'81 124 - rough running issues

[volpebob2]

Hi- I'm a new member to the forum. Working on a 124 Spider with MANY issues. It has been stored in my warehouse with a dozen other cars for many years, and now I'm working thru the problems to get it back on the road and reliable.

Current problem is rough idle, and erratic, rough, uneven firing all the way through the RPM spectrum. Bogs down on acceleration.
Interestingly, although I haven't done a fuel pressure reading yet, when I clamp down (restrict) the fuel feed line to the rail, the idle goes up and the hesitation as throttle input is applied disappears. Unfortunately, although it appears the car is running way rich, that can't be the only problem, as driving the car it still has major bogging-under acceleration issues.

Here is what I've done so far that is (could be) related to current problem:

1. New timing belt, water pump; Cam timing is spot on.
2. New Crane Cams Fireball Coil and Spark Module (coil failed immediately) , so I bought an MSD Blaster coil locally and rewired it ...... again.
3.Removed the ballast resistor that was mounted on the passenger side of the firewall, since none of the wiring diagrams I found showed that component on an '81 Spider, and no one could tell me whether or not it needed to be in the circuit or not.
4. Cleaned and replaced fuel in tank.
5. Replaced fuel filter
6. Replaced Valve cover and Cam Block gaskets,
7. Distributor is timed

Car ran pretty well while I solved other problems, then 1st replacement col failed, and now it runs really rough.
I'd really appreciate any ideas...

[RRoller123]

Make sure the airflow meter door swings freely through its entire range. A quick search here will provide a lot of info on this item with pics!

Pete

[divace73]

also make sure the system between the AFM and throttle is completely sealed, you may want to clean you injectors as well.
There shouldn't be a ballast resister on the FI cars. Just a note that the stock marelli coils rarely fail.
If from what you are saying by restricting the fuel flow helps the car go better, maybe an injector is stuck open??

[narfire]

I agree regarding the injectors. have them cleaned and the little internal filter changed. If it was running rough at the lower rpms, I would also look at the AFM and re set the pins on the track.
The AFM flap was a good thing to look at as well.

[RRoller123]

Agreed. OK Injectors did a great job on mine, with very fast turnaround.

[volpebob2]

Thanks guys. Really appreciate the input. I'll do all of that. One more thing..... How sensitive are these motors to skipping a notch or two on the can belt? In timing the motor, it bogged a few times while dialing the distributor in, and I was just thinking that the can timing might be off on 1 bank.
Again, your input is invaluable.
Bob

[narfire]

How sensitive are these motors to skipping a notch or two on the can belt?

The car will run( sort-of), but in my experience not as well when all is lined up properly.
Chris

[FiatMac]

Don't forget to check the cold start injector for staying open or leakage. Also the coolant temperature sensor and it's wiring should be checked. A bad sensor, broken wire or loose connector will cause the engine to run rich.

[volpebob2]

Thanks to all who posted valuable information and advise; I did check everything suggested, plus rechecked cam timing to be sure the motor didn't jump time. Also tried to pin-out the AFM to watch the sweep of the door and make sure that it is a linear progression from (I think) 9 volts down as the door opens up, but I couldn't find specs on which wires to test (although I remember doing the test on other Bosch injected cars).

Got it running better but still have a way go. I'm pulling the injectors next to watch their flow pattern and see if they're leaking.

You all have been extremely helpful thus far; if anyone has anything else to offer, please don't hesitate.