The car i just purchased was sitting for over a year. I tried the ATF a couple weeks ago before I started it up and the car ran okay, with vacuum at about 15psi. I started it again after two months and the vacuum has droped to 12psi with a lumpy idle. Any ideas.

 

Try the ATF trick again, maybe theres some carbon left in there, or maybe the ATF got into the oil and is causing problems. Perhaps an oil change and a good run for about 30 miles or so to burn off what could be left in it. Just a thought

 

Thanks, Iam like so many people out there trying to decide whether to pull the engine or not. The engine was worked on by Petit racing and should have 3mm seals so I can't see it blown that easily. The previous owner put alot of money into the car performance. I don't think the engine is bad, but I don't have a dealer over here to test it.

 

Might want to give that a try and see what happens, I'm sure other people could help you out a lot more than me, considering it's all 2nd hand info from me until my damn engine gets here!

 

Do a compression test on it. That will give you an idea on what is going on with the engine. Intake vacuum can also give you an idea about compression. However, things not working right influence it. Such as a vacuum hose is cracked. Do not want to pull the engine because a vacuum hose over the exhaust is cracked.

When you do the compression test, make sure the battery has a full charge and your starter can get the engine to about 250rpm. You can use a piston engine compresion tester. You just have to remove or hold open the valve the holds the pressure from compression.

In addition, intake vacuum is normally measured in Inches of Mercury. Not PSI. Pounds per square inch normally indicate pressure. Not vacuum.

James

 

Thanks James,

I have several broken vacuum lines. I was wondering if it made sense to fix all the lines and see if that corrects the idle and low vac. Thanks for the correction.

 

Um.. You have broken vac lines and you're wondering why you have low vacuum?

Yes, fix the broken lines.

PaulC

 

That explains a lot!