Idle/throttle issue suggestions

Post Mon Apr 27, 2015 9:45 pm

Been having this issue for a while now. Due to recently changing jobs which is 40 miles from home I've bought a fiesta as my daily. Plenty of time to get everything sorted on my e30 now!

It's a 320i but with an m20b25 in it.

Does anyone know what would cause this? (I hope who ever posted this on youtube doesnt mind me using it)

You can see/hear my main issue about half way through the video when he blips the throttle in the engine bay.

Any suggestions are welcome. Just taken the intake manifold off to send the injectors off this week. While it's off i'll change the gaskets, breather pipe washer/o-rings(is there meant to be one o-ring each end? I only had one on top).

When starting from cold, if Try to hold the revs around 1000-1500 rpm it sputters and bounces around. This goes away after about 2 mins but the issue in the video is present all the time. Not sure if both issues are related.

Cheers in advance guys !

Post Tue Apr 28, 2015 12:34 am

It could well be just an air leak, there's supposed to be an o ring at either end of the breather pipe. Once all back together might be worth checking the blue temp switch as well. Cheers

Post Tue Apr 28, 2015 1:27 am

Thanks for the reply bosers. I thought it could be but would an air leak cause this? I've ordered TB gasket, rocker cover gasket, intake manifold gasket, will have fresh injector o-rings and breather pipe o-rings very soon. Except for the main air intake pipe (about a month old so no cracks), where else should I be looking for an air leak?

Thanks!

Rhys

Post Tue Apr 28, 2015 7:06 am

Sounds good. Mine used to leak on the vacuum lines from brake servo to throttle body also, loads of joints there. Blue temp switch is other usual suspect. Good luck.

Post Tue Apr 28, 2015 9:32 am

I've checked the blue temp switch, all seems to be with ohm range at the ECU and the switch itself.

I'm curious about the brake servo leak.... When I had the b20 engine in there before I did the conversion it had the same problem, not as severe but it was still there. So I started to think what elements of the old setup did I still have in the car. The brake servo to throttle body lines are the only ones that stayed in the car. Not to sure where to check with these as I have a line coming from the brake servo, into a 90 angle with a little round cap on it, then two lines coming from this into the throttle body. I'll read up on this to find out how to check it and if it needs changing. Don't think it's been replace in 26 years!

Thanks for the info!

Post Tue Apr 28, 2015 9:10 pm

Sounds like it could be a goer. I must say I'm no expert, just sharing what I've been through. Hope it helps bud.

Post Wed Apr 29, 2015 11:07 am

Cheers mate. It does kind of make sense. Just hope it works when I get it all back together!