Hello Everyone, I've been working on my '89 GTU for about 10 years now and after tinkering and cursing I'm tired of acting smarter than I am .

I have a rebuilt and street ported engine by Atkins Rotary. I did my own emission removal and it hasn't really ran good since. Recently I got it to idle but I surges between 1200 and 2000 RMP and if I try and get it to go any lower it just dies on the low end. Also on start up it revs to about 4000 and holds for about 10-15 seconds before falling back to surge idle mode. It also runs really well at wide open throttle but that's about it.

I was going through the FSM and I tested my TPS sensors and they seem to be operating within the spec resistance. I also don't seem to have any noticeable vacuum leaks. I'm thinking I may have a vacuum hose routed to the wrong place or maybe I've removed too much stuff thinking it wasn't important. let me know what you guys/gals think I'm open to anything **almost**.

Thanks

 

Check your thermowax, something sounds messed up if it is idling to 4000rpm for the cold start; if you not remove it?
I think it'd be easier to help you if you could tell us what all you removed.

But I'd double check for vacuum leaks.
It is really hard to do an emissions removal and end up with a smooth running 13b without doing a lot of "adjusting".
I've got everything removed from my s4; including the thermowax and the extra set of butterflies. It doesn't idle cold but once it warms up it idles right at 750. It took about 3 weeks to get it there though.

 

ya I figured its going to take some trial and error. thank you for the advice ill check the thermowax.

I removed all the spider web stuff under the intake manifold all the solenoids the EGR, air pump, AC, 5th and 6th ports left closed with nothing hooked up to them. I tried to route the vacuum lines as close to factory but I'm sure as you know a lot of them went through those solenoids.