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)
Sam Stevenson

Exhaust Smells Sweet, No Smoke at All

Recommended Posts

Posted (edited)

I finally fulfilled my dream of owning a porsche.  I got myself a pretty rough 2001 porsche boxster base.  Unfortunately my current finances mean that owning a porsche and driving a porsche are still two seperate entities.

 

It had the engine codes 1126, 1128, 1130, and 1133.  The engine ran pretty rough until I cleaned the MAF sensor and now it seems to idle pretty smooth. (I did notice that as I ran the engine for ~10 minutes in between random repairs the idle seems to be a little shakier than I would like it to be)

 

I also replaced all of the idle pulleys and put a new belt on.  While testing the pulleys before sealing the engine away in its tomb, I noticed the exhaust had a very distinct sweet smell.  I shut the engine off right away and got to looking around for some sort of coolant leak.  I am about 3 hours into the search with no luck at all.  there is some moisture up by the power steering pump filler cap that the previous owner said was a small spill while filling up the power steering fluid, but other than that the engine seems completely dry.  I don't see the coolant level drop at all either.

 

I have started pulling the plugs to see if the spark plugs are clean from water getting in the combustion chamber or something, but I would expect a fair bit of smoke if that was the case.  I only got the drivers side spark plugs out so far and they look a little old, but none of them seem abnormal and they all have similar amounts of wear.

 

I am really at a loss here. 

 

I am sure this is something in this forum, but searching for "sweet smell" just yields people talking about a lot of smoke coming out of the exhaust.  Whenever I try to look up no smoke it just shows a ton of results for people talking about how they got no smoke after replacing the AOS.

 

Best,

Sam

Edited by Sam Stevenson
forgot to mention coolant level staying constant and wrote codes wrong

Share this post


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

If your testing of (idle) pulleys did not include checking your water pump pulley for play whilst you had the belt off, it may be a good idea to do so if only to rule that out.

 

You haven't mentioned anything about temperature so presumably that is normal when the engine is up to full operating temperature?

Share this post


Link to post
Share on other sites
Posted (edited)
28 minutes ago, wizard said:

If your testing of (idle) pulleys did not include checking your water pump pulley for play whilst you had the belt off, it may be a good idea to do so if only to rule that out.

 

You haven't mentioned anything about temperature so presumably that is normal when the engine is up to full operating temperature?

I made sure to check the water pump for sure.  It seemed perfectly fine for me and I didn't notice any small coolant leaks when I looked underneath.

 

I also had no problems with overheating, but I've only gotten the car to full operating temperature twice

 

I just decided on a whim to double check the codes and I think I ended up adopting the codes that I found while researching.  The actual codes on my car are 

P1126, P1128, P1130, and P1133

Edited by Sam Stevenson
got codes wrong

Share this post


Link to post
Share on other sites
Posted (edited)

Have you cleared those codes subsequent to cleaning your MAF and have they returned?

 

Is your car manual or Tiptronic?

 

Does the part number on the blue cap to your coolant reservoir end with '04'?

 

Your engine oil is presumably as it should be with no condensation under the cap?

 

 

Edited by wizard
Reference to engine oil added

Share this post


Link to post
Share on other sites

Second the coolant cap. Also check the trunk for any coolant leaking there. If the coolant reservoir is cracked it will leak into the trunk and make the carpet wet. In my case this crack was small and not enough that the coolant leaked to the ground, only to the trunk, so worth a quick and easy check. Also only happened under increased pressure such as when the car has been running for a while.

Share this post


Link to post
Share on other sites

I haven't been able to clear codes yet

 

It is the 5 spd manual

 

coolant cap is blue with part number 996.106.447.00 (I did notice a little bit of fluid here that I didn't remember before.  I do think I tightened the cap pretty good though)

 

Engine oil cap is as it should be.

 

Got all the spark plugs out and they all look fine.  From my prior experience this would indicate that there is no coolant getting into any of the combustion chamber.  Since the smell is near the exhaust I'll check the coolant tank and remove the trunk carpeting and see.

 

Share this post


Link to post
Share on other sites

Replacing the coolant reservoir cap with the latest '04' version is possibly the least expensive preemptive maintenance that there is on a Porsche. Strongly recommended.

Share this post


Link to post
Share on other sites
1 hour ago, wizard said:

Replacing the coolant reservoir cap with the latest '04' version is possibly the least expensive preemptive maintenance that there is on a Porsche. Strongly recommended.

