and changed out the other coolant temp sensor and no dice. Not a huge deal, because at least I got some use out of it (guages work now) so it wasn't a total loss. The 2nd one I replaced was probably okay.

Yeah I've googled this problem up and just can't seem to find much help on the internet. Most things I've seen suggested are stuff I've either already looked into, or things that just really shouldn't be the problem in my case.

I'm worried it could be the tranny because i do know that popping the tranny in neutral bogs the RPM's (just during the switch) and when you back out of a parking spot and you're changing back into "DRIVE", it bogs down the RPMs and sometimes it'll cut off. So I'm wondering if I'm having this problem at stops because the tranny is shifting down to first or something. Still wouldn't explain the disappearance of this problem when the engine is warm.

Just confuses the hell out of me because the problem goes away when it gets warm. The coolant temp sensor really made a lot of sense. But now I've changed them both and haven't seen a change, at least not immediately. I had to drain a little coolant out so I could remove a hose to get to them, and I haven't replaced that coolant yet, but those temp sensors are on the other side of the thermostat anyways.

Zac

[96-eclipse-gst]

I don't see any way how it could be the transmission. Its gotta be something else, like they said intake mani is a possibility, something could be leaking. We just need to work through all the possibilities.

[ZacFields]

Well i've taken care of a few of them already so at least we're part-way there :)

Umm, from what I'm reading online, just because I changed the coolant temp sensor doesn't mean that it still isn't the problem. They say often it's actually the wiring of the coolant temp sensor that goes bad rather than the sensor itself.

It could be anything. I'd say I just need to start with the free fixes, then work my way up starting with the cheapest fixes.

Zac

[TbTalon94]

The wiring they would be talking about is the wires that go directly into the back of the plug. They get corroded easily and break off or get frayed. Just check them over and if it looks bad or corroded then just cut the plug off and wire it back a little bit.

Again check for vacuum leaks and stuff like that :yawinkle:

[Drifte]

the more you tell me about it the more it sounds like idle control valve. Its common for them to get dirty, when they do they dont work right. I thought I had a bad one once, $180 new because they dont remanufacture them..although i figured out how to rebuild them. I sprayed it though, with battery cleaner, and its as good as new.

WIth your tranny...since its time anyway, get it flushed, find out if that model trans uses a tranny filter. If it does, replace it too, and consider yourself lucky if it does have a filter!

[ZacFields]

I haven't checked the wires on that coolant temp sensor yet. I looked at them and it was hard to tell.

Do you guys think I should unplug the coolant temp sensor and start up and drive the car to see if there's any difference at all? If it's functioning properly, shouldn't I notice if I unplug it? And if the wiring really is bad somewhere down the line, there shouldn't be any difference at all if I unplug it.

Zac

[Drifte]

that'll do it zac. just make sure you do it during a cold start.

[ZacFields]

well gosh darn that's been one of my better car ideas as of late. hah.

I'm at work now, but I'll give this a try tomorrow hopefully. Should be a quick and easy way to rule something out, if nothing else.

Zac

[ZacFields]

Update:

Haven't messed with the car in a couple days. This problem sucks, but its not really a pressing problem. Ashley seems to think it is getting worse, though. She said today after she'd been driving the car for 10 minutes or so and the car was at operating temperature, she stopped at a light and the idle just hovered right at 200 and didn't even itself out, whereas usually it just drifts down to around 200 and then evens back out to about 750 which I've taken to be normal.

I'm starting to wonder about vacuum leaks and the idle valve control. I have two questions:

1. How would someone test for a vacuum leak?

2. Where is the idle control valve and is this something I can/should check on my own?

I may update this post in a little bit as I'll probably google this info now, but figured if anyone had any advice knowing my limited mechanical abilities :)

Zac

[ZacFields]

Tried to get to the idle control motor today and couldn't find it. I've been able to find numerous articles on how to remove it from a 4g63, which I find funny because on those engines it is in plain sight and all you need is a damn screwdriver.

