hello. i have been facing an issue with my warm start ups lately. if the car is cold it fires right up, if the car is warm it has to be jumped and tap the throttle body repeatedly. i replaced 3 new batterys. and a starter. alternator puts out good charge. tuner (pure drive performance) messed with it a little bit and it is still doiing the same problem. any ideas? it only does it when its warm.
evo 8. 4g64 long rod. 280 cams. 6262pt

 

Ill bet its the front ecu sticking its close to the throttle body location

 

can u please explain little better?

 

might be the voltage regulator on the alternator, maybe when it gets hot it cannot regulate the voltage and does not charge the battery, there are diodes in there and they could have possibly gone bad, should not be expensive, but you have to remove the alternator to replace it.

 

car is holding steady 14.2 v when started, and wouldnt that not charge the battery at all time? hard starts are only when fully warmed up

 

Scan the ECU coolant temperature when warm. A wrong coolant temperature reading results in the wrong mixture for start.

 

coolent tem was tested okay

 

What do you mean when you say tap the throttle body?

 

peddeling it. not wot... on and off multiple times

 

Front ecu has the mfi relay and mine sticks sometimes Its inside the fuse box under the hood I get a no start where its acts like its dead tap on front ecu starts right up.

 

I'm trying to think what that would do: maybe sticking throttle plate, maybe jar the ISC into working, maybe just foot exercise.

You might try a crank at WOT followed by a crank with the throttle closed. If that works it is getting flooded.

Another possibility is that you getting a weak signal from the crank sensor when hot.

 

Did you check your IAC valve?

 

I had the same issue with a customer's car, and it turned out to be that he neglected to install the delete plug for the injector resistor pack. If you are running High z injectors, I'd check that out.

 

I have the resistor box installed and it has always been installed. NY injectors are low z.

 

I had this problem on an old Saturn SC2. Replaced the coolant temp sensor fixed the issue.