Stuttering Problem

[KlubFoot]

I have a 95' Eclipse GSX and I have been having some problems lately. In 2,3,4,5 gears my car stutters when I nail it but rides smoothly if I'm just driving normal. I'm thinking that this might have something to do with the turbo since I don't boost in 1st gear but I do in the remaining gears. If my turbine was pitted would this cause this to happen? Please let me know. THanks.

 

Taran

[Guest 1bad66duece]

HAVE YOU CHECKED YOUR FUEL PRESSURE?

[Renner]

How many miles are on your car? And how has it been treated over its life? Is this just an intermittent problem? Did this just suddenly start occurring one day, or has it been gradually getting worse over time? Is it better or worse when cold or hot, or does it act the same all the time? Does the car idle normally, or does it idle high, or surge from low to high?

 

If you post a few more specifics about the problem, we might be able to help you diagnose it.

 

You may have already done all these, but here are some suggestions as to where I would start:

 

First I would check for a boost and/or vacuum leak. Check all of your hose clamps on your intake and boost tubes and make sure that they are tight and that the rubber tubes are not cracked. This is pretty easy to do yourself so it won’t cost you any money. If you have a boost hose that is just slightly loose the car will drive fine at near idle speeds but will not run right as soon as you build boost pressure because it could be blowing buy, throwing off your air/fuel ratio.

 

Next I would check your fuel pressure as 1bad66duece suggested. It could be low due to a dying fuel pump or something simple like a clogged fuel filter, when was the last time you replaced your fuel filter?

 

Also, has the car had all of its other regular maintenance stuff performed? What kind of condition are your air filter and spark plugs in? A severely clogged air filter or excessively worn plugs could make the car misbehave.

 

What kind of gas are you putting in the car? If you are using the cheapest 86 octane you can find, the car will probably have some detonation on boost, making it run like crap.

 

There are a number of other things that it could be as well, loose harness connector somewhere, or even partially clogged injectors that can’t move enough volume under boost enrichment. Your fuel pressure regulator could be dying as well; the fuel pressure test will help identify this.

 

Unless you know that something was actually ingested into your turbo, chances of it actually being the problem are slim if it isn’t smoking like crazy.

 

I don’t know how mechanically inclined that you are, but if you want somebody to check it out I might be able to lend you a hand. I am doing some work for friends on the side right now, so if you want some help my rates are pretty reasonable. smile.gif Send me an e-mail at burton.122@osu.edu

 

Or if you get an absurd dealer estimate to fix your car, post the details on here. There are a lot of knowledgeable car folk on this board that could help keep you from getting screwed.

 

Hope this helps.

[GRN96WS6]

Damn Brett I think you about covered it all

 

 

I wish I knew half the stuff you do smile.gif

[Renner]

<BLOCKQUOTE>quote:</font><HR>Originally posted by MR. EARS:

Damn Brett I think you about covered it all

 

 

I wish I knew half the stuff you do smile.gif<HR></BLOCKQUOTE>

 

You know plenty of stuff that I don't, you know how to break shit good!

[GRN96WS6]

And don't you ever forget it tongue.gif

[Renner]

<BLOCKQUOTE>quote:</font><HR>Originally posted by MR. EARS:

And don't you ever forget it tongue.gif<HR></BLOCKQUOTE>

 

I guess breaking shit is the best way you learn how to fix it right?

[GRN96WS6]

Oh so true oh so true smile.gif

[SupraGlue]

Like Brett said, you need to post more details about your car, otherwise we're just guessing.

 

In which case, I'd guess that the most likely cause is that your plugs are misfiring under boost due to either too large a gap or carbon fouling.

 

You either need new spark plugs at a narrower gap, or you need to drive your car harder (aka an Italian tuneup).

[KlubFoot]

Okay... first off I'd like to say thanks for all of that info! I'm gonna try to answer those questions as reasonable as I can and maybe you can tell me whats up.

Okay first off it's a...

95' GSX with 75k miles

As far as I know the car has been regularly maintained and never driven hard (untill i bought it )

The problem started about 4 weeks ago all of a sudden and since then it has been getting worse.

