I hate this car so much! It's so close to being perfect. I have an 89 which I bouught cheap. The S5 engine had lost a rotor, so I scrapped that engine and put in a low milage S4. (Yah I know I should've put another S5) Financial reasons though, as I only paid $200 for the S4 car. I used the S5 harness, ECU, and all externals, I only replaced the shortblock. I blocked off the EGR, with a plate I ordered from Racing Beat. I replaced the AFM, as it was out of specs. I also replaced the fuel injectors, the TPS, and Intake air thermosensor. All of that fixed I no longer gett a chek engine light. I start the car, but it won't idle, and it runs a little rought at times in the upper range. It is not smoking or anything like that, but the catalytic converter was glowing bright orange after I ran the car for a few minutes. I wonder if the ECU is smoked. BTW compression is good. If anyone has one locally that I could try and see if that's the problem I'd be grateful to them. It's a N351. Also I don't think there's any vaccum leaks and I am 99.9% sure all the vacuum hoses are correctly routed.

 

dude my cat would turn glowing orange to and the carpet would start to smoke.. never fig it out i sold it it might have turned red because i used the pacesetter header i have no idea but i know what you are feeling

 

Does anyone know if the S4 fuel pump is not supplying enough fuel to the S5 injectors? I replaced the fuel pump in the S5 out of my S4

 

Hmm, clogged cat?

 

No, they are the same pump prettymuch, flow wise at least.

 

id check that out...it can cause alot of problems.

 

Rip off your exhaust after the manifold and try and see if it's better...

 

I unhooked the exhaust and there was no improvement. I also unhooked the AFM and the car will run and drive (sort of) but I tested the AFM and everything checked out. I replaced the spark plugs again. Nothing really improved. I think the ECU is smoked. Is there any way I can test it to see if it's bad. BTW I think the previous owner hooked the battery up backward. That might cook the computer.

As far as the catalytic converters, the precat is somewhat melted. I replaced the Catco main cat that was on there with a good stock one. The main cat was the one that was glowing. One more question. There is a vacuum line on the air injection tube thast goes to the main cat, but I don't know where the other end of the vacuum line goes. Does anyone know anything about that?

 

Dude, are your cats old and plugged up? Careful! You'll carbonize that engine and kill it. What are the miles? If you're around 100K miles on the original cats, replace them. Trust me. But say goodbye to it being a cheap car because those things are costly.

 

or just get a race pipe

 

title updated to reflect actual thread

 

I feel for you, I have an 87 gxl and i just replaced the engine with a LOW mileage (approx. 30,000 miles) engine, and the f'ing thing wont turn over. Engine cost me $1,200. New battery, new plugs, new wires, the injectors all open, (i resently torn off the throttle body/upper intake manifold to check the primaries). fuel pressure is good, good spark at all four. I have no clue whats wrong, I want to blow up the car

 

Sorry about that.

 

Nope, just pops the 80A main fuse. ...Uh...I don't know that from experience, or anything

 

this really isnt going to solve any of your problems, but:
remember your ecu is trying to run the 9.4:1 rotors now instead of the 9.7:1 rotors. i cant really see that being a BIG problem, but a problem with no fuel correction...

however, this could be the reason you're idle is a little rough and the high rpms aren't smooth.

 

if ur cat is glowing, ur running lean lean lean. ur gonna kill it

 

he said he unbolted the exhaust before the cat and nothing changed..

 

how doe sthat affect if he is running lean or not? O2 sensor?

 

you are very very lucky if that is all that happened. mopst of the time it also takes out the ECU, but then the car won't even start.

 

Other way around... he is running rich.

Since the S5 ECU thinks the spark plugs are in different spots for timing that they are for a S4 engine, I would say his timing is probably way off, and he is running radically rich.,

Also the fact that he does not know if there are any vac leaks (he just suspects there are not) suggests that he needs to go back and check everything, as vac leaks are probably the easiest of all things to check and know for sure.

 

I have cheched for vacuum leaks and can't find any. I did that when I replaced the primary injectors yesxterday

 

I don't think that's the problem. From what I understand the O2 sensor does nothing until the vehicle is warmed up fully

 

I've heard of this swap with no problems before.

 

The swap will work just fine (idle will be a bit lopey, but that's about it) Check for vac leaks, that's what it sounds like more than anything else.