Idle going down by itself day after day

[Nacho-RT74]

why you could get the idle going down by itself if nothing has being changed ?

I had set the idle at 800 RPMs, and since 2 weeks ago I have felt like is going down and down slowly day after day.

right now is touching 500 RPMs.

I have got even engine stalling when turning on the A/C and gearing ( need to note I have an idle solenoid to increase throttle when Compressor is on and set it back to the original RPMs set ), and being worst if in Reverse.

[twodko]

Vacuum problem?

[Nacho-RT74]

mmmm... well...  I got the booster diaphragm ( sp? ) broken and it is rebuilt now... sounds maybe something to check. Maybe I had set the iddle with a vacuum leak on booster, and now fixed, could affect... is it posible ?

[justcruisin]

Might be vacuum, might be a good idea to check your ignition timing though. If it's retarded it might be a loose distributor but if it's tight and the timing is retarded I would be checking valve timing in case the timing gear on the cam is starting to slot. Are you loosing power?

[Nacho-RT74]

not loosing power. Engine has 6 month running since rebuilt, everything new

[elacruze]

Dirty valves. Is most of your driving time around town and slow? Go on the fast road and make 2-3 full throttle runs until 3rd gear and see how much better it runs and idles.

[Chryco Psycho]

the only time I had a situation like that , the pistons were too tight in the bore & started to sieze , it eventually ripped the wrist pin out of one piston .

[randy73]

I saw this once, the person forgot to tighten the Distributor down tight after setting the timing.

[Nacho-RT74]

Dirty valves. Is most of your driving time around town and slow? Go on the fast road and make 2-3 full throttle runs until 3rd gear and see how much better it runs and idles.

well even thats true that I mostly drives around town and slow, I go to another city on highway at 70-90 mph to visit my GF maybe once by week

[Nacho-RT74]

I saw this once, the person forgot to tighten the Distributor down tight after setting the timing.

its tight, but will recheck that

[Nacho-RT74]

the only time I had a situation like that , the pistons were too tight in the bore & started to sieze , it eventually ripped the wrist pin out of one piston .

ouch!

need to note... when hot, sometimes cranks slowler than when cold at starting up

[Chryco Psycho]

Pistons were fitted too tight got approx 3000 miles on the break in before it failed .

[Nacho-RT74]

well, on my build, were made "by the book". Pistons instructions were provided to the machine shop

[b5blue]

Crap in the idle circuit? Plugs fowling? 

[AirborneSilva]

Dirty valves. Is most of your driving time around town and slow? Go on the fast road and make 2-3 full throttle runs until 3rd gear and see how much better it runs and idles.

I go to another city on highway at 70-90 mph to visit my GF maybe once by week

Well there's your problem, you need to visit the GF a bit more to keep the idle up.......  Oh wait, you're talking about your car 

[Nacho-RT74]

[Nacho-RT74]

IT LOOKS the faulty device was the Ignition Coil. Somehow the iddle was kinda still close the correct RPMs, BUT the tach was reading even worst that the idle it was. Installed also a clear distributor cap just to check how it was everything inside.

So at the end, changed the FBO coil for an MSD Blaster 2, and IT LOOKS everything got back to normal.

need to note that Troy ( RTgarage owner ) told me about on all their test, the Rev-V-Nator didn't get nice results with the FBO coil, so advice me to change it for a MSD Blaster 2 coil... what I already had it ( one that I bough used, and still have one new on its box just in case )

will know better on next days.

[Nacho-RT74]

Definitelly, IT WAS THE COIL!!!!

dunno why at this moment I have even better oil pressure!