Help! Tracked the car and ran into problems
03-30-2003, 08:06 PM
#1
Help! Tracked the car and ran into problems
Hi guys,
I tracked my 993tt on Sunday and afer an hour of track time (broken up into three 15 min segments) she ran into problems
. First the CEL came on. She still ran well and as I had had my cats removed thought it might be an O2 fault and took her out again. This time when accelerating hard out of a turn the CEL started flashing indicating a misfire which could be felt. I immediately backed off and pitted. No obvious faults noted when I lifted the engine cover i.e. loose hoses, wires etc. but decided to call it a day. On the drive back the CEL didn't flash but stayed on. Car felt strong and was definitely boosting but gauge read zero boost. Any ideas anyone? During the track session, the oil temp was pegged at Ten o'clock so I'm wondering if track problems could be temp. related. Ambient temps were 40 deg C that day.
The good news is that just before I ran into problems I smoked a R34 skyline with a claimed 600Hp under the bonnet. Outbraked him just before a long straight, took him on the inside and pulled away from him when exiting!! My 993tt has 'only' a factory 430Hp Turbo S conversion c/w the additional oil cooler!
Summary of problems:
1. Flashing CEL/misfire during track session.
2. Zero boost gauge reading (but definitely still boosting.
3. High oil temps?
Thanks in advance
,
Kris
'97 993tt
'89 964 C4
I tracked my 993tt on Sunday and afer an hour of track time (broken up into three 15 min segments) she ran into problems
. First the CEL came on. She still ran well and as I had had my cats removed thought it might be an O2 fault and took her out again. This time when accelerating hard out of a turn the CEL started flashing indicating a misfire which could be felt. I immediately backed off and pitted. No obvious faults noted when I lifted the engine cover i.e. loose hoses, wires etc. but decided to call it a day. On the drive back the CEL didn't flash but stayed on. Car felt strong and was definitely boosting but gauge read zero boost. Any ideas anyone? During the track session, the oil temp was pegged at Ten o'clock so I'm wondering if track problems could be temp. related. Ambient temps were 40 deg C that day. The good news is that just before I ran into problems I smoked a R34 skyline with a claimed 600Hp under the bonnet. Outbraked him just before a long straight, took him on the inside and pulled away from him when exiting!! My 993tt has 'only' a factory 430Hp Turbo S conversion c/w the additional oil cooler!
Summary of problems:
1. Flashing CEL/misfire during track session.
2. Zero boost gauge reading (but definitely still boosting.
3. High oil temps?
Thanks in advance
,Kris
'97 993tt
'89 964 C4
03-30-2003, 08:55 PM
#2
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don't know much about your boost problems, but regarding the oil temps, its important the weight you use. Porsche recently has started recommending 0-40 weight, Mobil 1 which is what every Porsche dealer will put in your car.
For me this is crap when you track the car. When I did an oil change I was not aware that they put 0-40, run on the track and had similar high temps close to the 10 oclock. When I went to my present mechanic and before another event I wanted to change the oil again so I could not believe the thin,watery black stuff that came off my engine with just below 1500 miles on since the dealer oil change!!!! Then I learned of the new "intruction".... We used the good old 15-50 Mobil 1 and in the Texas heat ( over 40 celcius) my track temps were back to max 9 oclock...
For me this is crap when you track the car. When I did an oil change I was not aware that they put 0-40, run on the track and had similar high temps close to the 10 oclock. When I went to my present mechanic and before another event I wanted to change the oil again so I could not believe the thin,watery black stuff that came off my engine with just below 1500 miles on since the dealer oil change!!!! Then I learned of the new "intruction".... We used the good old 15-50 Mobil 1 and in the Texas heat ( over 40 celcius) my track temps were back to max 9 oclock...
03-30-2003, 09:02 PM
#3
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Kris,
I am not sure what to make of your CEL problems, though I can't help but wonder if they might be related to removing the cats. Do you have one of the OBD systems that will let you read your fault codes?
When I track the car, I unplug the wire leading into the oil cooler temp sensor (accessed by removing the right front headlight). This forces the oil cooler fan to run on high all the time. This little trick keeps my oil temp significantly cooler (around 8 - 8:30 instead of 9:30 - 10).
