Loss Of Compression

[Dano]

Ever since I got my '95 Cobra, when I gear down or come to a natural stop - at about 15 - 20 mph, the compression just seems to cut out! The other night I parked in my driveway, which has a pretty good slope to it, and left the trans in 1st gear ... well, when I came out in the morning, the car had rolled down the driveway, and stopped with the rear wheels in the gutter (must have moved very slow). I experimented yesterday, and shut it off in the driveway, in 4th gear, and it rolled backwards. I'd like to know if any other '95 owners have had this problem when "gearing down."

Dan

 

[blk96SVT]

I dont know if this is your problem, but I think that there is a recall on your E-brake causing it to roll back. I had one on my '96 Cobra. I dont know, but when you said that you had it in first on a sloped driveway and in the morning it had rolled it sounds like maybe your car hasnt had the recall performed. I might be wrong though.

Tim

 

[cobra331]

You're right

The gear itself should hold with ful compression. The motor shouldn't be able to rotate just from the weight of the car, unless you have one helluva steep driveway. There is a recall on our e-brakes. To test this just park it with the brake and leave the tranny in neutral. Watch it though, you don't want it to end up in the street!! If it holds it's not your brake. You'll have to do a compression test and leakdown test. Make sure all of your spark plugs are screwed in all the way to about 7 ft/lbs of torque.

 

[Dano]

Thanks for the input guys ... I had the E-brake recall done last year, so I guess the problem is still a problem.

Dan

 

[94CobraPace]

You need to do a leak down test on the car. A leak down test will tell you where the cylinder pressure is leaking from, rings, HG, valve guides. It definatly is leaking down and you should be loosing power. Most good shop should be able to do a leak down test if you don't have a compressor.

 

[Dano]

Good input ... thanks, I'll check in to having it done.

Dan

 

[Venom_Injected]

if u left ur car on a slop with out the e-brake on and in gear, there is a chance it will roll. compression inside of a cylinder will slowly leak down if theres a load on it, (I.E. a car left in gear on a slope). if your engines not missing and you dont notice any power loss, im sure your engine is fine.

 

[Dano]

WTF ... THAT is a welcomed suggestion! You know, it does make sense that under a load, it would leak down; however, I'm sure I have parked on a hill before, with the trans in 1st or rev, and never experienced the "roll away" before.

Dan

 

[Venom_Injected]

dont know how to that...