i overheated my S5 na. So the only thing i could get here in Mexico was a fc 86 na. I bought the whole car(salvage) for about $450 dls. I put only the engine of the fc 86 on my car. I cancelled the EGR valve on the 86 cause i didn't found the solenoid valve for it on my S5. The engine starts but dies. If I rpm it, it doesn't dies. even warm it dies(wants to be running but dies). I took it out for a ride and when i get around and above the 3500 the check engine turns on and don't want to rpm more. it FEELS like a bad sparkplug, but they're new. Another thing, when the car is parked I rpm it up to 7000 and leave it there, the check engine light turns on too and does the same thing when driving it. I think it's the sec. injectors. I've checked all the Hayness' manual says but everything's ok.

When i tried to check the ecu error codes it doesn't give me any code at all. The light turns on and stays like that. The check engine light turns on only when I use the car above the 3500, so i can't drive above the 50mph. Any ideas?

 

have you checked for vacuum leaks????????????????????????????????????????????? ????????????

 

Right there, putting a S4 engine in S5, theres going to be issues as the engines are different

Sorry I don't know all the differences

 

Yes, no leaks.

 

That's right FlybRE, i'm using everything of the S5 only S4 engine. I Changed the front cover so i could use the electronic omp.

 

So you bolted the S5 intake manifolds onto the S4 block? If you didn't grind down the top of the rear iron, you will have a big vacuum leak between the LIM and UIM. I dealt with this vacuum leak when I swapped an S5 manifold onto my S4 NA, and every time the manifold felt like it was seated properly. I had to take out far more metal than I realized.

You can find pictures here in this S5 manifold conversion writeup: http://homepage.mac.com/carldavis/intake/mod.html.

The 4th picture down shows the area that must be ground down.

 

That's right Rotary, i bolted the S5 upper intake manifold. I'm using the S4 lower intake manifold. I was using the lower S5 intake manifold (without the mods)but i had the vacuum leak you are talking about. I realized that when i put my hand on the MAF and the engine didn't failed. So i changed to the S4 LIM and the S5 UIM. I did a mod to the S5 UIM,what we call a "mexican mod"(cheap, fast, easy mod) haha. After that, the engine started much better and solve the vacuum leaks. I did the same thing with the MAF and the engine dies.

That's the area where i grounded down. Thanks Rotary for the url.
I'm new with the rotary engines but i'm learning really interesting things here. Thanks for the help.

 

My S5 is working now, i found the vacuum leak and solved the problem. I have another problem, i hope someone could help me out, again! . My S5 works great, but when i get up to 3500 rpm, 4000rpm the check engine light turns on and if i try to speed up after that, it's kind of difficult for the engine to do it but it speeds up. It rpm's and speeds up, with some difficulty but it speeds up slowly. It seems that something is not working right, but i don't know what might be. May be some dirty injectors? any ideas? Thanks to everyone for the help.