How bad are these compression numbers?

Not very good. Should be above 200lbs. Since it is so even I suspect a bad gauge, a bad method, maybe a cam timing issue. Something like that. We just never see them go bad evenly. Warm or cold makes no important difference on 355. The Mahle rings have so little gap cold they will make great compression cold. I do it on fresh motors still on the engine stand and Mahle rings will give perfect compression in those engines.

I would not buy without some answers. It may be OK but it may not be. At this point there is no way to know. The guy who did the compression test should be able to give some answers. I have never, not once in over 40 years handed someone a compression test and just shrugged.

 

What city is the car in? Is there any good reason it was not taken to someone who knows the car better? Ferraris have their own idiosyncrasies and you really want it looked at by someone who knows those. If you tell us a city someone around here should be able to guide you to that guy.

 

Doubtful (but not impossible) you have valve guide trouble on a low mileage '99. And if compression was actually that low the car would run like dog ****. People have posted correct comp test procedure here in the past. Print it out, give it to your mechanic, and ask him to do it again. Make sure battery is charged and throttle is wide open. Your numbers look like he forgot put put the pedal to the floor.

 

I have tested with throttle plates closed and open, no discernible difference on the F355 I tried that on. Still the results look like user or equipment error. 130 psi is super low.

 

It's very odd to see them perfectly consistent, but low.
How many cranks?
What's the battery fully charged? You'll actually see a difference if the engine is slowly turning over versus fast turning over with a fully charged battery
Was it a particularly low pressure weather day?
Just brainstorming ideas, maybe a bunch of little factors added up to being low. Could be a bad gauge.

 

Throw HF tester into the trash.

Retest with compression tester worth using.

In it's entirety. Hose and gauge.

 

I'd start by buying a different gauge and hand it to him. Small investment in the scheme of things. Heck you can probably "rent" one from a parts store. Cranking appears fast enough but I'm not sure I trust the motion on the gauge.. The first pop into around 120 is promising then it really stalls out. Even if there's poor compression I'd expect it to climb a little on each following crank.

I wouldn't throw it out yet until you have a known controlled test to validate against. And Hammer down just in case.

tester sealed well into the hole?
how does it run?

 

Having the throttle open is old boiler plate procedure but in reality doesn't matter on most modern cars. Have performed many times both ways on 355 and theres no difference as a prior poster said.

Oil on threads is from an oil leak into the plug well and not from oil in cylinder.

 

Its not that I do not travel to San Anntonio to do PPI. I have been to foreign countries to do PPI.

I do not do PPI for non locals who want me or already have me service their cars. Too long a story to tell but last time I did that nearly landed me a trumped up lawsuit.

 

Harbor Freight compression gauge with a professional mechanic who you had to pay for the work. Time to move on. All your questions would have been readily answered by anyone that has decent experience on the 355. I am not saying that to be snooty. This model is not something an average BMW or even Porsche mechanic has much knowledge with.

 

The numbers seem low, but what odd is they are really consistent. Usually, a problem is on one or a few cylinders, not all uniformly. It sort of looks like a Guage issue. A problem on all 8 cyliders yet giving all consistent results sounds more like a procedure or equipment issue, but without redoing it with a different Guage, it makes it hard to tell what's really going on.

Sent from my SM-G990U using FerrariChat.com mobile app

 

San Antonio has people who can help you. I will reserve comment on the dealer.

Go to the Texas forum and ask the San Antonio guys there.

 

I had a 360 guy have a PPI by a generic service. They missed over $10,000 worth of stuff because it was 360 specific.

The brakes and tires were accurately described but nothing else was.

 

You should give us a little more info on the car, manual or F1 ? color? just so people are careful when buying incase its back on the market and these results aren't disclosed

 

Seems like you're blaming the car for an incompetent mechanic. Would be easy to get a compression test done right.

 

That is a good attitude. Not to mention it's funny as hell.