If the timing was out of wack alittle, would it cause it to have low vacuum reading on the boost gauge? I did the 1-2-1 shift at the track and thought i bent some valves, but i did a compression test and it was fine, but it got to dark to check timing to see if it had jumped or not.

 

anyone?

 

You should do a leak down test, that will determine if you have any bent valves. The motor will definetely have less vacuum if the valves are bent.

 

if the compression was perfect across the board, shouldnt i not need to do a leak down test?

 

the car does not smoke or have any sort of misfire. I even put like 200 miles on the car since this has happened. That's why im leaning toward jumped timing hopefully.

 

your timing shouldn't have anything to do with your boost gauge. What exactly is the gauge doing?

 

Oh wait your asking about the vac back pressure.... It's quite possible.... But if your timing was out of wack even by a tooth you would be able to tell... Check for boost leaks?

 

what does vacuum actually tell you about the motor?

 

What exactly is your car doing and is it doing it only under boost?

 

its only reading 10 inch of vacuum, as where before i did the 1-2-1 shift it was reading like 20 inch of vacuum.

im confused. the compression is perfect. im making full boost(15psi) it doesnt smoke or anything.

Its just not reading proper vacuum and thats it.

 

the gauge is reading proper boost but not proper vacuum? do you have any vacuum leaks?

 

Sounds like slightly bent valves. Just had a car in the shop like that. Need to do a leakdown test to make sure so it doesnt burn any valves. Good luck.

 

thanks man. im doing that next.

 

The only thing I can think of is check your vac lines going to your boost gauge then check your lines from your wga just to make sure there is no leaks... That kinda stumps me too bro... Just check your lines.... Also what kind of bov do you have?

 

a compression test is not a leakdown test. as stated above, you can have some slightly bent valves that can cause low vac. and also if your timing is out of whack you will have low vac also.

 

Line up all the timing marks and if they are all on then progress with the leakdown test.

 

if they are "slightly" bent. how much power does that rob you of?

 

it wont necessarily rob you of power. The compression loss is what is robbing the power and with out knowing how much "slightly" is refering too. It is going to be hard to say.

 

thats irrelevant, bent valves need to be fixed.

 

thanks for the input. new itr valves are going in this week.