2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Check engine light, but no check code error displayed

Thread Tools
 
Search this Thread
 
Old 12-18-11, 03:56 PM
  #1  
Senior Member

Thread Starter
 
rotorpower27's Avatar
 
Join Date: May 2006
Location: Northern california
Posts: 307
Likes: 0
Received 0 Likes on 0 Posts
CA Check engine light, but no check code error displayed

I don't want to make this post too confusing but here is the situation.

I bought a 89 gxl an and put my 88 gxl na motor into it (block only). All electronics emissions intake, MOP plugged in, ports all functional, from the 89 bolted to it.
(The 88 motor was running great in my car before the crash, avg 17 mpg)
The car is stock, other than the 88 block.
Car idles well and tps adjusted recently

_____________________
Problems I am having:
> lack of top end power
> 14 mpg
> random check engine light
> no error codes listed
> Hard start always
> misfire feeling in 5th gear around 2.7k rpm on the freeway.
>Fuel smell inside the car, when I drive hard.
_____________

Questions:
> Why is there no error code being displayed? the check engine light showed up when i was driving in 5th gear on the freeway. i pulled off and the light remained on. I turned the key off and jumpered the test terminal, turned the key to on and no CEL was listed. The check engine light does not come on often. It also flickered once when I tried to rev past 7.5krpm.

>Lack of top end power, i know this because i ran this motor in my daily driven 88, and top end power was good. But now in this 89 the top end power sucks, will just drop off at 5.5k. My current guess is either fuel related, spark timing, or that it is in limp mode. The lack of top end power happens even if the check engine light is off.
(I have a safc1 and if i go full lean or rich on top end, it has little effect. safc does show a clean tps reading)

> I am getting a AEM wideband soon and will have a better handle on afr.

I will leave it at that for now, and feed more info based on questions
Old 12-18-11, 04:45 PM
  #2  
Senior Member

Thread Starter
 
rotorpower27's Avatar
 
Join Date: May 2006
Location: Northern california
Posts: 307
Likes: 0
Received 0 Likes on 0 Posts
view picture then video
http://www.youtube.com/watch?v=e-KTQ...ature=youtu.be
Attached Thumbnails Check engine light, but no check code error displayed-2011-12-12_08-08-24_240.jpg  
Old 12-18-11, 05:18 PM
  #3  
Rotary nut for 15 years.
 
-RotorDemon-'s Avatar
 
Join Date: Dec 2011
Location: Gresham, OR
Posts: 118
Likes: 0
Received 1 Like on 1 Post
Mine flickered when the TPS was on it's way out. I could adjust the TPS where it needed to be but checked it with a multimeter and it was flying all over the place. Jump the diagnostic wire again but this time give it about 1/4 throttle and turn the key on and see if it throws a code then.

Second of all see if the IAT is plugged in.
Old 12-18-11, 11:48 PM
  #4  
Senior Member

Thread Starter
 
rotorpower27's Avatar
 
Join Date: May 2006
Location: Northern california
Posts: 307
Likes: 0
Received 0 Likes on 0 Posts
I checked my intake air temperature sending unit in the Tb and also in the AFM. While i had the AFM out I tested the function of the slid/flap resitance. I found that is was all wacy. I had this same problem with my 88 flap AFM and had to clean the carbon slide, which is easy on that design, however the s5 AFM is not so easy. Here is what I dd. I will be able to try it soon, and let you know how it works.
Tested
http://www.youtube.com/watch?v=sVOys..._order&list=UL
After taking it apart and testing it.
http://www.youtube.com/watch?v=tFs9W..._order&list=UL
and a fun clip of cutting it and putting it back together.
http://www.youtube.com/watch?v=itjuX..._order&list=UL
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
07-01-23 04:40 PM
Kyo
2nd Generation Specific (1986-1992)
6
04-13-19 09:24 AM
befarrer
Microtech
3
08-22-15 05:52 PM
elfking
3rd Generation Specific (1993-2002)
3
08-19-15 09:48 PM



Quick Reply: Check engine light, but no check code error displayed



All times are GMT -5. The time now is 08:25 PM.