junkman2

I have a computer that will not give codes.The eng is hard to start and
when started runs real bad and will not get above 2000 RPM if you try to
go past this RPM the eng dies.The check eng light will come on when you
turn the switch on and cycle off like normal.I have checked the
cam,crank,map and mass and all seem to be ok also the fuel pressure is
ok.I have tried to make the ECM read some known faults by going through 3
or 4 crank cycles and it will not show the faults.Is this a good sign of a
bad ECM?I also need to know would a new ECM need a key flash.Thanks

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hyundaitech

I'm not convinced you have an ECM problem. In fact, I think it's unlikely.
I also don't know what specifically you're doing to attempt to induce a
trouble code.

Based on your description, I'd recommend checking potential mechanical
issues. Since you've verified the fuel pressure (presumably with a
gauge), I'd recommend checking the camshaft timing and the catalytic
converters. Improper cam timing or a clogged converter will cause the
issue you're having.

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junkman2

I have doubled checked the cam timeing and crank sensor (new belt new
sensor).The car was running good and all at once it slowed down and would
not pull.The only bad reading I can find is the mass output volts (0
volts ign on eng not running)I get 1 volt of which the manual indicates
bad mass or comp.I don't think the cat. would stop up that quick.The car
is about 300 mi. from me and at the time all I had was a code reader.I
disconnected the map sensor and went through about 5 crank cycles the eng
ran the same but I never got a code.I am back home now and getting a
laptop to go back and try to get a better read out.I have read that some
of the ECM (92-96) had faulty capacitors and would give problems after
(5yr).I am a retired mechanic and this is my daughters car.The eng has new
plugs,1 new coil and new timing belt.I hope when I go back the laptop will
get a better reading.

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Old_Timer

On Wed, 05 Mar 2008 17:50:41 -0600, "junkman2" <pflan@bellsouth.net>
wrote:

>I have doubled checked the cam timeing and crank sensor (new belt new
>sensor).The car was running good and all at once it slowed down and would
>not pull.The only bad reading I can find is the mass output volts (0
>volts ign on eng not running)I get 1 volt of which the manual indicates
>bad mass or comp.I don't think the cat. would stop up that quick.The car
>is about 300 mi. from me and at the time all I had was a code reader.I
>disconnected the map sensor and went through about 5 crank cycles the eng
>ran the same but I never got a code.I am back home now and getting a
>laptop to go back and try to get a better read out.I have read that some
>of the ECM (92-96) had faulty capacitors and would give problems after
>(5yr).I am a retired mechanic and this is my daughters car.The eng has new
>plugs,1 new coil and new timing belt.I hope when I go back the laptop will
>get a better reading.

It was a completely different car and a long time ago but a similar
symptom.
I tried everything imaginable before someone told me it must be a
plugged cat.

It was a plugged cat.

Old_timer

hyundaitech

In regard to the coverter, it all depends on whether a chunk suddenly fell
out.

The MAP sensor is used only for checking proper purge activity. The MAF
is used to determine air flow, and is a major input to the computer's
operating strategy. Still, I wouldn't suspect a MAF sensor as a likely
candidate in this case. They don't tend to fail suddenly, but rather tend
to skew their results over time, typically resulting in a fuel trim type
code.

I can count on one hand the number of Hyundai engine or transmission
computers I've had to replace because of a fault within the computer, and
all were either made well before (think 90-94 Excel--Mitsu) or well after
('06 and newer-- Delphi) this Santa Fe was produced. I agree it's a
nonzero probability, but it's low enough that replacing the computer
should be a last resort only after everything else has been verified or
ruled out.

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junkman2

I knew the map sensor was not the problem.I unplugged it to see if I could
get a fault code after about 5 crank cycles of which I did not.I have done
numerous test on other ECM and got codes with that action on other autos.My
question was is why I can't get a code out of this ECM that way.These crank
cycles were at normal temp.

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hyundaitech

I'm not sure why this doesn't produce a code. I'd think it should. But
you also shouldn't condemn the ECM because it doesn't. It'd be a costly
low-percentage guess.

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