Hey guys I've been noticing that everyonce and a while my car idles really low, bout 500-700 rpms, at the same time as it idles bad I notice that my pressure reads -12ish in Hg. When it is idleing nice its at about -20 in Hg. It mostly does it when the engine has been run for about 30 minutes or so, but I also get it sometimes when i start it up cold, I even have to give it gas to turn over. Only mod i can figure would affect this is my HKS SSQV, but it doesn't always happen which is throwing me off. As far as I can tell I don't have any vacum leaks. Any ideas? Its been happing for last 1k miles, I just drove from Wisconson to Georgia. Thanks.
bad idle
- Thread starter solid400
- Start date
the bov could definately be the culprit if it is not recirculated. I have a blitz super sound that is not recirculated and i have the same problem, except my car stalls often. I am currently in the process of piping it back in to the turbo inlet. Gonna miss that psssshhhh, but I'm sick of re starting my car at every red light.
M
MisterTurbineTwister
Guest
This is more of a common problem than you think. My car did this to some extent and there are a few things that are usually the cause:
The first thing I would do is to adjust and clean or at least inspect your Idle Speed Control valve. Second I would check, clean the Throttle position sensor. The Idle Speed Control Valve's function is just that. It controls the speed of idle at different temperatures according to what it's adjusted to. Sometimes they can become full of deposits and give false idle speeds.
If the problem occurs when you shut the car off and turn it back on after having it sit, but not long enough for the car to be cold on start up again, it could be heat soak.
Heat soak, put simply is just a term used for when the fuel inside the injection rail vaporizes or otherwise becomes too hot to burn or run consistantly through the injectors. It will cause some stumbling if the engine is hot on start up.
If you are experiencing hard start up when cold, it could be the cold start injector causing problems.
The first thing I would do is to adjust and clean or at least inspect your Idle Speed Control valve. Second I would check, clean the Throttle position sensor. The Idle Speed Control Valve's function is just that. It controls the speed of idle at different temperatures according to what it's adjusted to. Sometimes they can become full of deposits and give false idle speeds.
If the problem occurs when you shut the car off and turn it back on after having it sit, but not long enough for the car to be cold on start up again, it could be heat soak.
Heat soak, put simply is just a term used for when the fuel inside the injection rail vaporizes or otherwise becomes too hot to burn or run consistantly through the injectors. It will cause some stumbling if the engine is hot on start up.
If you are experiencing hard start up when cold, it could be the cold start injector causing problems.
well i found the problem, one of the wires to the VSV thing had been cut, so i patched that up and now she runs like a pro
Idealsupra said:vacuum switching valve.... more then that... SEARCH
i'm pretty sure i've read every post heh (<-loser) since we got hacked and i cant remember us ever realy covering what the vsv does.
americanjebus said:
http://www.supramania.com/forums/showthread.php?t=128&page=2&pp=10&highlight=vacuum+valve
i win
scroll down a bit and it/i explain it... and wrongly might i add because im dyslexic and stuffs hahaha... CK made sure to point that out since its very rare that i say something wrong and its corrected on the next page 1st post... that will at least get you started...
ok so my rewireing job didn't go too well, I see from the other threads that you can bypass the VSV if you are getting rid of the ERG system. Can I bypass the VSV (FPU) without doing anything else, or will this screw something up.
i dont have either my EGR or my FPU VSV.... havent for awhile...just make sure you route your vacuum lines correctly and there shouldnt be a problem...
HOWEVER...i have heard in some cases that taking out the FPU will make the car hard to start sometimes...so if i were you i would take it out..but keep the VSV...if no problems then ditch...if problems then put it back in...
HOWEVER...i have heard in some cases that taking out the FPU will make the car hard to start sometimes...so if i were you i would take it out..but keep the VSV...if no problems then ditch...if problems then put it back in...