As Danny suggested, I stick to 15W-50 as well in all seasons.
The boost pressure sensor can go bad, and this might explain your reading of zero boost.
Good luck!
I am not sure what to make of your CEL problems, though I can't help but wonder if they might be related to removing the cats. Do you have one of the OBD systems that will let you read your fault codes?
When I track the car, I unplug the wire leading into the oil cooler temp sensor (accessed by removing the right front headlight). This forces the oil cooler fan to run on high all the time. This little trick keeps my oil temp significantly cooler (around 8 - 8:30 instead of 9:30 - 10).
As Danny suggested, I stick to 15W-50 as well in all seasons.
The boost pressure sensor can go bad, and this might explain your reading of zero boost.
Good luck!
03-30-2003, 09:37 PM
#4
Thanks guys! <img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" /> Will check on the oil viscosity tip Danny and Anir. I think she's got 0-40 in it now but that's coming out immediately after this (never thought about this one..) and will pour in the 15-50.
Thanks for the tip on the oil cooler temp and boost sensors Anir. Quick question, how do I remove the headlight and wheres the boost sensor located?
cheers,
Kris
'97 993tt
'89 964 C4
Thanks for the tip on the oil cooler temp and boost sensors Anir. Quick question, how do I remove the headlight and wheres the boost sensor located?
cheers,
Kris
'97 993tt
'89 964 C4
03-30-2003, 09:43 PM
#5
Oh yeah Anir, forgot about OBD-2. Yes it's onboard and I picked up this cool PC software that will alow me to read some of the codes. Will update once I get round to it.
cheers,
Kris
cheers,
Kris
03-30-2003, 10:13 PM
#6
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Kris,
To remove the right front headlight, simply loosen your trunk liner. Just to the inboard of the light, within the trunk itself, you will see a small gold lever held in place by a rubber stop. Simply rotate the lever clockwise about 120 - 180 degrees and the headlight housing will move forward slightly. It can then be pulled out.
You'll see the wire plugged into the oil cooler temp sensor at the top of the oil cooler assembly, just past and below the floor of the sheetmetal housing the headlight. There's a small wire along the bottom of the plug that must be pushed in to remove the plug (it slides left). Then, make sure to tie the loose plug securely to something so that it can't slip down unintentionally into the fan.
You might be able to find some pics on <a href="http://www.p-car.com" target="_blank">www.p-car.com</a> , in the DIY section dealing with oil cooler troubleshooting.
Best of luck.
To remove the right front headlight, simply loosen your trunk liner. Just to the inboard of the light, within the trunk itself, you will see a small gold lever held in place by a rubber stop. Simply rotate the lever clockwise about 120 - 180 degrees and the headlight housing will move forward slightly. It can then be pulled out.
You'll see the wire plugged into the oil cooler temp sensor at the top of the oil cooler assembly, just past and below the floor of the sheetmetal housing the headlight. There's a small wire along the bottom of the plug that must be pushed in to remove the plug (it slides left). Then, make sure to tie the loose plug securely to something so that it can't slip down unintentionally into the fan.
You might be able to find some pics on <a href="http://www.p-car.com" target="_blank">www.p-car.com</a> , in the DIY section dealing with oil cooler troubleshooting.
Best of luck.
03-30-2003, 10:16 PM
#7
Here's a DIY for the fan switch:
<a href="http://p-car.com/diy/fanswitch/" target="_blank">http://p-car.com/diy/fanswitch/</a>
It's much easier than pulling the headlight everytime.
<a href="http://p-car.com/diy/fanswitch/" target="_blank">http://p-car.com/diy/fanswitch/</a>
It's much easier than pulling the headlight everytime.
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03-30-2003, 11:39 PM
#8
Thanks for the info guys. Never knew the headlight could be popped that easily Anir! By the way, why bruised and battered former owner of a Ducati 900 SS? I had a Kawasaki ZZR900 that bit me. Broke my collarbone and left leg in three places. It was fun while it lasted though..! Sticking with cars for the moment!
