New and have a tech question

[StangLaura]

Okay I guess first I'll introduce myself.. I'm Laura and I'm 22 and from Houston

The car in question is a 95 rs at

the problem: Basically the car will cut out like someone hit a kill switch... if the car has enough momentum it just stutters and bucks a little and keeps going... if the car is stopped or rolling when this happens it will totally die out.

what we've replaced: tps, map sensor, coolant temp sensor, fuel system has been cleaned, wires/plugs, fuel filters, umm and I can't think of anything else right now...

no codes are showing

we were thinking electrical short or that it needs a new computer... possibly camshaft position sensor (although I've been told this would throw a code)

I've looked through the faq, tuning, and articles and haven't really found anything with similar symptoms except for the stuttering being similar to losing 4th gear in the at...

so before before we keep throwing money at it I figured I'd see if there were any common problems with this that I'm just not finding...

Any help would be appreciated...

 

[98eclipseRS]

hmm... don't know what to tell you, I don't mean this in any negative way what so ever but you might be better off asking this question at 2gnt.com most of the guys on this site now the most about the 4g63 and the mitsu tranny. You could also pm doug99rs he is the n/t wiseman on this site if anyone could help you out it would be him. Good luck, you usually don't see the n/t acting up.

 

[Shifty]

Checked the Cat Converter?

 

[StangLaura]

will do.. I did see a lot of turbo talk here... thanks for the recommendation though

edit: the cat is bad I think but I don't know about bad enough to cause these problems... it passed emissions but there is some rattle from it I believe...

 

[leakyfaucet]

Unlikely, but your car may have jumped timing. Another thought that comes to mind is a clogged fuel filter, also unlikely. Did this happen all of a sudden or slowly get that way? More info is needed!

Check your spark plugs. What color are they?

Black=rich
White=lean

That will give you a better idea of what to look for.

 

[StangLaura]

fuel filter has been changed...

timing actually sounds reasonable if it jumped a tooth or something...

plugs are good

i really don't know how much of a progression it's been... it's my little sister's car and she didn't have her liscense when we bought it so it sat for about 6 months and got driven about once a week. Now that she has been driving it it seems that it has progressed... but I take it that the problem existed before we bought the vehicle

 

[leakyfaucet]

plugs are good

I understand that they've been changed but what color are they? If you meant they're good as in they're the proper brownish color after the car's been driven, then okay.

Sorry, I re-read your first post and realized you already said the fuel filter has been changed.

This is a tough one. I want to say ignition coil but I doubt the car would run at all like that.

Why do you have stang in your name? Did you have one? I have a 93 5.0, that's why I'm interested.

 

[StangLaura]

plugs are good as in proper color

coil has been changed too

someone on 2g said that the 95s are pretty bad about ecu's so that may be the problem..

and yeah I have a 2000 mustang the eclipse is my little sisters car

 

[leakyfaucet]

Sorry, I can't think of anything right now. I doubt it's the computer if it runs worth a shit at any point but if that's all you can think of, test it before you go and replace another properly working part.

How well does the car run? Undrivable or just a little crappy?

What model stang is it?

 

[StangLaura]

Sorry, I can't think of anything right now. I doubt it's the computer if it runs worth a shit at any point but if that's all you can think of, test it before you go and replace another properly working part.

How well does the car run? Undrivable or just a little crappy?

What model stang is it?

car is drivable but since it's my sisters first car she won't drive it since it's cut out in the middle of intersections. (which is understandable)

it runs fine otherwise... tranny will probably need to be replaced within a year or two but thats kinda expected... ummm i think acceleration is where it should be... barely gets out of it's own way ...

as for the other cars... my dads got a 88 gt, I've got a 00 v6 (that will have a 351 in it eventually) have a 96 z26 and am also getting a 89 iroq hopefully this weekend

but I'm a 5.0 junkie so if you have any questions I definately know more about those than dsm's

 

[11scndtalon]

hey laura, has the top speed slowly gone down on your sisters car? i would say it could definately be a clogged cat if thats the case cuz i've had that happen to me b4

 

[StangLaura]

I don't really know about the top speed... it usually doesn't get taken above 70... I'm gonna try to check the cat tonight... I don't even know if it's flanged in or welded.. if it's flanged I may go ahead and gut it since it needs to be replaced anyway... I'm also going to do the voltage tests on the ecu.... most of the 2gnt guys are saying that it sounds like ecu...

if the cat was clogged would that cause the exhaust to be rich at all?

