A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto newsgroups » Technology
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Hyundai Excel Ambiguous Codes Read - continued



 
 
Thread Tools Display Modes
  #1  
Old April 9th 06, 11:51 PM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued

This is a continuation of a post with the same name. Briefly, the 91
Hyundai Excel I own idles roughly and smokes sometimes even though it
seems mechanically OK (cylinder pressure within spec).

I am hoping COMBOVERFISH responds to this post as he was absolutly
right in suggesting a multimeter would show a trouble code when a scope
did not. After the last post, I replaced the oxygen sensor and the
symptoms are similar.

Diagnostic Codes
1 2 5 2 5 2 5 2 5 ... which I take to mean Barometric pressure sensor.
So far I have no idea where this is or how to test it.

Oxygen Sensor
I replaced the sensor although a good ground may have prevented me from
detecting that the old one was working. In any case the behavior is
unchanged. On warm start, I measure between 150-300 Mv initially. After
5 minutes the signal has increased to the range 890-1000 Mv. The engine
idles roughly and when accelerated, smokes. Unhooking the oxygen sensor
seems to produce no change in the smoking behavior or the oxygen sensor
reading.

Am I reading the codes correctly and what is the barometric pressure
sensor?
Is it possible that the oxygen sensor is not connected to the ECM?
Any suggestions happily accepted.
Thanks

Ads
  #2  
Old April 10th 06, 02:33 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued

Further tests;

After disconnecting the negative battery terminal for 30 secs, the
codes seem to be reset. The diagnostic codes are 11111111111111111...

The behavior at the exhaust pipe/oxygen sensor is the same - an initial
reading of 0-100Mv and no exhaust pipe smoke rising to 850-950Mv with
smoking.

Disconnecting the oxygen sensor does not change these symptoms and does
not change the diagnostic code which is still 11111111... No overall
engine warning light comes on.

Why does disconnection of the oxygen sensor not change the diagnostic?

Thanks for any ideas.

  #3  
Old April 10th 06, 06:38 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued


wrote:
> Further tests;
>
> After disconnecting the negative battery terminal for 30 secs, the
> codes seem to be reset. The diagnostic codes are 11111111111111111...
>
> The behavior at the exhaust pipe/oxygen sensor is the same - an initial
> reading of 0-100Mv and no exhaust pipe smoke rising to 850-950Mv with
> smoking.
>
> Disconnecting the oxygen sensor does not change these symptoms and does
> not change the diagnostic code which is still 11111111... No overall
> engine warning light comes on.
>
> Why does disconnection of the oxygen sensor not change the diagnostic?
>
> Thanks for any ideas.

=============
=============

Put a new PCM in the car.



~:~
MarshMonster
~:~

  #4  
Old April 10th 06, 08:28 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued


>
> Put a new PCM in the car.
>

Do you mean PCM as in the following;

"2002 Hyundai XG350
Even though a cable is connected to the accelerator pedal, this vehicle
is drive-by-wire. The cable leads to a pedal position sensor under the
hood, and the powertrain control module (PCM) operates the throttle."

I can't find any reference to a PCM in the Haynes manual, however the
following components are described;
Fuel rail and injectors
Fuel pressure regulator
Throttle position sensor
ECM
Idle speed control actuator
Air flow sensor
Engine coolant Temperature sensor
Intake air temperature sensor
Crankshaft position sensorMFI control relay
Vehicle speed sensor
Oxygen sensor

This is a 91 Hyundai Excel - would it have one? Any suggestions on what
its function is or where to find it? Any suggestions regarding those
other components?

Tkx

  #5  
Old April 10th 06, 11:38 PM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued

Consider the PCM to be the same as the ECM.

Powertrain Control Module versus Engine Control Module...


  #6  
Old April 11th 06, 02:55 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued

Is there some conclusive test for an ECM failure?
Is there something significant in the car's behavior that I described
or are these units prone to failure?

The following is originally from a vendor forum, I think.