Thanks for that tip on the oil cooler switch Jeff, will definitely do it.
cheers,
kris
'97 993tt
'89 964 C4
Thanks for that tip on the oil cooler switch Jeff, will definitely do it.
cheers,
kris
'97 993tt
'89 964 C4
04-03-2003, 03:49 AM
#10
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Anir:
<strong>The boost pressure sensor can go bad, and this might explain your reading of zero boost.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">This is an interesting point -- from what understand, the boost gauge uses the MAF (air flow) to interpolate -- there's no actual OBD II sensor to read intake vacuum or pressue.
Someone with service manuals should be able to clear this up for me.
<strong>The boost pressure sensor can go bad, and this might explain your reading of zero boost.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">This is an interesting point -- from what understand, the boost gauge uses the MAF (air flow) to interpolate -- there's no actual OBD II sensor to read intake vacuum or pressue.
Someone with service manuals should be able to clear this up for me.
04-25-2003, 10:32 PM
#11
Hi guys,
Sorry for the late turnaround. Finally got around to putting all that advice and info in place. The boost problem was due to one of the recirculating valves blowing off a hose! Loose clamp! Had to get the intercooler off to fix this. Have changed oil for 15-50. Also tried a slightly different approach on the oil cooler fan circuit. I just bridged tha ballast resistor (shorted it out of circuit). It runs on high speed the instant it detects oil temps at the 8.30 postion on the gauge which then drops quickly to 8.00. For those who want to do this I'd advise taking the bumper off. It's a LOT easier than trying to get the oil cooler off to access the resistor. Great instructions at <a href="http://www.p-car.com" target="_blank">p-car.com</a> to remove the bumper!
She's running great again, boost gauge works ( Carrera GT- The manual shows the sensor on the intake side. It appears to be a dedicated sensor for the gauge but how it extrapolates intake vacuum into boost I haven't figured out yet...) and most importantly oil temps are down when pushing hard! <img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" />
Thanks again for everything,
cheers,
Kris
'97 993tt
'89 964 C4 (Soon to be sold- sniff...)
Sorry for the late turnaround. Finally got around to putting all that advice and info in place. The boost problem was due to one of the recirculating valves blowing off a hose! Loose clamp! Had to get the intercooler off to fix this. Have changed oil for 15-50. Also tried a slightly different approach on the oil cooler fan circuit. I just bridged tha ballast resistor (shorted it out of circuit). It runs on high speed the instant it detects oil temps at the 8.30 postion on the gauge which then drops quickly to 8.00. For those who want to do this I'd advise taking the bumper off. It's a LOT easier than trying to get the oil cooler off to access the resistor. Great instructions at <a href="http://www.p-car.com" target="_blank">p-car.com</a> to remove the bumper!
She's running great again, boost gauge works ( Carrera GT- The manual shows the sensor on the intake side. It appears to be a dedicated sensor for the gauge but how it extrapolates intake vacuum into boost I haven't figured out yet...) and most importantly oil temps are down when pushing hard! <img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" />
Thanks again for everything,
cheers,
Kris
'97 993tt
'89 964 C4 (Soon to be sold- sniff...)
04-26-2003, 12:15 AM
#12
Addict
Rennlist Member
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Krish,
Funny timing on your follow-up post. I just got my car back from a race shop after suffering almost identical symptoms following the Mid Ohio DE last weekend. Turned out to be a loose hose, as well!
The shop owner, John Wright (who takes care of Larry Schumacher's cars), emphasized the need to avoid excessive oil levels. When you track your car, the oil can expand from the greater-than-ordinary heat, leading to higher levels. This can cause some oil to end up in the intake. Also, the oil can work itself onto the hoses, and help them get loose and blow off under sustained boost.
Even with the oil cooler running high constantly, I briefly approached 10 o'clock on the oil temps after a hard 25" run. I'll be adding the Cargraphic GT auxiliary cooler this month. An ounce of prevention...
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
Funny timing on your follow-up post. I just got my car back from a race shop after suffering almost identical symptoms following the Mid Ohio DE last weekend. Turned out to be a loose hose, as well!
