hello i posted a thread awhile back about my 82 sc having cis problems. i seam to have worked alot of it out but i still have a stumble at about 1/4 throttlle and from that point up it sort of clears up with the exception being it sounds like a lean pop in the intake now and then as rpm increases. i have been a mechanic all my life but i only have domestic and japanese experiance. here is what i have done new o2 sensor because it was still oem, o2 control relay was bad, checked fuel pressure, operating pressure, checked and cleaned injectors, changed inj o-rings,flushed fuel system except distributer,changed wur it had a 090 on it which is for a 930 as far as i can tell,tore down ing. dist and cleaned and lubed advance mechs,installed msd msd coil and oem pickup coil,new spirocore wires,new fuel filter. i have checked for vac leaks but i dont find any.the car starts and idles great. it feels to me like i am running out of or low on fuel. can you take the fuel dist apart without junking it? please help i have always wanted one of these cars but this one is going to get me divorsed.

 

I'm not familiar with the CIS air flow meter. If it is similar to the one used on the 84-94 911's, it could be worn tracks on the circuit board. If so, I've successfully repaired mine, and can let you know how.

 

thanx but the airflow meter on the73 to 83 cis is mechanical. air flow lifts the meter plate in a venturi and pushes on a plunger.

 

have you tried the fuel pump ? not reslly sure about this one but it is a known weak link ..

 

I would check the mixture, spark plugs and then like Iceman said the fuel pump.

Might be getting weak, low pressure at low RPM's

John

 

I would not recommend taking the fuel distributor apart because it may leak afterwards. Does the flat spot occur in both warm and cold conditions? Do you have access to an air fuel meter? If so, then you can start to isolate the problem. On Pelican, some guys have modified their warm up regulators to allow some adjustment.

 

thanx for the insight guys everything mentioned has been checked and it all points to an intake manifold leak so look out im goin in. ill keep you posted

 

it took me 90 minutes to take the entire CIS unit out , not that bad at all. i did a partial drop and took the whole CIS unit out . It may be an oportunity for you to inspect/ replace the airbox while your in there. it is only about 400.00 or so.

 

When I rebuilt my 3.0, several of the the rubber booties that connect the runners to the airbox were cracked and open... whodda thunka that???

I'm no expert, but that probably messes up the air/fuel mix.

Also check the injectors... these can go bad too...

These cars are over 30 years old.... lots of simple stuff can go bad.

When up to snuff, the CIS system works great, so keep at it.

 

yup i ended up replaceing all 6 sleeves and so glad i ordered them ..