[Jernsoul77]

Hello everyone, I have a 2005 Hyundai Tiburon GT with 172,000 miles on it. It's been repoed about 3 times over the year and life has definitely taken its toll on this vehicle.

I have a very odd issue, the car has no problem starting if it's the first time it started that day or for a while, if I take it somewhere like a grocery store and try and leave 45 minutes later it will crank but not turnover, I'll sit in the car for about 5-10 minutes, crank it again and hold it, and it will slowly come to life like it's struggling to get fuel. I can always here the fuel pump turn on when I turn the car on and while the car is running I have absolutely no issues.

I think my problem might be caused by some wire connections but I cannot determine what they are called, I do have pictures. These connectors are completely trash, the plastic is falling away, the prongs are loose and corroded. Any help is greatly appreciated! Thanks!

 

[chase206]

The blue and white connectors are knock sensors. I don't believe they will prevent your car from starting but if the connection is flaky it would cause your ignition timing to shift to "save" the motor from pre-ignition.

The issue you describe sounds like a flaky crank angle sensor. When it starts to go it typically gets worse as it warms up and gets better as it cools down. When the problem occurs, check to see if you have spark. If you lack spark or it looks to be irregular then it's most likely the crank angle sensor. Without a clean crank signal your ECU won't be able to fire your coils with any degree of accuracy so for safety sake it won't fire the coils. The crank position sensor is quite expensive for the OEM brand NTK but it's still less expensive than replacing the fuel pump assembly so I would start there first:

More Information for NTK EH0220

Remember to buy ONLY Hyundai, Siemens, Mando or NTK branded crank angle sensors. All other brands are inferior and make the problem much worse.

 

[Jernsoul77]

The blue and white connectors are knock sensors. I don't believe they will prevent your car from starting but if the connection is flaky it would cause your ignition timing to shift to "save" the motor from pre-ignition.

The issue you describe sounds like a flaky crank angle sensor. When it starts to go it typically gets worse as it warms up and gets better as it cools down. When the problem occurs, check to see if you have spark. If you lack spark or it looks to be irregular then it's most likely the crank angle sensor. Without a clean crank signal your ECU won't be able to fire your coils with any degree of accuracy so for safety sake it won't fire the coils. The crank position sensor is quite expensive for the OEM brand NTK but it's still less expensive than replacing the fuel pump assembly so I would start there first:

More Information for NTK EH0220

Remember to buy ONLY Hyundai, Siemens or NTK branded crank angle sensors. All other brands are inferior and make the problem much worse.

Sorry trying to wrap my head around the the pre-ignition motor saving thing

Although, I have already replaced a Camshaft position sensor, where might I be able to locate that crank position sensor? Thanks again!

 

[chase206]

The knock sensors detect "pinging" from the engine and trigger the ECU to relax the ignition timing. It's literally a microphone that listens for "knock" aka "pre-ignition" aka "pinging." If the wiring to those sensors is flaky it may trigger a false positive for pre-ignition therefore your ignition timing may be relaxed but it would still run.

The crank angle sensor is located just above the starter motor. Have a look at this response to a post for images that will guide you there:

Where's the location of the Crankshaft Sensor on my...

check engine light came on right after my car had trouble starting...the code came up for the Crankshaft sensor...can anyone tell me where it's located @? How hard is it to replace? Help me pleaseeeeeee! Thanks in advance.

www.newtiburon.com

 

[Jernsoul77]

The knock sensors detect "pinging" from the engine and trigger the ECU to relax the ignition timing. It's literally a microphone that listens for "knock" aka "pre-ignition" aka "pinging." If the wiring to those sensors is flaky it may trigger a false positive for pre-ignition therefore your ignition timing may be relaxed but it would still run.

