1981 fiat 124 spider's idle cannot get past 690 rpm - engine dies

[benfiat124]

Hi,

I sent my cylinder head to be overhauled due to bad compression on number 4 cylinder(30).After installing the head the numbers were 1-100 2-105 3-100 4-100. It seems low but the engine runs smoother now. The problem now is I cannot set the idle past 690 rpm.

The engine dies right away if I try to raise the idle speed. I have set the cam timing and crank pulley to their proper marks with the aux pulley to 1 o’clock when I set the timing belt. I have checked all possibilities of vacuum leaks but didn’t find any. When I try moving the distributor clockwise or counter clockwise, the engine will die. When I move the throttle linkage to give gas, the engine dies. When I open up the idle screw mixture counterclockwise the engine dies.

I notice though when I put a timing light the illuminated mark is about 1 inch past the 0 degree btdc. I tried to move the illuminated light closer to 0 degree btdc by rotating the distributor but it does not move either way.

I replaced the fuel pressure regulator, fuel pump and filter, all fuel injectors, cold start injector, ecu, maf sensor, coolant sensor, distributor vacuum diaphragm, alternator, double head relay by the ecu, and the throttle position sensor. Checked all fuel lines for blockage.

I’d really appreciate if anyone has any ideas on what is causing the problem.

[focodave]

Did this problem exist before you R&R'd the head?
Did you check your valve tappet clearances?
Is the Catalytic converter still on the car? If it is clogged, it could produce your symptoms.

[Nut124]

The compression numbers seem very low. How were they measured? Was the gas pedal at idle or pushed down to the floor?

Does the engine respond to gas pedal? Does it run under load? Can you drive it?

Are you saying that the observed timing does not change when you rotate the dizzy? If so, that would make no sense at all.

[wetminkey]

focodave recalls my year-long experience of a clogged cat,...
Unbolt your exhaust at the end of the exhaust manifold and blow through the tailpipe. When I tried, I was UNABLE to, and my converter was plugged solid with exhaust-crap. My car acted exactly like yours'. I've done mechanics for years, and I was shocked at what little the converter will clog with!
Checking, and adjusting (with shims), each of the valve clearances is of utmost importance, since these are 'solid-lifter' cams.
I believe that my newly rebuilt engine compression #s are in the 145 - 150 range, but that should not affect whether the engine runs up to better than 2000 rpm, or not. Compression should be measured with the carb wide open,...
Sorry that I can be of no help with the fuel injection portion of your system - many others can.
Best of luck!