 

[69trgt6]

Rich exhaust would cause the cat to go bad. That and overly aggressive use of octane booster and/or dry gas. All three cause the cat to get too hot and that could melt the ceramic internals of the cat causing it to clog. If it's clogged and the plugs that you replaced look good, hard to tell what caused it, but gutting it will definitely prevent it from clogging again. Typically a car with a semi-clogged cat will idle ok, but lose power and start to stumble at high RMP and engine loads bacause it cannot get rid of the exhaust. It's also not typically intermittent.

 

[leakyfaucet]

Running rich will NOT overheat the cat causing it to melt.

 

[RBurroughs]

what about a bad alternator?

 

[69trgt6]

Leaky,
I've been in the automotive bussiness for over 10 years professionally and better than 20 years as a hobbiest. I have seen the negative effects of a rich running vehicle on a catalytic converter. You may not believe, but I've seen it with my own eyes. Admittedly, it was on some of the earlier honeycomb converters, but it happened. Funny enough, one of the cars I saw it happen to was a 5.0 Mustang of mine, dealer actually replaced the H pipe for free.

 

[leakyfaucet]

Leaky,
I've been in the automotive bussiness for over 10 years professionally and better than 20 years as a hobbiest. I have seen the negative effects of a rich running vehicle on a catalytic converter. You may not believe, but I've seen it with my own eyes. Admittedly, it was on some of the earlier honeycomb converters, but it happened. Funny enough, one of the cars I saw it happen to was a 5.0 Mustang of mine, dealer actually replaced the H pipe for free.

Are you sure you're not confusing it clogging the cat with melting? I've had something similar happen to my 5.0. The aftermarket cats I had have two big chunks of honeycomb inside. While running incredibly rich from failed o2 sensors, the more rearward part broke out and clogged part of the exhaust. I had to pull the H pipe and bang the crap out with a broomstick.

Running rich, the exhaust should be cooler. I can put my hand on the end of my longtubes and the exhaust only warm. I don't see how a little warm air is going to melt the cats, unless it totally screws with some chemical in the cat.

 

[Doug99RS]

Okay I guess first I'll introduce myself.. I'm Laura and I'm 22 and from Houston

The car in question is a 95 rs at

the problem: Basically the car will cut out like someone hit a kill switch... if the car has enough momentum it just stutters and bucks a little and keeps going... if the car is stopped or rolling when this happens it will totally die out.

what we've replaced: tps, map sensor, coolant temp sensor, fuel system has been cleaned, wires/plugs, fuel filters, umm and I can't think of anything else right now...

..

I would want to know if the memory is being reset each time you stall out. It could be the computer going bad causing a loss of power to everything it controls OR to one of many things needed to keep the engine running.

Of those sensors in question, I would check the crank sensor wiring located just above the oil filter on the back side of the block. If the crank sensor signal goes hay-wire then you will stall out completely. The headgasket on the 420A is well known for leaking. I've personally seen a few wiring harnesses for the crank sensor fully saturated with oil causing the wires to short together.
Doug

 

[StangLaura]

I would want to know if the memory is being reset each time you stall out. It could be the computer going bad causing a loss of power to everything it controls OR to one of many things needed to keep the engine running.

Of those sensors in question, I would check the crank sensor wiring located just above the oil filter on the back side of the block. If the crank sensor signal goes hay-wire then you will stall out completely. The headgasket on the 420A is well known for leaking. I've personally seen a few wiring harnesses for the crank sensor fully saturated with oil causing the wires to short together.
Doug

ok on the crank sensor... is there an easy way to get to all the stuff? like I can barely reach it to unplug it I can't even imagine trying to splice wires there...

 

[Doug99RS]

You've got to jack the car up in order to get to it. Once the car is up in the air then you will have a good bit of room to work with compared to going in from the top. Did you find any problems down there?
Doug

 

[Defiant]

Wild guess, but make sure the battery isn't shorting against the underside of the hood.