NEW 347 WON'T IDLE
- Thread starter Zeffer
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Had it running tonight (sort of) vacuum gauge only shows about 10" and I swear I can hear a distinct high pitched whistle like a vacuum leak. I've smoke tested it and only thing that seemed weird was a lot of smoke from oil filler cap, replaced pcv just because, new one acted just like the old one. I used my stethoscope trying to pinpoint the noise and can't seem to, however when I removed the oil fill cap and put the stethoscope hose in the noise seemed to be pronounced.
At this point I feel I have an intake manifold leak from intake to valley, the vacuum gauge seemed to fluctuate in a pattern as well.
Any thoughts guys??
As always, thank you for your help!
At this point I feel I have an intake manifold leak from intake to valley, the vacuum gauge seemed to fluctuate in a pattern as well.
Any thoughts guys??
As always, thank you for your help!
Funny you should mention that...I never noticed this whistle until I replaced the throttle body, had a BBK and I replaced it with a BBK. If that is what is causing the whistle, how do you get rid of it? I will try plugging the TB hose to the fill cap and check for vacuum tomorrow.
Thank you!
Ahhh, I heard a few things, rounding off the sharp edges at the opening for the IAC was the mentioned the most, I just lived with the whistle,
I like the F# when the IAC is working. It’s not like the car is quiet enough for that to be annoying.
On the old hosting service, (so it should still get searchable here), there was a thread how to of exactly how to round off the air passages with a Dremel.
OK....
I totally eliminated all vacuum lines to the engine and smoke tested just the engine, plugged off pcv at intake as well as vent to oil fill tube. Not a leak to be found, this eliminates the intake manifold gasket. Put all vacuum lines back on and smoke tested again, nothing seen. I'm pretty confident I don't have any vacuum leaks. I performed the base idle reset procedure to a tee, set timing to 12 degrees, adjust tps (only could get it to 1.05v) which I assume is OK?
Unhooked battery for 10 minutes, plugged in IAC and started engine, it now seems to idle with a minor surge. The vacuum is only 10" is this the best I'm going to get with my cam choice?
I totally eliminated all vacuum lines to the engine and smoke tested just the engine, plugged off pcv at intake as well as vent to oil fill tube. Not a leak to be found, this eliminates the intake manifold gasket. Put all vacuum lines back on and smoke tested again, nothing seen. I'm pretty confident I don't have any vacuum leaks. I performed the base idle reset procedure to a tee, set timing to 12 degrees, adjust tps (only could get it to 1.05v) which I assume is OK?
Unhooked battery for 10 minutes, plugged in IAC and started engine, it now seems to idle with a minor surge. The vacuum is only 10" is this the best I'm going to get with my cam choice?
New to forums....sorry for all the separate video posts!!
Anyone have any comments on the videos or something that I need to check further?
BTW, I have my valves set at zero lash and then 3/4 turn, is that correct?
Anyone have any comments on the videos or something that I need to check further?
BTW, I have my valves set at zero lash and then 3/4 turn, is that correct?
Boostedpimp
Dirt-Old 20+Year Member
I would think with that cam at 850 RPM you should be seeing 13.0 to 13.5", 10 sounds pretty damn low
Any idea's why my vacuum would only be 10", I've confirmed I have no leaks, timing is set, rockers are set at zero lash plus 1/2 turn.
Boostedpimp
Dirt-Old 20+Year Member
What is the idle speed?
If it were me, I'd probably do a leak down test first If I was 100 percent sure their were zero vacuum leaks and I didn't use the wrong length pushrods but off the top of my head only reasons I can think of would be late ignition/valve timing, low compression, bent/damaged valves, collapsed lifter clearance to small due to wrong size pushrods or......a faulty vacuum gauge.
manicmechanic007
5 Year Member
One issue to think about is how tight the new motor is
Sometimes that are so tight they need to run for a few hours to break them in a bit and then they will idle
In your case You will need to do some tuning as well as get the TB leak figured out
The code reader is likely to go off like an x wife with the engine mods
Sometimes that are so tight they need to run for a few hours to break them in a bit and then they will idle
In your case You will need to do some tuning as well as get the TB leak figured out
The code reader is likely to go off like an x wife with the engine mods
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