"...But, I have to ask, if you drove your car to the dealer with this
problem what part of the computer failed? My experience with bad
computers is really bad, as in you can hardly get anywhere with the
vehicle. Or you just can't get anywhere. Car computers are real tough
pieces of silicone. I've seen wiring harnesses melted together and
after the repair the computer shook itself and went back to work...."

Are there some other steps that I can go through to test the
sub-components and rule out a simpler problem? What are the likely
sources, given the symptoms or are there no other possible
explanations?

Thanks

  #7  
Old April 11th 06, 06:35 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued


wrote:
> Is there some conclusive test for an ECM failure?
> Is there something significant in the car's behavior that I described
> or are these units prone to failure?
>
> The following is originally from a vendor forum, I think.
>
> "...But, I have to ask, if you drove your car to the dealer with this
> problem what part of the computer failed? My experience with bad
> computers is really bad, as in you can hardly get anywhere with the
> vehicle. Or you just can't get anywhere. Car computers are real tough
> pieces of silicone. I've seen wiring harnesses melted together and
> after the repair the computer shook itself and went back to work...."
>
> Are there some other steps that I can go through to test the
> sub-components and rule out a simpler problem? What are the likely
> sources, given the symptoms or are there no other possible
> explanations?
>
> Thanks


I just happened on your new posts by chance. the ECM, you
basically have to verify that all inputs, outputs, powers and grounds
are functioning properly before you condemn it. If your Hyundai ECM is
the same build type and manufacture as similar year Mitsubishis, then I
would highly suspect it as the cause of nonsensical garbage codes. You
still need to check powers and grounds to the ECM, and ATLEAST make
sure that the input signals are sensible.

It is difficult to test an O2 sensor on a vehicle with a concurrent
funky ECM problem. You can force it to read rich by pinching off the
fuel pressure return hose, and you can force it to read lean by
introducing a large vacuum leak. Those two methods will tell you if it
is capable of reacting to known conditions by producing from 0 - 1 volt
accordingly. Chances are that your new sensor is OK, so you can move
on to other suspect areas for now.

The possible code 25 refers to a failure in the barometric circuit
inside the airflow meter. This could cause a large shift in fuel trim
if it was way off calibration, or shorted/open. Similar story: I had
a Land Cruiser in the shop that was setting a baro code. This
particular vehicle, unlike other Toyotas, inferred calculated Baro
readings from other sensors. IOW, it set a bizarre baro code even
though it didn't have a real baro sensor. It turns out that the ECM
was so far off in it's baro calculation that it ran extremely lean to
the point of near misfire and very high NOx (failed an emissions
inspection). A new ECM fixed the Land Cruiser.

If you are still suffering black smoke out the exaust, perhaps you
could find a junkyard airflow meter to try out. Your car uses a Karmen
Vortex design that outputs a frequency to the ECM based on airflow,
plus discrete air temp and baro inputs. There's plenty to go wrong
with this design that could send a false richening command to the ECM.
If the AFM is hard to find or too expensive to purchase as a quick
cheap parts swap, then it's back to more diagnosis. I am having too
difficult a time with deciphering these codes over usenet to be of much
use. I don't feel confident that you are getting consistent results
from the code retrieval process - and I blame Hyundai for that, not
you. Their service info seems pretty useless.

Toyota MDT in MO

  #8  
Old April 12th 06, 01:23 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued


Comboverfish wrote:
> wrote:
> > Is there some conclusive test for an ECM failure?
> > Is there something significant in the car's behavior that I described
> > or are these units prone to failure?
> >
> > The following is originally from a vendor forum, I think.
> >
> > "...But, I have to ask, if you drove your car to the dealer with this
> > problem what part of the computer failed? My experience with bad
> > computers is really bad, as in you can hardly get anywhere with the
> > vehicle. Or you just can't get anywhere. Car computers are real tough
> > pieces of silicone. I've seen wiring harnesses melted together and
> > after the repair the computer shook itself and went back to work...."
> >
> > Are there some other steps that I can go through to test the
> > sub-components and rule out a simpler problem? What are the likely
> > sources, given the symptoms or are there no other possible
> > explanations?
> >
> > Thanks

