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Hard Start

10K views 60 replies 8 participants last post by  oni888 
#1 ·
From some time i have problem in engine start, when engine is hot its start normal but if its stay like 10h i have very big problem on starting engine, maf is good, fuel filters are changed, do you think its fuel pomp?, engine start and its stop i must try 3-4 time to start but when its start for some time if i give some rmp its Choking i have no idea what can its be
 
#2 ·
If we had "cold start injectors" I would say to deal with that (I know older Nissan I6's had them as well as others).

Since we don't have them, I would wonder if the IAC is sticky/failing.

When were the plugs & wires last changed?
Do you have any CEL's? If so, what are they?

What year Tib & what engine?
Any mods (looking for intake, exhaust, cams, SC, etc...... not lights, stereo or wheels).>:D
 
#3 ·
Your idle air control valve is probably crappy. If you start the car with your foot slightly on the gas pedal, does it start easier?
If it does, keep the revs up at about 1500 for about 10 seconds before you let off, it should stay alive.
 
#5 ·
IAC is on the UIM just behind the TB (throttle body..... actually just behind the TB valve.....).
 
#7 ·
I would use TB cleaner or carb cleaner to clean the IAC. If you're careful, you can reuse the gasket.
 
#9 ·
You cleaned the IAC? If so, how did it look before cleaning?

Any CEL's? (never mind, re-read your earlier posts and you said, "No CEL's").

You could also do an ECU reset. Disconnect the battery, hold the brake pedal down ~30 seconds, reconnect the battery & try to start. The 1st time may be hard as it figures out where the crank & valves are. The ECU may have learned an issue and a reset goes back to "mid ground".

Do you have an OBD-II scanner? Curious what your LTFT's are.

You can also pull a couple of front plugs to see how they look.
 
#10 · (Edited)
Yea i got obd and tlft1 0,8 ltft2 1,6. O.k ill do reset tomorrow. I had lean problem but its was maf. After changing its was good. Its was 6 mc ago, IAC was dirty in black thing, but its was not hard to clean it. TB was clean, the spark plugs can do that problem??
 
#11 ·
Usually old spark plugs will always be an issue, but then again, lot's of little issues can add up over time. Best to get things in top shape as needed.

Let us know if the ECU reset helps or hurts.

BTW, your LTFT's...... is that 8% & 16%? If it's 16%, sounds like the ECU is not happy and adding fuel which could be an airleak after the MAF.
 
#13 ·
Ahhhh..... OK. Those values look better, just making sure.:grin2: The ideal is usually under +/- 6-8%. The closer to "0" the better.

Sounds good, keep in touch as you go further. Hope it works out.:smile2:
 
#15 ·
I don't think so. If it was a battery issue, why does it run like crap once running (from a cold start)?
From a "hot start", it runs fine.

Just curious why you made your statement.
 
#18 ·
Have you tried to find any vacuum leaks? maybe a small one where when you start it cold it causes a problem, but when the engine heats up the metal all expands and closes it up. It could also be what is throwing the numbers out slightly as well.
 
#20 ·
Okej battery have 11.9v its good. Ecu reseted ans do nothing syoll hard to start, but i forgot to tell you that when i give some gas i hear shots in engine mostly in air filter line, its possible that engine oil is geting and giving that sound?
 
#21 ·
Ok, battery have 11.9v its good. Ecu reset and do nothing still hard to start, but i forgot to tell you that when i give some gas i hear shots in engine mostly in air filter line, its possible that engine oil is getting and giving that sound?
11.9 is low. Fully charged but having sat for a couple hours the battery should be 12.6-12.9 volts.
Engine running at low idle volts should be ~13.4-13.8 and high idle 13.8-14.6.

As to the sounds, oil should not be anywhere in the intake tubing or filter. It could be in the UIM from the PCV system. It may be worth checking the PCV itself and see if it's stuck open. Just remove the hose, unscrew the valve and shake it end to end. You SHOULD hear it move inside. If not, carb cleaner, gas, brake cleaner, etc. can clean the gunk out.
 
#24 · (Edited)
Its possible that engine temp sensor is failing and its doing mine problem?. Hyundai got one or two sensors i mean one for dashboard and other for injection ecu.


Or maybe its ignition coil failing? Its possible to do that problems?
Yes, it could be a coolant temp sensor.

As to a failing coil, they usually act up when they get warm/hot.

Quick question, have you watched battery voltage when you do a "cold start" to see what it does? I would check "at rest voltage", then start the car and see where it is just after starting and how fast it comes up.
 
#27 ·
So, when you get out in the morning the battery is 12.5VDC? What happens to the voltage as you crank and right after it's running? If it drops a lot, it could be a cell going bad allowing a larger drop in voltage.
It should come up into the 13VDC range pretty quickly once the engine is running.
 
#30 ·
When I start, it's dropping to 11.5-10.9 and rising to 13.4
Sounds like the battery & charging system are OK.

So, enough of that.

As an aside, I'm assuming your temps are in "*C"? Not that it is an issue, just checking (we Americans still use "*F").:wink2:
 
#35 ·
I'm still waiting for new spark plug wires, but I did a test run on the car and sprayed window cleaner. I just see lots of little sparks on wires and near coil, a think the wires are my problem now.
Well, old wires could do that, especially if it's wet/humid out. The ~40K volts try to find the easy path to ground. Going through the outside of the wire to the engine block is easy compared to trying to jump the spark plug gap in a ~165PSI combustion chamber.

Since you're doing ignition wires, I would also do spark plugs since the same parts (intake & UIM) have to be removed to do the wires.
Just make sure you get the 2 electrical plugs by the throttle body connected to the correct part and that you get the throttle body support bracket on the OUTSIDE of the throttle body (NOT between the throttle body and the upper intake manifold).

PS, it takes me a little longer to do some replies so it's better for an online translator to give you something in your native language (if you use a translator).:grin2:
 
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