PDA

View Full Version : bouncing idle


BaD_HeX
03-10-2007, 07:32 PM
I'm having some issues on my N/A 1.8L protege. Upon cold start when the engine is at high idle (when warming up) the RPMs bounce until it is warm instead of the steady normal drop. Basically it sounds like I'm sitting in the parking lot and revving my car like a tool. This only happens during a cold start and not every time. Any thoughts?

My guess is MAF or EGR, or some temp sensor. I thought I read another thread awhile back about someone else having the same issue and used break cleaner on the MAF to fix things.
gone_fishin
03-10-2007, 07:43 PM
iradic idling is likely due to a failing intake manifold gasket. I had the exact same problem in my 1.8 a couple years back and it was the IM gasket. Save yourself 2-300 bucks at the dealership and replace it yourself. I can give you a how-to if you'd like.
BaD_HeX
03-11-2007, 12:59 PM
How would you suggest testing for that? Spray something around the gasket and see if the engine revs?

A how-to would be helpful if you have one.
gone_fishin
03-11-2007, 01:27 PM
How would you suggest testing for that? Spray something around the gasket and see if the engine revs?

A how-to would be helpful if you have one.

you got it :)
red95_240sx
03-12-2007, 11:35 PM
EGR and MAF(headbang)
P-Funk!
03-13-2007, 11:44 AM
Nope - i gotta' say vacuum leak as well. Spray carb cleaner around the IM gasket (assuming you don't hear any hissing anywhere else... The idle will come up (and it might hiss as well) when you have found it.

Since you (may) have to do the IM gasket - consider doing a VICS red loctite fix and VTCS removal. Consider adding a thermoblok phenolic spacer. Consider doing the rear motor mount at the same time with the intake out - it will never be easier!

Take the intake out by unbolting the bottom half first... to acccess the bottom IM bolts at the head.
gone_fishin
03-13-2007, 11:51 AM
Removing the Intake Manifold is a how-to in itself. But, I did a pretty thorough writeup for someone a few weeks back.
red95_240sx
03-13-2007, 12:19 PM
oh bouncing idle?
BaD_HeX
06-01-2007, 06:01 PM
Ok *update*

- I checked for vaccum leaks. Sprayed carb cleaner all the way up the intake to the block and found nothing.
- Cleaned out the EGR and made sure it wasn't stuck closed/open.
- Cleaned the MAF sensor.

I'm not sure what to do from here. The only time I get the strange idle is when the car is warming up and throttling down. As soon as it reaches temp it idles like it's brand new. No codes in the log at all. Any other suggestions?

I know for sure that my power stearing pump is starting to go out (loud chugging noise when you turn the wheel all the way to one side at a stand still, you can feel the wheel is harder to turn after a long drive too) but I don't think that it would be causing this.
red95_240sx
06-02-2007, 12:05 AM
IAC valve/motor now...
BaD_HeX
06-04-2007, 03:46 PM
Now that I think of it, the IAC makes sense. I have a K&N oil filter that probably gunked it up.

Someone have a picutre of where the IAC is located on a 3gen protege? Maybe a part# on the gasket I'd need for it?
red95_240sx
06-04-2007, 04:48 PM
i think its round...all i know. on second thought, i reset the ECU, made another patch for my MAF and tightened it back up, and the idle has been perfect.
Witchdoktor
06-04-2007, 05:39 PM
Now that I think of it, the IAC makes sense. I have a K&N oil filter that probably gunked it up.

Someone have a picutre of where the IAC is located on a 3gen protege? Maybe a part# on the gasket I'd need for it?

on my 99 1.6L it's right under the throttle body. two phillip screws hold it. I had it off reused the gasket. but if you need a gasket check out montgomery mazda (online vendor) - http://www.mazdas247.com/forum/forumdisplay.php?f=249