The shop owner, John Wright (who takes care of Larry Schumacher's cars), emphasized the need to avoid excessive oil levels. When you track your car, the oil can expand from the greater-than-ordinary heat, leading to higher levels. This can cause some oil to end up in the intake. Also, the oil can work itself onto the hoses, and help them get loose and blow off under sustained boost.
Even with the oil cooler running high constantly, I briefly approached 10 o'clock on the oil temps after a hard 25" run. I'll be adding the Cargraphic GT auxiliary cooler this month. An ounce of prevention...
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
04-26-2003, 12:19 AM
#13
RL Technical Advisor
Carrera GT, et al:
The digital boost guage uses a sensor installed in the intake manifold.
The MAFS provides signal information to the ECU for boost control.
The digital boost guage uses a sensor installed in the intake manifold.
The MAFS provides signal information to the ECU for boost control.
04-26-2003, 02:09 AM
#14
Rennlist Lifetime Member
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">This is an interesting point -- from what understand, the boost gauge uses the MAF (air flow) to interpolate -- there's no actual OBD II sensor to read intake vacuum or pressure.
Someone with service manuals should be able to clear this up for me. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Actually there is a sender and it sits on the left side of the fresh air intake. To the left of that is the BOV. The unit sits on a neck that carries a vacuum line over to the intake. The sender does not screw into the intake rather into the fresh air inlet to which the MAF sits on the opposite side. The MAF not under pressure on the inlet side of the turbo.It is not pressurized. Often when the BOV looses a line it will throw a secondary air injection error. From the picture you can see the line that has the allen in it. This is orginally where the sender sits. The filter is where the MAF orginally sat.
<img src="http://boards.rennlist.com/upload/Sender.JPG" alt=" - " />
Someone with service manuals should be able to clear this up for me. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Actually there is a sender and it sits on the left side of the fresh air intake. To the left of that is the BOV. The unit sits on a neck that carries a vacuum line over to the intake. The sender does not screw into the intake rather into the fresh air inlet to which the MAF sits on the opposite side. The MAF not under pressure on the inlet side of the turbo.It is not pressurized. Often when the BOV looses a line it will throw a secondary air injection error. From the picture you can see the line that has the allen in it. This is orginally where the sender sits. The filter is where the MAF orginally sat.
<img src="http://boards.rennlist.com/upload/Sender.JPG" alt=" - " />
04-26-2003, 02:52 AM
#15
Geez Anir,
Quoted by Anir </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> When you track your car, the oil can expand from the greater-than-ordinary heat, leading to higher levels. This can cause some oil to end up in the intake. Also, the oil can work itself onto the hoses, and help them get loose and blow off under sustained boost.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Your reply cleared up a question I had, How the heck did that hose blow off? There was oil evrywhere around that area! Heck of a mess to clean up! I did notice the oil level gauge reading high once oil temps were at 10 but thought nothing of it...
So the million dollar question, what oil levels should we be running? My gauge was reading just below the midlevel mark at normal oil temps but went off the scale once I hit the 10 o'clock mark!! Would appreciate input on this anyone.
On the boost sensor, does anyone know how a sensor located on the intake and only detecting intake vacuum be called upon to provide manifold absolute pressure to the boost gauge?
cheers,
Kris
'97 993tt
'89 964 C4
Quoted by Anir </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> When you track your car, the oil can expand from the greater-than-ordinary heat, leading to higher levels. This can cause some oil to end up in the intake. Also, the oil can work itself onto the hoses, and help them get loose and blow off under sustained boost.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Your reply cleared up a question I had, How the heck did that hose blow off? There was oil evrywhere around that area! Heck of a mess to clean up! I did notice the oil level gauge reading high once oil temps were at 10 but thought nothing of it...
So the million dollar question, what oil levels should we be running? My gauge was reading just below the midlevel mark at normal oil temps but went off the scale once I hit the 10 o'clock mark!! Would appreciate input on this anyone.
On the boost sensor, does anyone know how a sensor located on the intake and only detecting intake vacuum be called upon to provide manifold absolute pressure to the boost gauge?
cheers,
Kris
'97 993tt
'89 964 C4