Ok guys,



Probably the fifth thread I have made about this car.



S5 NA motor from my vert, ran perfect, stuck it into a coupe and it runs like ****. Obviously something swap related.



The car does not like to start when cold. It will crank over no problem and likes to start cold when the battery is almost totally dead. Weird as hell.



Not flooded.



AFM works, fuel flows thru the rails.



Thermosensor is new and reads fine at the ECU and so does the start signal.



Compression was 90 PSI across the board and that is when I was doing the test with the throttle closed so it is probably closer to 95-100psi.



TPS has been adjusted as well.



Fuel Lines are not backwards.

 

Now here is a history of the issue with a few more details than I had initially in my other threads with it running worse now.



When I first swapped it over into the coupe I had the fuel lines backwards and changed fuel pumps thinking that was the problem. I realised my folly and switched the hoses back around. (who would have thought that the s4's and s5 lines are opposite but in the same exact location).



Took the car for a short run up the street, no problem starting it but realised I forgot to tighten the lug nuts. 'oh:



Fixed that issue but then it was flooded from such a short drive.



Took it back down the street and pretty much since then it has been a pain in the *** to start if memory serves me right (this was a year ago).



Shortly thereafter, or maybe even before the hard cold starting the car would not crank at all. I took the starter off and tested it and it was fine. Come to find out the main relay had blown. Replaced it and it started fine, to an extent.



When the motor was cold (not cold outside) the car wouldnt start for anything. You would have to crank forever.



Vid: YouTube - jism21's Channel



This cranks much different than when flooded. The noise is the other car i was using to jump the battery.



Once the car started the first time it never had a problem starting right back up again. You could drive it around town and come back out and it would start back up. The longer you let it sit the more cranks it would take to get it to run.



Once it sat over night, forget about it.



Funny thing is I also noticed is that when it is cold, if you roll start it, the car starts right up. No bullshit or anything.



During this time I also lost my tach signal. Car started just as shitty but I was thinking it had something to do with the trailing coil so I replaced it. Got my tach back but still same problem.



Once the car starts and drives fine it seems weak as hell. Like it isnt getting the right spark or right fuel. I am more inclined to think spark.



The reason for this is if I get on it hard core and shift at around 6k rpm I have a fireball shoot 4 feet out of the exhaust on a backfire. On an NA. Whoa.



Now we put a battery in it just to use it yesterday cuz the diff mount went out in the s4NA. The terminal was loose as hell and my cousin was complaining that it ran horrible. Im thinking it was running solely on the alternator cuz the terminal wouldnt stay connected for **** on the positive side and you had to have someone hold it just to get it started. That was only yesterday on that battery. I took it for a spin and if you hit the breaks the lights would almost go out and and the car would sputter.



Anything past 5k rpms and the spark seemed to break up, like there was no power. It would just sputter.



When this motor was in my vert it ran like a raped date. Now it runs like an downs syndrome kid at the special olympics.

__________________

 

Recap:



Hard to start when motor cold.



Likes roll starting (someone please explain how roll starting helps).



Stuttering past 5k rpm. Fireball.



Starts fine when warm. Killed main relay once and tach signal (trailing coil).



Using harness and computer that came with motor from other car (doing ls1 swap into vert) however using drivers side harness that was on the car.



Checked timing as well, all was fine.



I also had to remove the dash when i did install of the motor because I broke the pipe to the heater coil and kept filling the floor board with coolant. I wonder if I screwed up something electrically because when I first did the swap the motor would start right up, at least the first few times. Come to think of it it was after this and removing the dash and fixing the heater core that I had the starting issues.



Any ideas on electrical or spark issues?

 

so you put the s5 motor into an s5 car? do you have any codes?

 

I didnt hear any beeping. I tried pulling CEL codes but failed. Any link on how to do it again? Search is my friend but I am about to fall asleep where i sit.

 

on an s5 there is a 1 pin connector by the battery, ground it, turn the key on, but don't start it and it'll blink out the codes