how much difference is there???i searched and saw most say fram are junk,but even if staying with AC Delco how much difference between them,i think mine calls for CV 774C the one in it is AC Delco but CV789C is this right or wrong????the walmart reference says the fram is FV184,but i found it's supposed to be FV191,are these close enuf???

 

FV191/cv789c is the one designed for the LB9, use it as long as thats still the motor you have in there. The FV184/cv774c is designed for the L03 motor.

 

I don't think the part numbers are significant. What is critical is the size/shape of the pintle and oriface, and the two springs used to control the pintle movement. The valve is supposed to be calibrated to provide a specified flow rate at a given vacuum. Each valve application has a design flow curve, and the flow must be correct across the range of vacuum test points.

I don't know if any of those you listed is "close enough", but I know the wrong valve or a poorly made one can really screw up the works. I chased a problem on a TBI for more than a week trying to find the "EGR fault" and reason I couldn't set minimum air and thuse get the correct target idle. It all came down to a brand new replaceement PCV that wasn't right. I removed the new Fram PCV and cleaned and installed the old AC, and everything magically went back to normal.

 

i'm chasing a high idle problem,went thru the steps and made no difference,been assuming vacuum leak,but been unable to find it,bought the fram pcv at walmart,and just didn't seem it was right one,(size and tubing connector ok),my 92 factory manual lists the AC 774c one,but that's not what was in it,the existing one at first didn't rattle until i shook it pretty hard,now seems to sound better,wouldn't it be something to have spent all this time trying to get the idle correct and it be a gummed up pcv

 

Could very well be sucking loads of air thorough the PCV giving you wacky idle.

the FV184/cv774c valves are "designed" for the L03 (305 TBI) motor, pick up the right one (FV191/cv789c) and even if thats not causing the idle problems it was only a few bucks.

 

well i could have waited and got a AC one from chevrolet,but got an echlin from NAPA the # 2-9229 it is very well made and is visibly identical to the AC,of course it still doesn't help my fast idle problem,sure would be nice to have a tech 1 or 2 scan tool,anyway,on very first start every morning is the best it is,after the 7 mile 15 minute trip the CES comes on and the thing idles up even higher???until the light comes on it idles @1400,after the light comes on @1800,this can't be good,can a bad o2 sensor,either open or low voltage(lean) cause all of this??b4 i start just changing sensors i want to get a better understanding of this?????will the codes 13,43,and 44 do alot of damage if i drive it on a long trip next weak,seems after a highway cruise the CES will go off,if mainly around town it stays on all the time

 

Have you checked the EGR valve for leakage? Power brake booster? Eother of those can leak enough to cause a high idle. The ECM will simply react and try to maintain correct fuel for that TPS and MAP reading. That's what happened to me with teh bad PCV valve.

Have you set the throttle minimum air position?

Is the MAP sensor itself sealed well (that little rubber grommet?) and indicating the correct voltage at indicated vacuum?

Do you have a vaccum reading at idle?

 

permits,tried to set idle ,no change with IAC disc,thought found problem for sure when replaced the PCV,the hose appeared OK,but was hard,when removed it came apart,replaced with new hose and valve,still no change in idle,have not checked MAP voltage. is this area where one of the hard lines are supposed to be sealed?it's passenger side in front of distributor under and to the rear of MAP

 

i posted this pic in my other pcv valave post and no answers,so try it fresh,this is in front of distributor,passenger side back corner

 

What you have circled appears to be the EGR solenoid. Is there a problem in that area?

 

same,the rear one looks sealed,the front one has the open area around the hard line,so Thanx,looks like i need to try and reset min air,replace O2 sensor,reset or clear codes and drive it to Ga. Tuesday morn

 

The hard line at the EGR solenoid connector is sealed farther down the connector. Give a gentle tug on that hard line just to make sure it is sealed.

You should try to set minimum air before proceeding. Make absolutely certain that you use a separate diagnostic tachometer for this. The factory tach in the dash is nowhere near accurate enough for this purpose.