Running rough, black smoke after new cam belt, new ignition module etc

[Jallajalla]

Am I a tooth off? I need some advice and motivation.

The car is a 81’ FI. Imported to Europe from USA in the 80s. I have replaced the cam belt, cam seals, crank seal, aux shaft seal, crank sprocket, belt tensioner, water pump, ignition module and spark plugs. I also cut the lobe off the aux shaft. Installed oil pressure instrument, - removed the clock. Installed headlight relays and LED bulbs (dash only, left the charging bulb as is).

Everything seems to be working except from the engine running very rough and a lot of black smoke.

The engine is all dressed up again with all covers on just missing coolant. Before adding coolant I started the engine for a few seconds just to see that everything was OK. It was not…. It starts easily but fills the garage with black smoke and sounds awful. Before starting the car I removed the pink and black cable to the ignition coil and ran the engine on the battery a few turns to see that the oil pressure was OK, - I did not want to start it due to the modified aux shaft.

To replace the cam seals I had to remove the camshaft sprockets which of cause moved the cams a few degrees. I aligned them to their marks again afterwards. (Before removing the old belt I put a mark on the belt corresponding to the hole on the sprockets to be able count the number of teeth between them as an extra possible check (adds up). I am sure I have only turned the cams slightly and that they fit their marks correctly before putting on the new belt.

What I found difficult was the belt tensioner. Keeping the belt tight when feeding it over the cam sprockets. May my problem now be that the tensioner moves the cams off alignment with the crank? If so, I guess filling up with coolant and try to adjust the ignition will not help much? Do I have to remove the covers and align everything again? I find this a little strange , - 1 teeth off should really be visible on the markings. When I put the crankshaft pulley back with the new belt everything lined up OK. Should I start with putting back the old spark plugs, ignition module? The old spark plugs and ignition module is OK. The old ignition module (under the coil) has a bad connector but is OK. Any suggestion would be appreciated.

[wizard124]

I recently resolved a rough running issue. Make sure the connector at the coolant temperature sensor is on properly. This is the sensor on the coolant "T" at the front of the engine.

Next, I would remove the timing belt cover and check for proper cams and crank alignment. I remember needing to cheat the crankshaft CCW a bit when fitting the belt so that when all slack was removed between the intake and crankshaft sprockets, the marks aligned with the tensioner set.

It's a good idea to turn the engine over a couple of full revolutions using the crankshaft nut to check for alignment and interference problems.

[18Fiatsandcounting]

Since you cut off the fuel pump lobe on the aux. shaft, you don't need to worry about timing that. On some engines, that lobe can strike the #2 connecting rod if the pulley is mistimed.

If your engine is at TDC by the timing pointer on the passenger side of the crankshaft pulley, and the two marks on the cam pulleys line up with the nubs in the camboxes, then your timing belt would appear to be OK.

Any chance you changed the ignition timing while doing all this work?

Just a thought: If there is no coolant, the temperature sensor may not know what the engine temp is, and it could be causing the fuel injection system to run way too rich. Which would explain the black smoke and rough running.

-Bryan

[Jallajalla]

Thank you for your kind help. It is OK now. I have filled up with coolant, prepared for adjusting the ignition and top up of coolant tomorrow!

I followed tip from you both.

Removed the cambelt cover, checked everything, - all markings still looked OK. Checked cyl#4 TDC and distributor, cables OK. Swapped back to the old spark plugs. Fired up for a few seconds. I think it was a bit better than before (??) but still running rough. I checked the sensor on the T in front of the engine and put everything back after fitting a new gasket to the T. Filled up with coolant. Started the engine and "Eureka" it fired up as before. Sounds good, no smoke!

Again; thank you so much for your time and good advice.

- Roar (Yes, it is a quite common name in Norway. No wonder I like cars..)