I put an s5 n/a engine into an s4 car. I started it up last night and it went right away to 3k and then it died. I tried again this morning and it did it a couple more times and same thing, it wouldn't idle. But now when i try to get it to fire up it won't even try. It is like it has no spark, and i tried de-flooding it and it didn't work. Could someone please tell me what i may need to do to get this thing going? thanks

 

You will have to clarify greatly. An S5 engine is far from plug 'n play in an S4 chassis, as virtually none of the wiring is directly compatible. It is generally not advised if you can help it. Which method did you choose?

1) S5 front/emissions harness, S5 NA ECU, S5 NA AFM, S5 NA MAP sensor, S5 NA TPS?

2) S4 NA intake manifold on S5 NA block, S4 NA ECU, all S4 NA wiring & sensors?

3) Hacked up/rewired mix of S4/S5 wiring to adapt it to plug into S5 ECU and sensors?

4) Standalone EMS and its own harness and sensors?

 

We took everything off of the s4 block and put it onto the s5 block.

 

is the afm plugged in?

 

If you think it may have no spark just pull the spark plug, plug it into the cable, press the thread of the plug to the block and see if you get a spark while turning the engine with the starter. While doing be careful wit the plug an just grab the ceramic (high voltage!)

 

Well, one thing that's going to happen if you use an S4 LIM on an S5 block is the port air openings won't match up. You'll have a gaping hole below the intake ports on the center iron that leads to the exhaust ports. This shouldn't keep it from starting/idling, but it's going to cause one heck of an exhaust leak.

See LIM differences here: http://homepage.mac.com/carldavis/intake/mod.html.

The most likely scenario is probably going to be a large vacuum leak. Were all new gaskets used on the intake?