Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)
clipod

Loss of performance after warm up

Recommended Posts

Hi Everyone,

I have a boxster 01, 5 speed manual, 70k milage. I got it from a person who sold it around 64K. I did a 60K service on it.

This is my first car so didnt knew much when I brough it. After I brought the car I noticed that around 3000 RMP it shakes. So after some research changed front engine mount. Also did wheel balancing too. Still small amount of vibration can be felt under my seat when the RPM is around 3000. Have the same problem when enging idles.

Recently I have been facing performance loss. I dont rev upto higher RPM's. The best I do is until 4000RPM. But I like quick accelaration from 1500-3200 so I drive just between that mark. When the engine is cold it performs good enough. But once the engine gets warmed up(when the temp. gauge stays around 200 degrees), after a while of driving it looses its performance. I dont get those quick accelearations. Also I have to step on my accelaration pedal a little more(on my top gear).

I spoke with my mechanic (JONES AUTOWERKS, San antonio,TX), he rev's upto 6000 and says it works fine. 6-7 mechanics tested that but everyone say its fine. Deep down I feel there is something wrong and would like to know.

Previously I used to accelarate between signal lights which I stopped now.

Things I felt which may be Culprits:

1) MAF sensor

2)Coolant Tank

3)Any wheel bearings which puts more effort on the engine to turn the wheels

4)Idiling the car.

5) AOS

6)Vacume leaks

Recently changed the alternator and read some where that I should not take the car for short trips. Since then I dont stop the car for short trips, so I have to idel it if there are lot of stops. Thats the only car I have so I use it for day to day purpose.

But I am not able to judge properly coz the thing happens after engine get warmed up.

Also need some recommendations how to drive a manual transmission. How much people generally rev the car before changing to higher gear. And I have this habit of pressing gas pedal a little before letting of the clutch go coz when I change gears it gives a jerk and hence wanted a smoother gear change. But the funny thing is, if I do like that then the performace is not good when compared to not giving accelaration until the remove my foot from the clutch totally. Its like the car is asking for sometime to breath....... I took it to another mechanic and he said that its because its a v6 and so its not that responsive.

Banging my head as I want the feel of a perfect drive which is not happening at all.

Share this post


Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

He said your Boxster is a V-6??????? A Porsche mechanic? Are you serious? You do not have a "V-6". Did you get an inspection of the car bedfore you bought it?

It doesn't sound like there is anything wrong with your car besides the way you are driving it.. Drive it hard... Why are you babying it? Shift right before redline.. That's what it is made for..

I take my Turbo on short trips everyday (same with my past Porsches.) That is not really an issue unless you never get the car up to temperature...

If you're convinced you have a problem take your car to a reputable Porsche shop and have them test the AOS and check for fault codes..

  • Upvote 1

Share this post


Link to post
Share on other sites

Drive the car like a normal car. Let it warm up by driving gently for the first 15km and after that occasionally and legally wind it up to where the valve timing changes and a bit beyond at least...say 5k plus or more. I'd try and wind it up once every trip once it was warm but it is too fuel-expensive to run at high revs all the time. Be careful with the downshifts, get in the wrong gear and you can break an engine. You'll get the hang of it.

Change the oil at about 6km or at least once a year.

Your temperature reading is higher than most I hear about...right on the right side of the 8 in the 180 mark is where mine always settled. You have a Boxer horizontally opposed 6 cylinder engine, not a V-6. It isn't a gas guzzling race car but it always had more than enough acceleration for me. I'd find a good Porsch-experienced mechanic and ask him to look at why the oil temp seems to run hotter than typical and why it loses power when warm. And maybe check the cluch action.

Share this post


Link to post
Share on other sites

This may be a bit out there, but some of the symptoms described are the same as I was having with my car with a burnt up coil pack, but before they got really bad and started setting off the flashing misfire light. It would run fine until warmed up, which is probably when the coil or housing expanded enough to lose contact.

Before any CEL's started occurring, the bad coil manifested as a roughness under load, and loss of power across the rev range, but especially low rpms. For an inexperienced driver, this could make shifting a real pain. I found myself shifting super late to compensate for the lack of torque.

Idle was not compromised at all, although I'm sure it would have been if I'd continued to drive it that way.

Worth checking out, clipod. Did you do coils and plugs at your 60k service?

BTW - 200 degrees is HOT for these engines. You really shouldn't drive it at that temp, aluminum motor and all....

Are you sure it's reading that? My needle (2000 Box S, stock) points at the "0" in 180 and NEVER moves, even last summer in 110 degrees driving 110 mph in the desert.