The crank angle sensor is located just above the starter motor. Have a look at this response to a post for images that will guide you there:

Where's the location of the Crankshaft Sensor on my...

check engine light came on right after my car had trouble starting...the code came up for the Crankshaft sensor...can anyone tell me where it's located @? How hard is it to replace? Help me pleaseeeeeee! Thanks in advance.

www.newtiburon.com

Thank you very much, I will keep this post updated

 

[The_Evenger]

Does it crank over slowly when it's struggling to start?

 

[Jernsoul77]

Does it crank over slowly when it's struggling to start?

No, the crank is always consistently a healthy sound, just like its missing something.

When it begins to start it is very slow, like I start hearing the engine finally starting, get about 500rpm, all while still cranking and it takes ab 4-5 seconds and a gas pedal press up to 3000rpm for it to relax and idle off

 

[Jernsoul77]

The knock sensors detect "pinging" from the engine and trigger the ECU to relax the ignition timing. It's literally a microphone that listens for "knock" aka "pre-ignition" aka "pinging." If the wiring to those sensors is flaky it may trigger a false positive for pre-ignition therefore your ignition timing may be relaxed but it would still run.

The crank angle sensor is located just above the starter motor. Have a look at this response to a post for images that will guide you there:

Where's the location of the Crankshaft Sensor on my...

check engine light came on right after my car had trouble starting...the code came up for the Crankshaft sensor...can anyone tell me where it's located @? How hard is it to replace? Help me pleaseeeeeee! Thanks in advance.

www.newtiburon.com

Ok, I replaced the Crank sensor and nothing really changed, it still takes a while of holding the crank down until it actually starts

I let it idle for about 5 minutes and as soon as I shifted into drive the engine turned off, I still had battery an everything but the engine quit. When I shift without the car turned on it makes this really odd electrical buzz sound I recorded it but its too big to upload, maybe this is a separate issue? Thanks

 

[Charlie-III]

The knock sensors detect "pinging" from the engine and trigger the ECU to relax the ignition timing. It's literally a microphone that listens for "knock" aka "pre-ignition" aka "pinging." If the wiring to those sensors is flaky it may trigger a false positive for pre-ignition therefore your ignition timing may be relaxed but it would still run.

The crank angle sensor is located just above the starter motor. Have a look at this response to a post for images that will guide you there:

Where's the location of the Crankshaft Sensor on my...

check engine light came on right after my car had trouble starting...the code came up for the Crankshaft sensor...can anyone tell me where it's located @? How hard is it to replace? Help me pleaseeeeeee! Thanks in advance.

www.newtiburon.com

To add to this for general info, yes, when an ECU gets "knock hits" (bad fuel, ignition system, etc.) it pulls timing.
Why do I bring this up?
I dealt with an engine that had been run low on oil more than once. Rod bearings were failing (duh). The limited power of the engine lowered even more such that it was almost impossible to do the shorter "high hill route" out of town.
Every time I checked oil, it was fine, level and color.
Every time I checked codes, nothing was there.
What I found was that the driver used a scanner and cleared knock codes (and all other codes). Thus, the knock sensor pulled timing as far as it could, killing power. Clearing the codes reset the ECU to baseline and the power was back. Until the next time the rod bearing made noise and the knock sensor told the ECU and it pulled timing.
OK, enough said on this by me.....have a nice day.

 

[chase206]

What brand crank sensor did you use? I have doubts that you found a Hyundai, Siemens, Mando or NTK branded sensor in the last 23h since mentioning it. If you bought from a local parts store like Oreillys, throw it out and try again.

That electrical buzz you are hearing is probably the TPS and IACV harness plugs getting swapped. I've heard of the IACV buzzing but I've never witnessed it myself. So take that with a grain of salt. Could also be the IACV simply freezing in position and you're hearing the servo motor vibrating.

 

[Jernsoul77]

What brand crank sensor did you use? I have doubts that you found a Hyundai, Siemens, Mando or NTK branded sensor in the last 23h since mentioning it. If you bought from a local parts store like Oreillys, throw it out and try again.

