Engine is off in its own world HELP!!!!

[Anonymous]

My engine decided to begin running in its own little world this week.

What do you mean Jimbo do you ask?

Well the thing seems to spin-off on its own?
I know, this is hard to describe?

When I get in and let it warm up it runs steady, I hit the gas and the engine revs up (makes a sort of whirlly sound) and comes back down real slow like. Even though I just pop the throttle?

I hold the car at 2000 RPMs and let off and it drops down "Slowly". From the engine the throttle lever moves normal it opens and closes quickly? The spin-off as I am calling it now is coming from inside the beast.

It also has a sort of Whirm, Whirm, Whirm that is a very deep vibration at low idle, and a pulse at high RPMs, this is not a hard or heavy thing, you can feel it in your teeth and your foot more than you can hear it?


For the most part the car has run great for about a month since I got the timing right. And I still have power, I am just worried this is getting more noticeable quickly. Sunday it was soft and OK. Today it was running high and very noticeable.

Any thoughts or suggestions. I have the car, you, and two days with nothing to do but fix this problem. I am starting tomorrow morning and I now have internet in the garage. I only wish I had a digital camera.

 

[Anonymous]

Any other symptoms- have you traced any of the sounds, etc?

 

[Anonymous]

is it a manual trans or an auto? is it possible for the torque converter to cause this? wellllll?????

 

[Anonymous]

i used to have the same problem, i have done many things to my engine, but if i remember correctly i adjusted the timing, you'll pry have to pull the distributor out and get your #1 to top dead center and get it back in and time it

 

[Anonymous]

Sounds like you might have a fast idle cam problem? If the choke opens ok, thats probably not it. Im not 100% on this, but I think the only thing that would allow the engine to do that would be in the carb/fuel system. Just wanted to put my two cents in.

Hope this helps!

 

[yellowstang]

kind of a stupid thing but is the spring on the carb still attached?? mine fell/broke off once and it seemed to do the same thing. i looked at that thing for hours till a neighbor walked up with abeer in his hand and said "hey look at this" i felt like such a dumb ass.
Pete

 

[Anonymous]

yea, that's true, thing is, when i got mine fixed i didnt have to replace any of the parts inside of the carburator or anything, i think i just screwed with the adjustment, i wish i could remember what all i did so i dont feel so stupid saying things

 

[Anonymous]

Is it mechanical? I would try and disconnect the throttle linkage, and pop the throttle up and watch what happens. If the linkage comes down slowly, then you can start to narrow down the problem. If it comes down right away, then you know it's internal to the carb.

Is the buttefly completely opened? Like was suggested below, I would back the fast idle cam all the way out so you can rule out. I would lower the idle screw as well down quite a bit to see if there is some binding.

The only other thing I can think of that would make the car run down slowly is too much gas. Could be a float level adjustment that is causing increased vaccum to pull fuel down the venturis?

Perhaps when your carb was rebuilt the bottom throttle plates were installed slightly off-center, causing some binding. The secondary in my Holley 5200 was off and there was a secondary transition stumble that i thought was jetting. Turns out it was a mechanical problem. I would take the carb off and fiddle with the mechanicals to make sure everything is running smoothly.

 

[BIGREDRASA]

Spritz some slick lubricant around all your carb linkages. Make sure the fast idle cam is not flopping around and making contact with the fast idle set screw. You'll recognize them, beacause they engage when the choke butterfly is closed, and leave the regular idle set screw sitting 1/8-1/4" from its stop.

 

[61Futura]

Could it be as easy as the dashpot threads turn easy and it vibrated out of adjustment while cruising down the highway?

 

[Anonymous]

OK more information.....

It is a C4 auto.
Carb is a Carter YF 1bbl.
DurasparkII dizzy and MSD control, Petronix Coil.
Heli-core wires, platinum plugs (New pulling to have a look today)
Everthing is pretty new....
Also running Sanden Compressor and Powermaster 100 amp Alt. (One wire)

This has really started to make itself know in the last couple of weeks...

I recently had an oil change and added EngineRestore for six cyl. And I installed the alternator and compressor.

To me it feels very lean. I have poor power and a little load pinging at 1700-2100 rpms? I am also going to change the air filter and PCV valve tomorrow and see if that helps.

But I think this engine has head problems. I can hear what I am thinking are the lifters sometimes. It seems like a rattle from under the hood I thought was Pre-ignition.

One other thing to note. My exhaust manifold is Crap..... The thing is rusted three times over and the tail pipe mounts at a wierd angle. I think some of the noise I hear may be exhaust leak.

 

[Anonymous]

Get yourself a good vacuum guage and hook up to manifold vacuum.

You can tell a lot about the contition of your valves, timing, etc. by checking vacuum. Most vacuum guages have tuning manuals that can help you pinpoint vacuum leaks, bad valves, etc.