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Discussion Starter · #1 ·
2003 Tiburon GT V6

86900 miles

Hello,

I've been reading about this issue here and it seems to be common with the Tiburon. I'm just wondering/hoping if anyone has any good ideas for what to do, as the NYS inspection expired in August. I will give a run down of where I am at:

After chasing a large leak code, then a purge flow incorrect code, now all of those are gone. However, I cannot set the monitors. The vehicle has 7, and you can pass in NYS with 1 incomplete. However, I can only get 3 to pass: MIS, CCM, and HRT. Those can pass just by following 1 loop of Hyundai's official drive cycle. However, I could not manage to get anything else to set, after almost a month and hundreds of miles of driving.

I decided to disconnect the battery at 86219, on October 23. I then did a drive cycle again and just got the 3 monitors to pass. At 86409, on October 28, I checked the monitors again, and nothing had changed. Frustrated, I disconnected a filler neck vent hose to try and force a large leak code back, as a sanity check. But as of today (11/18), it still hasn't even set a pending code for an evap leak!

I don't know what to do at this point. Its like Hyundai never set up their OBD2 monitors and system testing properly.

Any advice would be appreciated.
 

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Do the 3 monitors that pass show complete when you first turn on the ignition without starting the engine? I'm wondering if your ECU is missing it's memory power, It'll reset all the monitors every time you turn the key off if its missing that power feed.
 

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Do the 3 monitors that pass show complete when you first turn on the ignition without starting the engine? I'm wondering if your ECU is missing it's memory power, It'll reset all the monitors every time you turn the key off if its missing that power feed.
Good idea, I have chased that issue (ECU intermittent power loss) on another brand.

As to the removed hose not causing a EVAP large leak code, the ECU won't do some tests if other codes are there. It will NOT just run all tests anytime it wants. So, you have to get some readiness indicators set before the ECU will run other tests to set those indicators.

There are a number of threads here that spell out how to get indicators to set, this may be what you referred to.
 

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Discussion Starter · #4 ·
Do the 3 monitors that pass show complete when you first turn on the ignition without starting the engine? I'm wondering if your ECU is missing it's memory power, It'll reset all the monitors every time you turn the key off if its missing that power feed.
Yes, these 3 monitors remain passed when ignition is turned on, at the very start of driving. It is just the other 4 that are not passing.
 

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Good idea, I have chased that issue (ECU intermittent power loss) on another brand.

As to the removed hose not causing a EVAP large leak code, the ECU won't do some tests if other codes are there. It will NOT just run all tests anytime it wants. So, you have to get some readiness indicators set before the ECU will run other tests to set those indicators.

There are a number of threads here that spell out how to get indicators to set, this may be what you referred to.
1. The thing is that there are no current codes at all, or anything pending. I just disconnected the line to see if it even attempting the evap test. I just don't understand why now it isn't setting a code, because it was perfectly capable of setting a code for it about 2 months ago, before I fixed it.

2. I've seen those other threads (going back a decade, lol), but no one could really provide an "easy fix" other than showing the chart for the Hyundai drive cycle. I posted this just to see if any new info has come to light or someone could specifically help me. Any help would still be appreciated.
 

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Unfortunately that was my only "good" guess.

Only other thing I could think of is maybe your thermostat is opening early & blocking the ECU from reaching operating temp, stopping it from running tests where the engine needs to be warmed up? I also know some EVAP tests aren't run at certain fuel levels... but that's all I got.
 

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2006 Hyundai Tiburon SE
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In the US we technically only have 4 emissions monitors. There are the four that always seem to work as long as the engine starts. (Misfire, Fuel System, Components, SystemType) Then there are the four that we have trouble with that emissions testing actually cares about. Sounds like you need to have 3 of the 4 here (Catalyst, Evaporative Sys, O2 Sensor, O2 Sensor Heater)

This one is pretty obvious if you already did your research and stumbled on the forum. Attempt the drive cycles per this post and watch your readiness monitors live on an OBD2 reader before shutting down the car: Emissions/OBD2/OBDII Readiness


  • OH (Heated O2) - Confirmed by Tibutrauma
    + Start Vehicle, Idle for 15 mins.
  • C (Catalyst) - Confirmed by Tibutrauma
    + On the freeway, set cruise control for 55 mph, hold at 55mph for 8-10mins.
  • EV (Evap) - Confirmed by Tibutrauma
    + With 3/4 full fuel tank, accelerate at wide open throttle (W.O.T.) to 65 mph and hold (via cruise control) for 1-2 mins.
Often times I can get all four readiness monitors after my 2nd drive cycle even without shutting down the car. As long as you drive highway miles long enough, the 2nd drive cycle will take place on its own. All it takes is one sensor acting up but still operates within it's normal range for some of these readiness monitors to fail to set. Not every fault will show up as a CEL. For example a slightly faulty engine coolant temp sensor would show up as poor fuel economy and a foul smell out your tail pipe but rarely throws a CEL. Another example is a flaky crank angle sensor that provides a weak signal that rarely shows up as a CEL.

Can you provide a list of modifications? Such as cold air intake, headers, catback exhaust etc etc? Do you know if you have a modified ECU? Does it have any markings on it that lead you to believe it has been reflashed by SFR, NGM or Fiebruz? There are some poorly reflashed ECUs out there in circulation that lose their drive cycles after shutting down the car. It'd be good to rule that one out as well. Some aftermarket reflashes from NGM and Fiebruz actually delete the EVAP readiness monitors.

Do you have a bluetooth OBD2 tool that you can log a drive with? Maybe log a drive with the following sensors set to record and share the .CSV file from your drive:

Engine Coolant Temperature(°F)
Engine Load(%)
Engine RPM(rpm)
Fuel Trim Bank 1 Long Term(%)
Fuel Trim Bank 1 Short Term(%)
Fuel Trim Bank 2 Long Term(%)
Fuel Trim Bank 2 Short Term(%)
Intake Air Temperature(°F)
Mass Air Flow Rate(g/s)
O2 Volts Bank 1 sensor 1(V)
O2 Volts Bank 2 sensor 1(V)
Speed (OBD)(mph)
Throttle Position(Manifold)(%)
Timing Advance(°)
Turbo Boost & Vacuum Gauge(psi)
Volumetric Efficiency (Calculated)(%)

Sharing a drive log would help rule out any guesswork. I've troubleshooted for other members with drive logs and it works out most of the time. Don't forget to enable "fast communication" and set it to record sensor sweeps once every 0.5s or so. The OBD2 serial interface is fairly slow so 0.5s is about the fastest it will record.
 
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Unfortunately that was my only "good" guess.

Only other thing I could think of is maybe your thermostat is opening early & blocking the ECU from reaching operating temp, stopping it from running tests where the engine needs to be warmed up? I also know some EVAP tests aren't run at certain fuel levels... but that's all I got.
Fuel quantity, yes, usually between 1/4 and 3/4 tank of gas on the dash gauge.
 
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