Share this post


Link to post
Share on other sites

200 degrees is not hot for this engine. In fact, when the needle is pointing at 0 the coolant temp is probably between 200F and 210 F, the oil temp likely higher.

This has been discussed ad nauseum in the forums, but the dash temp gauge is both grossly innacurate and non-linear.

The reason why your needle doesn't move past the 0 in 180 is because a.) you're not driving it hard enough ;) and b.) typically around the middle of the 0 is when the low speed fans kick on which depending on your driving sytle will likely maintain the temp there. Around the right side of the 0 the high speed fans should kick on, and it should not get signifigantly hotter unless you are on the track driving at maximum RPM on a hot day.

On a cool day with a very healthy engine and cooling system, driving above 55mph it should actually drop on it's own more towards the 1 or 8, without the aid of the fans..

Share this post


Link to post
Share on other sites

Lets not confuse the indicated temp with the internal temp. Indicated temp on both my '99 and my '01S was at the right side of the 8 in the 180 and many others I've spoken to said theirs settled there too.

So unless the external temp is really really high (100F+) or you are driving at max RPM all the time or you are in some sort of traffic where your air intakes are blocked, there is something suspicious to me if yours settles at 200...like maybe a fan or temperature sensor or a water pump wearing or ....

Share this post


Link to post
Share on other sites

2k model with same mileage and problems

I have the exact same 3000 rpm shudder. My first thought, oh no!! IMS. So I jump on renntech to research and it seems like quite a common occurrence. Never really found a promising fix. Some said the motor mount like you tried, which i am planning on replacing soon, so I am disappointed to hear that did not work, however, let me tell you. In the 12k I've had the car, this shudder has not changed one bit. This leads me to think it is not really a problem as much as a minor annoyance. If it were an engine bearing or something internal it most certainly would have gotten worse over that mileage. I own a tire/suspension business where we fix vibrating cars all day long (i know how to diagnose a vibration) and if you are having the same

Share this post


Link to post
Share on other sites

Shudder as me then then I can tell you 100% it is not coming from tires/wheels/brakes or suspension. I would just live with that one unless it gets worse though. I would def start planning to replace the IMS bearing though. Do a search if you have not yet heard of this however I think that may just be impossible considering the insane amount of importance placed on it. If it fails which boxsters prone to this, you must replace the engine. Not fun for your wallet as Porsche motors are expensive and in high demand. Look into it just cause you should. Not because of your symptoms

I recommend getting that thing up in the power range every now and then. It is a Porsche. It's made to be driven hard for long periods of time. Tons of people run them wide open on the track for very long time periods. Pedro says "a redline a day keeps the mechanic away". Do a wiki search on "Italian tuneup". Warming it up properly is far more important than running it hard as far as engine longevity is concerned. When first started when motor is cold, do not just let it idle. It is best to immediately drive off. Oil must be pumped all the way out to the heads on the FLAT layout which needs some revolutions to spin the oil pump. I stay below 4k until motor is fully warm based on coolant temp gauge. When this is reached I will keep below 5500 rpms for the next 5 min or so. This is due to the fact that the oil takes longer to warm up to normal temp than the coolant. After a few min, I will then be free to take it to the redline if I so choose, which I do frequently!!

I have been working out a hesitation as well. Any check engine codes? I have gotten mine fixed aside from one thing the past two weeks. Started out with a tuneup where I replaced plugs, plug tubes, and cleaned out the throttle body/intake plenums etc. Prior to this I was getting the most minor engine hesitations on quick shifts. After I did the aforementioned maintenance procedures it drove sooo poorly. Definately not what i expected when I fired up for a test drive. Checked all the vacuum hoses etc and all were connected and new. Turns out, the battery needs to be disconnected and battery drained (press horn momentarily to drain capacitors etc) in order to let the ecu remap itself. What a difference. Took about 20 min of driving and then it performed wonderfully. I would start by cleaning throttle body/intake plenums. Plenty of write ups online , it's free, and considering the mileage it prob has never been done and starting to need it for the sake of keeping the vehicle in top shape. If you find lots of oiling he plenums then go ahead and hop on pelican parts and order a Air oil separator ( aos) and, trust me on this one, a pair of cable driven hose clamp pliers. This tool will save you so much time and frustration. And when the time comes for a coolant tank, which it prob will soon, it is even more fundamental then. Just got done doing these jobs last week. I really cannot even imagine doing this without these special pliers. It was enough trouble with them. Craftsman makes them and u can get them at sears if they have one in stock. My local sears only had 1!! I would start with the above and go from there. Inspect all vacuum lines while the intake manifold is apart. Make sure all vacuum lines go back together correctly!!!!

