I have a 1986 Plymouth Horizon (Auto, with AC) with a 2.2 4 cyl in it. The following things have just been done to the car: New Cap, Rotor, Wires, plugs, Rebuilt Carb, Replaced all Vacuum Hoses, Timed and set Idle Mixture best I could. It seems to run alright from 1200 rpm on up, but I can't get it to idle right. It should idle at 900 but the best I have been able to do is 1000-1200 without it dying. At low rpms, it acts like someone is briefly disconecting power to the ignition at really short intervals. Could anyone give me any insight of what might be causing this?

Regards,
Tony

 

Thanks for the reply.

Yes, I adjusted the idle as low as I could get it (100-1200) without dying. Then I adjusted the timing to spec (10 deg btdc). Then I adjusted the idle mixture until I acheived the best vacuum that I could (approx 20). Still can't get it to idle smoothly at spec (900). Idle is sporadic between 1000-1200 and it acts like someone is briefly disconecting power to the ignition at really short intervals. The engine pulses or lopes.

 

Any codes ?

 

Thanks Doc, ef8340 and challenger for replying.

Doc asked "Any codes ?":

I don't know if there are any codes because I don't have a computer to hook up to it yet. There is no check engine light lit, but I don't know if this vehical has one.


ef8340 asked "what about the choke? maybe sticking":

Choke is working as it should.


challenger asked "TALudwick do you have a meter with rpm readings on it ? or some one you no have one":

Yes I used a timing light and a tach/dwell meter to try and get the timing and idle set properly.


I am going to try spraying some carb cleaner around the manifold gasket with the engine running to see if I can detect any vacuum leaks there, because I have eliminated them everywhere else. I even clogged the brake booster vacuum line to eliminate the possibility of a leaky booster or bad HVAC components. I also plan to do a compression test. My wife was telling me that Jiffy Lube will check for codes free when you get an oil change, so I will probably try that too.

I will keep you guys posted on the results. Thanks for your input.

Regards,
Tony

 

the rubber isolator under the carb is a know problem for vacuum leaks. was that changed?

 

please forgive me if my information is dated but early models used a combination rubber gasket/motor mount under the carb that often leaked. do you have something like that in you car?

 

GOOD CALL rich .... I had an 81 car with a 1.7 that had that prob.

 

i worked at a dealership.we sold a LOT of them!

 

C.... what is there is either a rubber sandwich gasket OR a solid alum one. The alum one is TUFF on a carb..... as I recall.