Wont idle...

[Tonefiend]

Hey guys, I have been driving my car everyday for the last couple months and it has been running great until recently.  2 weeks ago there was a noise coming from under the dash that sounded like a hamster with a bad leg on a squeaky exercise wheel. This lasted about a week and then resolved itself. For the record the heating and air conditioning has been disconnected and the motor has been disconnected.

 Once that had stopped the car has been true having trouble idling. It runs lumpy and rough and wants to die although it doesn't. The lights dim quite substantially as it is trying to stumble and die. When I am off idol it runs as good as ever. Sometimes it doesn't do it like today When I drove to work it was fine but after work it was running like crap again.

 I change the fuel filter and clean the car out and dialed in my idle mixture screws which made it run as good as it has ever run Except for that idle problem!

 I have replaced most of the electrical system over the last 2 years except for the coil and the Control box. Any ideas?

[Jamiez]

Alternator maybe?  At idle it turns a lot slower and might not be putting out enough power.  Slap a multi-meter on and see where you are at?

[dutch]

that sound under the dash, could it be you`re frying the ammeter?

[Chryco Psycho]

try some carb cleaner in the carb sometimes an air bleed will clog up or stick a wire into the bleeds

[Tonefiend]

Thanks guys.  Yeah I thought of the squeaky hamster cage noise could be the ammeter guage but it's working fine and it wasn't fluctuating at all. I thought maybe it was coming from right behind the firewall but it was only happening when the car was in drive with a load on the motor.  Put it in park and the revs come up and it didn't do it.

Regarding the alternator, good call I will check it out.  It's fairly new so it was probably a rebuild so that would lead me to believe the possibility it's failing is there. 

Cryco thanks again for the reply you always come up with some good info and I appreciate that.  I cleaned out the idle screws and they were dirty.  And I revved it up and choked it out with a rag a few times and shot some cleaner into the carb.  It ran great for 20 miles then same old problem but it still runs great past idle. I'll get a bit deeper into the cleaning.  I an still using my original gas lines so I am sure they are totally corroded out.   

I'll go after the air bleed and do a more thorough cleaning on the carb and put a meter on the alternator and see what happens.  Thanks guys!

[johannes]

....2 weeks ago there was a noise coming from under the dash that sounded like a hamster with a bad leg on a squeaky exercise wheel. ...For the record the heating and air conditioning has been disconnected and the motor has been disconnected.

Because your car has AC, the controls for heat and defroster is controlled by vacuum actuators.
My suggestion is that you have a vacuum leak under your dash....causing your idling problems...
You can easily rule this out, by blocking the vacuum hose going from intake manifoild to the bulkhead connection located aft of the sylinder head on the passenger side.....sort of hard to explain but I hope you understand....

...... vacuum leak = faulty idle.........

You can also "suck" on this vacuum hose, pretending YOU are the intake manifoild vacuum sorce.... and you shall NOT be able to detect a leak...
Let us know if this worked for you.....and please send us pics of the hamster.....

[Tonefiend]

Because your car has AC, the controls for heat and defroster is controlled by vacuum actuators.
My suggestion is that you have a vacuum leak under your dash....causing your idling problems...
You can easily rule this out, by blocking the vacuum hose going from intake manifoild to the bulkhead connection located aft of the sylinder head on the passenger side.....sort of hard to explain but I hope you understand....

...... vacuum leak = faulty idle.........

You can also "suck" on this vacuum hose, pretending YOU are the intake manifoild vacuum sorce.... and you shall NOT be able to detect a leak...
Let us know if this worked for you.....and please send us pics of the hamster.....

Thanks!  My AC has been removed so the vacuum line is long gone. However that leads to another area of exploration I will make sure the plugs and lines are A-Ok.   And yes if I catch that damn hamster!!!! 

[Tonefiend]

Well I've got an intake manifold leak on the passenger side.  That might be a good place to start!

[MEK-Dangerfield]

Well I've got an intake manifold leak on the passenger side.  That might be a good place to start!

   

I've been there before, but my leak was under the carb.   

[Tonefiend]

   

I've been there before, but my leak was under the carb.   

I haven't ruled out that possibility but it does appear to be leaking at the manifold down there.  I'm going to look into it further before I pull it apart. In fact I tightened it down a bit to see if that helped and it didn't do anything. 

[Chryco Psycho]

you may have blown out a section of the gasket with the backfire

[ShelbyDogg]

Light a cigarette and blow some smoke into the intake through a PVC hose. Start looking for smoke streams. A flashlight helps see the smoke. You can wrap the top of the carb with saran wrap to block it off too. Cheap man's smoke machine. I found a crack behind a Mitsubishi intake this way.

[Tonefiend]

Besides the intake leak I've been having electrical problems again.  I ripped everything out and installed a MSD Digital 6A.  Problem solved. The car runs much smoother now and hopefully trouble free.  I hooked it up just like the instructions say to do and it started right up no problems.  I bypassed the ballast resistor by just hooking those wires together.  I'll go back in and remove the wires that do not belong when I address the intake manifold.

[Chryco Psycho]