Re: check engine light

[Nathan Belo <belo@eskimo.com>]

On Wed, 2 Oct 1996, Chris Lemon wrote:

> Anyone have any ideas on this one...I've almost reached the end of my rope
> of  knowledge...but would like very much to solve this...
> 
> I keep getting the infamous "check" warning in my 90 (115k)...and I'm
> getting real tired of it!  Here's why:
> 
> I dump the codes and I get a fault for the ECU temp sensor.  I check the
> sensor resistance and harness voltage and both seem fine.  The fault was
> intermittent so I figured that maybe the sensor was going out in spurts.
> Linda could get me one for cheap so I ordered.
> 
> I replaced the sensor, along w/ thermostat (which, BTW, you *can* do w/o
> removing the P/S pump), and the fault is still there.  Now it seems to only
> be present sporadically when the engine is warm (1/2 way on gauge) and
> sometimes when I'm driving (i.e., throttle open).  I cannot, however,
> replicate this every time; sometimes the lamp will light while idling and go
> away once I get moving again...
> 
> I'm thinking that when it lights while I've got my foot into it that the ECU
> is giving me a knock warning (...but I ONLY use 93 octane gas) and retarding
> the timing.  If I back my foot off the pedal the light will go away and come
> back when I put my foot back on it...*sometimes*.  Like I said...there is no
> solid pattern here as to when I can get the lamp to light.  When I dump the
> codes, however, I *still* and *only* get the code for ECU temp sensor, even
> though the sensor and harness check out.
> 
> This sucks!  I'm getting sick of looking at this thing blink...and my
> friends asking me what's wrong with my car...
> 
> Could the knock sensor be picking up the slight exhaust leak that my car
> has??  Any ideas on any of this??
> 
> ==========================================    
> Chris Lemon          
> br00206@binghamton.edu         
> http://www.geocities.com/CollegePark/1710/  
> ==========================================
> 
> 
My car does the same thing, but it usually would occur when tuning was
needed.  A couple weeks ago it came on when I hit a serious pothole.  So
what I did was look for another pothole and it turned off.  It was
annoying because everytime I hit a hard bump it would come on.  Obviously
something was loose, but now it doesn't do it.  If you don't care about
your rims, mine are bent ;) .  Sometimes it comes on lightly and I just
rev the engine  to turn it off.

Nathan Belo
Seattle
'88 90 Q