Hi,

I recently had my car rebuilt, with a large street port. I also had a fmic, bigger rad, 1680cc secondary injectors, fuel pressure regulator, fuel pump upgrade, decat, downpipe, back box and a power fc installed. Recently i have been getting problems with my idle, once the car has been out for a nice drive I can turn it off, leave it for a while and then when i turn it on again the idle bounces about all over the place. This ranges from about 200 to 900rpm. Up and down like a yoyo. After a while this will stop but the vacuum seems a lot lower. Around 380mg/hg or whatever it is. Which seems a little low for a fresh rebuild. Sometimes it can be around 320mg/hg.

Another thing I should mention is that the car sometimes has trouble starting, it will just turn over without trying to fire. If I leave it for a while then turn the key again it seems to start after a few seconds. This only happnens when the car is starting from warm temperature. Not only am I getting these problems but the car seems to give a violent jerk around 3800rpm under moderate acceleration. I have made sure that the ground wires are all good as this is usually the case but they all seem OK. I should also mention that it only seems to do one violent jerk then other times there is a very small one or nothing at all. I have also checked for vacuum leaks but I cant seem to find anything. I have new sparks and the fueling should all be good as the car was also mapped too. I believe that all these problems could be linked but I'm not sure.

Any Ideas would be greatly appreciated.
Thanks

 

check for vacuum leaks again, and be very critical

is the engine broken in?

 

Yeah the engine has been broken in. I'll check again. I really dont want to have to take it back to the guy who rebuilt it again, could it be anything serious or is that a bad question to ask? lol

 

hmmm sometimes if the builder doesnt have the good rep it can be caused from something in the engine that was not done properly. but it does sound like a vacuum leak do you still have the stock twins?

 

Yeah I do, could be something in the rats nest but I dont really fancy taking the upper inlet manifold off lol. The guy who rebuilt my engine has done about 30 others before me. He knows his stuff. Steve Rivetts was the guys name. I will have a good look for vacuum leaks tomorrow maybe with something to spray around that will ignite is sucked into the engine.

 

Also thought that id mention the car does pop a lot of the time too, sounds like it's misfiring at idle, im guessing this is fairly normal for a rotary though