I Googled around a bit and was also told, based on symptoms, that I might have a vacuum leak. After the engine has been running for a while and driving around a bit, sometimes at stops like traffic lights, the car would stall, kinda stuttering. Like I'm pressing the gas and breaking repeatedly back and forth. After a few gears pass, it stops. Doesn't do it all the time, but definitely after driving a bit. I can smash the gas a bit to rev up when taking off to where it doesn't do it, but I wanna find out if there is a leak like suggested. What's the best method to finding this "leak"? I read on Google somewhere that a vacuum gauge won't work reliably on atkinson engines. Is this true? And if so, does this apply to the 07 Ion-2 2.2? Thanks

 

According to Wikipedia regarding the Atkinson cycle engines, "While originally seen exclusively in hybrid electric applications such as the earlier-generationToyota Prius , later hybrids and some non-hybrid vehicles now feature engines with variable valve timing, which can run in the Atkinson cycle as a part-time operating regimen, giving good economy while running in Atkinson cycle, and conventional power density when running as a conventional, Otto cycle engine."

The 2.2L Ecotec does not have variable valve timing (at least up until 2007), so it would never be in an Atkinson cycle even part-time. And most variable valve timing strategies do not affect the engine at idle, so you wouldn't have to worry about it affecting vacuum readings at idle anyway.

 

Thanks. It's actually when I take off. But bow that you mention at idle. I just remembered it does do it at idle and even in park and in park it has shut off the engine. Forgot about that. What does this sound like?

 

How much troubleshooting have you done, and how much experience do you have in troubleshooting? Do you have a CEL or have you scanned for codes? Have you recently replaced anything on the engine? The symptoms you describe are considered 'drivability' issues, and the causes can be many things. Have you cleaned the throttle body?

Your original question was regarding a vacuum leak. You can use a vacuum gauge, but without knowing what vacuum a 'good' engine should have for given RPM/load/etc., it may not do you much good. Here is a pretty good YouTube video for finding intake vacuum leaks. He describes symptoms of small and large vacuum leaks, and how to find where the leak may be.

 

Sorry for the late reply, but i haven't done any troubleshooting as of yet but i purchased a vacuum gauge already. I have done a bit of troubleshooting. I work on my two cars when it's something easy enough. I have scanned for codes but I need to clear them and scan again as I have repaired a few things that's made this car run a LOT better. One was a simple motor mount. This car only has one and the difference after replacing it was so night and day it was crazy. It got rid of a LOT of vibration for one that I didn't know where from. Car sat for years before I replaced the head damaged due to snapped timing chain. I'm guessing the motor mount was affected and then got worse sitting. It also got rid of an issue of the engine revving up really high when driving and turning the wheel left.

Another repair was was a cv axle seal leak. There was a loss of power and shifting issues where I would have to give it more gas than before the timing chain situation and it would take forever to switch from gears 1 and to but was fine after that. Replaced that seal then drained and filled the trans fluid a few times and I'm SO happy that fixed the shifting issue. It takes off like it's supposed to now. It shifted terribly at first, after it engine warmed up and I drove a bit. Hasn't the last couple of times I've driven it. Hopefully all is good.

Sorry to ramble but just giving a bit of background as far as "troubleshooting". I think at least the transmission being in a better state now may get rid of some codes but I'm not sure. I'll check today. I'll clean the throttle bottle to be sure but I don't think that's it. I checked out that video and I've actually learned a lot from him over the years. He mentioned brake bosster as being a possible leak issue and made me remember that when I press the brake it makes a hissing noise. Could that be it? I have to look into that now.

Another thing is when I was replacing the head i pulled the intake manifold off and a plastic piece broke off. Someone I knew at the time was guiding me through it an came up with a fix and it might have affected the air intake. I might use the brake cleaner approach to check it. Would you recommend the vacuum gauge over the brake cleaner/propane method? Which is better.

Thanks

 

Sounds like you've been quite effective in your repairs to this point. Good job! As far as using a vacuum gauge for troubleshooting, as I pointed out, you need to know what is 'good' for that to provide any meaningful data. There was a time (many years ago) when you were looking for 16-18 inches (or more) of vacuum at idle as a baseline for diagnosing problems. And it was important to know whether you were measuring intake manifold or (carburetor) venturi vacuum. So unless you know what numbers you're looking for, a vacuum gauge may not be much help. A scanner that can read live data can give you your manifold pressure/engine vacuum readings. More important in troubleshooting is watching your upstream O2 sensor reading and your long term and short term fuel trim readings. The video does talk about this. So I would be on the side of using propane or brake cleaner to find a vacuum leak. If you found, based on a vacuum gauge analysis, that you suspected a leak, this is the method you would use anyway.

Your suspicion about the brake booster is well founded - the hissing noise. If you are using a scanner and monitoring upstream O2 sensor and fuel trim readings, see what happens when you clamp off or disconnect and plug your vacuum line to the booster.

 

EcoTec with one motor mount?
I call BS (standard phrase for me, you'll get used to it)

 

There are four mounts for the engine/transmission package, but three of them are bolted to the transmission. So technically speaking, there is only one 'motor' mount.

 

Correct

 

Thanks! Actually proud of myself, not being a mechanic.

My scanner actually does read live data so I'll look into it and share what I find. Will also look into the brake booster and also check a few suspected areas with brake cleaner then report back

Thanks