Drive it short trips, long trips, or whatever. It doesnt matter. I would avoid unnecessary idling though ie leaving it running at your stops. First off I recommend watching an episode of bait car on TruTV to see how quick some people come to the moral conclusion to hop in. Add on the fact it is a PORSCHE. It garners attention. I would lock that thing up always. Secondly. The flat six motor design makes the oil flow design unnatural so you want to keep that oil pumping so your heads/valve train stay properly lubricated. I try to idle as little as I can get away with.

Working the clutch just takes practice. Soon enough it will be natural. Having a consistently performing motor will help. Good luck. Keep me posted and lemme know if u have any more questions. I got mine in November and already put almost 13k on it just because I can't get enough of it. I have learned so much about this car in the short time I've had it. When not driving, I'm online looking at Porsche stuff. I hope this helps. Also let me know if there are any check engine lights

Share this post


Link to post
Share on other sites

Have you checked for any fault codes? Are you saying the engine will not rev when under a load?

Share this post


Link to post
Share on other sites

Thank you guys for all your responses. I had been so stressed out with my car coz its taking too much of time and not letting me think about my work.

But I stopped thinking about my car and now I am back with more problems.

My coolant tank is totally empty. I cannot see any traces of coolant from outside. But when I called a reputed mechanic in San Antonio( Jones Autowerks) he asked me to check if the coolant light is on.

But unfortunately its off. So he is like there is still some coolant.

Previously if I dont drive the car for few days and I start it used to release white smoke at the beginning. But now it stopped doing that.

So now I am thinking the coolant is missing. Last time when I did the 60k service they said no error codes everything looks fine.

Also I babied the car and I agree. Now I am not driving less than 3000RMP mark. My 4th and 5th gears are awesome. But I am totally sure that my 2000-3000 mark suck real bad. Previously when I was completely new with the car, it used to fishtail if I did not control my throttle. Now no signs of fishtail.

And these days after my fan's start running no matter what, even though the temparature decrease I have to press the throttle a little bit more to get the same speed. Like assume I used to press the accelaration pad half way down for reaching 70Mile mark on my 4th gear. Now I have to press a little bit more than half.

I am planning to add some coolant in the car and see if atleast I get a little bit of performance but my mechanic recommends to change coolant tank itself not just adding coolant.

What do you guys say about that?

Also can someone give me an idea about IMS affecting the performance of the car?

**** I should have brough a newer porsche. Couldnt afford it at that time. Now I regret.

Share this post


Link to post
Share on other sites

If you are losing coolant, you need to identify the cause fast! Boxster M96s are sensitive to cooling and cooling depends on the water/anti-freeze circulating successfully. Lose the engine and it could cost you the car.

Classic causes are water pump seals, head gaskets, water/oil heat exchangers, filler tube cracks, radiator cracks, and internal engine failures.

First thing is look at the oil and see if there is any intermix. What color is the oil? Coffe with milk color says intermix and point to some of the causes, leaks to another set. Look at the plugs, are any different from the others?

Share this post


Link to post
Share on other sites

If you are losing coolant, you need to identify the cause fast! Boxster M96s are sensitive to cooling and cooling depends on the water/anti-freeze circulating successfully. Lose the engine and it could cost you the car.

Classic causes are water pump seals, head gaskets, water/oil heat exchangers, filler tube cracks, radiator cracks, and internal engine failures.

First thing is look at the oil and see if there is any intermix. What color is the oil? Coffe with milk color says intermix and point to some of the causes, leaks to another set. Look at the plugs, are any different from the others?

The oil looks just fine.

Share this post


Link to post
Share on other sites

When you put water/anti-freeze into the coolant tank, does any end up on the ground? If you look at the front of the engine by removing the panel behind the seats, do you see anything odd looking around the water pump shaft/seal? We are looking for leaks that are external to the engine/heads, if we don't find any, we get it flatbedded to the nearest engine specialist and hand him the keys and our wallets. And just filling the tank is not enough if air has gotten into the cooling system, the system must be totally free of air eith by using a vacum pump or burping the system. An air pocket can allow a hot spot which can cause an engine failure.

I can't emphasize enough how important to an aluminum engine having a functioning coolant system is. (Been there, lost one..an Alfa). I wouldn't run the car until I find out what is happening and fix it.

Share this post


Link to post
Share on other sites

2k model with same mileage and problems

I have the exact same 3000 rpm shudder. My first thought, oh no!! IMS. So I jump on renntech to research and it seems like quite a common occurrence. Never really found a promising fix. Some said the motor mount like you tried, which i am planning on replacing soon, so I am disappointed to hear that did not work, however, let me tell you. In the 12k I've had the car, this shudder has not changed one bit. This leads me to think it is not really a problem as much as a minor annoyance. If it were an engine bearing or something internal it most certainly would have gotten worse over that mileage. I own a tire/suspension business where we fix vibrating cars all day long (i know how to diagnose a vibration) and if you are having the same

Motor mount and/or flywheel can cause the vibration at 3000 RPMs. The flywheel is a dual-mass unit that starts to fail after time/mileage.

