My son has a 86 NA car that he just had the engine rebuilt. It was rebuilt by Rotorsports Racing in Kannapolis, NC. Everything appears to be well done and professionally built, however, he is having issues with it running correctly. Its a S5 n/a keg, built with all new seals, new apex seals, blueprinted, etc. He is still running the S4 wiring, and he is using the S5 lower intake, and he has the S4 upper intake all the S4 electrical components. The first issue we are having is that when we install the CAS, start the car and let it run, the timing is way off. The pointer is approx 1 inch away from the leading timing mark, and the mark is towards the passenger side being off (hope that makes sense). We have tried to re-stab the CAS, and each time the timing gets worse and the car runs worse. We line it up according to the FSM, and it continues to be off. The car will not Rev properly, it seems sluggish. We did try to drive it and it had no power. We do have the TPS unplugged right now, but not sure it would cause the issues that he is having.

Any help would be greatly appreciated. And yes, we have searched all the threads, but its possible we could have missed something.
Thanks

 

I'm not 100% sure but I believe there might be some differences between a S4 and a S5 ECUs.

 

As Gabriel82 pointed out, S4 / S5 ECU's are different. Not sure if that is causing the problem, but since the timing is definitely in question:

Are you stabbing the CAS with the top cover removed (two philips screws)? The CAS has a habit of moving when you install it, making it hard to line up.

1. Remove the top cover on the CAS.
2. Align the gear on the CAS properly Check this thread for pictures of the alignment.
Once it's aligned, you can see how looking through the top cover will show you if the gear moves.
3. Put the engine at Top Dead-Center (it's the first alignment mark on the pulley. I believe it's yellow, but it's the "first" one when you turn the engine clockwise if you are facing it from the front bumper).
4. Stab the CAS while looking at the gear to make sure it doesn't move much. It may move a tiny bit as it slots into the drive gear on the engine, but far less than one tooth in my experience. If it moves more, pull it out and realign it before trying again. It can be a bit fiddly, but you'll get it. Once aligned, make sure it sits flush.
5. Jumper the initial check connector (two pin green connector by the coils, this guy here) This prevents the car from advancing timing or trying to alter the idle.
6. Use your timing light to set timing as normal. It must be warm, so you'll have to wait until the car warms up all the way. Be sure to tighten the CAS lockdown when done, but don't crank it down. Just make sure it's comfortably snug.

 

CAS drive gear inside front cover was installed backwards. You can still get it to run fine you will need to install the CAS clocked all the way to one side and maybe even file the slot to get additional adjustment.

 

the TPS not being plugged in will change the timing

 

He's running the S4 ECU and S4 electrical. So I'm not sure that would have anything to do with it, But I guess it could be a possiblity.

 

We have taken the CAS out, cover off, and restabbed it. I had a timing issue with mine from way back when I was learning, so we set it according to the thread that I had from 12 years ago. I'm 90% sure that I have it right.

 

That was my initial thought, however, is there a way to see this without pulling the front cover back off? and when I install the CAS, it lines up perfectly like it should. Would it still do that?

Would it change it as much as we are seeing? Its gotta be at least 45 degrees off or even more???

 

Not really. There is a chamfer on the gear that must face the irons when installing the front bearing stack. Only way to change it is pull the cover off and flip it around.....While setting the checking the lash and making sure the needle bearing doesnt fall down on reinstallation. I've installed this backwards on my current motor...just have to play around with the cas to get the base timing. Not really all that big of a deal. Or maybe a bad cas and wiring...easy enough to check with the diagrams.

 

Ok, thanks for the advice. I think we're gonna check and find true TDC this weekend to be sure theres no problems with the pulleys, and then we'll try to set timing and then start looking
at other issues.

 

Ok, so we've been out messing with this car all day. So we ended up finding true tdc, set timing according to that, and still the same laggy throttle as before. The timing is actually staying on the new marks that I found, so that's a plus now. Also the pointers in the CAS are lining up properly when set to the new TDC. However, when you try to drive it, you go WOT, and the car just drags up to 4-5k. There's no bucking or any symptoms like that at the moment. I'm leaning towards he has some sort of an electrical issue causing this, but any other advice would be greatly appreciated