Just a friendly reminder

October 04, 2007, 09:04:57 PM

A few nights ago I was driving over to Brian's (atariman's) house and in the first few mins I was driving my car I heard a subtle popping noise. It only popped once and I thought nothing of it.

About 1 minute later the engine started sounding very strange and whenever I would slow down to a stop or be at a red light the whole car would shake violently. Although when I drove, the car ran just fine.

So, I made it to Brian's and we decided to check the spark plugs one by one to see if maybe a plug went bad. With the car running I pulled all of them on the drivers side and at plug #3 on the drivers side we found that the idle did not change. The same with the last plug on the passenger side.

So, obviously it very well could be a plug problem right?

We changed out the plugs with platinum autolights and accel superstock 8mm wires. Started the cat up, and we still had the same problem. So then we checked the coil. Still nothing!

Now we were fearing an internal problem. It was not a real cause for concern since I am switching to a roller block in 2 weeks but it was still very annoying.

I drove home and parked the car thinking that the cat's engine was on its last leg.

The next morning I was still a little curious and inspected the engine while it was running. That was when I saw that one of the caps on the vacuum tree was not there. I put my finger over the hole and LIKE MAGIC!!! :hick: the car kicked back into normal idle.

Thus, that is todays lesson Vacuum leaks even as small as a little cap off the vacuum tree can cause very strange reactions from your engine. They can confuse you into thinking that you may have an ignition or spark problem among other things.

ALWAYS CHECK THE VACUUM TREE! Especially if your car is idling strangely.

I assume that pop was a minor backfire that popped the cap right off the tree. :D

Nevertheless the cat gained some serious power after I secured the leak and I am starting to think that the cap was never on very good to begin with. :hick:

Just a friendly reminder

Reply #1 – October 04, 2007, 09:23:50 PM

these problems are even worse when it happens on a turbo car. good tip.