Ok guys here is the problem.

I have had alot of issues with this swap (NA S5 vert motor into s5 coupe) and have resolved alot of them, I just need to get this out of the way.

The car would not crank at all for a while and seemed to be the main relay and now it cranks fine.

When the car hasn't been driven for a day or two I really have to crank it for 30-45 seconds. It is not flooded and the plugs are dry. It just takes a while to catch. Even when it starts to catch it backfires a little bit and I still have to keep the starter going for it to really get it. Once it is running on its own it is awesome. Once the car is warm it will start up that much easier if I go into a store and then come out later or let it sit even for a few hours.

When I am cranking it however the tach moves and then when it starts it goes up to like 4grand as I am revving it then the tach goes to zero and the car drives fine. Figuring this out will probably solve the hard start issue. Thanks guys-

 

Possible that the water thermo sensor on the back of the water pump housing is off or one of the sockets in the plug is pushed back not making contact with the pin in the sensor.

The water thermo sensor determines how much fuel is delivered durning START. If it's not connected up the ECU will default to 176*F and deliver too little fuel during START but will work just fine once the engine is up to full temperature (approx 180*F).

 

Hailers I have had this problem before as I had replaced the waterpump once and pulled the wire off of the connector. It ran like **** until I fixed the problem. It would crank and run like **** until warm. This feels totally different.

I feel like I am not getting enough fuel. I check the plugs and they are dry. And why is my tach dying after it starts?

 

About the tach.........if it dies while starting, go for a ride. Then while the car is moving along, put the car in neutral and turn the key off. Then turn the key ON and put the car in gear and dump the clutch to get the engine going again. I bet the tach now works.

I"m guessing that the batt voltage is getting really low during your starts and the ECU is turning the Trail coil assy off as some sort of fail safe feature. Pure speculation. The only times I've had a tach die was when the battery was real low or the batt had to be jumpered. It's been a long time since that happened.

Don't have anything else to say about the starting problem. With a cold engine, once started the afr's will be a full point richer til the engine temp gets up to approx 120*F, then it'll get *normal* as far as afr go. Just saying when cold the engine should be running a bit rich, not lean............til the engine gets up to temp of 120*F.

 

damn its hopeless now. If hailers doesnt know what is wrong with it then I am surely screwed.

 

ok i swapped the trailing coil out and the tach works fine. The thing still is really hard to get started. Maybe I just have fouled plugs.

 

I was going to suggest to check the coil, now that you have swapped it out hopefully with a good known working one then clean or change your plugs and see if that helps. Maybe swap out the Leading coil too?