How to check for a vacuum leak?
#1
How to check for a vacuum leak?
Ok so i'm pretty sure the more people i talk to and the more i really think about it that i have a vacuum leak somewhere..I hear that poor mileage can come form a vacuum leak..When i first but in my vacuum gauge i had 21.5 vacum..And on my way home yesterday idling in my driveway i had 18..I sprayed starting fluid all under my hood and found no idle pick up...How do i go about finding a vacuum leak???Also as soon as i start my truck should i have maxium vacuum or will it take 5 or 10 minutes..Any help would be greatly appreciated..
Thanks
Thanks
#2
Join Date: Jun 2006
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Originally Posted by Big_Man_Brad
Also as soon as i start my truck should i have maxium vacuum or will it take 5 or 10 minutes..Any help would be greatly appreciated..
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#6
It won't hold manifold vacuum after shutdown, but it should hold in the reservoir(s). The best way to find a vacuum leak is with a smoke test where smoke is pumped into the manifold (engine off of course) and then it's just a matter of finding where the smoke is coming out to find the leak. However, that's not something an average do-it-yourself driveway mechanic would be able to do. Have you checked ignition timing? Ignition timing can influence both manifold vacuum readings and fuel economy (power too, of course), so if it isn't correct that could be another possibility.
#7
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#11
Yep they are plastic...Since my dad was home today he said he would help me..So my dad said that maybe my timing should be increased and first we did it by ear and he said it sounded the best then we did it with the light so now it's set at 17 degrees..He also told me that i got a miss..So we checked all the wires and they were good..I think its the passenger back cylinder..After work he said that were going to do a compression test..I hope everything goes ok...
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The compression is super the guy said..I don't remember the numbers right now..Than we hooked it up to his computer...Got not one single code..I was bumbed...He said my problem could be that the intake manifold where it hooks up to the throttle body its stightly bigger the throttle body for the mileage loss...And for the vacuum its where its suppose to be..He had no idea how i was getting 21.5 vacuum before...
#15
83 f100 4.9 6 cyl
I recently changed the intake manifold because it was leaking. I rebuild the carborator and it seems like I have a vacuum leak somewhere. I checked the compression on number 6 and I'm getting 95 psi and the rest are between 130-150 psi.
Does anyone know how I can fix this leak...?
Does anyone know how I can fix this leak...?
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