 

Okay, great.  I just ordered one and some spark plugs since I already have the old ones out.

Share this post


Link to post
Share on other sites
17 hours ago, Sam Stevenson said:

I finally fulfilled my dream of owning a porsche.  I got myself a pretty rough 2001 porsche boxster base.  Unfortunately my current finances mean that owning a porsche and driving a porsche are still two seperate entities.

 

It had the engine codes 1126, 1128, 1130, and 1133.  The engine ran pretty rough until I cleaned the MAF sensor and now it seems to idle pretty smooth. (I did notice that as I ran the engine for ~10 minutes in between random repairs the idle seems to be a little shakier than I would like it to be)

 

I also replaced all of the idle pulleys and put a new belt on.  While testing the pulleys before sealing the engine away in its tomb, I noticed the exhaust had a very distinct sweet smell.  I shut the engine off right away and got to looking around for some sort of coolant leak.  I am about 3 hours into the search with no luck at all.  there is some moisture up by the power steering pump filler cap that the previous owner said was a small spill while filling up the power steering fluid, but other than that the engine seems completely dry.  I don't see the coolant level drop at all either.

 

I have started pulling the plugs to see if the spark plugs are clean from water getting in the combustion chamber or something, but I would expect a fair bit of smoke if that was the case.  I only got the drivers side spark plugs out so far and they look a little old, but none of them seem abnormal and they all have similar amounts of wear.

 

I am really at a loss here. 

 

I am sure this is something in this forum, but searching for "sweet smell" just yields people talking about a lot of smoke coming out of the exhaust.  Whenever I try to look up no smoke it just shows a ton of results for people talking about how they got no smoke after replacing the AOS.

 

Best,

Sam

 

Sweet smells in the exhaust are oftent due to coolant being burned in the combustion process.  I would have the entire cooling system pressure tested as soon as possible.  This should not be treated lightly as it will only get worse.

Share this post


Link to post
Share on other sites
3 hours ago, JFP in PA said:

 

Sweet smells in the exhaust are oftent due to coolant being burned in the combustion process.  I would have the entire cooling system pressure tested as soon as possible.  This should not be treated lightly as it will only get worse.

 

Wouldn't I be able to notice that when I pull the spark plugs though?  I didn't notice anything out of the ordinary on any of the 6 spark plugs.

Share this post


Link to post
Share on other sites

One or more plugs might look marginally cleaner than the others.  It does not take a lot of coolant in the combustion to make it smell, but fortunately there are relatively easy tests like seeing if the cooling system holds pressure, or testing the space above the coolant in the surge tank for combustion by products that will confirm or eliminate an internal leak.

Share this post


Link to post
Share on other sites
Posted (edited)

I tried renting a pressure leak tester and threaded adapter from a local O'reilly, but nothing fit over my coolant reservoir cap.  Is there an adapter I can pick up for cheap?  preferably something I could pick up locally so I don't have to wait to get this test done.

 

I'm just getting anxious not being able to drive at all. 

 

I just ordered this part that claims to work.  Let me know if anyone knows otherwise so I can cancel the order.

https://www.amazon.com/gp/product/B01FIJZWEQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Edited by Sam Stevenson
adding link

Share this post


Link to post
Share on other sites
Posted (edited)

Just a little update

 

I decided to change the spark plugs while I was waiting for the stuff to check out the coolant pressure.  I also decided to rent a compression tester from autozone and test that while the plugs were out.  So first the results of that 

 

cyl 1 - 148

cyl 2 - 142

cyl 3 - 145

cyl 4 - 142

cyl 5 - 150

cyl 6 - 130

 

I think the compression tester I borrowed might have been reading a little high, but I never checked because I don't have a compressor.

 

Then I put the new spark plugs in and was careful to examine all of the ignition coils for cracks or tears (they actually look like they must have been replaced pretty recently).  I then reinstalled everything and went to turn the engine on so that I could also use the block tester that I borrowed from autozone as well.

 

The car started soon, but once I let off the key it started to idle very rough (as if it was running on 2-3 cylinders) and then it would stall.  

 

So far I have spent about 8 hours under the car removing the ignition coils again and double checking them for cracks and tears.  I also reinstalled the old plugs and that didn't do anything.

 

I checked the resistance of the terminals on all of the ignition coils and I didn't see any resistance across the primary coil and the third pin didn't show any shorting on any of the coils.