>
> I just happened on your new posts by chance. the ECM, you
> basically have to verify that all inputs, outputs, powers and grounds
> are functioning properly before you condemn it. If your Hyundai ECM is
> the same build type and manufacture as similar year Mitsubishis, then I
> would highly suspect it as the cause of nonsensical garbage codes. You
> still need to check powers and grounds to the ECM, and ATLEAST make
> sure that the input signals are sensible.
>
> It is difficult to test an O2 sensor on a vehicle with a concurrent
> funky ECM problem. You can force it to read rich by pinching off the
> fuel pressure return hose, and you can force it to read lean by
> introducing a large vacuum leak. Those two methods will tell you if it
> is capable of reacting to known conditions by producing from 0 - 1 volt
> accordingly. Chances are that your new sensor is OK, so you can move
> on to other suspect areas for now.
>
> The possible code 25 refers to a failure in the barometric circuit
> inside the airflow meter. This could cause a large shift in fuel trim
> if it was way off calibration, or shorted/open. Similar story: I had
> a Land Cruiser in the shop that was setting a baro code. This
> particular vehicle, unlike other Toyotas, inferred calculated Baro
> readings from other sensors. IOW, it set a bizarre baro code even
> though it didn't have a real baro sensor. It turns out that the ECM
> was so far off in it's baro calculation that it ran extremely lean to
> the point of near misfire and very high NOx (failed an emissions
> inspection). A new ECM fixed the Land Cruiser.
>
> If you are still suffering black smoke out the exaust, perhaps you
> could find a junkyard airflow meter to try out. Your car uses a Karmen
> Vortex design that outputs a frequency to the ECM based on airflow,
> plus discrete air temp and baro inputs. There's plenty to go wrong
> with this design that could send a false richening command to the ECM.
> If the AFM is hard to find or too expensive to purchase as a quick
> cheap parts swap, then it's back to more diagnosis. I am having too
> difficult a time with deciphering these codes over usenet to be of much
> use. I don't feel confident that you are getting consistent results
> from the code retrieval process - and I blame Hyundai for that, not
> you. Their service info seems pretty useless.
>
> Toyota MDT in MO

=========
=========
what he said.....
ditto


~:~
marsh

  #9  
Old April 13th 06, 04:55 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued

Here are a post or two from a tech service I subscribe to; The common thing
I noticed is bad grounds to and sor the computer and bad computers.

Good luck


--
Stephen W. Hansen
ASE Certified Master Automobile Technician
ASE Automobile Advanced Engine Performance
ASE Undercar Specialist

http://autorepair.about.com/cs/troub...l_obd_main.htm
http://www.troublecodes.net/technical/





-------------------------
Hi Group, Took over a month to get this vehicle back to the
shop for the fix. There is a technical service bulletin
pertaining to this very problem that involves repairing the
ground wire splice inside the main engine harness. Paul
Baldassarre of Hyundai suggested bulletin # 93-36-007-1. We
repaired the wire splice and the vehicle has over 500 miles
with no complaint of a check engine light or power loss. Also,
thanks to



------------------------
I believe I'm chassing the illusive ground problem... As an
IMPORTANT NOTE: This vehicle has been wrecked in the front end
& repaired with somewhat questionable quality.

All these codes & no MAF or CTS readings. Bevus & Butthead's
Stereo Shop installed an alarm - wiring not effecting this
situation, but we feel they leaned on the MAF plug & damaged
the MAF and or plug because we could get readings when we
wiggled the connector. Tighteneing contacts didn't helt, so we
replaced the MAF (rebuilt), and the connector - same problem.

I found & tightened several grounds under the hood, but don't
know if I've found them all - no help. Cleaned the throttle
body for the code 15 - no help.

The snap-on scanner said up front that codes 12,13,15,25 at
the same time mean bad maf connection.