Share this post


Link to post
Share on other sites

Hi guys, changed the coolant tank. My old coolant tank had a small hole and was leaking. Anyways though replacement in coolant tank didn't solve my performace problem. But recently I drove 300 miles and after I came back I started to see engine hesitation a lot. Finally the day came where my dashboard started showing check engine light. Took it to my mechanic. Surprisingly its AOS failure. Read error codes and the tool showed both o2 banks as fried. He did a glove test and he figured out right away that AOS was the culprit. Now I have replaced my AOS and my performace kinda came back. So happy to find the problem. But still engine hesitates and am thinking MAF has to be cleaned, air and pollen filters has to be replaced. Also I have a doubt about fuel filter too. When I press the gas pedal it kinda hesitates. During downhill it accelerates quick than uphill.(The different is very noticeable). Does anyone think if its MAF or fuel filter or any other symptoms? Or is it becuase the car needs to get adjusted with the new AOS installation?

Also quick update on my 3000 RMP vibration, the vibration actually minimized too.

Share this post


Link to post
Share on other sites

You might want to consider resetting your DME so it will relearn all fuel adaption. Simply disconnect battery for 5 minutes. Adaption takes a good 2-3 drive cycles and typically minimum of 20 miles.

If the performance is good again after battery reset then slowly gets worse you have more problems to solve, and typically those are related to an air intake leak.

Also clean the throttle body, plenum, replace air filter. You can clean the MAF, but be careful only use CRC MAF cleaner or similar and follow directions. You don't want to introduce any air intake leaks when doing this maintenance.

If your AOS was really bad and it was smoking you need to give the car a good thrashing to "clean everything out" of the system.

It can't hurt to use a bottle of techron or similar fuel injector cleaner in your next tank, and use a premium fuel like Chevron or Shell 91 octane.

I can't recall the MY on your car but yes if the fuel filter is original, it can't hurt to replace and is not difficult. Later model cars have fuel filter integrated in fuel pump.

Edited by logray

Share this post


Link to post
Share on other sites

You might want to consider resetting your DME so it will relearn all fuel adaption. Simply disconnect battery for 5 minutes. Adaption takes a good 2-3 drive cycles and typically minimum of 20 miles.

If the performance is good again after battery reset then slowly gets worse you have more problems to solve, and typically those are related to an air intake leak.

Also clean the throttle body, plenum, replace air filter. You can clean the MAF, but be careful only use CRC MAF cleaner or similar and follow directions. You don't want to introduce any air intake leaks when doing this maintenance.

If your AOS was really bad and it was smoking you need to give the car a good thrashing to "clean everything out" of the system.

It can't hurt to use a bottle of techron or similar fuel injector cleaner in your next tank, and use a premium fuel like Chevron or Shell 91 octane.

I can't recall the MY on your car but yes if the fuel filter is original, it can't hurt to replace and is not difficult. Later model cars have fuel filter integrated in fuel pump.

An update on the recent work on my car. Before I saw your response I have cleaned my MAF sensor as I heard that after AOS is fixed its recommended to clean MAF. But one doubt that I had with the cleaning of MAF is, I saw a sensor element(like a diode) attached on top of the plastic piece. Can I spray on that too also? Or do I have to just spray in those two holes as directed by pelicanparts. Anyways even though I have cleaned it I didn't see much improvement in the performance. One thing which I forgot was to disconnect batter(reset DME). My idle was really bad before. Now its considerably better after MAF cleaning. But hesistation while acceleration especially uphill is noticeable. I am going to clean throttle body cleaning this week and my mechanic said that mine is an electronic throttle and so before cleaning he asked me to tape the electronic ports. I am going to use a techron fuel injector cleaner too this week. One more thing which I saw was my idle is rough after I start my AC.Another question I had was if I remove my oil cap when engine is running should my idle go up? If the idle remains the same even though the the oil cap was off does that mean I have a vacume leak?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Similar Content

    • By eso1968
      Recently I have been thinking of an exhaust system upgrade for my 2005 997 C2S which I have been driving for quite some time. Can any of you guy help by suggestion on this issue? My 997 is basically standard apart from a set of BBS forged wheels. I am hunting for something that product nicer sound plus hopefully better flow and performance. Any experience and suggestions on where to shop, please reply.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.