Guys I have made a few posts on this car before.

I have an s5 na that I swapped another s5 na motor from my vert. Since I have done the swap it wants to be a serious pain in the *** to start when the motor is not warm. It is not my thermo sense, I have checked signals going to the ECU and they are good. I did kill the main relay and the Tach once before swapping out my trailing coil and relay.

Funny thing is if I roll start it when it is giving me problems sumbich starts right up. What is the deal with that?

 

Your starter may not be able to spin it fast enough on a cold start, possibly due to a bad connection?
Your battery might be on the way out and not be able to get it going from a cold start.
It might be time for a tune up, check the timing, plugs+wires etc, + some seafoam.
When it's cold it needs a more rich mixture to fire up because the fuel doesn't atomize well in the cold, your injectors could be a little dirty.

 

I'd say throw a thermo sensor in it anyways. They only cost 2 bucks.

 

new thermosensor, checked the starter and changed the battery already. This motor ran perfect in my vert before the swap and seems seemingly weak so I am going to rule out the injectors.

I did plug the fuel lines up backwards after install and flooded the hell out of it once or twice.

What I want to know is what fundamental of roll starting it would fix the issue so I could find the original problem.

 

also what is funny is the car will turn forever until the battery is almost dead and once it is on its last drop it starts right up. Of course this only happens when it is cold. When it is warm it starts right back up.

 

bump

 

come on seriously guys....

 

bumpfuckers

 

I may suggest making a new starting/charging harness. I have to do this on my vert when i do the engine swap because the starter cable is on its way out and it spins way to slow and sometimes it just clicks until you move the wire around on the starter.

here is a tech article from rotary ressurection all about doing this.
http://www.rotaryresurrection.com/2n...st_ground.html

 

maybe the injectors are dripping causing flooding, try holding the pedal to the metal before starting it will shut the injectors off in the s5 for deflooding, then give it a crank after that and see what happens

 

funny thing is that it isnt flooding either.

I simply want to know why roll starting helps.

 

timing

 

+1.

I'm willing to bet money on this or the starter wiring. Mine did the same thing till I redid the wiring down there. Use to click several times before cranking over. When it was cranking, it was way under standard cranking rpm. The starter should crank at 350rpm. If I had to guess, mine was probably somewhere around 250 before I redid the wiring and could ***DEFINATELY*** hear a difference.

Bad starter/wiring:
http://www.youtube.com/watch?v=QcI1s1L8G80

Good starter/wiring:
http://www.youtube.com/watch?v=6T32fmAp57I

Theirs a big difference.

 

Hmm. This has me thinking now because I do remember frying the main relay somehow or another and either slightly before or after replacing it I have always had this problem. I wonder if shitty wiring would have killed that relay.