Quote:
Originally Posted by 1990C4S
CIS diagnostic step #1. Fuel pressures....do you have gauges? Measure cold and warm pressures, as well as your pump pressure.
|
sorry, ALWAYS, start with looking for air leaks. if you jump into it with gages, you are likely to end up compensating for an air leak even if the pressures are off. someone will adjust their CP's, reset the mixture and not even think about air leaks. you do want to check pressures before adjusting or replacing anything.
when was the last time you changed the plugs, cap and rotor? i forgot this simple rule just recently thinking mine were still ok. fires up first hit now. this is another basic problem area to rule out early.
one way is to check for air leaks is with smoke. the other thing is to just replace all the places it can leak. the car is 30 years old, it would not hurt. this rules out everything. injector sleeves, injestor O rings, the rubber boots on the runners, intake gaskets, rubber hoses, replace it all. also check that metal pipe on the rear that goes to the aux air valve. paulporshe found a hole in his and mine has been rubbing. another place is the hose that goes to the brake booster. JW did a post about this. i checked mine with a hand vacuum pump. i pulled a vacuum, not with a shop vac, and let it sit for a few minutes.
check the thermo time valve, it should be closed, no vacuum, when cold, after 20 sec or so it should open and let vacuum through.
that procedure in the haynes manual is just a starting point for a rebuild, after the car is running, the mixture should be checked with an analyzer and reset.
i would think as the car is starting, hot or cold, the injectors would have to spray fuel or it would never start.