That electrical buzz you are hearing is probably the TPS and IACV harness plugs getting swapped. I've heard of the IACV buzzing but I've never witnessed it myself. So take that with a grain of salt. Could also be the IACV simply freezing in position and you're hearing the servo motor vibrating.

Yeah I went to AutoZone cause I didn't wanna wait for shipping, I can just return it to them with no problem. I will check the plugs but the only code the fine was throwing was the engine coolant temp sensor so idk

 

[chase206]

Engine coolant temp sensor affects your air/fuel strategy. If the ambient temperature outside is significantly higher than what the ECT is reporting to the ECU it will be excessively rich on startup and will have trouble maintaining the correct air/fuel ratio as the engine warms up. I would prioritize replacing the ECT if you have an active CEL for that.

 

[Charlie-III]

Engine coolant temp sensor affects your air/fuel strategy. If the ambient temperature outside is significantly higher than what the ECT is reporting to the ECU it will be excessively rich on startup and will have trouble maintaining the correct air/fuel ratio as the engine warms up. I would prioritize replacing the ECT if you have an active CEL for that.

Agreed for any manufacturer of fuel injected cars. The ambient temp sensor (and ECT.....engine coolant temperature sensor) tells the ECU how much fuel to use.
Having driven for years with carbs and manual/automatic chokes, I have 1st hand experience.
When a "modern" (early '80's and beyond) fuel injected car is close to correct, things are fine. Modding can be an issue though. Fixes on the side of the road,suck though.
Gone are the days of filing a set of points with your GF's nail file and gapping off your thumbnail so the engine starts after engine off but key on listening to the radio and arcing the points. Trust me.

Sigh, I sound like an old fart, next thing you know, I will be yelling at kids, "get off my lawn!".

 

[The_Evenger]

...That electrical buzz you are hearing is probably the TPS and IACV harness plugs getting swapped. I've heard of the IACV buzzing but I've never witnessed it myself. So take that with a grain of salt. Could also be the IACV simply freezing in position and you're hearing the servo motor vibrating.

there's something in the throttle body area that buzzes for a few seconds when I first turn on my ignition, I've always assumed it's the IACV. I know my 07 never did this, but my 04 has always done this.

 

[Jernsoul77]

What brand crank sensor did you use? I have doubts that you found a Hyundai, Siemens, Mando or NTK branded sensor in the last 23h since mentioning it. If you bought from a local parts store like Oreillys, throw it out and try again.

That electrical buzz you are hearing is probably the TPS and IACV harness plugs getting swapped. I've heard of the IACV buzzing but I've never witnessed it myself. So take that with a grain of salt. Could also be the IACV simply freezing in position and you're hearing the servo motor vibrating.

Would it be sufficient if I went to a Hyundai dealership to purchase parts? Or is it possible they could have aftermarket parts as well? Thanks

 

[Jernsoul77]

It was sitting for about 4-5 hours, I went out and started it with absolutely no problems. Idled for about 5 minutes, was able to switch through all the gears without it dying.

Turned it off. Went to turn it back on, cranked and sputtered then just cranking for 15 seconds, laid off so I don't kill the thing, now my gear shifter is making the infernal buzzing sound again. I have switched around the IACV and TPS plugs, and the throttle body is clean

 

[Jernsoul77]

It was sitting for about 4-5 hours, I went out and started it with absolutely no problems. Idled for about 5 minutes, was able to switch through all the gears without it dying.

Turned it off. Went to turn it back on, cranked and sputtered then just cranking for 15 seconds, laid off so I don't kill the thing, now my gear shifter is making the infernal buzzing sound again. I have switched around the IACV and TPS plugs, and the throttle body is clean

Like usual, I held the crank after about 5 minutes and it sputtered to life, I drove with the IACV and TPS plugs switched, that was not it, the car was struggling to drive and the car was not shifting when it was supposed to, very delayed, I have switched them back. My engine light is on, but the only code that comes up is for the Engine coolant temperature sensor, it makes sense because the gauge never has a reading it's always at 0