 

Could this be related to my previous problems with rough idle/lean condition and I just made the short worse by moving the cables around and possibly opening up a bigger hole in the insulation somewhere?

 

sorry to derail this thread from being about my engine being completely trashed... somehow I got myself in a situation where I need to fix a the car to get to a point where I can use the block tester.

 

I forgot to mention that I removed and cleaned the throttle body (it makes a horrible whine when the car is on with engine off).  There could be an intake leak from me not putting it on properly.  I'll check that soon

 

Edited by Sam Stevenson
forgot about cleaning the throttle body

Share this post


Link to post
Share on other sites

Would you be able to identify the plug that you removed from cylinder no.6 for closer inspection? 

 

As you are presumably intent on working on the car yourself, I would be considering an investment in a  Durametric. The car must be throwing codes, and shooting in the dark can prove costly.

 

 

Share this post


Link to post
Share on other sites

None of the spark plugs look like they have anything out of the ordinary.  I made sure to inspect the spark plugs carefully and there was nothing out of the ordinary.  I wish I had a picture now, but I've never had problems after changing spark plugs

 

I am already nearing the end of my budget for this project and I can't really afford a $300 tool right now.  I have been able to check the codes in a very basic sense through this process, but ever since I removed the spark plugs and cleaned the throttle body no codes have been set/pending.

 

I did remove the battery when I was working on the ignition coils/throttle body.

Share this post


Link to post
Share on other sites

Dumb question but are the wires to the coil packs in the correct order? They didn't get crossed during your plug change did they?

Share this post


Link to post
Share on other sites
50 minutes ago, mikefocke said:

Dumb question but are the wires to the coil packs in the correct order? They didn't get crossed during your plug change did they?

 first of all, no question is dumb.  I double checked and all the coil packs are plugging in correctly.

 

I am back to square one.  I am not sure what happened, but I tried to run it twice more today and the first time it stalled and the second time it idled okay (there is a little bit of unsteadiness that I will look into, but I am happy that it stays at about 800rpm now.

 

I idled the car for about 15 minutes and let it get up to tempurature.  It appears there is no problem with cooling (the tempurature was just above 180) and the block test did not change color.

 

I did spend those 15 minutes checking around the vacuum hoses and didn't hear any hissing, but I didn't hear anything extremely bad.  I do know that I still have the little filter at the bottom of the engine air filter (blocking cylinder 5) still off the car.

 

I have a little ELM327 code reader that didn't detect any codes through the stalling multiple times and there is no check engine light, which I thought was very strange.  I'll probably wait for the engine to cool and then try the new spark plugs again without unplugging the battery.  It seemed like the throttle body needed to learn or something.

Share this post


Link to post
Share on other sites

You mentioned at the outset that you had got yourself a "pretty rough 2001 ...".

 

Was the car driveable when you bought it? I ask this as perhaps fuel delivery is an alternative area for investigation.

 

After battery disconnection, there is indeed a short 'relearning' procedure. From memory, it's key on (but not start) for one minute followed by key off (but left in ignition switch) for 30 seconds.

 

You're best to Google that to verify as my memory is not what it was!

Share this post


Link to post
Share on other sites
11 hours ago, wizard said:

You mentioned at the outset that you had got yourself a "pretty rough 2001 ...".

 

Was the car driveable when you bought it? I ask this as perhaps fuel delivery is an alternative area for investigation.

 

After battery disconnection, there is indeed a short 'relearning' procedure. From memory, it's key on (but not start) for one minute followed by key off (but left in ignition switch) for 30 seconds.

 

You're best to Google that to verify as my memory is not what it was!

yes, I heard the throttle body working as well as I waiting with key on engine off, but I just kept trying it with the rough idle and it went away within 30 seconds of running (even if it stalled once)

 

I got the new spark plugs in and they work fine.  I used a block tester and found no exhaust gasses in my coolant.  Overall has been a pretty great day.

 

However, once I went to finally close the convertible top, it would not move.

 

So there is my next project 🙂  thanks for all your help guys!

I also have a fuel pressure gauge that I will use because it can't hurt to know if there is anything wrong with fuel pressure.

Share this post


Link to post
Share on other sites

Just in case you guys know anything.

 

The relay and fuse for the convertible top are both okay and the handbrake switch appears to be working as it should.  Windows will not go up.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

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.