Looks like to get to it on my 420a I would need to remove the throttle body, which is something im not comfortable with right now because I dont know what the hell i'm doing.

But the bright side is that I've read a lot of articles by people who are having the same problem as me and replacing that ISC has worked for a lot of them. Most of those guys did it on the 4g63 but I would imagine the ISC has the same function/problems on a 420a as well.

Guess I"ll have to find out if Andrew can get to that ISC for me. I'd like to try cleaning it first, but for the 420a engines the ISC is $50 I think.

Zac

[ZacFields]

Here's my recent post on dsmtuners.com, thanks to the tips from a lot of you guys and some research i've been doing online.


I will check for vacuum leaks. I have a few friends that have been working on DSMs for years that are going to be helping me in the coming weeks.

The good thing about this problem is that the car starts and runs fine, even though sometimes you've got to struggle with it to keep it running right after you start it when the engine is cold. So it might be a couple weeks before I'm able to get back to you guys about this, but I've bookmarked this topic so I will get back on here and let you guys know what did and didn't work. But for indexing purposes, here is what didn't work so far:

-Changed Coolant Temp Sensor (Actually changed both of them. In my 420a, there was one specifically for the guage in the dash, and the other one above it was the "functional" one that communicates with the MAF i guess)

-Changed out the spark plugs

-Changed Air Filter


That is the extent of what I've done so far to remedy this problem. I will update this as I do more things. From the research I've done, this is most likely the ISC motor though. That would explain why this happens when the RPM is dropping from regular acceleration RPM's. The ISC isn't "catching" the RPM's as they fall to the correct idle speed. If the drop in idle speed doesn't kill the engine, then it usually evens out to where it's supposed to be (750-850rpm). It'll drop down to 200, then it'll catch back up to 750-850. Sounds to me like a gunked up ISC motor from the reasearch i've done. It's just sluggish with catching that falling RPM. That would also explain why it gets better once the engine is warmer. Whatever grease/grime that is keeping it from operating correctly warms up and eventually it isn't as much of an issue anymore once the engine is warm.

Again, this is only an issue of "catching" the RPMs when they fall from say 2.5-3k or higher. The car actually idles just fine. No surging that I've noticed. If you get it idling, it will idle all day like it's supposed to.

Sorry for the long post, but I'm having a lot of trouble finding the correct solutions to this problem (EXE: Original poster tends to disappear after the problem is fixed and not take a moment to enlighten everyone as to what worked) so I'd like to fully log this situation for my engine (and the original poster who appears to have the exact same problem) so people that have this problem in the future won't have to waste a lot of money.

Seems like there's always a small fraction of this problem that is different with every situation.

Zac

If that makes any sense to you guys. That's how I'm rationalizing this problem.

The biggest update I can give you guys is that I was sitting in the garage today letting the car idle to warm up the engine (those hoses were rock solid cuz it was freezing balls today) and I was revving the engine slowly up to about 2,000 RPM's and letting it fall. It would idle fine at 750-850, but when I would rev to 2,000 and let it fall, it'd fall down to about 500 or so. Then I revved it up to 3,000 and let it fall, and that would kill the engine. It just wouldn't catch when the RPM's got down to idle speed.

So that's telling me that I've got a slow-to-respond gunked up ISC motor most likely. I mean... I don't know much about cars, but I've learned a lot through researching this problem and this is the most rational explanation I can come up with. Again, the car idles perfectly fine...it just seems slow to respond to a drop in RPM. If it's like grease and oil that is clogging up that little motor, then those are things that would be less of a factor when the engine is heated up.

:::Shrugs::: there's just so little definitive information about this particular problem out there on the net.

Zac

[Drifte]

sounds like gunked isc to me. couldnt tell ya where its at, but if ya let someone look at it they should be able to find it and tel ya just what ya need.