It is alot worse in the cold (boost loves cold weather) but it still happens once the car is warmed up. It only happens when I boost.

The idle is still the same as it has always been.

 

Check ups: When the problem first started occuring and I had no idea what was going on I took it to passen to see what they had to say. They checked it out and said that there was a bunch of oil in my spark plug wells like someone had spilled it in there. They replaced my plugs and wires and checked out my turbo. Rojer told me that something had gotten through the intake and pitted up my turbine and that may be a cause of the stutter.

The plugs and wires did not make a difference. I have since then had my oil changed and that's it.

Since I am still very much in the learning process with my car I would really have no idea as to how to check for a vaccum/boost leak or my fuel pressure.

As for fuel, i only run 93+ octane at ALL times. Nothing less has been fed into the gas tank since i have owned it.

 

Also another problem has recently started. When I start my car it turns on and then something clicks and grinds for about 1 sec. i have NO idea what this is either. Maybe the 2 are connected... maybe my car is just falling apart.

 

Thanks for all your help mann I really appreciate it.

 

Taran

[SupraGlue]

Your description still sounds like an ignition miss under boost to me. Did anyone at Passen tell you what kind of plugs and at what gap they put in? Did they show you the old plugs or give them to you? Did they check coil output as well?

 

The pitting business -- did he say it was the compressor or turbine wheel? Your post says turbine, and I have to doubt that, because it is a lot of work to get to a point where you can look at the turbine. Either way, that sounds like someone is trying to sell you a new turbo. It is very unlikely that your turbo is the cause of this problem.

 

Have you (or did they) pressurize the intake system and check for boost leaks? This is usually done by pulling the intercooler hose off the turbo and using either a bicycle pump or air compressor to pressurize everything post-turbo, then listening for leaks. What we usually do on Supras is use an empty soup can and fit an air nozzle to the end of it, then jam the can into the open IC pipe. You then pump it up to a pressure moderately higher than what you run (say 20 psi if you run 14), and listen for hissing air.

 

To check fuel pressure, you need to find a place to fit a gauge and sender into your fuel system. You don't want to run a mechanical gauge into your interior for safety reasons, btw.

 

Do you get any black smoke out of the exhaust under boost? You might want to have someone follow you and check to find out. That would tell you if you are running really rich, which might be an indicator of what's going on.

 

Okay Brett. Your turn.

[Renner]

Ok, thanks for the handoff Mark. smile.gif

 

Well, about the clicking and grinding noise, is this while you are actually starting the car? If so then it is probably something with your ring gear on your flywheel or the engagement gear on your starter. Which should not be related to your hesitation problem. If it is immediately after you start your car, then the return spring on the starter engagement gear is probably wearing out. Causing the gear not to immediately release giving you that grinding noise.

 

Like Mark said, it sounds like they were trying to sell you a turbo. I very seriously doubt that your turbo is the cause of your problem.

 

Well, hopefully Passen did actually replace your plugs, and hopefully they gapped them at least close to correctly. If this did not seem to improve your problem at all then it may be a problem with not getting enough fuel. Hopefully your coil packs are not going bad because those are not cheap to replace. So if after some testing and inspection your ignition checks out fine then something with your fuel supply is probably not right. It may be something simple like a fuel pressure regulator or maybe the filter or the injectors are a little clogged.

 

Unfortunately, I don’t really know what else to tell you without actually checking it out for myself. I might have a bit of time to take a look at it this weekend if you like. I am supposed to have some other friends cars to work on too, but I should have time for a quick look. At least that way if you want to take it someplace else to get fixed you have a pretty good idea of what the problem is before you get there. Send me an e-mail (burton.122@osu.edu) if you want some free advise and I can tell you when I am available this weekend. Or if you want, you can meet the group out at Hooters this weekend. Then you could have 70+ people standing around your car all at one time trying to figure out what is wrong, wouldn't that be fun!

 

-Brett

 

[ 22 February 2002: Message edited by: Renner ]