Ok here goes, car has been drivin once in 3 weeks and compression reads 70 front 75 rear. Also the spark plugs need to be replaced. Starts up really quickly even when cold and idles at 750 rpm.

Mechanic said that it could be from sitting for a while. Could this be the case?

 

^BUMP^

 

anyone?

 

PLLLLEEEAAASSSSEEEEE

 

what kinda compression tester, new or old, the PSI gauges are kinda iffy, but if its a good tester, its about time for a rebuild, does your car consume any oil or coolent on a regular basis, also the year and model of the car would help

yes it very well could be from sitting for awhile, buy some Marvel Mystery Oil and put about 4 oz in each spark plug hole and let is sit over night...this is an alternative to the ATF treatment, less abrasive on the oil seals...and it burns cleaner

 

Compression should be taken with engine warm. If that was done, what you see is what you have. Just drive it for a while and take it again. If you're not experiencing any driveability problems, just enjoy it and fix it when something happens.

 

also the throttle must wide open, and disconnect the crank angle sensor I think thats it

 

this is an error i mean reply

 

Compression was tested at the Mazda dealership. Guy said the spark plugs are toast, and the oil is super clean. Its a 1990 GXL w/ 147 000 on it. No smoke or anything during start up or idle problems drives like a new car.

 

Mazda Dealers are dumb as **** when it come to rotarys, get your self a Haynes Manual and Do it your self

 

Guy actually knows tonnes about them. He's the goto guy for rotarys around here

 

what's your altitude? That makes a big difference. The minimum at 1 mile high is about 65 psi.
I say just drive it, if you lose a seal then rebuild.

 

I am about 10 ft above sea level

 

I don't believe Mazda compression gauges register in psi as you have mentioned. A minimun on Mazda scale would be @ 6. Just change plugs and as I said before, just drive it. No use looking for trouble until it happens.

 

If they were using a real Mazda Rotary Compression tester then you should have received a graph showing what each lobe was doing.

The performance you describe doesn't sound like that of a 70psi engine. Do you ever have hot-start flood issues?

Compression testing can be done yourself anytime you want to with a regular gauge. If the numbers you got are really bothering you then I would pick up a gauge and see what you find.

My car runs good and I don't even want to know how low my compression is. I've got at least 120k, but dyno'd close to 200whp, so I'm not too worried anyway.