bb4 62mm throttle body fast/ jumping idle

Rossco D · Post by **Rossco D** » Fri Apr 07, 2017 1:47 pm

So yesterday vanzep and myself fitted a bigger throttle body to my bb4. There no check engine lights on the dash but the car now idles a little high and when you drive it on idle it jumps. Any ideas guys? I'm sure someone's had this issue. I'm going to rebleed the coolant and check for any leaks today. Failing that I'm hoping its an easy fix.

Post by **Merlin** » Fri Apr 07, 2017 1:56 pm

Air leak. It is sucking in too much air to the intake manifold. There is probably a vacuum leak somewhere, it could be on any of the hoses that connects to the IM.

Edit - Or the idle base screw needs adjusted. BUT!!!! don't touch this until every other possibility has been looked at.

Rossco D · Post by **Rossco D** » Fri Apr 07, 2017 2:30 pm

Yeah I thought it may be. I'll give the hoses a spray with wd40 after I've bled it and see if there are any leaks . Fingers crossed its an easy fix

Post by **Merlin** » Fri Apr 07, 2017 2:39 pm

Double check the mating between the TB and the IM. there maybe a hole in the gasket for something. But I'm sure you would have spotted that.

Rossco D · Post by **Rossco D** » Fri Apr 07, 2017 4:05 pm

Checked the lines and bled them but still the same. I don't think its the gasket as its a new thermal one that's been Honda bonded on.

Rossco D · Post by **Rossco D** » Fri Apr 07, 2017 4:10 pm

I think the guy I got if from has messed with the tps. Could this be the issue? If so is it difficult to set up?

Post by **Merlin** » Fri Apr 07, 2017 4:35 pm

The only way to can test the TPS is to measure its resistance or voltage, I cant remember. It's in the service manual in the Wiki. TBH these things are normally split hoses, quite possible if you have been rerouting old hoses.

Post by **vanzep** » Fri Apr 07, 2017 8:02 pm

had a look at this again today - no air leaks and coolant has been bled again - and hot idle is now around 800rpm - bounce has gone

fairly sure the problem was/is small air lock between fit/iacv. ive always found it difficult to bleed the coolant there as it is the highest point in the coolant system (the metal pipe). The rubber hoses and clamps at the fitv and iacv have seen better days but no leaks that i can see. We also did another ecu reset, loaded all the electrics up and waited until the fans come on and them left it to cool down.
Ive recently been using a large syringe to fill the fitv/iacv pipes with coolant before putting them back in place so we can try that if bouncing idle returns.
The slightly high idle could be due to something to do with the idle screw and idle settings so easily fixed.
Nothing to panic about Ross and almost all lude owners have had a bouncing idle at some point.

Lankysod07 · Post by **Lankysod07** » Sat Apr 08, 2017 12:05 am

Heya guys, I'm not too sure if this is the one you bought off me @vanzep but if it is, I thought I would mention that I myself never messed around with the TPS or the idle screw as merlin said they are last resort remedies.

I had exactly the same issues you are describing when I fitted one to my 5th generation. I bled the coolant twice for 45 minutes, cleaned my iacv and it didn't really help. It was running fine on warm temp idle, but after driving it down the road the idle would jump up to 1400 and start bouncing. Sayer putting up with it for about a week, it slowly calmed down and went away.

Hope you manage to get it sorted with relative ease buddy.

Post by **vanzep** » Sat Apr 08, 2017 10:41 am

Thanks for the info Lankysod07

Just in case Ross wants to adjust the idle - here is the link to how to do it from the wiki

http://www.ludegeneration.co.uk/topic15674.html