I'm having a hell of time trying to figure out why my truck is having intermittent/radom hard starts. It happens about once every few weeks. It basically cranks, sounds like its going to turn over but it doesn't.


I have a video of what is sounds like. Its not my truck but its sounds very smilliar.

http://s25.yousendit.com/d.aspx?id=1...Q1LYCIY7ZQ4Q86


I have done the following:

TSB on hard start one by toyota for Intermittent (replace of engine harness due insufficient groud)
TB, MAF, Idle thing cleaned
Spark plugs properly gapped and in good shape
Battery in good condition.
Fuel Kit tuned
Ground wires checked.


Specs for my truck:

>> Year:2003
>> Model: X Cab 4x4 TRD 5 spd
>> Motor: v6
>> S/C Gen:2
>> Milage S/C Installed:~8000. Fuel mods installed ~13,000 Total Milage
>> URD AFR Calibrator,
>> 2.2 super grip pully, Aquamist (1:1 methonal and DI H20)

Any recomendations or suggestions would be greatly appreciated.



Jim

 

Have your battery tested. It may be dieing.

EDIT: Read the whole post. LOL you say the battery is good. So I dont really know.

Sorry

 

timing? how does it idle?
only hard to start when warm? or cold too?
low mileage but... fuel filter?

 

Its not fuel filter as my overall performance is very solid. It seems like its more likey to happend during warms starts.

 

There has been discussion about hard/warm starting with 4Runners. Mine is hard to warm start sometimes. I suspect a vaporlock type of problem.

 

Can you defined vapor lock?

 

I thought fuel injection eliminated vapor lock?


Vapor lock is when the fuel inside the fuel lines is near a heat source. It can get hot enough to boil-causing air bubbles, which means the engine won't run-however I thought this is normally only a problem with carburetors.

 

My 04 Tacoma has a hard start like what you describe but it's not doing it as much as when I had fewer miles on her. I had the TSB done but it didnt help much. A tech at the stealership also had the same hard start but he didnt have the TSB done and his hard starts have decreased in frequency after putting more miles on his truck. Give it time. I'll bet the hard starts will decrease with time/mileage. Another thing to try when you have a hard start moment is to back the key off just a little bit (dont turn it completely off), wait a few seconds and then crank it again - it'll probably fire right up.

 

I have done quite a bit of research on this. I believe its a grounding problem and a fuel problem..meaning too much fuel in the cylinder. The fuel problem...you can really do much with it because all the components such a fuel pump and injectors are normal with no way to adjust them.

Trust me it gets worse with time. I have an 03 with 52K. It started to happend at around 15K. I'm going to do the big 3 wire upgrade and see if it will help.

Question for you though, on the second time my truck usually starts but very slowly and kinda weak. Does yours do that?

 

Sometimes it starts slow and weak on the 2nd try but others it fires right up on the 2nd try. I haven't had a hard start for a while...knock on wood...

What's the big 3 wire upgrade? I haven't heard of that (or done a search yet). After you do the upgrade, post on here and let us know if it helped.

 

Might sound funny, but have your water temp sensor tested. If it is not working, it is telling the computer that the motor is cold, so it trys to richen up the mixture. Giving to much fuel to a warmed up motor, mocking a flooded carb problem.

 

Thanks for the suggestion. I think the oppsite of this is happening though. During hot starts, ECM don't inject as much fuel than cold starts. So during warm starts, the sensor is warm to hot but the ECM sees it as hot and doesn't inject much fuel so does turn ove the engine.

I think it doesn't have enough fuel because on the second try it barely turns over. Don't know if thats the same symptum as a flooded motor?

Testing the temperature is kinda of PITA and there could be some variations but I doubt its the coolant temp. sensor. I'd probably just buy a brand new one instead.

 

Mine does this too. I never figured out why, though.

I found that if I leave the key in 'On' for 3 seconds (count em in my head 1...2...3...) and then turn it to start it catches right away.

Bill

 

Fuel pressure regulator might be sticking.