[ZacFields]

I guess its not such a matter of finding it, as it is a matter of getting the TB off. I'm just not very experienced at these things and don't want to end up messing something up. Once I get the TB off I'm sure it would be in plain sight. I've heard it's on the rear side of the engine up by the TB so....

Just gotta get the throttle body off and fixing it is as easy as removing 2 screws, spraying it down with some cleaner, and putting it back on. If doing that makes the problem go away (or at least makes it better) then you know for sure that's what the problem is. I've read that you can clean them but replacing them is a better option. I believe this part for the 420a is only like $50 though.

Maybe that would explain why it seems not to be the problem on the old 4g63's? I heard the isc motor on those are like $150+. Lots of people I've noticed misdiagnosing themselves on the 4g63 and end up spending all that money and that not even being the darned problem.

Zac

[Drifte]

420a and 4g63 are apples and oranges. cant really compare them, only thing thats the same is 4cylinders, 2.0l, and dsm shell.

[ZacFields]

Well I really wish I had a 4g63 when it comes to this problem. Seriously.... the ISC motor/servo on the 4g63 is right underneath where the intake connects to the TB. You don't have to remove a single thing to get to it. All you need is a phillips head screwdriver and you're all set.

on the 420a its apparantly BEHIND the TB, which means it would be basically impossible to get it off without first removing the TB, and as I said that looks to be somewhat of a big job.

Zac

[Drifte]

haha, well, its not quiet that easy on the 63, but an na 63 doesnt perform as well as the 420 either. Theirs ups and downs to both. If I had any free time we could do it over the weekend. My civics gettin a new waterpump this weekend tho, and oil.

[TbTalon94]

I'd help you to but this weekend I've got to put my Talon back together, and then put Andrew's Eclipse back together....ah another busy weekend with working on DSMs. Story of my life.

[ZacFields]

It's no huge rush. Really the car has been doing great as far as I can tell. This problem is just annoying at best. If anyone gets any free time on a Tuesday or Thursday and wants to help me out, let me know. I don't have a lot of tools at my house but I'd be willing to bring the car to your place, wherever.

I'm just ready to get this problem taken care of. Its breaking my spirit in DSMs. lol.

Zac

[ZacFields]

The problem has now been fixed... although I didn't really do anything.

I've read that sometimes this issue has to do with the ECU of the car, and that disconnecting the negative end of the battery for 60 seconds will reset the ECU.

The other day I was going to charge up the battery (some weird guy on the DSM forums said that he was 100% sure it was the battery... I was 100% sure it wasn't, but I figured I had the day off and nothing better to do) and so I unhooked the battery completely and plugged in the charger. The charger wouldn't charge the battery because it was already testing at plenty of power.

The whole process took me about 5 minutes once I removed the battery and then hooking up my charger and such. Ever since I plugged the battery back in, the car has run great. Even from cold starts.

My only concern is that when I read about this before, the person said it only fixed the problem temporarily. I'm hoping my problem is fixed completely. Maybe I'll have good luck and the problem was just that the battery hasn't been disconnected in over a year and a half.

Zac

*EDIT* Ashley claims its happening again, so apparantly it really is only a temporary fix? I still think I need to clean that ISC motor because that's what makes the most sense. I just thought it was very interesting that resetting the ECU temporarily fixed the problem...though I can't find anything online that tells me what to do if it is the ECU's problem.

Anyone think it's possible that the ISC motor is throwing off the ECU values and thus resetting the ECU (which restores the default values) makes it so the car runs fine until the ECU has time to adjust back to the improper readings it is getting from the engine? I read somewhere that a bad ISC motor is not good for the car's ECU.

[TbTalon94]

Sounds like it's a sensor somewhere. Reseting the ECU will reset all the values and everything will run fine as long as it isn't a mechanical problem, until the ecu figures out the sensor is bad then it will run in a sort of "limp" mode. Reseting the ecu kicks it back to factory defaults and thus fixes the problem temporarily.

I'd definatly check that ISC, and the wiring on other related sensors. It sure sounds something electrical.