Replaced cts - no help. Another thing I noticed is that I
loose ground to my scanner when I'm wrigling the MAF connector
(it goes to the 'no communication' frame. Are they the same
ground?



___________________ TEST AND REPAIR DATA ___________________

COMPUTER CODES AND DESCRIPTIONS

12 - MAF problem 13 - IAT problem 15 - IAC out of range 21 -
CTS out of range 25 - Baro pressure sensor circuit problem

____________________________ FIX ___________________________

Only two replies. It was suggested that bad grounds were the
main problem. Re-established grounds. Ran much better. Found
that 'Bevis' had jerked around the throttle stop to accomodate
for the poor idle. Re-adjusted stop and car runs great. Many
Thanks, John



> wrote in message
oups.com...
> This is a continuation of a post with the same name. Briefly, the 91
> Hyundai Excel I own idles roughly and smokes sometimes even though it
> seems mechanically OK (cylinder pressure within spec).
>
> I am hoping COMBOVERFISH responds to this post as he was absolutly
> right in suggesting a multimeter would show a trouble code when a scope
> did not. After the last post, I replaced the oxygen sensor and the
> symptoms are similar.
>
> Diagnostic Codes
> 1 2 5 2 5 2 5 2 5 ... which I take to mean Barometric pressure sensor.
> So far I have no idea where this is or how to test it.
>
> Oxygen Sensor
> I replaced the sensor although a good ground may have prevented me from
> detecting that the old one was working. In any case the behavior is
> unchanged. On warm start, I measure between 150-300 Mv initially. After
> 5 minutes the signal has increased to the range 890-1000 Mv. The engine
> idles roughly and when accelerated, smokes. Unhooking the oxygen sensor
> seems to produce no change in the smoking behavior or the oxygen sensor
> reading.
>
> Am I reading the codes correctly and what is the barometric pressure
> sensor?
> Is it possible that the oxygen sensor is not connected to the ECM?
> Any suggestions happily accepted.
> Thanks
>



  #10  
Old April 13th 06, 06:36 AM posted to rec.autos.tech
external usenet poster
 
Posts: n/a
Default Hyundai Excel Ambiguous Codes Read - continued

Thank-you all for you help so far. Until I read Stephen's post, I would
have assumed the MAF sensor for the reasons below - now I feel I
should, test or replace the ground splice.

MAF Tests
I performed the MAF tests in Haynes 4-24 (Air Flow Sensor 1994 and
earlier) Output voltage of the sensor when disconnected between pins 3,
6 should be 2.7-3.2 V (was .15-.03V). Voltage between pins 5,6 should
decrease when air intake is obstructed - it was 0V. The codes shown
after this test with MAF disconnected are
2,5 - Baro pressure sensor
1,2 - Airflow sensor
1,5 - Motor position sensor

Is this a good enough indication that the MAF has failed?

ECU
Resetting the ECU and disconnecting the coolant temperature sensor for
a general test of the diagnostic fcn of the ECU produces
1,5 - Motor position sensor

I guess the ECU is not meant to be interpreted by mugles :>

Ground
Is there any good test of the bad ground theory - such as connecting
the test ground on the ECU to the negative battery or the block with a
good thick conductor and seeing if the problem disappears or looking
for a voltage W.R.T. ground on the ECU test ground?

Thanks again for all the help - I'm proceeding with MAF replacement.

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
anyone know how to read brake lining codes? N8N Technology 9 March 14th 06 06:26 PM
Hyundai Excel Ambiguous Codes Read [email protected] Technology 6 March 7th 06 05:00 PM
How to basicially read OBDll Standardized Diagnostic Trouble codes Steve Honda 0 March 20th 05 07:00 AM
Jim Warman, I am still confused John Riggs Ford Explorer 14 November 29th 04 08:20 AM
Mitsubishi 4G15 Engine in Hyundai Excel Alex Docherty General 2 April 5th 04 09:01 AM


All times are GMT +1. The time now is 02:31 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.