View Full Version : HELP . 90 SC . Fuel PSI .........Dry black smoke on Exhaust

08-30-2017, 10:21 PM
So my 90 SC has something going on . Runs , , but has blow by coming out of the oil filler cap, then the fuel PSI , got 42 pounds injectors just checked with a gage today , reads about 35 PSI at just setting there running , give some gas and it jumps to 40-41 , then goes back to 34-35 PSI . When giving it gas a dry black smoke comes out the exhaust . Today we took off the exhaust , just running with the Kooks headers , was thinking maybe the cats were plugged . but that did not show any change .

So someone please tell me on what this could be , I'm in INDIANA , and welcome anyone to stop by and give it a look .

Could it be a bad fuel pump, not sure why it jumps from 34 to 41 PSI . OR a bad ring in the engine

Yet to do a PSI check on the cyl , but I can they that too .
Any reply would help ........Thanks. here or direct to Ballman32@aol.com

09-04-2017, 08:01 PM
Fuel pressure seems fine. If you unhook the vacuum line from the regulator the fuel pressure should read about 40 psi. No matter what you do with the throttle.

It kinda sounds like the cam sensor could be bad or not installed at the correct position.

Its pretty normal to have pressure in the crank case if you remove the oil cap. You would need to do a compression check to see if there is a problem in a cylinder.

09-04-2017, 08:22 PM
yes, did a few checks and talked with Dave D in Ohio , looks like its time for a rebuild , rings are bad . be bad good and strong for next year . Thanks for the reply . DW