Notices
996 Turbo Forum 1999-2005
Sponsored by:
Sponsored by:

Flashing Check Engine and Pressure Gauge Bouncing

Thread Tools
 
Search this Thread
 
Old 02-12-2011 | 01:31 PM
  #1  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default Flashing Check Engine and Pressure Gauge Bouncing

Hey guys,

Driving last night and got a "Drive to Workshop" message and (an intermittent) flashing check engine light (I can't say it was continuously flashing, more like coming on and then off). I know the flashing one generally means you should stop the car because it might be catastrophic or the catalytic converter is being harmed. However, when I checked the instrument cluster I noticed that the oil pressure gauge was all over the place. It would hold steady at 3 bar, then bounce up to 5, then down again. If I accelerated it would go to 4, or 5. The check engine light would go off if the oil pressure came up.

So, I continued driving to my destination thinking the oil-pressure sender unit was bad (again). When I got there, I checked the oil level and it was where I expected it to be. I used to get "Check oil pressure" messages where the gauge on the cluster would flatline while I was driving, and then come back up to what it should be. I replaced it and it has been fine for a year.

I guess I could check the wiring to make sure nothing popped off first. And I will pull the code when I get home with my Durametric. But, I think I can continue to drive the car as it seems to perform the same. What do you think? Anyone had this type of behavior?

Last edited by Bryce; 02-12-2011 at 02:35 PM.
Old 02-12-2011 | 01:59 PM
  #2  
raineycd's Avatar
raineycd
Racer
 
Joined: Dec 2008
Posts: 479
Likes: 5
From: 2002 TT - Colorado Springs
Default

Flashing check engine could also mean a misfire. Hard to tell without pulling the codes...
Old 02-12-2011 | 02:09 PM
  #3  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default

I suppose it could, but that would not explain why my oil pressure gauge was acting like a hooker's head in a John's lap.
Old 02-12-2011 | 02:19 PM
  #4  
jpflip's Avatar
jpflip
Three Wheelin'
 
Joined: Feb 2010
Posts: 1,526
Likes: 188
From: Montreal Québec Canada
Default

Sender seems to be bad again. But I would check the two wires going to it first. May be one of the screw is becoming loose ....
Old 02-12-2011 | 02:31 PM
  #5  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default

My only concern is that every reference to the oil pressure sender failing refers to "Check Pressure" message and the gauge briefly flat-lining before coming back up. Mine has a CEL (briefly flash, turn off) and "Drive to workshop." Hoping to get verification that someone else has had the gauge bounce around. I'll check the wiring today.
Old 02-12-2011 | 03:24 PM
  #6  
jpflip's Avatar
jpflip
Three Wheelin'
 
Joined: Feb 2010
Posts: 1,526
Likes: 188
From: Montreal Québec Canada
Default

I have to admit that when I had problem with the sender I only had the "check pressure message" . No cel but the ECU pick it up because when I connect Durametric and went into the "Cluster fault" it tells me that I had a fault with oil pressure.... But again no "drive to workshop"
Old 02-12-2011 | 04:50 PM
  #7  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default

Green wires appear to be affixed tightly to the sender, with nuts on top of them. Hopefully will be able to drive home fine (I really think so) and then check codes. Can't really check the wires on the bottom.
Old 02-12-2011 | 06:10 PM
  #8  
Macster's Avatar
Macster
Race Director
 
Joined: Sep 2006
Posts: 19,032
Likes: 256
From: Centerton, AR
Default

Originally Posted by Bryce
I suppose it could, but that would not explain why my oil pressure gauge was acting like a hooker's head in a John's lap.
If the engine rpms were ranging from normal to down down below normal hot idle the oil pressure gage could have been 'bouncing' due to a drop in oil pressure from the drop in rpms. As the problem temporarily went away and the CEL was turned off the engine rpms perked up and the oil pressure gage read higher.

(Also, if the engine running a bit rough a marginal connection in the oil pressure sender wiring could have been flopping about and this can account for the bouncing oil pressure reading.)

Chances are if there was a real oil pressure problem you'd have evidence of it now cause the engine would be manifesting the symptoms an engine with oil pressure issues manifests.

Just to be save though, you might consider verifying the oil pressure is ok.

Read the error codes and post what they are.

Sicnerely,

Macster.
Old 02-13-2011 | 02:37 AM
  #9  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default

Yeah, today I drove the car a tiny bit. The CEL went off on start. Car seemed okay. After a bit of driving I felt a slight hesitation like a misfire and the CEL came back, flashed a bit, then stayed steady.

I remembered fueling and only clicking the cap twice, so I reseated the cap. Did a few pulls in 2nd and 3rd and all seemed okay, but then I felt another misfire. Bleh. I'll limp the car home tomorrow and pull the codes.
Old 02-13-2011 | 09:40 AM
  #10  
raineycd's Avatar
raineycd
Racer
 
Joined: Dec 2008
Posts: 479
Likes: 5
From: 2002 TT - Colorado Springs
Default

You have any mods? Last time changed plugs or check the coil packs?
Old 02-13-2011 | 03:12 PM
  #11  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default

There is a GIAC flash, the only "mod," which I could reflash back to a stock-like program.

I changed plugs and coil packs myself at 60,000 in December of 2009. I have 69,000 on the odo now. Never a problem until today, so I think that job went fine.
Old 02-13-2011 | 03:15 PM
  #12  
raineycd's Avatar
raineycd
Racer
 
Joined: Dec 2008
Posts: 479
Likes: 5
From: 2002 TT - Colorado Springs
Default

What kind of plugs did you put in?
Old 02-13-2011 | 03:27 PM
  #13  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default

Bosch BA-6? I gapped them correctly, as far as I knew. They've been working well for 9,000 miles.
Old 02-13-2011 | 06:20 PM
  #14  
PorscheDoc's Avatar
PorscheDoc
Addict
Rennlist Member


Rennlist
Site Sponsor
 
Joined: Sep 2003
Posts: 8,058
Likes: 11
From: Under Your Car
Default

Originally Posted by Bryce
Bosch BA-6? I gapped them correctly, as far as I knew. They've been working well for 9,000 miles.
Hm, you should be using Bosch FR6LDC's in this engine.
Old 02-13-2011 | 07:14 PM
  #15  
Bryce's Avatar
Bryce
Thread Starter
Instructor
 
Joined: Feb 2009
Posts: 160
Likes: 0
Default

Yes, the FR6, those are the ones.



All times are GMT -3. The time now is 12:19 PM.